PLC (Programmable Logic Controller) control system and control method for gas dissolution and reoxygenation

Abstract

The invention provides a PLC (Programmable Logic Controller) control system and a control method for gas dissolution and reoxygenation. The system comprises a host PLC control master station, a plurality of precise regulation and control system PLC substations, a plurality of water quality monitoring system remote substations and an oxygen production system PLC substation. The control method comprises the following steps that required reoxygenation parameters, system pressure and water inlet flow are calculated, the operation frequency of a water pump is set, the water pump and gas flow are controlled through a PLC, accurate regulation and control of reoxygenation are achieved, feedback regulation and control are conducted through a water quality monitoring system remote substation, and therefore efficient and accurate reoxygenation is achieved. Through integrated control, accurate data acquisition, parameter optimization and efficient substation regulation and control, intelligent and unmanned efficient oxygen-enriched water production and accurate reoxygenation are achieved, and the lake water quality and the ecological environment are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of water environment treatment, and in particular to a PLC control system and a control method for gas-dissolved reoxygenation. Background Art

[0002] The aerosol reoxygenation system is mainly used for lake water environment management, improving dissolved oxygen in water, creating an oxygen-rich healthy habitat, and restoring the biodiversity of rivers and lakes. At present, there are PLC control systems used in lake reoxygenation devices on the market, but the reoxygenation devices with ordinary PLC control systems cannot accurately reoxygenate each reoxygenation point in the water body during the lake reoxygenation process. The limitations of ordinary PLC control systems in lake reoxygenation are quite obvious.

[0003] Since the PLC system usually runs according to the preset program, it is difficult for the traditional PLC system to achieve precise control for the dynamically changing water environment, such as the uneven distribution of flow rate and dissolved oxygen concentration. The water quality conditions at each reoxygenation point may be different, and the ordinary PLC control system cannot make real-time adjustments based on these differences, resulting in unsatisfactory reoxygenation effect. Since the ordinary PLC control system cannot accurately control the oxygen supply at each reoxygenation point, it is easy to cause oxygen waste or insufficient oxygen supply, thereby reducing the overall reoxygenation efficiency. In addition, due to the lack of precise control, the ordinary PLC control system often leads to low dissolved oxygen concentration in the oxygen-rich water produced by the system, and the expected ecological restoration effect cannot be achieved. Due to imprecise control, when injecting oxygen into the water body, the ordinary PLC control system may cause oxygen loss or escape, thereby reducing the utilization rate of oxygen. In addition, the ordinary PLC control system lacks effective monitoring and regulation of the oxygen mass transfer efficiency during the reoxygenation process, resulting in low overall mass transfer efficiency. The trend of modern water environment management is to develop in the direction of intelligence and unmanned operation. Due to the above limitations, the ordinary PLC control system is difficult to meet the requirements of this trend, which limits its application in modern water environment management.

[0004] In general, the current gas-dissolved reoxygenation PLC control system has the technical defects of low reoxygenation efficiency, low dissolved oxygen in the oxygen-rich water produced by the system, low oxygen utilization rate, low water oxygen mass transfer efficiency, and inability to achieve intelligent and unmanned operation. In view of this, it is necessary to design an improved gas-dissolved reoxygenation PLC control system and control method to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a PLC control system and control method for aerosol reoxygenation, which can accurately control the supply and distribution of oxygen through a multi-level communication network and an integrated control system, realize continuous monitoring and automatic adjustment of the lake water environment, thereby effectively improving water quality, restoring ecological balance, and reducing operating costs.

[0006] To achieve the above-mentioned invention object, the present invention provides a PLC control system for gas-dissolved reoxygenation, which includes a host PLC control main station, several PLC substations of a precise control system for controlling the flow of oxygen-enriched water, several remote substations of a water quality monitoring system for collecting water quality parameter data, and a PLC substation of an oxygen production system for controlling the preparation of oxygen-enriched water;

[0007] The host PLC control main station is wirelessly connected to the aforementioned substations respectively, and controls the oxygen production system PLC substation to regulate the preparation of oxygen-enriched water by receiving and processing the water quality parameter data transmitted by the remote substation of the water quality monitoring system, and sends oxygen-enriched water flow parameter adjustment and control signals to the precise control system PLC substation, so as to realize precise aerosol reoxygenation at each reoxygenation point in the water body.

[0008] As a further improvement of the present invention, the host PLC control master station includes a master station touch screen, a master station switch, a master station data acquisition and electrical control unit, and a data exchange cloud platform;

[0009] The water quality parameter data of the remote substation of the water quality monitoring system is transmitted and stored in the data exchange cloud platform, and the data exchange cloud platform further sends the processed data to the host PLC control main station.

