A control system for automatic discharge modification of power generation boiler

Abstract

The present invention relates to an automatic fixed-discharge transformation control system for a power generation boiler, and belongs to the field of automation technology. The system comprises a PLC cabinet, a front water-cooled wall header, a rear water-cooled wall header, a left water-cooled wall header, a right water-cooled wall header, a sewage electric gate valve, a sewage pipeline, an economizer, a sewage stop valve, a centralized sewage pipeline and a touch screen; the front water-cooled wall header, the left water-cooled wall header, the rear water-cooled wall header and the right water-cooled wall header are sequentially connected through water-cooled pipe wall pipelines to form a loop; two sewage stop valves are connected in series in each way of the water-cooled pipe wall pipeline, which are respectively a primary sewage stop valve and a secondary sewage stop valve; the primary sewage stop valve is a manual stop valve, and the secondary sewage stop valve is an electric stop valve; according to the set parameters, regular quantitative and sequential sewage discharge is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of automation and relates to an automatic setting and discharging transformation control system for a power generation boiler. Background Art

[0002] At present, there are many boiler continuous discharge control systems developed and applied in China. The technical development of boiler fixed discharge automatic control system is slow due to the difficulty in selecting control parameters and investment problems. Boiler fixed discharge is still mainly based on manual operation of manual valves, which is time-consuming and labor-intensive, requires the cooperation of many people, and has operational safety hazards, including:

[0003] (1) Current status and characteristics of sewage discharge

[0004] After desalination, the boiler feed water still contains some calcium, magnesium and other components that have not been completely desalted, which will form flocculent precipitation and water slag in the boiler. As the boiler water evaporates, the concentration of impurities continues to increase, causing scaling on the heating surface and affecting the heat exchange effect. Therefore. The boiler must be discharged regularly, but the boiler discharge rate and the discharge operation method will affect the boiler discharge effect. At present, the sewage is discharged manually once every 24 hours, and the on-site operators and DCS boiler monitoring cooperate with each other during the discharge. The differences in each employee's operating time and operating method and improper personnel cooperation often cause sharp fluctuations in the boiler water level, affecting the normal operation of the boiler and affecting the boiler's thermal efficiency.

[0005] (2) Methods of regular sewage discharge

[0006] The lower sewage outlet of the lower header of the water-cooled wall, the pipeline leads to a double set of series stop valves to the regular sewage expansion equipment, each boiler lower header and economizer sewage valve, 3# boiler 12 (8 lower header sewage valves, 3 economizer sewage valves), 4# boiler 12 (8 lower header sewage valves, 3 economizer sewage valves), 5# boiler 12 (8 lower header sewage valves, 3 economizer sewage valves), a total of 36 sewage valves. Manual sewage discharge time: 30 minutes / boiler, 8 lower header sewage valves 1 day / time. The opening requirement of the 1 to 8 valves of the lower header sewage discharge is symmetrical sewage discharge. The 4 sewage valves of the economizer are 3 days / time. It is not allowed to open more than two sewage valves at the same time. At present, it basically relies on manual operation, with low automation and low labor efficiency. On-site operation is time-consuming and labor-intensive, and it is difficult to accurately control the discharge time, resulting in large heat losses. The discharge time is difficult to accurately grasp, and the boiler discharge effect cannot be effectively guaranteed. Summary of the invention

[0007] In view of this, an object of the present invention is to provide a power generation boiler automatic scheduling modification control system to solve the above-mentioned problems.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] An automatic fixed-discharge transformation control system for a power generation boiler, the system comprising a PLC cabinet, a front water-cooled wall header, a rear water-cooled wall header, a left water-cooled wall header, a right water-cooled wall header, a sewage electric gate valve, a sewage pipeline, an economizer, a sewage stop valve, a centralized sewage pipeline and a touch screen;

[0010] The front water-cooled wall header, the left water-cooled wall header, the rear water-cooled wall header and the right water-cooled wall header are connected in sequence through water-cooled pipe wall pipelines to form a loop;

