Currently, there are a significant number of technological schemes for the biological treatment process, each of which differs in the number of aeration stages, the presence or absence of activated sludge regeneration, methods of introducing wastewater and return sludge into structures, the degree of purification, etc. Each type of structure is characterized by its own indicators of normal operation and requires an individual approach to the design of an automated control system.

The influences that can be used to build an automated control system are as follows:

Controlling the flow rate of return sludge in order to maintain the concentration of activated sludge in the aeration tank;

Controlling air flow in such a way as to maintain a given concentration of dissolved oxygen in the entire volume of the aeration tank;

Controlling the flow rate of activated sludge removed from the system to maintain a constant sludge age;

Changing the ratio of the volumes of the aeration tank and regenerator (while maintaining the constancy of their total volume) for the purpose of optimal sludge regeneration;

Distribution of incoming wastewater flow between parallel operating aeration tanks;

Maintaining the optimal pH value of the water entering the aeration tank

Controlling the flow of sludge discharged from settling tanks in order to maintain an optimal level of sludge in them and change it depending on the concentration and flow rate of the sludge mixture, the turbidity of the purified settled water, as well as the sludge index.

Traditional automated control systems use algorithmic models that connect control actions with input data (or their change). The disadvantage of traditional control methods in relation to the process of biological wastewater treatment is the multidimensionality and complexity of the created mathematical models with low accuracy and incompleteness of the initial information and ambiguity of the control criterion. On the other hand, situations that arise during the operation of a biological wastewater treatment unit often allow the use of formal reasoning methods for control that are close to the natural course of reasoning of a human expert. For biological treatment control problems, they can be significantly more effective than traditional control systems, especially in terms of time and cost of development and modification as system requirements and environmental conditions change, which is a critical factor in light of the continuous improvement of technology and increasing unit performance biological treatment. A characteristic feature of the managed facility is the inherent ability of the treatment station to adjust the technological scheme and change the composition of the equipment. This circumstance increases the requirements for openness, prospects and standardization of the created system. Changes in wastewater treatment quality standards, increasing the capacity of treatment facilities or adding new control parameters will require a complete reworking of the mathematical models of a traditional automated control system, while in an expert system it will only be enough to adjust the rules or add new ones.

In addition, in the process of managing biological treatment, problematic situations often arise, to overcome which it is necessary to use the experience of many experts, normative, technical, reference and regulatory information, which may not always be available to the operator. Managing the operation of treatment facilities is a complex task associated with the characteristics of the condition and functioning of treatment facilities. In practice, a wastewater treatment plant technologist who makes decisions on wastewater treatment management faces the following problems:

Lack of parameters for decision-making due to limited time reserve and high cost of specialized laboratory tests;

Incompleteness and inaccuracy of natural language instructions for decision making;

Insufficient theoretical knowledge about the wastewater treatment management process and lack of consideration of the operating features of a specific treatment plant.

The wastewater treatment process is carried out in a delayed response mode of the system and depends on many input signals. These signals are heterogeneous, arrive at different frequencies, and processing some of them requires time, as well as special laboratory conditions and expensive reagents. Wastewater treatment plants function partly due to the activities of a variety of living organisms, whose responses to the influence of input parameters are specific and interdependent. Optimal conditions for the existence of complexes of organisms that carry out wastewater treatment are very difficult to select due to the variability of these complexes depending on the composition of wastewater. Regulating the concentration of nutrients, maintaining the pH of the environment and temperature in the required range have a positive effect not only on the development of microorganisms, but also on the biochemical activity of the latter in water purification. To select optimal conditions for the functioning of microorganisms in aeration tanks, automated control systems are used, which are based on mathematical models (Table 1.2). Such systems have a number of disadvantages. They work well when the treatment plant is in normal operation and are poorly applicable in case of abnormal operation.

Naturally, when problem situations arise, the knowledge and experience of experts is needed, and the development of simulation models and programs for solving equations is clearly not enough. There is a need to use subjective information accumulated over the years, as well as incomplete data and objective information accumulated during the operation of treatment facilities.

The use of artificial intelligence methods and tools provides new opportunities for solving the problem of managing wastewater treatment plants. Expert systems based on artificial intelligence should ideally have a level of efficiency in solving informal problems that is comparable to or superior to human ones. In any case, the expert system “knows” less than a human expert, but the care with which this knowledge is applied compensates for its limitations. At the moment, there are a number of expert systems (ES) abroad that are used for wastewater treatment (Table 1.3).

Analyzing the examples from Table 1.3, it should be noted that to control a biological treatment unit, which is an element of an integrated domestic wastewater treatment system, it is most appropriate to use a rules-based system.

Table 1.2 - Models of classical control at biological treatment plants

Name	Application example	Equipment	Disadvantages of models	Advantages of the models
Correlation	Establishing relationships and interdependencies between water characteristics	Treatment plants	The presence of a large number of external factors, the mutual influence of microorganisms, interaction with the substrate leads to difficulties in choosing an adequate model for describing the system. Models are difficult to develop, often inaccurate, and oversimplify reality. Simulation modeling does not work with unknown or unmodeled situations. Qualitative data cannot be used for a numerical control model. Data is inaccurate or missing, sensors produce erroneous information or are missing, not all characteristics necessary for modeling are analyzed every day, which affects the accuracy of the models. The characteristics of inflowing water are highly variable and uncontrollable. Delay in obtaining data due to lengthy laboratory tests and analytical calculations.	Assessment of the behavior of wastewater treatment plants in response to a specific development scenario (operating conditions and characteristics of incoming water) and a medium- and long-term forecast of possible outcomes for certain treatment process actions Improving pollutant removal efficiency Reducing the consumption of electricity, chemical reagents and the cost of maintaining treatment facilities Development of alternatives for retrofitting existing wastewater treatment plants
Adaptive algorithm	To maintain the required oxygen level in the aeration tank	Aerotank
Pragmatic models Fundamental Models	Bacterial growth and substrate consumption	Aerotank
Simulation models Statistical synthesis	Modeling the evolution of treatment plant states	Treatment plants
Clustering	Classification of sensor data	Treatment plants
Stokes' law	Deposition Modeling	Sand trap
Guzman curve	Simulation of solids deposition
Optimization method	Optimizing sludge treatment	Primary, secondary settling tanks
Deterministic, predictive models	Precipitation	Primary, secondary settling tanks
Performance curves and stochastic models	Prediction of settling tank behavior	Primary, secondary settling tanks

Table 1.3 - Artificial intelligence tools developed for wastewater treatment plants

Name . Developer	Knowledge representation	Main functions and characteristics	Flaws
Real-time ES. (Baeza, J)		Regulation of the operation of treatment facilities. Managing the wastewater treatment process via the Internet.	Rule-based systems: Do not learn on the job Difficulties with the process of extracting knowledge and experience from source data Incapable of foresight, their area is limited by past predetermined situations. Case-based systems: The problem of indexing precedents in a knowledge base; Organization of an effective procedure for searching for closest precedents; Training, formation of adaptation rules; Removing precedents that are no longer relevant. Precedents and rules: There is no syntactic and semantic integration of system modules
ES for determining the condition of treatment facilities. (Riano) 4]		A system for automatically constructing rules used to identify the condition of treatment facilities.
ES for control of wastewater treatment plants. (Yang)		Expert system for determining the sequence of stages of water treatment at wastewater treatment plants
ES for OS control.(Wiese, J., Stahl, A., Hansen, J.)	Precedents	Expert system for identifying harmful microorganisms in an activated sludge system
ES to reduce damage from water pollution.	(University of North Carolina)	precedents
Assessing potential impacts for managing non-point sources of pollution in a river basin based on user information and decisions.	(University of North Carolina)	Real-time ES for wastewater treatment plant control, (Sanchez-Marre)
PPR for monitoring, integrated control and management of wastewater treatment plants. Combines into a frame structure: learning, reasoning, knowledge acquisition, distributed decision making.	(University of North Carolina)	Inference rules partly model data and expert knowledge. The system models empirical knowledge based on precedents.

The most typical form for solving control problems directly at the biological treatment unit are expert systems built on the basis of a production model, where knowledge is represented by a set of “if-then” rules. The main advantages of such an expert system are the ease of replenishment, modification and cancellation of information and the simplicity of the logical inference mechanism. To organize the structure of the expert system presented in Fig. 1.1, it is necessary to transform technological information into a decision-making structure that describes the operation of the knowledge base, and then, based on the selected software shell, to create a program for the operation of the expert system.

This will be the goal of this thesis: to adapt the experience of theoretical research and practical solutions in the field of using expert systems to control a biological wastewater treatment unit to a specific treatment process, taking into account the design parameters and the individual technological scheme of these treatment facilities adopted when designing. As well as the creation of a full-fledged process automation system and the selection of technical means for its implementation.

Figure 1.1 – Management structure of the wastewater treatment process

Introduction

Theoretical part

1.1 Fundamentals of wastewater treatment

2 Analysis of modern methods of wastewater treatment

3 Analysis of the possibility of automating wastewater treatment processes

4 Analysis of existing hardware (logic programmable PLC controllers) and software

5 Conclusions on the first chapter

2. Circuitry part

2.1 Development of a block diagram of the water level for filling the reservoir

2.2 Development of a functional diagram

3 Calculation of the regulatory body

4 Determining the controller settings. Synthesis of self-propelled guns

5 Calculation of parameters of the built-in ADC

2.6 Conclusion on the second chapter

3. Software part

3.1 Development of an algorithm for the functioning of the SAC system in the CoDeSys environment

3.2 Program development in the CoDeSys environment

3 Development of an interface for visual display of measurement information

4 Conclusions on the third chapter

4. Organizational and economic part

4.1 Economic efficiency of automated process control systems

2 Calculation of the main costs of the control system

3 Organization of production processes

4.4 Conclusions on the fourth section

5. Life safety and environmental protection

5.1 Life safety

2 Environmental protection

3 Conclusions on the fifth chapter

Conclusion

Bibliography

Introduction

At all times, human settlements and industrial facilities were located in close proximity to fresh water bodies used for drinking, hygienic, agricultural and industrial purposes. In the process of human use of water, it changed its natural properties and in some cases became dangerous in sanitary terms. Subsequently, with the development of engineering equipment in cities and industrial facilities, the need arose to establish organized methods for discharging contaminated waste water flows through special hydraulic structures.

Currently, the importance of fresh water as a natural raw material is constantly increasing. When used in everyday life and industry, water becomes contaminated with substances of mineral and organic origin. This water is commonly called waste water.

Depending on the origin of wastewater, it may contain toxic substances and pathogens of various infectious diseases. Water management systems of cities and industrial enterprises are equipped with modern complexes of gravity and pressure pipelines and other special structures that carry out the removal, purification, neutralization and use of water and resulting sediments. Such complexes are called drainage systems. Drainage systems also provide for the removal and purification of rain and melt water. The construction of drainage systems was determined by the need to ensure normal living conditions for the population of cities and populated areas and maintain the good condition of the natural environment.

Industrial development and urban growth in Europe in the 19th century. Led to the construction of drainage canals. A strong impetus for the development of urban sanitation was the cholera epidemic in England in 1818. In subsequent years, in this country, through the efforts of the parliament, measures were implemented to replace open canals with underground ones, standards for the quality of wastewater discharged into reservoirs were approved, and biological treatment of domestic wastewater was organized in irrigation fields.

In 1898, the first drainage system was put into operation in Moscow, which included gravity and pressure drainage networks, a pumping station and Lublin irrigation fields. She became the founder of the largest Moscow water disposal and wastewater treatment system in Europe.

Of particular importance is the development of a modern system for drainage of domestic and industrial wastewater, providing a high degree of protection of the natural environment from pollution. The most significant results were obtained in the development of new technological solutions for the efficient use of water in drainage systems and industrial wastewater treatment.