[0010] As a further improvement of the present invention, the data acquisition and electrical control unit of the master station collects data from the pressure sensor, the liquid level sensor, and the water inlet electromagnetic flowmeter using analog quantity and Ethernet communication; controls the frequency converter to drive the water pump using Ethernet communication, and controls the gas flow mass controller to control the balance of the intake air flow; further, the host PLC controls the master station to optimize and correct the PID parameters of the gas flow mass controller.

[0011] As a further improvement of the present invention, the PLC substation of the precise control system includes a substation touch screen, a substation switch, and a substation data acquisition and electrical control unit; the substation data acquisition and electrical control unit uses analog quantity and Ethernet communication to collect data from the water outlet electromagnetic flowmeter and the electric valve; and uses Ethernet communication to control the opening degree of the electric valve.

[0012] As a further improvement of the present invention, the remote substation of the water quality monitoring system includes a remote substation gateway, a remote substation data acquisition and electrical control unit;

[0013] The remote substation data acquisition and electrical control unit is wirelessly connected to the water quality sensor to collect various water quality parameter data.

[0014] In order to achieve the above-mentioned object of the invention, the present invention also provides a method for controlling gas-dissolved reoxygenation, which is controlled by the PLC control system of the gas-dissolved reoxygenation, and comprises the following steps:

[0015] S1. Calculate the reoxygenation parameters required for the reoxygenated water body, input the reoxygenation scale calculation formula and the actual measured reoxygenation data into the host PLC control main station, and determine the air intake volume of the host equipment of the reoxygenation system according to the reoxygenation scale;

[0016] S2. Calculate the system pressure required by the main equipment of the reoxygenation system, and input the system pressure calculation formula and the actual measured pressure data into the host PLC control main station;

[0017] S3. Calculate the water inlet flow required by the main equipment of the reoxygenation system based on the system pressure and reoxygenation scale;

[0018] S4, input the performance parameters of the water pump into the host PLC control main station, and determine the range of the water pump operating frequency according to the water pump performance parameters, system pressure, and water inlet flow;

[0019] S5, the host PLC controls the main station to control the inverter to drive the water pump to pump water to the main equipment of the reoxygenation system. The host PLC controls the main station to control the gas flow quality controller according to the parameter data of the oxygen production system PLC substation, and then adjusts the intake flow to meet the reoxygenation scale of step S1;

[0020] S6. The water quality monitoring system set up within a certain range of the reoxygenation water body transmits water quality parameter data to the host PLC control main station. The oxygen-enriched water produced by the main equipment of the reoxygenation system is led to the precise control equipment. The precise control system PLC substation controls the opening of the electric valve of the precise control equipment to adjust the flow of oxygen-enriched water and transports the reoxygenated water to the reoxygenation water body for reoxygenation.

[0021] As a further improvement of the present invention, in step S1, the calculation formula for the reoxygenation scale required for the reoxygenated water body is:

[0022]

[0023] M=M1+M2+M3

[0024] Where: M is the oxygen demand of water, kg; M1 is the oxygen demand of sulfide, kg; M2 is the oxygen demand of sulfate-reducing bacteria, kg; M3 is the oxygen demand of inhibited organisms, kg; B0 is the five-day biological oxygen demand, mg / L; C0 is the sulfide concentration of raw water, mg / L; V 有效 is the effective volume of the water body, m3; λ is an empirical parameter, dimensionless, 1.0-1.5; D0 is the dissolved oxygen limit, mg / L;

[0025]

[0026] Wherein: Q is the reoxygenation scale, Kg / h; t is the reoxygenation time, h; η is the dissolved oxygen efficiency, dimensionless 90%-95%.

[0027] As a further improvement of the present invention, in step S2, according to Henry's law, under isothermal and isobaric conditions, the solubility of a certain volatile solute in a solution is proportional to the equilibrium pressure of the solute on the liquid surface, and the calculation formula is:

[0028] Pg=H*x

[0029] Where H is Henry's constant, Pa; x is the gas mole fraction solubility, dimensionless; Pg is the partial pressure of the gas, Pa; Henry's constant is the oxygen constant, the temperature is 25°C; O2 dissolved oxygen is 70-90 mg / L;

[0030] The system pressure value is used as the basis for setting the pump operating frequency. The calculation formula is:

[0031]

[0032] Where: P is the system pressure, Pa; Pg is the partial pressure of the gas, Pa; η is the dissolved oxygen efficiency, 90%-95%; k is the outlet pressure loss coefficient, dimensionless 1.1-1.3; γ is the gas partial pressure compensation coefficient under high dissolved oxygen conditions, dimensionless 0.7-1.