[0011] The water-cooled pipe wall pipeline has two sewage stop valves connected in series on each route, which are a primary sewage stop valve and a secondary sewage stop valve;

[0012] The primary sewage shut-off valve is a manual shut-off valve, and the secondary sewage shut-off valve is an electric shut-off valve;

[0013] The sewage discharge is regulated by a sewage stop valve arranged on the sewage pipeline between the water-cooled pipe wall pipeline and the centralized sewage pipeline;

[0014] The sewage discharge is regulated by a sewage stop valve arranged on the sewage pipeline between the economizer and the centralized sewage pipeline;

[0015] The economizer is independent of the water-cooled tube wall pipeline;

[0016] The front water-cooled wall header, the left water-cooled wall header, the rear water-cooled wall header, the right water-cooled wall header and the economizer are provided with 12 electric stop valves: electric stop valve 1 to electric stop valve 12;

[0017] The electric stop valve is connected to the PLC cabinet signal;

[0018] The touch screen is connected to the PLC cabinet signal;

[0019] The electric stop valve is connected to the live wire U and the neutral wire N;

[0020] The electric stop valve 2 is connected to the live wire U and the neutral wire N;

[0021] The electric stop valve is connected to the live wire U and the neutral wire N;

[0022] The electric stop valve 4 is connected to the live wire U and the neutral wire N;

[0023] The electric stop valve 5 is connected to the live wire V and the neutral wire N;

[0024] The electric stop valve 6 is connected to the live wire V and the neutral wire N;

[0025] The electric stop valve 7 is connected to the live wire V and the neutral wire N;

[0026] The electric stop valve B is connected to the live wire V and the neutral wire N;

[0027] The electric stop valve 9 is connected to the live wire W and the neutral wire N;

[0028] The electric stop valve is connected to the live wire W and the neutral wire N;

[0029] The electric stop valve 11 is connected to the live wire W and the neutral wire N;

[0030] The electric stop valve 12 is connected to the live wire W and the neutral wire N;

[0031] The modified control system further includes a surge protector, which is connected to a live wire U, a live wire V, a live wire W and a neutral wire N;

[0032] The modified control system also includes a switching power supply, which is connected to a live wire U and a neutral wire N;

[0033] The modified control system also includes a PLC power supply for supplying power to the PLC cabinet, and the PLC power supply is connected to the live wire U and the neutral wire N;

[0034] The modified control system also includes a touch screen power supply for supplying power to the touch screen, and the touch screen power supply is connected to the live wire U and the neutral wire N;

[0035] The modified control system also includes a module power supply, which is connected to a live wire U and a neutral wire N;

[0036] The electric stop valve has 2 digital output DO signals, 6 digital input DI signals, interlocking signal, AI analog 4-20mA signal and fan status signal;

[0037] Among them, the two DO signals include valve opening signal and valve closing signal;

[0038] 6 DI signals include open position signal, close position signal, open over torque signal, close over torque signal, fault signal and remote signal;

[0039] The AI ​​simulates a 4-20mA signal as a drum liquid level signal, and the full scale of the liquid level is 20mA, which indicates the type of card, and the full scale of the liquid level is 20mA;

[0040] The relationship between the drum liquid level and the blowdown stop valve is: when the liquid level is lower than 36% of the liquid level, all electric blowdown stop valves are closed; when the blowdown stop valve is fully opened or a fault signal or over-torque signal is issued, all electric blowdown stop valves are closed;

[0041] Remote signal means there is a switch on site, which can be controlled on site;

[0042] All signals are transmitted to PLC for sewage control;

[0043] The sewage control is divided into the following five parts:

[0044] (1) Automatic program

[0045] The automatic program enters the start state after the PLC is powered on. To execute the boiler scheduled discharge, the equipment must first enter the automatic execution permission state; if the process requirements are met, the system has no total faults, no emergency stop button is triggered, all valves are in remote state, and all valves are selected as automatic state on the touch screen, the program considers that the system has entered the automatic program execution permission state; if the conditions are not met at any time during system operation, the system will exit the automatic program;