The prerequisites for the successful solution of these problems in the construction of drainage systems are developments carried out by highly qualified specialists using the latest achievements of science and technology in the field of construction and reconstruction of drainage networks and treatment facilities.

1. Theoretical part

1 Fundamentals of wastewater treatment

Wastewater is any water and precipitation discharged into reservoirs from the territories of industrial enterprises and populated areas through the sewer system or by gravity, the properties of which have been deteriorated as a result of human activity.

Wastewater can be classified by source into:

) Industrial (industrial) wastewater (generated in technological processes during production or mining) is discharged through an industrial or general sewage system.

) Domestic (domestic and fecal) wastewater (generated in residential premises, as well as in domestic premises in production, for example, showers, toilets) is discharged through the domestic or general sewer system.

) Surface wastewater (divided into rainwater and meltwater, that is, formed by the melting of snow, ice, hail), is usually discharged through a storm sewer system. Can also be called "storm drains".

Industrial wastewater, unlike atmospheric and domestic wastewater, does not have a constant composition and can be divided into:

) Composition of pollutants.

) Concentrations of pollutants.

) Properties of pollutants.

) Acidity.

) Toxic effects and effects of pollutants on water bodies.

The main purpose of wastewater treatment is water supply. The water supply system (of a populated area or an industrial enterprise) must ensure that water is obtained from natural sources, purified if required by consumer requirements, and supplied to places of consumption.

Water supply diagram: 1 - source of water supply, 2 - water intake structure, 3 - pumping station of the first rise, 4 - treatment facilities, 5 - clean water reservoir, 6 - pumping station of the second rise, 7 - water conduits, 8 - water tower, 9 - water distribution net.

To perform these tasks, the following structures that are usually part of the water supply system are used:

) Water intake structures through which water is received from natural sources.

) Water-lifting structures, that is, pumping stations that supply water to places of its purification, storage or consumption.

) Water purification facilities.

) Water pipelines and water supply networks used to transport and supply water to places of its consumption.

) Towers and reservoirs that play the role of control and reserve tanks in the water supply system.

1.2 Analysis of modern methods of wastewater treatment

Modern methods of wastewater treatment can be divided into mechanical, physicochemical and biochemical. In the process of wastewater treatment, sludge is formed, which is subjected to neutralization, disinfection, dehydration, drying, and subsequent disposal of the sludge is possible. If, according to the conditions of wastewater discharge into a reservoir, a higher degree of purification is required, then after the complete biological wastewater treatment facilities, deep treatment facilities are installed.

Mechanical wastewater treatment facilities are designed to retain undissolved impurities. These include gratings, sieves, sand traps, settling tanks and filters of various designs. Grids and sieves are designed to retain large contaminants of organic and mineral origin.

Sand traps are used to separate mineral impurities, mainly sand. Sedimentation tanks trap settling and floating wastewater contaminants.

To treat industrial wastewater containing specific contaminants, structures called grease traps, oil traps, oil and tar traps, etc. are used.

Mechanical wastewater treatment facilities are a preliminary stage before biological treatment. When mechanically purifying urban wastewater, it is possible to retain up to 60% of undissolved contaminants.

Physico-chemical methods for treating urban wastewater, taking into account technical and economic indicators, are used very rarely. These methods are mainly used to treat industrial wastewater.

Methods of physicochemical treatment of industrial wastewater include: reagent treatment, sorption, extraction, evaporation, degassing, ion exchange, ozonation, electroflotation, chlorination, electrodialysis, etc.

Biological methods of wastewater treatment are based on the vital activity of microorganisms that mineralize dissolved organic compounds, which are food sources for microorganisms. Biological treatment facilities can be divided into two types.

Figure 3 - Scheme of wastewater treatment using biofilters

Scheme of wastewater treatment using biofilters: 1 - grid; 2 - sand trap; 3 - pipeline for sand removal; 4 - primary settling tank; 5 - sludge outlet; 6 - biofilter; 7 - jet sprinkler; 8 - chlorination point; 9 - secondary settling tank; 10 - issue.

Mechanical wastewater treatment can be performed in two ways:

)The first method is to strain the water through screens and sieves, thereby separating out the solid particles.

)The second method is to settle the water in special settling tanks, as a result of which mineral particles settle to the bottom.

Figure 4 - Technological diagram of a treatment plant with mechanical wastewater treatment

Technological diagram: 1 - waste water; 2 - gratings; 3 - sand traps; 4 - settling tanks; 5 - mixers; 6 - contact tank; 7 - release; 8 - crushers; 9 - sand areas; 10 - digesters; 11 - chlorination; 12 - sludge areas; 13 - waste; 14 - pulp; 15 - sand pulp; 16 - raw sediment; 17 - fermented sediment; 18 - drainage water; 19 - chlorine water.

Wastewater from the sewer network first flows onto screens or sieves, where it is filtered, and large components - rags, kitchen waste, paper, etc. - are held. Large components retained by gratings and meshes are removed for disinfection. Strained wastewater enters sand traps, where impurities, mainly of mineral origin (sand, slag, coal, ash, etc.), are retained.

1.3 Analysis of the possibility of automation, wastewater treatment processes

The main goals of automation of wastewater systems and structures are to improve the quality of water disposal and wastewater treatment (uninterrupted discharge and pumping of wastewater, quality of wastewater treatment, etc.), reduce operating costs, and improve working conditions.

The main function of drainage systems and structures is to increase the reliability of the structures by monitoring the condition of the equipment and automatically checking the reliability of information and the stability of the structures. All this contributes to the automatic stabilization of technological process parameters and quality indicators of wastewater treatment, prompt response to disturbing influences (changes in the amount of discharged wastewater, changes in the quality of treated wastewater). The ultimate goal of automation is to increase the efficiency of management activities. The treatment plant management system has the following structures: functional; organizational; informational; software; technical.

The basis for creating a system is the functional structure, while the remaining structures are determined by the functional structure itself. Based on their functionality, each control system is divided into three subsystems:

operational control and management of technological processes;

operational planning of technological processes;

calculation of technical and economic indicators, analysis and planning of the drainage system.

In addition, subsystems can be divided according to the criterion of efficiency (duration of functions) into hierarchical levels. Groups of similar functions of the same level are combined into blocks.

Figure 5 - Functional structure of automated control systems for wastewater treatment plants

To increase the efficiency of data transfer, communication with control centers and management of water disposal, as well as wastewater treatment processes, we can recommend replacing the not always reliable telephone communication system with a fiber optic one. At the same time, most processes in automatic control systems for drainage networks, pumping stations and wastewater treatment plants will be performed on a computer. This also applies to accounting, analysis, calculations of long-term planning and work, as well as the implementation of the necessary documents for reporting on the operation of all wastewater systems and structures.

To ensure the uninterrupted operation of drainage systems, based on accounting and reporting analysis, it is possible to carry out long-term planning, which will ultimately increase the reliability of the entire complex.

1.4 Analysis of existing hardware (PLC programmable logic controllers) and software

Programmable logic controllers (PLCs) have been an integral part of plant automation and process control systems for decades. The range of applications in which PLCs are used is very wide. These can range from simple lighting control systems to environmental monitoring systems at chemical plants. The central unit of a PLC is the controller, to which components are added to provide the required functionality, and which is programmed to perform a specific task.

The production of controllers is carried out both by well-known electronics manufacturers, for example, Siemens, Fujitsu or Motorola, and by companies specializing in the production of control electronics, for example, Texas Instruments Inc. Naturally, all controllers differ not only in functionality, but also in the combination of price and quality. Since Siemens microcontrollers are currently the most common in Europe, they can be found both at production facilities and at laboratory benches, we will choose the German manufacturer.

Figure 6 - Logical module "LOGO"

Scope of application: control of technological equipment (pumps, fans, compressors, presses), heating and ventilation systems, conveyor systems, traffic control systems, control of switching equipment, etc.

Programming of Siemens controllers - LOGO!Basic modules can be performed from the keyboard with information displayed on the built-in display.

Table 1 Specifications

Supply voltage/input voltage: nominal value ~ 115 ... 240 V AC frequency ~ 47 ... 63 Hz Power consumption at supply voltage ~ 3.6 ... 6.0 W / ~ 230 V Discrete inputs: Number of inputs: 8 Input voltage: low level, not higher level, not less than 5 V 12 V Input current: low level, not higher level, not less than ~0.03 mA ~0.08 mA/=0.12 mAD discrete outputs: Number of outputs 4 Galvanic isolation yes Connecting a discrete input as a load Possible Analog inputs: Number of inputs 4 (I1 and I2, I7 and I8) Measuring range = 0 ... 10 V Maximum input voltage = 28.8 V Housing protection degree IP 20 Weight 190 g

The process of programming the Siemens controller comes down to software connection of the required functions and setting of settings (on/off delays, counter values, etc.). To perform all these operations, a built-in menu system is used. The finished program can be rewritten into a memory module enclosed in the "LOGO!" module interface.

The microcontroller "LOGO!", made by the German company "Siemens", is suitable for all technical parameters.

Let's consider domestically produced microcontrollers. In Russia at present there are not many enterprises that produce microcontroller equipment. At the moment, a successful enterprise specializing in the production of control automation systems is the OWEN company, which has production facilities in the Tula region. This company has been specializing in the production of microcontrollers and sensor equipment since 1992.

The leader of microcontrollers from OWEN is a series of PLC logic controllers.

Figure 7 - Appearance of PLC-150

PLC-150 can be used in various fields - from the creation of control systems for small and medium-sized objects to the construction of dispatch systems. Example Automation of a building's water supply system using the OWEN PLC 150 controller and the OWEN MVU 8 output module.

Figure 8 - Scheme of water supply to a building using PLC 150

Let's look at the main technical parameters of the PLC-150. General information is given in the table.

Table 2 General information

Design Unified housing for mounting on DIN&rail (width 35 mm), length 105 mm (6U), terminal spacing 7.5 mm Housing protection degree IP20 Supply voltage: PLC 150&22090…264 V AC (nominal voltage 220 V) with a frequency of 47…63 Hz Front panel indication 1 indicator power supply 6 digital input status indicators 4 output status indicators 1 communication status indicator with CoDeSys 1 user program operation indicator Power consumption 6 W

The resources of the PLC-150 logic controller are shown in Table 3.

Table 3 Resources

Central processor 32-bit RISC & 200 MHz processor based on the ARM9 core RAM capacity 8 MB Non-volatile memory for storing programs and archives in the CoDeSys kernel 4 MB Memory size 4 kV PLC cycle execution time Minimum 250 μs (non-fixed), typical from 1 ms

Information about discrete inputs is given in Table 4.

Table 4 Digital inputs

Number of discrete inputs 6 Galvanic isolation of discrete inputs, group Electrical isolation strength of discrete inputs 1.5 kV Maximum frequency of the signal supplied to a discrete input 1 kHz with software processing 10 kHz when using a hardware counter and encoder processor

Information about analog inputs is given in Table 5.

Table 5 Analog inputs

Number of analog inputs 4 Types of supported unified input signals Voltage 0...1 V, 0...10 V, -50...+50 mV Current 0...5 mA, 0(4)...20 mA Resistance 0.. .5 kOhm Types of supported sensors Thermal resistances: TSM50M, TSP50P, TSM100M, TSP100P, TSN100N, TSM500M, TSP500P, TSN500N, TSP1000P, TSN1000N Thermocouples: TKhK (L), TZhK (J), TNN (N), TKhA ( K), Chamber of Commerce and Industry (S ), TPP (R), TPR (V), TVR (A&1), TVR (A&2) Built-in ADC capacity 16 bits Internal resistance of analog input: in current measurement mode in voltage measurement mode 0...10 V 50 Ohm about 10 kOhm Sampling time of one analog input 0.5 s Basic reduced measurement error with analog inputs 0.5 % Galvanic isolation of analog inputs is absent

PLC-150 programming is carried out using the professional programming system CoDeSys v.2.3.6.1 and older. CoDeSys is a Controller Development System. The complex consists of two main parts: the CoDeSys programming environment and the CoDeSys SP execution system. CoDeSys runs on a computer and is used to prepare programs. The programs are compiled into fast machine code and loaded into the controller. CoDeSys SP runs in the controller, it provides loading and debugging of code, I/O maintenance and other service functions. More than 250 well-known companies manufacture equipment with CoDeSys. Thousands of people working with it every day solve industrial automation problems. Today CoDeSys is the most widespread IEC programming complex in the world. In practice, it itself serves as a standard and example of IEC programming systems.