[0033] As a further improvement of the present invention, in step S4, the host PLC controls the master station and the frequency converter to communicate using profint;

[0034] In step S6, the water quality parameters include but are not limited to one or more of dissolved oxygen, chemical oxygen demand, and ammonia nitrogen parameters; the water quality monitoring system is set in an area with a radius of 20m with the reoxygenated water body point as the center.

[0035] As a further improvement of the present invention, in step S6, the method for reoxygenating the reoxygenated water body point is as follows: the dissolved oxygen value is pre-set according to the process, the host PLC controls the main station to calculate the range of the target value to control the precise control system PLC substation, controls the opening of the electric valve to adjust the flow of oxygen-enriched water, and reoxygenates each reoxygenated water body point in the water body;

[0036] The processes include: black and odorous water treatment process, river and lake ecological restoration process, pipeline / box culvert / regulating pool deodorization process, ditch sludge remote degradation process, and customized process; different factory operation parameters are set according to different process selections.

[0037] The beneficial effects of the present invention are:

[0038] 1. The PLC control system for gas-dissolved reoxygenation provided by the present invention collects data from various sensors and integrates the process parameters and model parameters input by the touch screen of the main station. The host PLC controls the main station to accurately drive the work of various components and communicates with the oxygen generator PLC substation through Ethernet to control oxygen preparation. This integrated control system can effectively and smoothly produce ultra-nano oxygen-enriched water with a target dissolved oxygen concentration, ensuring that the dissolved oxygen content of the reoxygenated water body reaches the expected ecological restoration effect.

[0039] 2. The PLC control system for aerosol reoxygenation provided by the present invention adopts industrial Ethernet and 5G communication technologies. The host PLC control station is equipped with a touch screen, a switch, a 5G gateway, a data acquisition and electrical control module, and a data exchange cloud platform. The data acquisition and electrical control unit of the main station can accurately collect data from various sensors through analog and Ethernet communication methods. The comprehensive application of these technologies and integrated design enables the system to efficiently and accurately reoxygenate each reoxygenation point in the water body, realizing the intelligent and unmanned operation of the system, greatly improving the reoxygenation efficiency and the automation level of the system.

[0040] 3. The control method of gas-dissolved reoxygenation provided by the present invention accurately calculates the reoxygenation parameters, system pressure and water inlet flow, uses PLC to control the water pump and gas flow, accurately regulates the reoxygenation, and performs feedback regulation through the remote substation of the water quality monitoring system, thereby achieving efficient and accurate reoxygenation and effectively improving the lake water environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A flow chart of the steps of the gas-dissolved reoxygenation control method provided by the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0044] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0045] The present invention provides a PLC control system for gas-dissolved reoxygenation, including a host PLC control main station, a plurality of PLC substations of a precise control system for controlling the flow of oxygen-enriched water, a plurality of remote substations of a water quality monitoring system for collecting water quality parameter data, and a PLC substation of an oxygen production system for controlling the preparation of oxygen-enriched water;

[0046] The host PLC control main station is wirelessly connected to the aforementioned substations respectively, and controls the oxygen production system PLC substation to regulate the preparation of oxygen-enriched water by receiving and processing the water quality parameter data transmitted by the remote substation of the water quality monitoring system, and sends oxygen-enriched water flow parameter adjustment and control signals to the precise control system PLC substation, so as to realize precise aerosol reoxygenation at each reoxygenation point in the water body.

[0047] The gas-dissolved reoxygenation device includes a water pump, a frequency converter for driving the water pump, a gas flow mass controller, a reoxygenation system host device, a precision control device, and a water quality monitoring system.

[0048] The host PLC control main station is electrically connected to the frequency converter and is used to control the frequency converter.

[0049] The host PLC control main station is electrically connected to the gas flow mass controller and is used to regulate the gas flow mass controller.

[0050] The host PLC control main station is electrically connected to the reoxygenation system host equipment and is used for regulating the reoxygenation system host equipment.

[0051] The precise control system PLC substation is electrically connected to the precise control equipment and is used to control the flow rate of oxygen-enriched water.

[0052] The water quality monitoring system remote substation is electrically connected to the water quality monitoring system and is used to collect and transmit water quality parameter data.

[0053] The oxygen production system PLC substation is electrically connected to the reoxygenation system host device for regulating the preparation of oxygen-enriched water.

[0054] In some specific embodiments, the PLC control system of aerosol reoxygenation includes a host PLC control main station, a first precision control system PLC substation and a second precision control system PLC substation respectively connected to the host PLC control main station via industrial Ethernet, a first water quality monitoring system remote substation, a second water quality monitoring system remote substation, a third water quality monitoring system remote substation and a fourth water quality monitoring system remote substation respectively communicating with the host PLC control main station via 5G, and an oxygen production system PLC substation communicating with the host PLC control main station via Ethernet.