[0046] (2) Automatic cycle program of electric stop valve 1 to electric stop valve 8

[0047] When the automatic program is allowed to execute, manually press the automatic cycle button of electric stop valve 1 to electric stop valve 8, and the button light will light up; after pressing, the program will enter the automatic cycle logic of electric stop valve 1 to electric stop valve 8; electric stop valve 1 will automatically open, and after opening to the full extent, it will automatically close after a time delay, and after closing to the full extent, it will automatically open electric stop valve 2 after a time delay, and then complete the process in sequence until 8# valve is closed and then electric stop valve 1 is opened, and the cycle is executed; when it is necessary to stop, press the automatic cycle button of electric stop valve 1 to electric stop valve 8 again, the button light will go out, and the program will close all valves;

[0048] (3) Automatic cycle program of electric stop valve 1 to electric stop valve 12

[0049] When the automatic program is allowed to be executed, manually press the automatic cycle button of electric stop valve 1 to electric stop valve 12, and the button light will light up; after pressing it, the program will enter the automatic cycle logic of electric stop valve 1 to electric stop valve 12; electric stop valve 1 will automatically open, and after opening to the full extent, it will automatically close with an interval delay, and after closing to the full extent, it will automatically open electric stop valve 2 with an interval delay, and then complete the process until electric stop valve 12 is closed and then electric stop valve 1 is opened, and the cycle will be executed; when it is necessary to stop, press the automatic cycle button of electric stop valve 1 to electric stop valve 12 again, the button light will go out, and the program will close all valves;

[0050] (4) Fault judgment logic

[0051] The system monitors the status of fault points in real time during operation. Any abnormality at any point will trigger a total fault. There are 12 valve over-torque fault points, 24 valve switch timeout fault points, 1 liquid level lower than the set value fault point, and 1 fan non-operation fault point in the system. After the total fault is triggered, the system leaves the automatic cycle working mode.

[0052] (5) Automatic valve closing protection operation under fault and emergency stop conditions

[0053] The total fault and emergency stop signals are abnormal signals of the system. When any of the two signals is triggered, the system will enter the valve closing protection logic, first exit the automatic circulation logic, and close all valves at the same time to prevent steam leakage.

[0054] Optionally, the centralized sewage pipeline model is The model of sewage stop valve is DN25 6.3MPa.

[0055] Optionally, the electric stop valve 1 to the electric stop valve 12 receive a valve opening instruction and a valve closing instruction;

[0056] The valve opening command is executed by a one-touch start button to execute the PLC internal program cycle. When the opening command is issued, the sewage stop valve is implemented. The PLC receives the feedback signal and issues the valve closing command according to the preset time. The signal time is received at the opening position and the closing position to prevent over-delay or closing delay.

[0057] There are 12 electric stop valves in the system, and a valve control block is called to complete the switch control of a single valve; A / M is the manual and automatic state of the valve, DI_Remote / local is the remote state feedback signal of the on-site valve, DI_Fault is the on-site valve over-torque feedback signal, DI_open_position is the on-site valve open position feedback signal, DI_close_position is the on-site valve closed position feedback signal, open is the manual valve opening command, close is the manual valve closing command, Auto_open is the automatic valve opening command, Auto_close is the automatic valve closing command, DQ_open is the valve opening output,

[0058] DQ_close is the valve closing output; when the external signal has no over-torque and is in the remote state, the PLC program controls the valve opening and closing through the valve opening and closing output; when the A / M signal is 1, it means that the manual mode controls the valve opening and closing through the manual valve opening and closing command, and when the A / M signal is 0, it means that the automatic mode controls the valve opening and closing through the automatic valve opening and closing command; introduce the valve opening and closing time, open_time is the valve opening time, open_time_set is the maximum setting time when the valve is open output, when the valve opening time is greater than the maximum setting time, the program determines the valve opening timeout fault open_fault, similarly close_time is the valve closing time, close_time_set is the maximum setting time when the valve is closed output, when the valve closing time is greater than the maximum setting time, the program determines the valve closing timeout fault close_fault, any one of the valve opening and closing timeout fault and the valve over-torque fault triggers the valve fault fault output;