Synchronization of the PLC with a personal computer is carried out using the “COM” port, which is available on every personal computer.

The domestically produced OVEN microcontroller meets all the parameters. You can connect both analog and digital measuring devices with unified signals to it. The controller easily interfaces with a personal computer using a “COM” port, and remote access is possible. It is possible to coordinate the PLC-150 with programmable logic controllers from other manufacturers. The PLC-150 is programmed using the Controller Development System (CoDeSys), in a high-level programming language.

5 Conclusions on the first chapter

This chapter examined the basics of wastewater treatment, analysis of modern treatment methods and the possibility of automating these processes.

An analysis was made of existing hardware (logic programmable PLC controllers) and software for controlling technological equipment for wastewater treatment. An analysis of domestic and foreign manufacturers of microcontrollers was carried out.

2. Circuitry part

One of the important functions of automation is: automatic control and management of technological processes, equipment of pumping stations and treatment facilities, creation of automated workplaces for all specialties and work profiles based on modern technologies.

The main function of drainage systems and structures is to increase the reliability of the structures by monitoring the condition of the equipment and automatically checking the reliability of information and the stability of the structures. All this contributes to the automatic stabilization of technological process parameters and quality indicators of wastewater treatment, prompt response to disturbing influences (changes in the amount of discharged wastewater, changes in the quality of treated wastewater). The ultimate goal of automation is to increase the efficiency of management activities.

Modern drainage networks and pumping stations should, whenever possible, be designed to be controlled without the constant presence of maintenance personnel.

1 Development of a block diagram of the water level for filling the main reservoir

The block diagram of the automatic control system is shown in Figure 9:

Figure 9 - Block diagram

On the right of the block diagram is a PLC-150. To the right of it is an interface for connecting to a local network (Ethernet) for obtaining remote access to the controller. The signal is transmitted digitally. Via the RS-232 interface, coordination with a personal computer occurs. Since the controller is not demanding on the technical component of the computer, even a weak “machine” like a Pentium 4 or similar models will be sufficient for the correct operation of the entire system as a whole. The signal between the PLC-150 and a personal computer is transmitted digitally.

2 Development of a functional diagram

The functional diagram of the automatic water level control system is shown in Figure 10:

Figure 10 functional diagram

Parameters of the transfer function of the control object

According to the technical specifications we have:

H= 3 [m] - pipe height.

h 0= 1.0 [m] - set level.

Q n0 = 12000 [l/hour] - nominal flow.

d = 1.4 [m] - pipe diameter.

Op-amp transfer function:

(1)

Let's calculate the numerical values ​​of the transfer function.

Tank cross-sectional area:

(2)

Nominal incoming flow:

(3)

Transfer coefficient K:

(4)

Time constant T:

(5)

Thus, the transfer function for the control object will have the form:

(6)

The structure of the automatic control system is shown in Figure 0:

Figure 11 - Block diagram of the ACS

Where: Kr.o. is the transfer coefficient of the regulatory body (RO) of the incoming flow rate Qpo;

Kd - level sensor transmission coefficient h

Wp - transfer function of the automatic controller

Calculation of the regulator gain K r.o :

,

Where - change in incoming flow;

change in valve opening degree (in percent).

The dependence of the incoming flow on the valve opening degree is shown in Figure 12:

Figure 12 - Dependence of incoming flow on valve opening degree

Estimation of level sensor gain

The gain of the level sensor is defined as the ratio of the increment of the output parameter of the level sensor i[mA] to input parameter [m].

The maximum height of the liquid level that the level sensor must measure corresponds to 1.5 meters, and the change in the current unified output signal of the level sensor when the level changes in the range of 0-1.5 meters corresponds to 4-20 [mA].

(7)

General industrial level sensors have a built-in smoothing function for the output signal using a first-order inertial filter element with a settable time constant Tf in the range from units to tens of seconds. We select the filter time constant Tf = 10 s.

Then the transfer function of the level sensor is:

(8)

The structure of the control system will take the form:

Figure 13 - control system structure

Simplified control system structure with numerical values:

Figure 14 - simplified structure of the control system

Logarithmic amplitude-phase frequency characteristics of the unchangeable part of the system

The LAFCH characteristics of the unchangeable part of the ACS are constructed using an approximate method, which consists in the fact that for a link with a transfer function:

(9)

in a logarithmic coordinate grid up to a frequency of 1/T, where T=56 s is the time constant, the LFC has the form of a straight line parallel to the frequency axis at a level of 20 log K=20 log0.43=-7.3 dB, and for frequencies greater than 1 /T, LAF has the form of a straight line with a slope of -20 dB/dec to the coupling frequency 1/Tf, where the slope changes additionally by -20 dB/dec and is -40 dB/dec.

Mating frequencies:

(10)

(11)

Thus we have:

Figure 15 - LAPFC of the original open-loop system

2.3 Regulatory calculation for incoming and outgoing flows

We will select a regulatory body based on the conditional capacity Cv.

The Cv value is calculated according to the international standard DIN EN 60534 according to the following formula:

(12)

where Q is flow [m 3/h], ρ - density of liquids [kg/m 3], Δ p - pressure difference [bar] in front of the valve (P1) and behind the valve (P2) in the direction of flow.

Then for the flow regulator Q n0 according to the source data:

(13)

For a possible change in flow rate Qp during automatic control relative to its nominal value Qp 0The maximum value of Qp is taken to be twice the nominal value, that is .

The flow area diameter for the incoming flow is calculated as follows:

(14)

Similarly, for the outgoing flow we have:

(15)

(16)

2.4 Determining controller settings. Synthesis of self-propelled guns

The construction of the LAPFC of an open-loop ACS is based on a consequence of the theory of linear systems, which is that if the LAPFC of an open-loop system (consisting of minimal phase links) has a slope of -20 dB/dec in the region of significant frequencies (the sector cut off by ±20 dB lines), then:

the closed self-propelled control system is stable;

the transition function of a closed-loop automatic control system is close to monotonic;

regulation time

. (17)

Structure of an open-loop source system with a PI controller:

Figure 16 - Structure of the original system with a PI controller

Desired LFC (L and ) of the simplest type of open-loop ACS, which in closed form would satisfy the specified quality indicators, should have, in the vicinity of significant frequencies, a slope of the LFC equal to -20 dB/dec and an intersection with the frequency axis at:

(18)

In the region of low-frequency asymptote, to create a zero (according to technical specifications) static error δ st =0, the frequency characteristics of the open-loop system must correspond to the integrator of at least the 1st order. Then it is natural to form the desired LFC in this area in the form of a straight line with a slope of -20 dB/dec. as a continuation of Lz from the region of significant frequencies. In order to simplify the implementation of the ACS, the high-frequency asymptote must correspond to the high-frequency asymptote of the unchangeable part of the system. Thus, the desired LFC of the open-loop system is presented in Figure 0:

Figure 17 - Desired LAFCH characteristics of an open-loop system

According to the accepted structure of an industrial automatic control system, the only means of bringing the LAPFC of the unchangeable part L LF to L and is a PI controller with a transfer function LAPFC (at K R =1)

Figure 18 - LAFCH of the PI controller

Figure 14 shows that for in the low-frequency region, the LFC of the PI controller corresponds to the integrating link with a negative phase shift of -90 degrees, and for the frequency characteristics of the regulator correspond to the amplifier section with zero phase shift in the region of significant frequencies of the designed system with proper selection of the value of T And .

Let us take the controller integration constant equal to the time constant T of the control object, i.e. T And = 56, at K R =1. Then the LFC of the open-loop ACS will take the form L 1=L LF +L pi , qualitatively corresponding to the form L and in the figure, but with a lower gain. To match the LFC of the designed system with L and it is necessary to increase the open-loop gain by 16 dB, i.e. 7 times. Therefore, the controller settings are determined.

Figure 19 - Synthesis of self-propelled guns. Defining controller settings

The same controller settings are obtained if from L and graphically subtract L LF and, based on the type of LFC of the resulting sequential corrector (PI controller), restore its transfer function.

As can be seen from Figure 12 at T And =T=56 s, the transfer function of the open-loop system has the form , which includes an integrating link. When constructing the LFC corresponding to W p (p) transmission coefficient K p 0,32/7850must numerically correspond to the frequency of intersection of the LFC with the axis ω at frequency With -1, where With -1 or K p =6,98.

With the calculated settings of the controller, the ACS is stable, has a transition function close to monotonic, control time t R =56 s, static error δ st =0.

Sensor equipment

The 2ТРМ0 meter is designed for measuring the temperature of coolants and various media in refrigeration equipment, drying cabinets, ovens for various purposes and other technological equipment, as well as for measuring other physical parameters (weight, pressure, humidity, etc.).

Figure 20 - Meter 2ТРМ0

Accuracy class 0.5 (thermocouples)/0.25 (other types of signals). The regulator is available in 5 types of housings: wall-mounted H, mounted on DIN rail D and panel-mounted Shch1, Shch11, Shch2.

Figure 21 - Functional diagram of the ARIES 2 TRM 0 device.

Figure 22 - Dimensional drawing of the measuring device

Device connection diagram:

The figure shows a diagram of the terminal block of the device. The pictures show the connection diagrams of the device.

Figure 23 - Device connection diagram

Device terminal block.

The BP14 multichannel power supply is designed to supply stabilized voltage 24 V or 36 V to sensors with a unified output current signal.

The BP14 power supply is available in a housing with mounting on a D4 DIN rail.

Figure 28 - Power supply

Main functions:

Conversion of alternating (DC) voltage into stabilized DC in two or four independent channels;

Starting current limitation;

Overvoltage protection against impulse noise at the input;

Overload, short circuit and overheat protection;

Indication of the presence of voltage at the output of each channel.

Figure 29 - Connection diagram of a two-channel power supply BP14

AC input frequency 47...63 Hz. Current protection threshold (1.2...1.8) Imax. Total output power 14 W. The number of output channels is 2 or 4. The nominal output voltage of the channel is 24 or 36 V.

Figure 30 - Dimensional drawing of the power supply

Output voltage instability when the supply voltage changes ±0.2%. Output voltage instability when the load current changes from 0.1 Imax to Imax ±0.2%. Operating temperature range -20...+50 °C. Output temperature instability coefficient voltage in the operating temperature range ±0.025% / °C. Electrical insulation strength - input - output (rms value) 2 k.

SAU-M6 is a functional analogue of the ESP-50 and ROS 301 devices.

Figure 31 - Level switch

Figure 32 - Connection diagram for SAU-M6

Three-channel liquid level indicator OWEN SAU-M6 - designed to automate technological processes associated with monitoring and regulating liquid levels.

Figure 33 - Functional diagram of SAU-M6

SAU-M6 is a functional analogue of the ESP-50 and ROS 301 devices.

The device is available in a wall mounting housing type N.

Level switch functionality

Three independent channels for monitoring the liquid level in the tank

Possibility of inverting the operating mode of any channel

Connecting various level sensors - conductometric, float

Working with liquids of different electrical conductivity: distilled, tap, contaminated water, milk and food products (weakly acidic, alkaline, etc.)

Protection of conductometric sensors from salt deposition on the electrodes by powering them with alternating voltage

Figure 34 - Dimensional drawing

Technical characteristics of the device: rated supply voltage of the device is 220 V with a frequency of 50 Hz. Permissible deviations of the supply voltage from the nominal value are -15...+10%. Power consumption, no more than 6 VA. Number of level control channels - 3. Number of built-in output relays - 3. The maximum permissible current switched by the contacts of the built-in relay is 4 A at 220 V 50 Hz (cos > 0.4).