[0055] The host PLC control master station includes a master station touch screen, a master station switch for providing network connection between various components, a master station 5G gateway for providing wireless connection to the external network, a master station data acquisition and electrical control unit, and a data exchange cloud platform for storing data and performing data analysis.

[0056] The data acquisition and electrical control unit of the master station uses analog quantity and Ethernet communication to collect data from pressure sensors, liquid level sensors, and water inlet electromagnetic flowmeters; uses Ethernet communication to control the frequency converter to drive the water pump; uses Ethernet communication to control the gas flow mass controller to control the balance of the intake air flow, and controls the master station through the host PLC to optimize and correct the PID parameters of the gas flow mass controller.

[0057] The first precision control system PLC substation and the second precision control system PLC substation both include a substation touch screen, a substation switch for providing network connection between various components inside the substation, and a substation data acquisition and electrical control unit; the substation data acquisition and electrical control unit uses analog quantity and Ethernet communication to collect data from the water outlet electromagnetic flowmeter and the electric valve; and uses Ethernet communication to control the opening degree of the electric valve.

[0058] The first water quality monitoring system remote substation, the second water quality monitoring system remote substation, the third water quality monitoring system remote substation and the fourth water quality monitoring system remote substation all include a remote substation 5G gateway and a remote substation data acquisition and electrical control unit; the remote substation data acquisition and electrical control unit all use 485 communication to communicate with the water quality sensor to collect water quality data.

[0059] Example 1

[0060] Based on the above-mentioned PLC control system of gas-dissolved reoxygenation, Example 1 of the present invention provides a control method of gas-dissolved reoxygenation, which mainly includes the following steps:

[0061] S1. Calculate the reoxygenation parameters required for the reoxygenated water body, and write the reoxygenation scale calculation formula into the host PLC control main station and the main station touch screen program, fill the actual measured reoxygenation data into each parameter area of ​​the main station touch screen, and use a holding type memory in the host PLC control main station program to determine the air intake volume of the reoxygenation system host equipment according to the reoxygenation scale;

[0062] The calculation formula for the reoxygenation scale required for the reoxygenated water is:

[0063]

[0064] M=M1+M2+M3

[0065] Where: M is the oxygen demand of water, kg;

[0066] M1 is the oxygen demand of sulfide, kg;

[0067] M2 is the oxygen demand for inhibiting sulfate-reducing bacteria to reduce sulfate, kg;

[0068] M3 is the biological oxygen demand, kg;

[0069] B0 is the five-day biological oxygen demand, mg / L;

[0070] C0 is the raw water sulfide concentration, mg / L;

[0071] V 有效 is the effective volume of water, m3;

[0072] λ is an empirical parameter, dimensionless, 1.0-1.5

[0073] D0 is the dissolved oxygen limit, mg / L;

[0074]

[0075] Where: Q is the reoxygenation scale, Kg / h;

[0076] t is the reoxygenation time, h;

[0077] η is the dissolved oxygen efficiency, dimensionless 90%-95%;

[0078] S2. Calculate the system pressure required by the main equipment of the reoxygenation system. According to Henry's law, under isothermal and isobaric conditions, the solubility of a volatile solute (usually a gas) in a solution is proportional to the equilibrium pressure of the solute on the liquid surface. The calculation formula is:

[0079] Pg=H*x

[0080] Where H is Henry constant, Pa;

[0081] x, is the gas mole fraction solubility, dimensionless;

[0082] Pg is the partial pressure of the gas, Pa;

[0083] The Henry constant is the oxygen constant, the temperature is 25°C, and the O2 dissolved oxygen is 70-90 mg / L;

[0084] The above calculation formula is written into the host PLC control main station and the main station touch screen program. The data is filled into each parameter area of ​​the touch screen through the actual measured pressure data. The host PLC control main station program adopts a holding type memory. The system pressure value can be used as the basis for setting the water pump operating frequency.

[0085]

[0086] Where: P is the system pressure, Pa;

[0087] Pg is the partial pressure of the gas, Pa;

[0088] η is the dissolved oxygen efficiency, 90%-95%;

[0089] k is the outlet pressure loss coefficient; dimensionless 1.1-1.3;

[0090] γ is the gas partial pressure compensation coefficient under high dissolved oxygen conditions; dimensionless 0.7-1;

[0091] S3, calculate the water inlet flow rate required by the main equipment of the reoxygenation system. According to the mole fraction solubility of the x gas in S2 and the reoxygenation scale calculated in step S1, the required water inlet volume can be determined as the basis for setting the operating frequency of the water pump;