[0059] The automatic operation conditions are that there is no total system failure, no emergency stop button is triggered, all valves are in remote state, and all valves are selected as automatic state on the touch screen;

[0060] After the system starts the automatic cycle logic, it first triggers the first position to start the automatic operation; the program uses the displacement transfer instruction to complete the transfer of each step;

[0061] Each time the valve is switched into place, the displacement instruction is executed and the next logic is entered;

[0062] After the automatic opening instruction of the electric stop valve 1 is set, wait for the valve opening signal of the electric stop valve 1, close the automatic opening instruction after the interval delay, open the automatic closing instruction, and so on until the last valve is closed and then jump back to the opening of the electric stop valve 1 to complete a large cycle;

[0063] Fault judgment: There are 12 single valve faults in total, and any one of them can trigger a total fault;

[0064] There are 12 single valve over-torque faults in total, and any one of them triggers the total fault;

[0065] The boiler liquid level is less than the set value and there is no fan running signal, which triggers a general fault.

[0066] Optionally, the electric stop valve 1 to the electric stop valve 12 are also connected to a valve opening indicator light and a valve closing indicator light, respectively.

[0067] Optionally, the electric stop valve 1 to the electric stop valve 12 are also respectively connected to automatic sewage discharge indicator lights.

[0068] Optionally, the modified control system also includes a remote indicator light and a fault indicator light.

[0069] Optionally, the electric stop valve 1 to the electric stop valve 12 are also respectively connected to an open position signal light, a closed position signal light, an open torque signal light, a closed torque signal light, a fault signal light and a remote signal light.

[0070] Optionally, the modified control system further comprises a socket, and the socket is connected to a live wire U and a neutral wire N;

[0071] The modified control system also includes a switching power supply, which is connected to a live wire U and a neutral wire N;

[0072] The modified control system also includes a backup power supply, which is connected to the live wire U and the neutral wire N;

[0073] The PLC cabinet also includes an in-cabinet lighting fan, which is connected to a live wire U and a neutral wire N.

[0074] The beneficial effect of the present invention is that regular, quantitative and sequential sewage discharge is achieved according to set parameters.

[0075] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0077] Figure 1 This is a schematic diagram of the sewage pipelines of 3#, 4# and 5# boilers before the transformation of the present invention;

[0078] Figure 2 This is a schematic diagram of the sewage pipeline after the transformation of the present invention;

[0079] Figure 3 It is the PLC principle diagram of the present invention;

[0080] Figure 4 The boiler system of the present invention Figure 1 ;

[0081] Figure 5 The boiler system of the present invention Figure 2 ;

[0082] Figure 6 The boiler system of the present invention Figure 3 ;

[0083] Figure 7 It is the configuration diagram of the boiler PLC system in the present invention;

[0084] Figure 8 This is the wiring diagram of the boiler touch screen in the present invention;

[0085] Fig. 9 This is the wiring diagram of the boiler analog input module in the present invention;

[0086] Fig.10 Wiring the boiler digital output module in this invention Figure 1 ;

[0087] Fig.11 Wiring the boiler digital output module in this invention Figure 2 ;

[0088] Fig.12 Wiring the boiler digital output module in this invention Figure 3 ;

[0089] Fig.13 Wiring the boiler digital output module in this invention Figure 4 ;

[0090] Fig.14 Wiring the boiler digital input module in this invention Figure 1 ;

[0091] Fig.15 Wiring the Boiler Digital Input Module in the Invention Figure 2 ;

[0092] Fig.16 Wiring the boiler digital input module in this invention Figure 3 ;

[0093] Fig.17 It is the sewage discharge control flow chart of the present invention;

[0094] Fig.18 This is a logic diagram of the valve control block;

[0095] Fig.19 It is a logic diagram of the automatic permission condition program;

[0096] Fig. 20 It is the logic diagram of shift instruction in valve cycle logic;