Figure 35 - Discrete I/O module

Module of discrete inputs and outputs for distributed systems in the RS-485 network (ARIES, Modbus, DCON protocols).

The module can be used in conjunction with programmable controllers OWEN PLC or others. MDVV operates in an RS-485 network if there is a “master” in it, while MDVV itself is not the “master” of the network.

discrete inputs for connecting contact sensors and transistor switches of the n-p-n type. Possibility of using any discrete input (maximum signal frequency - 1 kHz)

Possibility of generating a PWM signal from any of the outputs

Automatic transfer of the actuator to emergency mode in case of network traffic disruption

Support for common Modbus protocols (ASCII, RTU), DCON, ARIES.

Figure - 36 General connection diagram of the MDVV device

Figure 37 - Functional diagram of MDVV

MEOF are designed to move the working elements of shut-off and control pipeline valves of the rotary operating principle (ball and plug valves, butterfly valves, dampers, etc.) in systems for automatic control of technological processes in various industries in accordance with command signals coming from regulating or control devices . The mechanisms are installed directly on the fittings.

Figure 38 - Design of the MEOF mechanism

Figure 39 - Dimensions

Installation diagram of the Metran 100-DG 1541 sensor when measuring hydrostatic pressure (level) in an open tank:

Figure 40 - Sensor installation diagram

The operating principle of the sensors is based on the use of the piezoelectric effect in a heteroepitaxial silicon film grown on the surface of a single-crystal artificial sapphire wafer.

Figure 41 - Appearance of the device

A sensing element with a monocrystalline silicon-on-sapphire structure is the basis of all sensor units of the Metran family of sensors.

For a better overview of the liquid crystal indicator (LCD) and for ease of access to the two compartments of the electronic converter, the latter can be rotated relative to the measuring unit from its installed position at an angle of no more than 90° counterclockwise.

Figure 42 - Diagram of the external electrical connection of the sensor:

Where X is the terminal block or connector;

Rн - load resistance or the total resistance of all loads in the control system;

PSU is a DC power source.

2.5 Calculation of built-in ADC parameters

Let's calculate the parameters of the built-in ADC of the PLC-150 microcontroller. The main parameters of the ADC include the maximum input voltage U max , number of code bits n, resolution ∆ and conversion error.

The ADC capacity is determined by the formula:

Log 2N, (19)

where N is the number of discretes (quantum levels);

Since the ADC is built into the selected PLC-150 controller, we have n=16. ADC resolution is the input voltage corresponding to one in the least significant digit of the output code:

(20)

where 2 n - 1 - maximum weight of the input code,

input = U max - U min (21)

At U max = 10V, U min = 0V, n = 16,

(22)

The larger n, the smaller and the more accurately the output code can represent the input voltage.

Relative resolution value:

, (23)

where ∆ is the smallest discernible step of the input signal.

Thus, ∆ is the smallest discernible step of the input signal. The ADC will not register a signal of a lower level. In accordance with this, resolution is identified with the sensitivity of the ADC.

The conversion error has static and dynamic components. The static component includes the methodological quantization error ∆ δ To (discreteness) and instrumental error from the non-ideality of the converter elements. Quantization error ∆ To is determined by the very principle of representing a continuous signal by quantized levels spaced from each other by a selected interval. The width of this interval is the resolution of the converter. The largest quantization error is half the resolution, and in the general case:

(24)

Relative largest quantization error:

(25)

The instrumental error should not exceed the quantization error. In this case, the total absolute static error is equal to:

(26)

The total relative static error can be defined as:

(27)

Next, let's calculate the resolution of the built-in DAC of the PLC-150 microcontroller. The resolution of the DAC is the output voltage corresponding to one in the least significant digit of the input code: Δ=U max /(2n -1), where 2 n -1 - maximum weight of the input code. At U max = 10B, n = 10 (bit capacity of the built-in DAC) let’s calculate the resolution of the microcontroller DAC:

(28)

The larger n, the smaller Δ and the more accurately the output voltage can represent the input code. Relative value of DAC resolution:

(29

Figure 43 - Connection diagram

Figure 44 - Connection diagram

2.6 Conclusion on the second chapter

In this chapter, a structural and functional diagram was developed. The calculation of the regulatory body, the determination of the regulator settings and the synthesis of the ACS were carried out.

Parameters of the transfer function of the control object. Selected sensor equipment. The parameters of the ADC and DAC built into the OWEN PLC 150 microcontroller were also calculated.

1 Development of an algorithm for the functioning of the SAC system in the CoDeSys environment

Professional development of industrial automation systems is inextricably linked with CoDeSys (Controller Development System). The main purpose of the CoDeSys complex is the development of application programs in the languages ​​of the IEC 61131-3 standard.

The complex consists of two main parts: the CoDeSys programming environment and the CoDeSys SP execution system. CoDeSys runs on a computer and is used to prepare programs. The programs are compiled into fast machine code and loaded into the controller. CoDeSys SP runs in the controller, it provides loading and debugging of code, I/O maintenance and other service functions.

More than 250 well-known companies manufacture equipment with CoDeSys. Thousands of people working with it every day solve industrial automation problems.

The development of application software for the PLC-150, as well as many other controllers, is carried out on a personal computer in the CoDeSys environment running Microsoft Windows. The code generator directly compiles the user program into machine codes, which ensures the highest performance of the controller. The execution and debugging system, code generator and function block libraries are specially adapted to the architecture of the PLC series controllers.

Debugging tools include viewing and editing inputs/outputs and variables, executing a program in cycles, monitoring the execution of the program algorithm in a graphical representation, graphically tracing the values ​​of variables over time and by events, graphical visualization and simulation of process equipment.

The main CoDeSys window consists of the following elements (they are arranged from top to bottom in the window):

) Toolbar. It contains buttons for quickly calling menu commands.

) An object organizer with POU, Data types, Visualizations, and Resources tabs.

) Separator between the Object Organizer and the CoDeSys workspace.

) The work area in which the editor is located.

) Message window.

) Status line containing information about the current status of the project.

The toolbar, message box, and status bar are optional elements of the main window.

The menu is at the top of the main window. It contains all CoDeSys commands. The appearance of the window is shown in Figure 45.

Figure 45 - Window appearance

Toolbar buttons provide quicker access to menu commands.

A command called using a button on the toolbar is automatically executed in the active window.

The command will be executed as soon as the button pressed on the toolbar is released. If you place your mouse pointer over a toolbar button, after a short period of time you will see the name of this button in the tooltip.

The buttons on the toolbar are different for different CoDeSys editors. You can get information regarding the purpose of these buttons in the description of the editors.

The toolbar can be disabled, Figure 46.

Figure 46 - Toolbar

The general view of the CoDeSys program window is as follows, Figure 47.

Figure 47 - CoDeSys program window

The block diagram of the operating algorithm in the CoDeSys environment is shown in Figure 48.

Figure 48 - Block diagram of functioning in the CoDeSys environment

As can be seen from the block diagram, after turning on the microcontroller, the program is loaded into it, variables are initialized, inputs are read, and modules are polled. There is also a choice of switching between automatic and manual mode. In manual mode, it is possible to control the valve and control the MEOF. Then the output data is recorded and messages are generated via serial interfaces. After which the algorithm goes into a cycle of reading inputs or the work ends.

2 Program development in the CoDeSys environment

We launch Codesys and create a new project in the ST language. The target file for ARM9 is already installed on your personal computer; it automatically selects the required library. Communication with the controller is established.

reg_for_meof:VALVE_REG; (*regulator for PDZ control*)

K,b:REAL; (*control curve coefficients*)

timer_for_valve1: TON; (*emergency shutdown timer*)

safety_valve_rs_manual: RS;(*for manual valve control*)

reference:REAL; (*set the rotation angle of the PDZ*)_VAR

(*during setup, we record the signal from the MEOF position sensor and calculate the values ​​ain low and high, initially we will assume that the sensor is 4-20 milliamps and at 4 mA the PDZ is completely closed (0%), and at 20 mA it is completely open (100%) - configured in the PLC configuration *)NOT auto_mode THEN (*if not automatic mode*)_open:=manual_more; (*open by pressing a button*)_close:=manual_less; (*close by pressing the button*)

safety_valve_rs_manual(SET:=valve_open , RESET1:=valve_close , Q1=>safety_valve); (*emergency valve control*)

(*during setup, we record the signal from the pressure sensor and calculate the values ​​ain low ain high, initially we assume that the sensor is 4-20 milliamps and at 4 mA the tank is empty (0%), and at 20 mA it is full (100%) - configured in PLC configurations *)

IF pressure_sensor< WORD_TO_REAL(w_reference1) THEN reference:=100; END_IF; (*если уровень меньше "w_reference1", то открываем заслонку на 100%*)

IF pressure_sensor> WORD_TO_REAL(w_reference1) THEN (*set the rotation angle - decrease in proportion to the increase in the “pressure sensor” level --- angle =K*level+b *)

K:=(-100/(WORD_TO_REAL(w_reference2-w_reference1)));

b:=100-K*(WORD_TO_REAL(w_reference1));

reference:=K*pressure_sensor+b;

(*timer for emergency flap control*)

timer_for_valve1(

IN:=(pressure_sensor> WORD_TO_REAL(w_reference2)) AND high_level_sensor ,

(*condition for opening the emergency valve*)

IF timer_for_valve1.Q

reference:=0; (*close MEOF*)

safety_valve:=TRUE; (*open the emergency valve*)

safety_valve:=FALSE;

(*regulator for controlling the damper*)_for_meof(

IN_VAL:=reference ,

POS:=MEOF_position ,

DBF:=2 , (*controller sensitivity*)

ReversTime:=5 , (*no more than 600 inclusions*)

MORE=>MEOF_open ,

LESS=>MEOF_close ,

FeedBackError=>);_IF;

(*data conversion for display in Scad*)

w_MEOF_position:=REAL_TO_WORD(MEOF_position);_level:=REAL_TO_WORD (pressure_sensor);

(*indication of the mode for filling the auto-manual buttons*)_out:=auto_mode;

(*indication of the output for filling the emergency valve close/open buttons*)_out:=safety_valve;

3.3 Development of an interface for visual display of measurement information

To develop the visual display interface, the Trace Mode 6 program was chosen, because it has all the functions and characteristics we need:

has a fairly wide range of capabilities for simulating technological processes on a graphic screen;

All standard programming languages ​​for SCADA systems and controllers are available;

user-friendly graphical interface;

fairly simple connection to a programmable logic controller;

The full version of this system is available on the manufacturer’s website. race Mode 6 is designed for automation of industrial enterprises, energy facilities, intelligent buildings, transport facilities, energy metering systems, etc.

The scale of automation systems created in Trace Mode can be anything - from autonomously operating control controllers and operator workstations, to geographically distributed control systems, including dozens of controllers exchanging data using various communications - local network, intranet/Internet, serial buses based on RS-232/485, dedicated and dial-up telephone lines, radio channel and GSM networks.

The integrated project development environment in the Trace Mode program is shown in Figure 49.

Figure 49 - Trace Mode 6 IDE

The project navigator allows you to quickly navigate between project sub-items. When you hover over one of the items, a comment appears that allows you to understand the content.

Figure 50 - Project navigator

The mnemonic diagram of the project, the storage tank of the first stage of wastewater treatment is shown in Figure 0. It includes:

Control panel (possibility of selecting control mode, ability to adjust dampers);

Displaying the rotation angle of the PDZ;

Indication of water level in the tank;

Emergency discharge (when the water in the tank overflows);

Measurement information tracking graph (water level conditions and valve position are displayed on the graph).