[0092] S4. According to the relevant parameters of the water pump, the data value of the performance curve of the water pump is written into the host PLC control main station and the touch screen program of the main station, and the parameters of the water pump are written into the frequency converter, and the range of the water pump operating frequency is determined by inputting the water pump performance parameters, the water inlet flow rate required by the main equipment of the reoxygenation system, and the system pressure required by the main equipment of the reoxygenation system to the host PLC control main station; the host PLC control main station and the frequency converter controlling the water pump adopt profint communication;

[0093] S5. After the relevant parameters are input on the touch screen of the master station, the host PLC controls the master station to control the frequency converter to drive the water pump to pump water to the host equipment, and the host PLC controls the master station to communicate with the oxygen generator PLC substation, and transmits the pressure and purity of the oxygen of the oxygen generator PLC substation and the operating parameters of the oxygen generator to the host PLC control master station. The host PLC controls the master station to control the gas flow quality controller through Ethernet communication to control the intake flow to meet the reoxygenation scale of step S1;

[0094] S6. The oxygen-rich water produced by the main equipment of the reoxygenation system is led to the precise control equipment, which transports the reoxygenated water to the reoxygenated water body point. A water quality monitoring system is set up within a certain range of the water body point. The host PLC controls the water quality parameter indicators transmitted by the main station through each water quality monitoring system remote substation. The precise control system PLC substation reoxygenates each reoxygenation point in the water body. The water quality parameter indicators include dissolved oxygen (DO), chemical oxygen demand (COD), and ammonia nitrogen parameters. The water quality monitoring system is set in an area with a radius of 20m with the reoxygenated water body point as the center.

[0095] The specific method for reoxygenating the reoxygenation point is: pre-setting the dissolved oxygen (DO) value according to the process, the host PLC controls the main station to calculate the range of the target value to control the precise control equipment, and the PLC substation of the precise control system controls the opening of the electric valve to adjust the flow of oxygen-enriched water to accurately reoxygenate each reoxygenation point in the water body.

[0096] The PLC control system for gas-dissolved reoxygenation provided by the present invention also includes a human-machine interface and a process scheme, which are specifically described as follows:

[0097] The human-machine interface is set on the host PLC control master station:

[0098] System login, enter the preset administrator account and password on the human-machine interface login page to obtain administrator operation permissions. You can perform the following operations on the equipment: manual operation, automatic operation, parameter viewing, parameter modification, operation data viewing, operation fault history viewing, operation process viewing, substation system operation and setting, and operation data download.

[0099] Permission settings: according to actual needs, different operation permissions can be set by setting different accounts and passwords. Administrator permissions allow you to perform all operations; engineer permissions allow you to perform operations, modify parameters, and view them; operator permissions allow you to perform operations and view them.

[0100] Main process screen: The main process screen consists of high-efficiency oxygen production system, high and low pressure water inlet systems, ultra-nano aerosol equipment system, precise control system, water quality monitoring system, energy consumption system, etc.

[0101] The operating status of all equipment can be monitored in the main process screen, including whether the equipment is in "local", "remote control", "running", "stopped", "fault", "fully open", "fully closed", "communication status", etc., and the operating parameters of each system can be monitored, including but not limited to the total water inlet flow, water inlet pressure, operating current of each water pump, operating frequency of each water pump, filter blockage, main engine operating pressure, air inlet flow, air inlet pressure, air source pressure, cumulative water inlet flow, cumulative air inlet quality, air inlet mass number, outlet water equivalent dissolved oxygen, outlet water flow of each system, opening of each valve, oxygen production system and other related operating parameters, water quality monitoring system data and other auxiliary system operation conditions.

[0102] Equipment control, manual operation, each water pump in the system can be set for manual operation. During manual operation, it can be started, stopped, and the frequency can be set individually, and the status and operating parameters associated with it can be displayed.

[0103] Each electric valve in the system can be set for manual operation. During manual operation, it can be opened, closed, and the opening degree can be set individually, and the associated status and operating parameters can be displayed.

[0104] The precision control system and oxygen production system can be set to "local control" or "remote control". When in local control, the human-machine interface configured by the substation system is used for operation; when in remote control, the human-machine interface of the main station system is used for operation.

[0105] Automatic operation, select automatic operation on the human-machine interface. The host system automatically runs according to the system process and the set operating parameters, and controls the coordinated operation of each substation equipment. This setting can realize the automatic control of the entire reoxygenation system. The main process screen also includes an alarm and fault handling module, which can display the equipment operation status and fault information in real time for timely processing. The system also has data recording and analysis functions, which can store and analyze operating data to provide data support for optimizing process parameters and improving system operation efficiency. Through the human-machine interface, operators can easily monitor and control the entire reoxygenation system to ensure stable and efficient operation of the system.