[0097] Fig.21 This is the logic diagram of the 1# valve opening delay to the shift instruction in the valve cycle logic;

[0098] Fig. 22 This is the logic diagram of the 1# valve opening signal in the valve cycle logic;

[0099] Fig.23 This is a diagram illustrating the fault judgment logic;

[0100] Fig.24 It is the logic diagram of the total valve fault triggered by any valve over-torque alarm in the fault judgment logic;

[0101] Fig.25 This is the logic diagram of the fault judgment logic in which the boiler liquid level is less than the set value triggering a total fault and the wind operation signal is lost triggering a total fault. DETAILED DESCRIPTION

[0102] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0103] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0104] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0105] (I) Technical characteristics, key technologies and key processes

[0106] Before the transformation: The initial process flow is that each boiler is divided into 4 lower water-cooled wall headers and 12 sewage pipes of the economizer are all led to the sewage main pipeline nearby. Two stop valves DN25 6.3MPa are connected in series for each circuit. Figure 1 The figure shows the schematic diagram of the sewage pipeline before the transformation.

[0107] (II) Specific content of transformation implementation

[0108] (1) Hardware:

[0109] ① Before the renovation, the water-cooled pipe wall pipelines were all controlled by manual stop valves, and two stop valves were connected in series in each route. The renovation content is: the secondary sewage stop valve in each of the two sewage stop valves is changed to an electric stop valve, the valve diameter and parameters remain unchanged, and the type is changed to a stop valve. The primary sewage stop valve remains unchanged. Figure 2 shown.

[0110] ② The 12 sewage pipelines of the 3# boiler remain in their original positions. Since there is no installation position for the electric valve, only the valves need to be properly moved. The pipelines, stop valves and gate valves of the 4# and 5# boilers are re-arranged in a unified manner.

[0111] ③Three sets of PLC cabinets are installed on site to facilitate tracking and monitoring during on-site operation.

[0112] (2) Specific content of implementation, PLC system logic program design:

[0113] Function 1: On-site startup.

[0114] Function 2: Control modes include automatic / interlocking / manual.

[0115] Manual mode: Click the 1#~12# start button to select the start valve opening according to the order of demand, but the execution time of the closed valve is determined by the PLC internal program time to automatically close. The best setting of the opening and closing time of each electric control stop valve and the best operation order are gradually adjusted according to the boiler liquid level setting and sewage discharge during the debugging process.

[0116] Automatic mode: directly click the start button (clicking the 1#~12# buttons is invalid at this time), start the 1#~12# electric stop valves in sequence according to the preset program inside the PLC, and determine the closing time of the electric stop valves according to the preset time program.

[0117] Interlocking mode: directly click the start button (clicking the 1#~12# buttons is invalid at this time), start the 1#~12# electric stop valves in sequence according to the preset program inside the PLC, and determine the closing time of the electric stop valves according to the preset time program. At the same time, when the program is running, all stop valves, regardless of whether they are open or not, will be automatically closed when the DCS boiler drum liquid level low alarm signal is output to the PLC. And the program is automatically in a stopped state. Clicking the start button at this time is invalid.

[0118] Function 3: Emergency stop. When an abnormality occurs during operation or is found on site, click the emergency stop button. All electric gate valves in the program will be closed regardless of manual or automatic operation.

[0119] PLC principle Figure 3 As shown. 3# boiler, 4# boiler, and 5# boiler each have 1 set of PLC cabinets. Each set of PLC cabinets provides 1 AC380V power supply (three-phase five-wire system). Each set of PLC controls 12 electric stop valves. Each electric stop valve has 2 DO signals (open valve, close valve), 6 DI signals (open position, close position, open torque, close torque, fault, remote). Interlocking signal, 1 AI analog 4~20mA signal (boiler liquid level signal), and 1 DI signal (fan status). The PLC cabinet completes the power supply control circuit of all electric stop valves, with a touch screen, which displays all status information, data recording, alarm recording, and trend recording for more than 3 months.