Figure 51 - Mnemonic diagram of a storage tank

The actual damper rotation angle (0-100%) is displayed under the "Position Position" field, which allows you to more accurately monitor the measurement information.

Figure 52 - PDZ position

The arrows to the left of the tank change color from gray to green when the PLC exits are triggered (signal from the ACS), i.e. If the arrow is green, then the water level is higher than the sensor.

The slider on the scale is a level indicator (based on the metran pressure sensor) (0-100%).

Figure 53 - Level indicator

Control can be carried out in two modes:

) Automatic.

When you select a mode, the color of the corresponding button changes from gray to green and this mode becomes active for use.

The "Open" and "Close" buttons are used to control the valves manually.

In automatic mode, it is possible to set tasks on which the angle of rotation of the PDZ will depend.

To the right of the “task 1” field, enter the level in the tank at which the PDZ rotation angle will begin to decrease.

To the right of the “task 2” field, enter the level in the tank at which the pressure limiter will be completely closed.

An emergency valve also operates automatically in case of possible water overflow. The emergency valve opens when the level is exceeded above “task 2” and when the upper level sensor (ALS) is activated within 10 seconds.

Figure 54 - Emergency reset

For easy tracking of measurement information, water level status and valve position are displayed on a graph. The blue line shows the water level in the tank, and the red line shows the position of the damper.

Figure 55 - Graph of level and damper position

4 Conclusions on the third chapter

In the third chapter, an algorithm for the functioning of the system was developed in the CoDeSys environment, a block diagram of the system’s functioning was constructed, and a software module for input/output of information into the automated process control system was developed.

An interface for visual display of measurement information was also developed using the Trace Mode 6 program for the automatic control system.

4. Organizational and economic part

1 Economic efficiency of automated process control systems

Economic efficiency is the effectiveness of an economic system, expressed in relation to the useful end results of its functioning to the resources expended.

Production efficiency consists of the efficiency of all operating enterprises. Enterprise efficiency is characterized by the production of a product or service at the lowest cost. It is expressed in its ability to produce the maximum volume of products of acceptable quality with minimal costs and sell these products at the lowest costs. The economic efficiency of an enterprise, in contrast to its technical efficiency, depends on how well its products meet market requirements and consumer demands.

Automated process control systems ensure increased production efficiency by increasing labor productivity, increasing production volume, improving the quality of products, rational use of fixed assets, materials and raw materials and reducing the number of employees at the enterprise. The introduction of control system differs from conventional work on the introduction of new technology in that it allows the production process to be transferred to a qualitatively new stage of development, characterized by a higher organization (orderliness) of production.

The qualitative improvement in the organization of production is due to a significant increase in the volume of information processed in the control system, a sharp increase in the speed of its processing and the use of more complex methods and algorithms to develop control decisions than those used before the implementation of automated process control systems.

The economic effect obtained from the implementation of the same system depends on the level of organization of production (stability and customization of the technological process (TP)) before and after the implementation of automated process control systems, i.e. it can be different for different enterprises.

Justification for the development (or implementation) of new technology begins with a technical assessment, by comparing the designed design with the best existing domestic and foreign models. High economic efficiency of a new device or device is achieved by incorporating progressive technical solutions into its design. They can be expressed by a system of technical and operational indicators that characterize this type of device. Progressive technical indicators are the basis for achieving high economic efficiency - the final criterion for evaluating new technology. This does not detract from the importance of technical indicators when assessing economic efficiency.

Typically, the economic indicators of the effectiveness of new technology are few and the same for all industries, and technical indicators are specific to each industry and their number can be very large in order to comprehensively characterize the technical parameters of products. Technical indicators reveal the extent to which a new device satisfies the need for production or work, and also the extent to which it is linked with other machines that are used or designed for the same process.

Before starting design (or implementation), it is necessary to become thoroughly familiar with the purpose for which the device is being created (implemented), study the technological process in which it will be used, and get a clear idea of ​​the scope of work to be performed by the new product. All this should be reflected in the technical assessment of the new machine (device) product.

An assessment of an enterprise's activities must take into account the results and costs of production. However, practice shows that assessing production units only using indicators of the cost-result approach does not always aim them at achieving high final performance results, finding internal reserves, and in fact does not contribute to increasing overall efficiency.

2 Calculation of the main costs of the control system

When determining the economic efficiency of introducing mechanization and automation means, answers to the following questions must be obtained:

how technically and economically progressive are the proposed means of mechanization and automation and whether they should be accepted for implementation;

what is the magnitude of the effect from implementation in production.

The main costs of creating a control system consist, as a rule, of the costs of pre-design and design work Sn and the costs Sob for the purchase of special equipment installed in the control system. At the same time, the cost of design work includes, in addition to the costs associated with the development of the project, the costs of developing software and implementing the control system, and the cost of equipment - in addition to the cost of control computer equipment, devices for preparing, transmitting and displaying information, the cost of those units of technological equipment , the modernization or development of which is caused by the operating conditions of the equipment in the process control system - automated process control system. In addition to the costs of creating a control system, the enterprise also incurs the costs of its operation. Thus, the annual costs for the control system are:

(30)

where T is the operating time; usually T = 5 - 7 years; - annual operating costs, rub.

Operating costs for the control system:

(31)

Where - annual wage fund of personnel servicing the control system, rub.; - depreciation charges and fees for funds, rub.; - costs for utilities (electricity, water, etc.), rub.; - annual costs for materials and components, rub.

Depreciation charges and fees for funds:

(32)

Where - cost of equipment of the i-th type, rub.; - depreciation coefficient for the i-th type of equipment; - coefficient of deductions for funds.

Annual wage fund of personnel servicing the control system:

(33)

Where - working time of service personnel per year, h; - average hourly rate of service personnel, rub.; - shop overhead ratio; m′ - number of personnel servicing the control system and specialized devices of technological equipment, people.

The cost estimate for the control system includes the following cost items:

costs of capital equipment;

costs for additional equipment;

workers' wages;

contributions for social needs;

cost of machine time;

overheads.

The basic salary of Sosn performers, rubles, is determined by the formula:

WITH basic = T cool *t With * b, (34)

where tс is the duration of the working day, hours (tс = 8 hours); - the cost of 1 person-hour (determined by dividing the monthly salary by the number of hours to be worked per month), rubles-hour.

The average cost of 1 person-hour is 75 rubles

The labor intensity of the work is 30.8 man-days.

WITH basic = 30.8 * 8 * 75 = 18,480 rub. (35)

Additional salary Additional salary, rubles, is accepted in the amount of 15% of the basic salary.

Add = 0.15 * 18,480 = 2,772 rubles.

Contributions for social needs Sotch, rubles, are calculated from the amount of basic and additional wages in the amount of 26.2%

WITH report = 0.262 * (C basic + C extra ), (36)

Sotch = 0.262 * (18480 + 2772) = 5568 rub.

Costs for materials SM are:

C1 - cost of the PLC-150 Microcontroller (average cost 10,000 rubles);

C2 - cost of the power supply (average cost 1800 rubles);

C3 - cost of sensor equipment (average cost 4000 rubles);

C4 - cost of a PC (average cost of a PC is 15,000 rubles, Pentium DC E6700, GA-EG41MFT-US2H,2 x 2GB,500Gb);

C5 - other expenses (consumables, wires, fastenings, etc.);

cm = C1 + C2 + C3 + C4 + C5

C1 = 10,000 rub.

C2 = 1800 rub.

C3 = 4000 rub.

C4 = 15,000 rub.

C5 = 9000 rub.

cm =10000+1800+4000+15000+9000= 39800 rub.

Machine time is the period during which a machine (unit, machine, etc.) performs work on processing or moving a product without direct human influence on it.

The cost of computer time is determined by the formula:

WITH mv = T mung bean * C martyr , (37)

where Tmash is the time of use of technical means, h;

Cmch - cost of a machine hour, which includes depreciation of technical equipment, maintenance and repair costs, cost of electricity, rub.-hour.

The time required to use technical means is equal to the labor intensity of the performers’ work and is 412 hours.

The cost of a machine hour is 17 rubles.

Smv = 412 * 17 = 7004 rub.

Snak's overhead costs include all costs associated with management and maintenance. There are no such expenses in this case.

The cost estimate for the development of an automated enterprise system is presented in Table 0.

Table 6 - Development costs

Expense item Amount, rub. Percentage of the total Cost of materials 39800 54.2 Basic salary 1848025.1 Additional salary 27723.7 Contributions for social needs 55687.5 Cost of machine time 70049.5 Total 73624100

Thus, the cost of the control system is 73,624 rubles.

Figure 56 - Basic costs for the control system

3 Organization of production processes

The organization of production processes consists of uniting people, tools and objects of labor into a single process for the production of material goods, as well as ensuring a rational combination in space and time of basic, auxiliary and service processes. One of the main aspects of the formation of a production structure is to ensure the interconnected functioning of all components of the production process: preparatory operations, main production processes, and maintenance. It is necessary to comprehensively substantiate the most rational organizational forms and methods for carrying out certain processes for specific production and technical conditions.

The principles of organizing the production process represent the starting points on the basis of which the construction, operation and development of production processes are carried out.

The principle of differentiation involves dividing the production process into separate parts (processes, operations) and assigning them to the relevant departments of the enterprise. The principle of differentiation is opposed to the principle of combination, which means the unification of all or part of different processes for the production of certain types of products within one site, workshop or production. Depending on the complexity of the product, production volume, and the nature of the equipment used, the production process can be concentrated in any one production unit (workshop, area) or dispersed across several units.

The principle of concentration means the concentration of certain production operations for the manufacture of technologically homogeneous products or the performance of functionally homogeneous work in separate workplaces, areas, workshops or production facilities of the enterprise. The feasibility of concentrating similar work in separate areas of production is determined by the following factors: the commonality of technological methods that necessitate the use of the same type of equipment; capabilities of equipment, such as machining centers; increasing production volumes of certain types of products; the economic feasibility of concentrating the production of certain types of products or performing similar work.

The principle of proportionality lies in the natural combination of individual elements of the production process, which is expressed in a certain quantitative relationship between them. Thus, proportionality in production capacity presupposes equality of site capacities or equipment load factors. In this case, the throughput of the procurement shops corresponds to the need for blanks of the mechanical shops, and the throughput of these shops corresponds to the needs of the assembly shop for the necessary parts. This entails the requirement to have in each workshop equipment, space, and labor in such quantities that would ensure the normal operation of all departments of the enterprise. The same throughput ratio should exist between the main production, on the one hand, and auxiliary and service units, on the other.

4.4 Conclusion on the fifth chapter

In this chapter, in accordance with the assignment for the diploma project, the economic efficiency of implementing automated process control systems was determined. The main provisions were also reviewed and the main costs of the control system were calculated.

5. Life safety and environmental protection

1 Life safety

When creating complex automated control systems, systems design is increasingly being practiced, in the early stages of which issues of workplace safety and ergonomic support are raised, which contain large reserves for increasing the efficiency and reliability of the entire system. This is due to the comprehensive consideration of the human factor during its stay in the workplace. The main objective of safety measures is to protect human health from harmful factors, such as electric shock, insufficient lighting, increased noise levels in the workplace, increased or decreased air temperature in the work area, increased or decreased air humidity, increased or decreased air mobility. All this is achieved as a result of conducting and implementing a set of procedures and activities interconnected in meaning, logic and sequence, carried out during the development of the man-machine system and during its operation. The topic of the diploma project is “Automated control system for the process of wastewater treatment after a car wash with the development of a software module for the OWEN microcontroller.” Due to the specifics of this workplace, the enterprise purifies wastewater using chlorine, and chlorine is classified as an hazardous chemical substance (HAS).

Therefore, to ensure health protection and high labor productivity, it is necessary to investigate dangerous and harmful factors when working at an enterprise with the likelihood of hazardous chemical emissions.