[0106] Process solution:

[0107] Process application selection: Depending on the specific situation, the following process applications can be selected in the human-machine interface: black and odorous water treatment process, river and lake ecological restoration process, pipeline / box culvert / regulating tank deodorization process, ditch sludge remote degradation process, and custom parameter process; the system will set preset factory operation parameters according to different process application selections, and related parameters can also be optimized and modified.

[0108] Operation mode selection, according to the specific situation, the following operation modes can be selected in the human-machine interface: Time control mode, you can set the start and stop time of multiple groups of equipment, open during the day and close at night, open in the morning and close at noon, and open at midnight. When setting the time control mode, the priority is higher than other control modes.

[0109] 1. Flow mode: The flow mode can be set in combination with the time control mode. From 9:00 a.m. to 12:00 p.m., the main equipment of the reoxygenation system uses 10 kg / h of oxygen for reoxygenation, and from 12:00 noon to 5:00 p.m., the equipment uses 5 kg / h of oxygen for reoxygenation.

[0110] 2. Concentration mode: The concentration mode can be set in combination with the time control mode. In winter, the equipment operates with an output of 95 mg / L of dissolved oxygen equivalent to reoxygenated water, and in summer, the equipment operates with an output of 70 mg / L of dissolved oxygen equivalent to reoxygenated water.

[0111] 3. Dissolved oxygen mode: According to the water quality dissolved oxygen value feedback device, the corresponding water body dissolved oxygen target value can be set for the main equipment of the reoxygenation system. The water body dissolved oxygen target value is set to 12mg / L. The system will automatically adjust the flow mode and concentration mode of the main equipment of the reoxygenation system in real time according to the difference between the actual value and the target to make the water body close to 12mg / L.

[0112] 4. Precision control mode, configure the substation flow distribution dissolved oxygen precision control system and the remote station water quality monitoring system. The raw water passes through the ultra-nano system to form super-oxygenated water, enters the flow distribution dissolved oxygen precision control system, divides into multiple paths and then connects to the corresponding divided areas of the lake. The corresponding area is equipped with a water quality monitoring floating station, and the corresponding data is fed back to the flow distribution and dissolved oxygen precision control system. The system adjusts the flow of super-oxygenated water in each area according to the relevant parameters. The area that meets the water quality requirements reduces the flow, and the area that does not meet the water quality requirements increases the flow. The dissolved oxygen target values ​​of different points can be set separately. The equipment is set with 8 reoxygenation points and 8 sets of water quality monitoring systems. The target values ​​of the reoxygenation points are all set to 12mg / L. After the equipment has been running for a period of time, the dissolved oxygen at some points exceeds 12mg / L, and some points are lower. The equipment automatically adjusts the reoxygenation capacity (flow value) of each point. The system ensures that the efficiency of improving water quality is accelerated when the flow of each area is balanced, and ensures that the flow of each area of ​​the control system does not affect the system balance of the ultra-nano equipment after the flow changes.

[0113] 5. Customized mode: Customize a reasonable operation mode according to the specific project. When the outlet box culvert is under treatment, different waters will be reoxygenated on sunny and rainy days. At this time, it is necessary to set the sunny and rainy day mode. Through the precise control system, the system will switch to different reoxygenation points for reoxygenation on sunny and rainy days.

[0114] Parameter setting: the parameters of each system can be set and viewed in the human-machine interface, including general parameters and process parameters.

[0115] Inlet flow, including: range setting, upper limit setting, lower limit setting, delayed sampling, pump blockage flow, filter blockage flow, fault shutdown flow, etc.

[0116] Water pump settings: upper limit operating frequency, lower limit operating frequency, upper limit current, etc.

[0117] Water inlet pressure setting: range setting, lower pressure limit, upper pressure limit, fault shutdown pressure, filter blockage pressure, etc.

[0118] Inlet pressure: range setting, upper pressure limit, lower pressure limit, fault shutdown pressure, filter blockage pressure, etc.

[0119] Inlet flow: range setting, flow setting, daily cumulative flow, fault shutdown setting, etc.

[0120] Main machine pressure: range setting, pressure range setting, fault shutdown pressure, unloading pressure, etc.

[0121] Oxygen production system: substation parameter settings (including purity, air pressure, flow, etc.).

[0122] Precision control system: substation parameter settings (including flow, opening, quantity, etc.).

[0123] Water quality monitoring system: main station display and calculation range setting, upper and lower limit setting, fault value setting.

[0124] Operation mode parameter settings: time control mode (including time setting, etc.), flow mode (including time control setting, flow setting, etc.), concentration mode (including time control setting, equivalent dissolved oxygen setting), dissolved oxygen mode (including dissolved oxygen target setting, PID-related parameter setting), precise control mode (including point setting, target value setting, precise adjustment substation setting).