[0120] Click the one-touch start button, the boiler drum liquid level is normal, 1~8# electric gate valves are closed, and 1# drain valve is opened;

[0121] If the 1# drain valve is open normally and the time set for the 1# drain valve is reached, the 1# drain valve will be closed; if the 1# drain valve is not open, an alarm record will be made;

[0122] If the 1# drain valve is closed normally, then open the 2# drain valve; if the 1# drain valve is not closed, then record an alarm;

[0123] If the 2# drain valve opens normally and reaches the time set for the 2# drain valve, the 2# drain valve will be closed; if the 2# drain valve does not open, an alarm will be recorded;

[0124] If the 2# drain valve is closed normally, then open the 3# drain valve; if the 2# drain valve is not closed, then record an alarm;

[0125] And so on, the cycle returns until the 1# sewage valve is closed.

[0126] like Figures 4 to 16 As shown, each boiler has 1# to 8# blowdown valves in the lower header and 9# to 12# blowdown valves for the economizer. There are 12 for 3# boiler, 12 for 4# boiler and 12 for 5# boiler.

[0127] Valve electric actuator: local / remote conversion knob. When the knob is in the local position, the valve can be operated on the electric actuator. When the knob is in the remote position, the valve can be operated on the PLC cabinet door.

[0128] The PLC cabinet door layout is as follows:

[0129] 1 manual / automatic conversion switch, 12 illuminated buttons for opening valves 1#-12#, 12 illuminated buttons for closing valves 1#-12#, 1 emergency stop button, 1 fault indicator light (fault signal of electric actuators for valves 1#-12#), 1 fault reset button, 1 automatic start button for valves 1#-8#, 1 automatic start button for valves 1#-12#, 1 remote feedback indicator light (electric actuators for valves 1#-12# are all in remote state), and 2 standby buttons.

[0130] The specific operations of remote PLC cabinet are as follows:

[0131] (1) In manual mode:

[0132] The conversion switch is selected as manual, the remote feedback indicator light is on, and there is no fault signal. You can select the 1#~12# valve open or close button to control a valve separately.

[0133] (2) In automatic mode:

[0134] The conversion switch is set to automatic, the remote feedback indicator light is on, there is no fault signal, the liquid level signal sent by DCS is normal [can be set], the fan status signal sent by DCS is normal, press the "1#-8# valve automatic start" button, the PLC program starts 1#~8# electric valves in turn, 1# valve opens, after opening to the full extent (the 1# valve opening signal is displayed on the touch screen), it stops for 1s, the program executes the 1# valve closing instruction, after the 1# valve is fully closed (the 1# valve closing signal is displayed on the touch screen), it stops for 1min [time adjustable]. Execute the 2# valve opening / closing instruction, the process is the same as 1# valve, and the cycle is executed until the 12# valve ends. Press the "1#-12# valve automatic start" button, the execution process is the same as 1#-8# valve.

[0135] If the valve takes more than 15 seconds [adjustable time] during the opening command process and the valve opening signal is not received, the program determines that the valve is faulty and the valve is closed immediately. The valve fault signal is displayed on the touch screen.

[0136] Interlocking conditions: After the boiler drum liquid level low alarm signal is output to this PLC system or the fan stop signal is sent to the PLC, the PLC will automatically close all valves when executing the automatic program. And all programs are in the stop state. At this time, in the manual / automatic state, clicking any "start" button is invalid. It is not allowed to open two or more sewage valves at the same time.

[0137] Emergency stop function: When an abnormality occurs or is found during valve operation, press the "red emergency stop button". Regardless of manual / automatic operation mode, the program will cut off the output signals of all electric gate valves, causing all electric valves to close immediately.

[0138] like Fig.17 As shown, sewage control includes the following five parts:

[0139] (1) Conditions for automatic program execution

[0140] The automatic program enters the start state after the PLC is powered on. To execute the boiler scheduled discharge, the equipment must first enter the automatic execution state. According to the process requirements, the system has no total faults, no emergency stop button is triggered, all valves are in remote state, and all valves are selected as automatic state on the touch screen. If the above conditions are met, the program considers that the system has entered the automatic program execution state. How to exit the automatic program execution state when the conditions are not met during system operation.