Dangerous and harmful factors when working with hazardous chemicals

Poisoning with emergency chemically hazardous substances (HAS) during accidents and disasters occurs when hazardous substances enter the body through the respiratory and digestive organs, skin and mucous membranes. The nature and severity of the lesions are determined by the following main factors: the type and nature of the toxic effect, the degree of toxicity, the concentration of chemicals in the affected object (territory) and the timing of human exposure.

The above factors will also determine the clinical manifestations of the lesions, which in the initial period may be:

) phenomena of irritation - cough, sore and sore throat, lacrimation and pain in the eyes, chest pain, headache;

) increase and development of phenomena from the central nervous system (CNS) - headache, dizziness, feelings of intoxication and fear, nausea, vomiting, a state of euphoria, impaired coordination of movements, drowsiness, general lethargy, apathy, etc.

Protection from dangerous and harmful factors

To prevent the release of chlorine, the enterprise must strictly follow safety rules, provide instructions when handling hazardous substances, and control the admission of hazardous substances.

The enterprise must have protective equipment in case of emergency situations. One of such means of protection is the GP-7 gas mask. The gas mask is designed to protect the respiratory system, vision and face of a person from toxic substances, biological aerosols and radioactive dust (AS, BA and RP).

Figure 57 - Gas mask GP-7

Gas mask GP-7: 1 - front part; 2 - filter-absorbing box; 3 - knitted cover; 4 - inhalation valve assembly; 5 - intercom (membrane); 6 - exhalation valve assembly; 7 - shutter; 8 - headplate (occipital plate); 9 - frontal strap; 10 - temple straps; 11 - cheek straps; 12 - buckles; 13 - bag.

The GP-7 gas mask is one of the latest and most advanced models of gas masks for the population. Provides highly effective protection against vapors of toxic, radioactive, bacterial, emergency chemically hazardous substances (HAS). It has low breathing resistance, provides reliable sealing and slight pressure of the front part on the head. Thanks to this, it can be used by people over 60 years of age and patients with pulmonary and cardiovascular diseases.

Figure 58 - time of protective action of GP-7

Figure 59 - Technical characteristics of GP-7

What to do in case of a chlorine release accident

When receiving information about an accident with hazardous substances, put on respiratory protection, skin protection (cloak, cape), leave the area of ​​the accident in the direction indicated in the radio (television) message.

You should exit the chemical contamination zone in a direction perpendicular to the direction of the wind. At the same time, avoid crossing tunnels, ravines and hollows - in low places the concentration of chlorine is higher.

If it is impossible to leave the dangerous zone, stay in the room and carry out emergency sealing: tightly close windows, doors, ventilation openings, chimneys, seal the cracks in windows and at the joints of frames and go up to the upper floors of the building.

Figure 60 - Scheme of evacuation from the contaminated zone

After leaving the danger zone, take off your outer clothing, leave it outside, take a shower, rinse your eyes and nasopharynx. If signs of poisoning appear: rest, drink warm water, consult a doctor.

Signs of chlorine poisoning: sharp pain in the chest, dry cough, vomiting, pain in the eyes, lacrimation, loss of coordination of movements.

Personal protective equipment: gas masks of all types, gauze bandage moistened with water or 2% soda solution (1 teaspoon per glass of water).

Emergency care: remove the victim from the danger zone (transportation only lying down), remove clothing that is restricting breathing, drink plenty of 2% soda solution, rinse the eyes, stomach, nose with the same solution, rinse the eyes with a 30% solution of albucid. Darkened room, dark glasses.

5.2 Environmental protection

Human health directly depends on the environment, and primarily on the quality of the water he drinks. The quality of water affects the vital functions of the human body, its performance and overall well-being. It is not for nothing that so much attention is paid to ecology and, in particular, to the problem of clean water.

In our time of advanced technological progress, the environment is becoming more and more polluted. Wastewater pollution from industrial enterprises is especially dangerous.

The most widespread pollutants in wastewater are petroleum products - an unidentified group of hydrocarbons from oil, fuel oil, kerosene, oils and their impurities, which, due to their high toxicity, are, according to UNESCO, among the ten most dangerous environmental pollutants. Petroleum products can be present in solutions in an emulsified, dissolved form and form a floating layer on the surface.

Factors of wastewater pollution with petroleum products

One of the environmental pollutants is oil-containing wastewater. They are formed at all technological stages of oil production and use.

The general direction of solving the problem of preventing environmental pollution is the creation of waste-free, low-waste, waste-free and low-waste industries. In this regard, when accepting, storing, transporting and distributing petroleum products to consumers, all necessary measures must be taken to prevent or minimize their losses as much as possible. This problem must be solved by improving technical means and technological methods for refining oil and petroleum products at oil depots and pumping stations. Along with this, local collection devices for various purposes can play a useful role, allowing them to collect spills or leaks of products in their pure form, preventing them from being removed with water.

With limited possibilities for using the above-mentioned means, wastewater contaminated with petroleum products is generated at oil depots. In accordance with the requirements of existing regulatory documents, they are subject to fairly deep cleaning. The technology for purifying oil-containing waters is determined by the phase-dispersed state of the resulting oil product - water system. The behavior of petroleum products in water is, as a rule, due to their lower density compared to the density of water and extremely low solubility in water, which is close to zero for heavy grades. In this regard, the main methods of purifying water from petroleum products are mechanical and physico-chemical. Of the mechanical methods, sedimentation has found the greatest use, and to a lesser extent, filtration and centrifugation. Of the physicochemical methods, flotation, which is sometimes classified as a mechanical method, attracts serious attention.

Purification of wastewater from petroleum products using settling tanks and sand traps

Sand traps are designed to separate mechanical impurities with a particle size of 200-250 microns. The need for preliminary separation of mechanical impurities (sand, scale, etc.) is determined by the fact that in the absence of sand traps, these impurities are released in other treatment facilities and thereby complicate the operation of the latter.

The operating principle of the sand trap is based on changing the speed of movement of solid heavy particles in a liquid flow.

Sand traps are divided into horizontal, in which the liquid moves in a horizontal direction, with a rectilinear or circular movement of water, vertical, in which the liquid moves vertically upward, and sand traps with a helical (translational-rotational) movement of water. The latter, depending on the method of creating a screw movement, are divided into tangential and aerated.

The simplest horizontal sand traps are tanks with a triangular or trapezoidal cross-section. The depth of sand traps is 0.25-1 m. The speed of water movement in them does not exceed 0.3 m/s. Sand traps with circular water movement are made in the form of a round conical-shaped tank with a peripheral tray for the flow of waste water. The sludge is collected in a conical bottom, from where it is sent for processing or disposal. Used at flow rates up to 7000 m3/day. Vertical sand traps have a rectangular or round shape, in which wastewater moves with a vertical upward flow at a speed of 0.05 m/s.

The design of the sand trap is selected depending on the amount of wastewater and the concentration of suspended solids. The most commonly used are horizontal sand traps. From the experience of oil depots, it follows that horizontal sand traps must be cleaned at least once every 2-3 days. When cleaning sand traps, a portable or stationary hydraulic elevator is usually used.

Sedimentation is the simplest and most frequently used method of separating coarsely dispersed impurities from wastewater, which, under the influence of gravitational force, settle at the bottom of the settling tank or float to its surface.

Oil transportation enterprises (oil depots, oil pumping stations) are equipped with various settling tanks for collecting and purifying water from oil and oil products. For this purpose, standard steel or reinforced concrete tanks are usually used, which can operate in the mode of a storage tank, settling tank or buffer tank, depending on the technological scheme of wastewater treatment.

Based on the technological process, contaminated water from oil depots and oil pumping stations unevenly flows to treatment facilities. For a more uniform supply of contaminated water to treatment plants, buffer tanks are used, which are equipped with water distribution and oil collection devices, pipes for supplying and discharging wastewater and oil, a level gauge, breathing equipment, etc. Since oil in water is in three states (easily, difficult to separate and dissolved), once in the buffer tank, easily and partially difficult to separate oil floats to the surface of the water. Up to 90-95% of easily separable oils are separated in these tanks. To do this, two or more buffer tanks are installed in the treatment plant circuit, which operate periodically: filling, settling, pumping. The volume of the tank is selected based on the time of filling, pumping and settling, and the settling time is taken from 6 to 24 hours. Thus, buffer tanks (settlement tanks) not only smooth out the uneven supply of wastewater to treatment facilities, but also significantly reduce the concentration of oil in water.

Before pumping the settled water out of the tank, the floating oil and precipitated sediment are first removed, after which the clarified water is pumped out. To remove sediment, drainage from perforated pipes is installed at the bottom of the tank.

A distinctive feature of dynamic sedimentation tanks is the separation of impurities in the water as the liquid moves.

In dynamic settling tanks or continuous settling tanks, the liquid moves in a horizontal or vertical direction, hence settling tanks are divided into vertical and horizontal.

A vertical settling tank is a cylindrical or square (in plan) tank with a conical bottom for easy collection and pumping of settling sediment. The movement of water in a vertical settling tank occurs from bottom to top (for settling particles).

A horizontal settling tank is a rectangular tank (in plan) 1.5-4 m high, 3-6 m wide and up to 48 m long. The sediment that has fallen at the bottom is moved to the pit with special scrapers, and removed from it using a hydraulic elevator, pumps or other devices. sump. Floating impurities are removed using scrapers and transverse trays installed at a certain level.

Depending on the product being captured, horizontal settling tanks are divided into sand traps, oil traps, fuel oil traps, gasoline traps, grease traps, etc. Some types of oil traps are shown in Figure 0.

Figure 61 - Oil traps

In radial round-shaped settling tanks, water moves from the center to the periphery or vice versa. High-capacity radial settling tanks used for wastewater treatment have a diameter of up to 100 m and a depth of up to 5 m.

Radial settling tanks with a central wastewater inlet have increased inlet velocities, which causes less efficient use of a significant part of the settling tank volume in relation to radial settling tanks with a peripheral wastewater inlet and purified water withdrawal in the center.

The greater the height of the settling tank, the longer it takes for a particle to float to the surface of the water. And this, in turn, is associated with an increase in the length of the sump. Consequently, it is difficult to intensify the settling process in oil traps of conventional designs. As the size of settling tanks increases, the hydrodynamic characteristics of settling deteriorate. The thinner the layer of liquid, the faster the process of ascent (settling) occurs, all other things being equal. This situation led to the creation of thin-layer sedimentation tanks, which by design can be divided into tubular and plate.

The working element of a tubular settling tank is a pipe with a diameter of 2.5-5 cm and a length of about 1 m. The length depends on the characteristics of the pollution and the hydrodynamic parameters of the flow. Tubular sedimentation tanks with small (10) and large (up to 60) pipe inclinations are used.

Sedimentation tanks with a low pipe slope operate in a periodic cycle: water clarification and washing of the pipes. It is advisable to use these settling tanks for clarification of wastewater with a small amount of mechanical impurities. The lightening efficiency is 80-85%.

In steeply inclined tubular sedimentation tanks, the arrangement of the tubes causes the sediment to slide down the tubes, and therefore there is no need to flush them.

The operating time of settling tanks practically does not depend on the diameter of the tubes, but increases with their length.

Standard tubular blocks are made from polyvinyl or polystyrene plastic. Typically, blocks are used with a length of about 3 m, a width of 0.75 m and a height of 0.5 m. The cross-sectional size of the tubular element is 5x5 cm. The designs of these blocks make it possible to assemble sections from them for any capacity; sections or individual blocks can easily be installed in vertical or horizontal settling tanks.

Plate sedimentation tanks consist of a series of parallel plates, between which liquid moves. Depending on the direction of movement of water and deposited (floated) sediment, settling tanks are divided into direct-flow ones, in which the directions of movement of water and sediment coincide; countercurrent, in which water and sediment move towards each other; cross, in which water moves perpendicular to the direction of sediment movement. Plate counterflow sedimentation tanks are the most widely used.