[0125] Other process calculation related parameter settings.

[0126] Fault alarm: the system can automatically execute fault alarm, and can execute warning and shutdown according to the set value.

[0127] Including: pressure alarm, flow alarm, blockage alarm, inverter fault alarm (water pump), communication fault alarm, valve fault alarm, system fault alarm, water quality parameter alarm, oxygen production system alarm, control system alarm, etc.

[0128] The alarm can be cleared manually or automatically, and the alarm is recorded in detail in the alarm table.

[0129] The alarm can be set up by different roles and cooperate with the 4G gateway to push alarm information to each role (including WeChat push, SMS push, voice call push, etc.).

[0130] Data reports include relevant parameter records, process parameter records, water quality parameter records, trend charts, etc. in system operation. Mainly include: daily water inlet flow statistics, daily power consumption statistics, water inlet pressure, flow trend chart, daily air inlet flow statistics, air inlet pressure, flow trend chart, power on / off records, host pressure trend chart and historical statistics, system reoxygenation volume, effluent equivalent dissolved oxygen statistics, precise control system switching action statistics, flow statistics of each reoxygenation point, operation records, etc., real-time viewing and downloading of data reports for analysis.

[0131] Such settings can facilitate operators to select process applications, operating modes, parameter settings and fault alarms, ensuring that the system operates stably according to the preset process flow and parameters. The data report function provides detailed data records and trend analysis during system operation, which helps operators to understand the system operation status in a timely manner and adjust and optimize the operating parameters. Through the alarm push function of the 4G gateway, real-time notification of key information can be achieved to ensure a quick response when problems arise. Through such settings, the efficient and stable operation of the reoxygenation system can be ensured to achieve the expected water environment management effect.

[0132] In summary, the present invention provides a PLC control system and control method for gas-dissolved reoxygenation. The system includes a host PLC control main station, several precision control system PLC substations, several water quality monitoring system remote substations and oxygen production system PLC substations. The control method includes the following steps: calculating the required reoxygenation parameters, system pressure and water inlet flow, setting the water pump operating frequency, using PLC to control the water pump and gas flow, achieving precise control of reoxygenation, and feedback control through the water quality monitoring system remote substation, thereby achieving efficient and accurate reoxygenation. Through integrated control, precise data acquisition, parameter optimization and efficient substation control, intelligent, unmanned, efficient oxygen-rich water production and precise reoxygenation are realized, improving the water quality and ecological environment of the lake.

[0133] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A PLC control system for gas-dissolved reoxygenation, characterized in that: It includes a host PLC control main station, several PLC substations of the precise control system for controlling the flow of oxygen-enriched water, several remote substations of the water quality monitoring system for collecting water quality parameter data, and a PLC substation of the oxygen production system for regulating the preparation of oxygen-enriched water; The host PLC control main station is electrically connected to the aforementioned substations, respectively, and controls the oxygen production system PLC substation to regulate the preparation of oxygen-enriched water by receiving and processing the water quality parameter data transmitted by the remote substation of the water quality monitoring system, and sends oxygen-enriched water flow parameter adjustment and control signals to the precise control system PLC substation, so as to realize precise aerosol reoxygenation at each reoxygenation point in the water body.

2. The PLC control system for gas-dissolved reoxygenation according to claim 1, characterized in that: The host PLC control master station includes a master station touch screen, a master station switch, a master station data acquisition and electrical control unit, and a data exchange cloud platform; The water quality parameter data of the remote substation of the water quality monitoring system is transmitted and stored in the data exchange cloud platform, and the data exchange cloud platform further sends the processed data to the host PLC control main station.

3. The PLC control system for gas-dissolved reoxygenation according to claim 2 is characterized in that: The data acquisition and electrical control unit of the master station collects data from the pressure sensor, liquid level sensor, and water inlet electromagnetic flowmeter using analog and Ethernet communication methods; controls the frequency converter to drive the water pump using Ethernet communication, and controls the gas flow mass controller to control the balance of the intake air flow; further, the host PLC controls the master station to optimize and correct the PID parameters of the gas flow mass controller.

4. The PLC control system for gas-dissolved reoxygenation according to claim 1 is characterized in that: The PLC substation of the precise control system includes a substation touch screen, a substation switch, and a substation data acquisition and electrical control unit; the substation data acquisition and electrical control unit uses analog quantity and Ethernet communication to collect data from the water outlet electromagnetic flow meter and the electric valve; and uses Ethernet communication to control the opening degree of the electric valve.