[0141] (2) Automatic cycle program of valve #1-8

[0142] When the automatic program is allowed to execute, manually press the 1-8# valve automatic cycle button, and the button light will light up. After pressing, the program will enter the 1-8# valve automatic cycle logic. Start from 1# valve and open it automatically. After opening it completely, it will automatically close after the interval delay. After closing it completely, it will automatically open 2# valve after the interval delay. Then, it will be completed in sequence until 8# valve is closed and then 1# valve is opened. The cycle will be executed. If you need to stop, press the 1-8# valve automatic cycle button again, the button light will go out, and the program will close all valves.

[0143] (3) Automatic cycle program of valve #1-12

[0144] When the automatic program is allowed to execute, manually press the 1-12# valve automatic cycle button, and the button light will light up. After pressing, the program will enter the 1-12# valve automatic cycle logic. Start from 1# valve and open it automatically. After opening it to the full extent, it will automatically close after the interval delay. After closing it to the full extent, it will automatically open 2# valve after the interval delay. Then, it will be completed in sequence until 12# valve is closed and then 1# valve is opened. The cycle will be executed. If you need to stop, press the 1-12# valve automatic cycle button again, the button light will go out, and the program will close all valves.

[0145] (4) Fault judgment logic

[0146] The system monitors the status of fault points in real time during operation. Any abnormality at any point will trigger a general fault. In this system, there are 12 valve over-torque fault points, 24 valve switch timeout fault points, one liquid level below the set value fault point, and one fan non-operation fault point. After the general fault is triggered, the system leaves the automatic cycle working mode.

[0147] (5) Automatic valve closing protection operation under fault and emergency stop conditions

[0148] The total fault and emergency stop signals are abnormal signals of the system. When any of the two signals is triggered, the system will enter the valve closing protection logic, first exit the automatic circulation logic, and close all valves at the same time to prevent steam leakage.

[0149] 1. Valve control block description

[0150] like Fig.18 As shown, this system has 12 electric switch valves, and a valve control block is called to complete the switch control of a single valve. A / M is the manual and automatic state of the valve, DI_Remote / local is the remote state feedback signal of the on-site valve, DI_Fault is the on-site valve over-torque feedback signal, DI_open_position is the on-site valve open position feedback signal, DI_close_position is the on-site valve closed position feedback signal, open is the manual valve opening command, close is the manual valve closing command, Auto_open is the automatic valve opening command, Auto_close is the automatic valve closing command, DQ_open is the valve opening output,

[0151] DQ_close is the valve closing output. When the external signal has no over-torque and is in remote state, the PLC program can control the valve opening and closing through the valve opening and closing output. When the A / M signal is 1, it means that the manual mode can control the valve opening and closing through the manual valve opening and closing command. When the A / M signal is 0, it means that the automatic mode can control the valve opening and closing through the automatic valve opening and closing command. Since the system uses an electric valve, the valve opening and closing requires time. We introduced the valve opening and closing time. Open_time is the valve opening time, and open_time_set is the maximum setting time when the valve is open. When the valve opening time is greater than the maximum setting time, the program determines the valve opening timeout fault open_fault. Similarly, close_time is the valve closing time, and close_time_set is the maximum setting time when the valve is closed. When the valve closing time is greater than the maximum setting time, the program determines the valve closing timeout fault close_fault. Any of the valve opening and closing timeout fault and the valve over-torque fault triggers the valve fault fault output.

[0152] 2. Automatically allow conditional program description

[0153] like Fig.19 As shown, the automatic operation conditions are that there is no total fault in the system, no emergency stop button is triggered, all valves are in remote state, and all valves are selected to automatic state on the touch screen.

[0154] 3. Valve cycle logic description

[0155] like Fig. 20 As shown in the figure, after the system automatically cycles through the logic, it first triggers the automatic start. The program uses displacement transfer instructions to complete the transfer of each step.

[0156] like Fig.21 As shown, each time the valve is switched into place, the displacement instruction is executed and the next logic is entered.