Figure 62 - Settling tanks

The advantages of tubular and plate sedimentation tanks are their cost-effectiveness due to the small construction volume, the possibility of using plastics that are lighter than metal and do not corrode in aggressive environments.

A common disadvantage of thin-layer sedimentation tanks is the need to create a container for the preliminary separation of easily separated oil particles and large clots of oil, scale, sand, etc. Clots have zero buoyancy, their diameter can reach 10-15 cm with a depth of several centimeters. Such clots very quickly damage thin-layer sedimentation tanks. If some of the plates or pipes are clogged with such clots, then in the rest the fluid flow will increase. This situation will lead to deterioration in the operation of the sump. Schematic diagrams of settling tanks are shown in Figure 0.

5.3 Conclusions on the fifth chapter

This section discussed the main issues of life safety and environmental protection. An analysis of dangerous and harmful production factors was carried out. Protective measures were also developed for the release of chlorine. In addition, this chapter examined the main tasks of protecting the environment, and proposed the installation of a horizontal settling tank to purify wastewater from petroleum products.

Conclusion

In this diploma project, a software component was developed for an automatic control system for wastewater treatment after a car wash.

The basics of operation and modern methods of wastewater treatment were reviewed. As well as the possibility of automating these processes. An analysis of existing hardware (logic programmable PLC controllers) and software for control systems was carried out.

The hardware of the control system for controlling the wastewater treatment process of a car wash has been developed.

An algorithm for the functioning of the system in the CoDeSys environment has been developed. A visual display interface has been developed in the Trace Mode 6 environment.

Bibliography

automation wastewater treatment

1. Lectures on the courses “Electronics” and “Technical measurements and instruments”. Kharitonov V.I.

2. “Management of technical systems” Kharitonov V.I., Bunko E.B., K.I. Mesha, E.G. Murachev.

3. "Electronics" Savelov N.S., Lachin V.I.

Technical documentation for car washing MGUP "Mosvodokanal".

Zhuromsky V.M. Course of lectures on the course "Technical means"

Kazinik E.M. - Methodological instructions for the implementation of the organizational and economic part - Moscow, publishing house MSTU MAMI, 2006. - 36 p.

Sandulyak A.V., Sharipova N.N., Smirnova E.E. - Methodological instructions for implementing the section “life safety and environmental protection” - Moscow, publishing house MSTU MAMI, 2008. - 22 p.

Technical documentation MGUP "Mosvodokanal"

Stakhov - Treatment of oily wastewater from oil products storage and transportation enterprises - Leningrad Nedra.

Website resources http://www.owen.ru.

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Introduction

Automation of technological processes and production, at the present stage, is being introduced into all industries. One of the main advantages of automated process control systems is the reduction, even complete elimination, of the influence of the human factor on the controlled process, reduction of personnel, minimization of raw material costs, improvement of the quality of the manufactured product, and ultimately a significant increase in production efficiency. The main functions performed by such systems include monitoring and control, data exchange, processing, accumulation and storage of information, generation of alarms, generation of graphs and reports.

1. Characteristicwaste water to enterprises

Wastewater is any water and precipitation discharged into reservoirs from the territories of industrial enterprises and populated areas through the sewer system or by gravity, the properties of which have been deteriorated as a result of human activity.

Wastewater is:

Industrial (industrial) wastewater (generated in technological processes during production or mining) is discharged through an industrial or general sewerage system

Domestic (domestic and fecal) wastewater (generated in residential premises, as well as in domestic premises in production, for example, showers, toilets) is discharged through the domestic or general sewer system

Surface wastewater (divided into rainwater and meltwater, that is, formed when snow, ice, and hail melts) is usually discharged through a storm sewer system.

Industrial wastewater can be separated:

According to the composition of pollutants:

Contaminated primarily with mineral impurities;

Contaminated primarily with organic impurities;

Contaminated with both mineral and organic impurities;

By concentration of pollutants.

There are two main groups of pollutants in wastewater - conservative, i.e. those that are difficult to enter into chemical reactions and are practically not biodegradable (examples of such pollutants are salts of heavy metals, phenols, pesticides) and non-conservative, i.e. those that can, incl. undergo self-purification processes of reservoirs.

The composition of wastewater includes both inorganic (particles of soil, ore and waste rock, slag, inorganic salts, acids, alkalis); and organic (petroleum products, organic acids), incl. biological objects (fungi, bacteria, yeast, including pathogens).

Technological process of the object

The entire outdoor installation is equipped with a concrete covering with a slope towards the drain trays to collect precipitation and possible spills of processed products.

The collection from the drain trays is sent to recessed containers E-314/1.2, located at different ends of the installation (process diagram). The water collected in the containers is pumped out by pumps N-314/1.2 into the chemically contaminated sewerage system (CPS) at the WWTP, subject to satisfactory results of the analysis of the collected water and obtaining permission for pumping from the shift foreman of the WWTP. During pumping, the presence of an oil layer is monitored, and if it is detected, pumping is stopped.

If the water is significantly polluted, it is diluted, if possible, with recycled water or transported by sludge truck to the sludge storage facility at the WWTP.

If an oil layer is detected, it is sent for recycling through container O-23 using a fuel truck. The level in tank E-314/1 is controlled by the LIA - 540 device.

Process flow diagram

Disadvantages of the existing system:

- there is no way to monitor and analyze the level of the oil layer taken from the sensor, which in turn does not allow us to control the entire technological process.

- there is no automated process control and management system.

- one of the main advantages of automated process control systems, which is not observed in this system, is reducing the influence of the so-called human factor on the controlled process, reducing personnel, minimizing raw material costs, improving the quality of the final product, and ultimately a significant increase in production efficiency.

- existing devices embedded in the system are subject to environmental influences.

General principles for constructing automated monitoring and control systems for technological processes

There are various principles for constructing technological process control systems, which are determined by: 1) the operator’s place in the control chain and 2) the territorial location of technological facilities.

Based on the first principle, the following options for constructing systems are possible.

The information system allows management personnel to monitor the progress of the ongoing process using secondary measuring instruments, depending on the readings, make one or another decision on regulating the progress of the process and, if necessary, make adjustments using manually controlled devices.

Depending on the technical base of measuring instruments, the following methods of implementing measuring systems are possible:

In the first case, indicating instruments are used as secondary measuring devices. This method allows the operator to monitor the progress of the process using the readings of pointer or digital instruments, enter data into the accounting journal, make a decision on regulating the progress of the process and carry it out. Despite the archaic nature of this method, it is still widely used, especially since it is possible to supplement measuring instruments with various signaling and remote control means;

In the second case, recording devices are used as secondary measuring instruments: automatic recorders, potentiometers and other similar devices that record on chart paper. This method also requires constant operator monitoring of the process, but relieves him of the routine procedure of recording readings. The above cases are characterized by the difficulty of finding the necessary values ​​recorded at different time intervals, and a certain complexity of statistical data processing, because they require manual processing or manual input into a computer, the difficulty of creating a closed-loop control system;

In the third case, the implementation of an information system involves a combination of means for measuring, processing and storing information based on an electronic computer. The use of computer technology makes it possible to create an automatic system for complex processing of information about the technological process. Such a system allows for a flexible approach to data processing depending on its content; in addition, the required statistical processing of the received data, storage and presentation of them in the required form on the display screen and hard media is provided, and information is easily transmitted over long distances. This makes it possible to organize an automated system for collecting, processing, storing, transmitting and presenting information.

At the present stage of technology development, information and control systems built on the basis of digital computer technology serve as the basis for automated and automatic control and management systems for technological processes and production in general.

One of the types of automated control systems is an information and advisory system, otherwise called a decision support system or an expert system. This type of system implements the automatic collection of technological data from the facility, the necessary processing, storage and transmission of information. Processing information allows you to convert it into a format suitable for storage in a database, extracting the required data from it, on which the synthesis of recommendation information is possible.

The development of information and advisory systems is the automatic control system (ACS). The construction of self-propelled guns is possible both on the basis of analog and digital elements. The most promising basis, at this stage of technology development, is microprocessor block-modular systems for collecting information, further processing of information using industrial computers, synthesis of control actions and transmission of control signals to the control object by transmitting modules of a block-modular system for collecting and transmitting information.

The use of modern computer technology also makes it possible to organize the transfer of information between various automatic control systems, provided there are communication lines and appropriate information transfer protocols. Thus, an automatic control system built on a similar principle provides a solution to the problem of managing and monitoring a technological object, and the ability to integrate the system with other levels of the hierarchy.

Based on their territorial location, monitoring and control systems are divided into centralized and distributed systems.

Centralized systems are characterized by the fact that control objects are geographically dispersed and controlled from a central control point implemented on a digital control machine. Despite the advantage that all information about the state of the technological process is concentrated in one control point and control is carried out, such a system is significantly dependent on the condition and reliability of communication lines.

Distributed control systems allow you to control dispersed objects that are affected by autonomous control controllers. Communication with the central point is carried out by so-called supervisory control over the entire course of the technological process, and the necessary correction signals are also generated and transmitted to autonomous control controllers.

In addition to analyzing the general principles of constructing automated monitoring and control systems and the requirements imposed by state standards when designing such systems, the customer's requirements for an automated process control system were taken into account.

First of all, today it is necessary to combine the automated control system for technological processes and the central control room into a single information system. It is equally important to automate pipelines. This will allow you to accurately and quickly obtain important technological information: pressure, temperature, consumption of the transported substance.

This kind of information is needed by technologists to carry out preventive and repair work and assess the stability of the technological process. Measuring the amount of transported carbon dioxide is necessary for technological accounting. Ultimately, prompt access to information appears, which improves the quality of management decision-making.

The following tasks were set and solved in the work:

1) A thorough study of the entire technological process and justification of the need to implement an automated system.

2) Selection of sensors and devices to implement the task.

3) Selection of system hardware.

4) Development of a functional diagram taking into account the introduction of elements of process automation.

5) Development of software and hardware for an automated process control and management system.

6) Description of the functionality and technical capabilities of the implemented automated system.

Functional diagram of an object with an integrated automated system And theme

Description of the functional diagram of the automated system

The functional diagram of automation of a technological facility is shown in Fig. (2). The diagram shows the location of the primary measuring transducers of technological control. The system sensors are made of materials that are resistant to environmental influences and have an explosion-proof design, as well as pressure resistance up to 10.0 MPa. Automated pumping of wastewater from tank E-314/1 is carried out using a control valve position LV 540/1, working with a wave radar level sensor position LIDC 540 Rosemount 5300 (at phase separation). When the water level reaches 100%, the control valve FV 540/1 opens. Which supplies circulating water to the container due to hydrostatic force. When the oil layer is reached, which is detected by the LIDC 540 level sensor (at the phase interface), the valve closes.

2. List of devices used

1) LevelLIDA- 540: Rosemount 5300

The Rosemount 5300 is a two-wire guided wave level transmitter for measuring level, interface, and solid solids. Rosemount 5300 provides high reliability, advanced security measures, ease of use and unlimited connectivity and integration into process control systems.

Operating principle Guided wave level meters:

The Rosemount 5300 is based on Time Domain Reflectometry (TDR) technology. Low power microwave nanosecond radar pulses are directed down a probe immersed in the process fluid. When a radar pulse reaches a medium with a different dielectric constant, part of the pulse energy is reflected in the opposite direction. The time difference between the moment of transmission of the radar pulse and the moment of reception of the echo signal is proportional to the distance according to which the liquid level or interface level of two media is calculated. The intensity of the reflected echo signal depends on the dielectric constant of the medium. The higher the dielectric constant, the higher the intensity of the reflected signal. Guided wave technology has a number of advantages over other level measurement methods, since radar pulses are virtually immune to the composition of the medium, the tank atmosphere, temperature and pressure. Since the radar pulses are guided along the probe rather than freely propagating throughout the tank, guided wave technology can be successfully used in small and narrow tanks, as well as in tanks with narrow nozzles. For ease of use and maintenance in various conditions, the 5300 level transmitters use the following principles and design solutions:

Modularity of designs;

Advanced analog and digital signal processing;

Possibility of using several types of probes depending on the conditions of use of the level gauge;

Connection with a two-wire cable (power is supplied through the signal circuit);

Supports the digital HART communications protocol, providing digital data output and remote instrument configuration using a Model 375 or 475 Handheld Communicator or a personal computer running Rosemount Radar Master software.