5. The PLC control system for gas-dissolved reoxygenation according to claim 1 is characterized in that: The water quality monitoring system remote substation includes a remote substation gateway, a remote substation data acquisition and electrical control unit; The remote substation data acquisition and electrical control unit is wirelessly connected to the water quality sensor to collect various water quality parameter data.

6. A method for controlling gaseous reoxygenation, characterized in that: The PLC control system of the gas-dissolved reoxygenation according to any one of claims 1 to 5 is used for control, comprising the following steps: S1. Calculate the reoxygenation parameters required for the reoxygenated water body, input the reoxygenation scale calculation formula and the actual measured reoxygenation data into the host PLC control main station, and determine the air intake volume of the host equipment of the reoxygenation system according to the reoxygenation scale; S2. Calculate the system pressure required by the main equipment of the reoxygenation system, and input the system pressure calculation formula and the actual measured pressure data into the host PLC control main station; S3. Calculate the water inlet flow required for the main equipment of the reoxygenation system based on the system pressure data and the reoxygenation scale; S4, input the performance parameters of the water pump into the host PLC control main station, and determine the range of the water pump operating frequency according to the water pump performance parameters, system pressure, and water inlet flow; S5, the host PLC controls the main station to control the frequency converter to drive the water pump to pump water to the main equipment of the reoxygenation system, and the host PLC controls the main station to control the gas flow quality controller according to the parameter data of the oxygen production system PLC substation, thereby adjusting the intake flow to meet the reoxygenation scale of step S1; S6. The remote substation of the water quality monitoring system set up within a certain range of the reoxygenation water body transmits the water quality parameter data to the host PLC control main station. The oxygen-enriched water produced by the main equipment of the reoxygenation system is led to the precise control equipment. The PLC substation of the precise control system controls the opening of the electric valve of the precise control equipment to adjust the flow of oxygen-enriched water and transports the reoxygenated water to the reoxygenation water body for reoxygenation.

7. The method for controlling gaseous reoxygenation according to claim 6, characterized in that: In step S1, the calculation formula for the reoxygenation scale required for the reoxygenated water body is: M=M1+M2+M3 Where: M is the oxygen demand of water, kg; M1 is the oxygen demand of sulfide, kg; M2 is the oxygen demand of sulfate-reducing bacteria, kg; M3 is the oxygen demand of inhibited organisms, kg; B0 is the five-day biological oxygen demand, mg / L; C0 is the sulfide concentration of raw water, mg / L; V 有效 is the effective volume of the water body, m3; λ is an empirical parameter, dimensionless, 1.0-1.5; D0 is the dissolved oxygen limit, mg / L; Wherein: Q is the reoxygenation scale, Kg / h; t is the reoxygenation time, h; η is the dissolved oxygen efficiency, dimensionless 90%-95%.

8. The method for controlling gaseous reoxygenation according to claim 6, characterized in that: In step S2, according to Henry's law, under isothermal and isobaric conditions, the solubility of a certain volatile solute in a solution is proportional to the equilibrium pressure of the solute on the liquid surface, and the calculation formula is: Pg=H*x Where H is Henry's constant, Pa; x is the gas mole fraction solubility, dimensionless; Pg is the partial pressure of the gas, Pa; Henry's constant is the oxygen constant, the temperature is 25°C, and the O2 dissolved oxygen is 70-90 mg / L; The system pressure value is used as the basis for setting the pump operating frequency. The calculation formula is: Where: P is the system pressure, Pa; Pg is the partial pressure of the gas, Pa; η is the dissolved oxygen efficiency, 90%-95%; k is the outlet pressure loss coefficient, dimensionless 1.1-1.3; γ is the gas partial pressure compensation coefficient under high dissolved oxygen conditions, dimensionless 0.7-1.

9. The method for controlling gas-dissolved reoxygenation according to claim 6, characterized in that: In step S4, the host PLC controls the master station to communicate with the frequency converter using profint; In step S6, the water quality parameters include but are not limited to one or more of dissolved oxygen, chemical oxygen demand, and ammonia nitrogen parameters; the water quality monitoring system is set in an area with a radius of 20m with the reoxygenation water body point as the center.

10. The method for controlling gas-dissolved reoxygenation according to claim 6, characterized in that: In step S6, the method for reoxygenating the reoxygenated water body point is as follows: the dissolved oxygen value is pre-set according to the process, the host PLC controls the main station to calculate the range of the target value to control the precise control system PLC substation, controls the opening of the electric valve to adjust the flow of oxygen-enriched water, and reoxygenates each reoxygenated water body point in the water body; The processes include: black and odorous water treatment process, river and lake ecological restoration process, pipeline / box culvert / regulating pool deodorization process, ditch sludge remote degradation process, and customized process; According to different process selections, different factory operation parameters are set.

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