2) F.V.540 -shut-off control valve

The shut-off and control valve is designed to automatically control the flow of liquid and gaseous media, including aggressive and fire hazardous ones, as well as to shut off pipelines.

The principle of operation of the control valve is to change the hydraulic resistance, and, consequently, the throughput of the valve by changing the flow area of ​​the throttle assembly. The movement of the plunger is controlled by a drive. When the actuator rod moves under the influence of a control signal, the valve plunger makes a reciprocating movement in the sleeve. Depending on the required conditional throughput and flow characteristics, a set of holes or profiled windows is made on the cylindrical surface of the bushing. The area of ​​the holes through which the working medium is throttled depends on the height of the plunger.

A direct or reverse-acting diaphragm-spring drive converts changes in the pressure of compressed air supplied to the working cavity into rod movement. In the absence of compressed air pressure in the working cavity of the drive, the plunger, under the influence of the force developed by the spring, is installed in the lowest position in the NC drive (version - normally closed).

The positioner is designed to improve the positioning accuracy of the actuator stem and the valve stem connected to it.

3) Technographer-160M

Instruments indicating and recording TECHNOGRAPH 160M are designed for measuring and recording via twelve channels (K1-K9, KA, HF, KS) voltage and direct current, as well as non-electrical quantities converted into direct current electrical signals or active resistance.

The devices can be used in various industries to control and record production and technological processes.

The devices allow you to:

Position control;

Indication of the channel number on a one-digit display and the value of the measured value on a four-digit display;

Analog, digital or combined registration on a chart tape;

Data exchange via RS-232 or RS-485 channel from a PC;

Measurement and recording of instantaneous flow (root extraction), as well as recording of average or total flow per hour.

Registration is carried out by a six-color felt-tip pen print head, the recording resource is one million dots for each color.

Interface parameters: baud rate 2400 bps, 8 data bits, 2 stop bits, no parity and no ready signals.

4) Versatileth industrial regulator KR5500

Universal industrial regulators KR 5500 series are designed for measuring, indicating and regulating DC power and voltage or active resistance from pressure, flow, level, temperature sensors, etc.

Regulators can be used in metallurgical, petrochemical, energy and other industries to control and regulate production and technological processes. The undoubted advantage of these devices is the extended range of climatic conditions for their use: they can operate in a temperature range of -5...+55°C and a humidity of 10...80%.

Universal industrial regulators of the KR 5500 series are high-precision and reliable devices of the most modern level, with a user-programmable control law (P, PI, PID) and with 1 or 2 outputs of various types. Data exchange with a PC is carried out via RS 422 or RS 485 interfaces. The root extraction and squaring functions allow you to control not only the temperature, but also other parameters of technological processes - pressure, flow, level in units of the measured value. The measurement results are displayed on the LED display.

Purpose

Regulators with digital display and programmable type of control law - PID, PD, P - are designed to measure and regulate temperature and other non-electrical quantities (pressure, flow, level, etc.), converted into electrical signals of DC power and voltage.

Conclusion

automated waste technological control

In this work, the issue of automating the technological process of collecting wastewater treatment was considered.

Initially, it was established what parameters we needed to control and regulate. Then the objects of regulation and equipment with which the set goal can be achieved are selected.

The high efficiency of using automated control of parameters and optimization of the operation of various technological systems with mechanisms operating in variable modes has been confirmed by many years of world experience. The use of automation makes it possible to optimize the operation of technological installations and improve the quality of products.

Bibliography

1. Design documentation for workshop IF - 9. OJSC "Uralorgsintez" 2010

2. Rosemount 5300 Guided Wave Level Transmitters. Operating Manual.

3. Product catalog “Modern means of control, regulation and registration of technological processes in industry” NFP “Sensorika” Yekaterinburg.

4. Automation of production processes in the chemical industry / Lapshenkov G.I., Polotsky L.M. Ed. 3rd, revised and additional - M.: Chemistry, 1988, 288 p.

5. Catalog of products and applications of Teplopribor OJSC, Chelyabinsk

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Automation of wastewater treatment plants

The scope of automation work in each specific case must be confirmed by economic efficiency and sanitary effect.

At treatment plants the following can be automated:

1. devices and instruments that record changes in process conditions during normal operation;
2. devices and instruments that provide localization of accidents and ensure prompt switching;
3. auxiliary processes in the operation of structures, especially for pumping stations (filling pumps, pumping drainage water, ventilation, etc.);
4. wastewater disinfection facilities that have undergone treatment.

Along with a comprehensive automation solution, it is advisable to automate individual technological processes: distribution of wastewater across structures, regulation of levels of precipitation and sludge.

Partial automation in the future should provide for the possibility of transition to comprehensive automation of the entire technological cycle.

The relatively small implementation of automatic control units in wastewater treatment technology at food industry enterprises is explained by the fact that most treatment plants have low or medium productivity, due to which capital costs for automation are often expressed in significant amounts and cannot be compensated by corresponding savings in operating costs. In the future, automatic dosing of reagents and monitoring the efficiency of wastewater treatment will be widely used at wastewater treatment plants.

Technical requirements for automation of wastewater treatment processes can be summarized as follows:

1. any automatic control system must allow for local control of individual mechanisms during their inspection and repair;
2. the possibility of controlling two methods simultaneously (for example, automatic and local) must be excluded;
3. transferring the system from manual control to automatic control should not be accompanied by shutting down the mechanisms in operation;
4. the automatic control circuit must ensure the normal flow of the technological process and ensure the reliability and accuracy of the installation;
5. during a normal shutdown of the unit, the automation circuit must be ready for the next automatic start;
6. the provided locking must exclude the possibility of automatic or remote start after an emergency shutdown of the unit;
7. in all cases of disruption of the normal operation of an automated installation, an alarm signal must be sent to a station with constant duty.

1. pumping stations - main units and drainage pumps; switching on and off depending on the liquid level in tanks and pits, automatic switching when one pump breaks down to a backup one; giving an audible signal in cases of failure of pumping units or overflow of the level in the receiving tank;
2. drainage pits - emergency level alarm;
3. pressure valves of pumping units (when starting the unit on a closed valve) - opening and closing, interlocked with the operation of the pumps;
4. mechanical rakes - work in accordance with a given program;
5. electric heating devices - turning on and off electric heating devices depending on the room temperature;
6. receiving tanks of sludge pumping stations - resuspension of waste liquid;
7. pressure pipelines of sludge pumping stations - emptying after stopping the pumps;
8. building grates with mechanical cleaning - turning on and off mechanical rakes depending on the difference in levels before and after the grate (grid clogging) or according to a time schedule;
9. sand traps - turning on the hydraulic elevator to pump out sand according to a time schedule or depending on the sand level, automatically maintaining a constant flow rate;
10. settling tanks, contact tanks - release (pumping) of sludge (sediment) according to a time schedule or depending on the sludge level; operation of scraper mechanisms according to a time schedule or depending on the sludge level; opening the hydraulic valve when starting the movable scraper truss;
11. wastewater neutralization stations, chlorination stations based on thorny lime - dosing of the reagent depending on the wastewater flow.

A characteristic feature of wastewater from food industry enterprises is the lack of nitrogen and phosphorus standards for biochemical processes.

Therefore, there is a need to add missing elements in the form of nutrients.

Application of additives involves the difficulty of adjusting the volume of additives depending on the size of wastewater and contaminants. Taking into account the changing flow of wastewater, dosing of nutrients is especially difficult, therefore, to measure the flow of wastewater, the Soyuzvodokanalproekt Institute has developed an automation scheme in which diaphragms and float indicating differential pressure gauges of the DEMP-280 type with induction sensors are used.

Pulses from the differential pressure gauge are transmitted to the electronic ratio regulator ERS-67, which, using an electric actuator of the MG type, acting on the control valve, brings the consumption of nutrients into accordance with the size of the wastewater influx. In this case, the necessary calculated ratio between the consumption of wastewater and nutrients is set to the regulator depending on the change in the concentration of pollutants in the wastewater entering the treatment plant.

Mechanical cleaning processes include filtering water through screens, sand collection and primary settling. The block diagram of automation of mechanical wastewater treatment processes is shown in Fig. 52.

Fig.52. ACS block diagram:

1 – distribution chamber; 2 – stepped pit grate; 3 – horizontal sand trap; 4 – primary settling tank; 5 – sand bunker

Grates are used to capture large mechanical impurities from wastewater. When automating screens, the main task is to control rakes, crushers, conveyors and gates on the supply channel. Water passes through the grate, on which mechanical impurities are retained, then, as waste accumulates, the stepped grate is turned on and cleared of waste. Automatic devices on the grates are turned on when the difference in wastewater levels before and after the grates increases. The angle of inclination of the grille is 60 o -80 o. The rake is switched off either by a contact device that is triggered when the level drops to a preset value, or by using a time relay (after a certain period of time).

Next, after retaining large mechanical impurities, the runoff is sent to sand traps, which are designed to capture sand and other undissolved mineral contaminants from wastewater. The operating principle of the sand trap is based on the fact that, under the influence of gravity, particles whose specific gravity is greater than the specific gravity of water, as they move along with the water, fall to the bottom.

A horizontal sand trap consists of a working part, where the flow moves, and a sedimentary part, the purpose of which is to collect and store fallen sand until it is removed. The residence time of liquid in a horizontal sand trap is usually 30 - 60 s, the estimated diameter of sand particles is 0.2 - 0.25 mm, speed movement of waste water 0.1 m/s. Automatic devices in sand traps are used to remove sand when it reaches the maximum level. For normal and efficient operation of the sand trap, it is necessary to monitor and control the level of sediment; if it rises above the permissible value, it will become agitated, and the water will be contaminated with previously settled substances. Also, automatic sand removal can be carried out at certain time intervals, established based on operating experience.

The effluent then enters the primary settling tank to retain floating and precipitated substances. Water moves slowly from the center to the periphery and drains into a peripheral trench with flooded holes. To remove sludge from wastewater, a slowly rotating metal truss with scrapers mounted on it is used, raking the sludge to the center of the settling tank, from where it is periodically pumped out by a hydraulic elevator. The residence time (settling) of the waste liquid is 2 hours, the water speed is 7 m/s.

Automation of the process of physical and chemical wastewater treatment

In wastewater treatment systems using physical and chemical methods, pressure flotation is most widely used. With this treatment method, wastewater is saturated with gas (air) under excess pressure, which is then quickly reduced to atmospheric pressure.

In Fig. Figure 53 shows a block diagram of an ASR with stabilization of the quality of purified water by changing the flow rate of the recirculation flow carrying a fine gas phase into the flotator.

The system consists of a flotation tank 1, turbidity meter 2-1, which measures the concentration of suspended particles in purified water, alarm 2-3, flow meter 1-1, regulator 1-2, control valves 1-3, which regulates the flow of wastewater entering the flotator , and valve 2-2, which regulates the flow rate of the circulation flow saturated with air in the pressure receiver 2.

The signal that occurs when the concentration of suspended matter in water increases above a preset value at the flotator output is sent from turbidity meter 2-1 to the regulator, which increases the recirculation flow rate through valve 2-2. The new amount of gas reduces the turbidity of the treated wastewater. At the same time, as the recirculation flow rate through the flotation tank increases, a deviation signal appears at the output of flow meter 1-1, which is sent to regulator 1-2. This regulator reduces the flow of wastewater into the flotator in 1-3 steps, ensuring a constant total flow through it.

Rice. 53. Diagram of the ASR process for wastewater treatment by pressure flotation