[0157] like Fig. 22 As shown, after the automatic opening instruction of valve #1 is set, it waits for the signal of valve #1 opening to be in place, closes the automatic opening instruction after a time delay, and opens the automatic closing instruction, and so on until the last valve is closed and then jumps back to valve #1 to open, completing a large cycle.

[0158] 4. Fault judgment logic description

[0159] like Fig.23 As shown, there are 12 single valve faults in total, and any one of them can trigger a total fault.

[0160] like Fig.24 As shown, there are 12 single valve over-torque faults, and any one of them triggers the overall fault.

[0161] like Fig.25 As shown, the boiler liquid level is less than the set value and there is no fan running signal, triggering a total fault.

[0162] The present invention can achieve:

[0163] (1) Boiler discharge control: effective, reasonable and orderly automatic classification control of each discharge pipe of the boiler, which can not only ensure the discharge effect, but also reduce the boiler discharge rate and improve the boiler operation efficiency.

[0164] (2) One-button PLC start mode, full automation control.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. 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 solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A control system for automatic setting and transformation of power generation boilers. Features: The system includes a PLC cabinet, a front water-cooled wall header, a rear water-cooled wall header, a left water-cooled wall header, a right water-cooled wall header, a sewage electric gate valve, a sewage pipeline, an economizer, a sewage stop valve, a centralized sewage pipeline and a touch screen; The front water-cooled wall header, the left water-cooled wall header, the rear water-cooled wall header and the right water-cooled wall header are connected in sequence through water-cooled pipe wall pipelines to form a loop; The water-cooled pipe wall pipeline has two sewage stop valves connected in series on each route, which are a primary sewage stop valve and a secondary sewage stop valve; The primary sewage shut-off valve is a manual shut-off valve, and the secondary sewage shut-off valve is an electric shut-off valve; The sewage discharge is regulated by a sewage stop valve arranged on the sewage pipeline between the water-cooled pipe wall pipeline and the centralized sewage pipeline; The sewage discharge is regulated by a sewage stop valve arranged on the sewage pipeline between the economizer and the centralized sewage pipeline; The economizer is independent of the water-cooled tube wall pipeline; The front water-cooled wall header, the left water-cooled wall header, the rear water-cooled wall header, the right water-cooled wall header and the economizer are provided with 12 electric stop valves: electric stop valve 1 to electric stop valve 12; The electric stop valve is connected to the PLC cabinet signal; The touch screen is connected to the PLC cabinet signal; The electric stop valve is connected to the live wire U and the neutral wire N; The electric stop valve 2 is connected to the live wire U and the neutral wire N; The electric stop valve is connected to the live wire U and the neutral wire N; The electric stop valve 4 is connected to the live wire U and the neutral wire N; The electric stop valve 5 is connected to the live wire V and the neutral wire N; The electric stop valve 6 is connected to the live wire V and the neutral wire N; The electric stop valve 7 is connected to the live wire V and the neutral wire N; The electric stop valve B is connected to the live wire V and the neutral wire N; The electric stop valve 9 is connected to the live wire W and the neutral wire N; The electric stop valve is connected to the live wire W and the neutral wire N; The electric stop valve 11 is connected to the live wire W and the neutral wire N; The electric stop valve 12 is connected to the live wire W and the neutral wire N; The modified control system further includes a surge protector, which is connected to a live wire U, a live wire V, a live wire W and a neutral wire N; The modified control system also includes a switching power supply, which is connected to a live wire U and a neutral wire N; The modified control system also includes a PLC power supply for supplying power to the PLC cabinet, and the PLC power supply is connected to the live wire U and the neutral wire N; The modified control system also includes a touch screen power supply for supplying power to the touch screen, and the touch screen power supply is connected to the live wire U and the neutral wire N; The modified control system also includes a module power supply, which is connected to a live wire U and a neutral wire N; The electric stop valve has 2 digital output DO signals, 6 digital input DI signals, interlocking signal, AI analog 4-20mA signal and fan status signal; Among them, the two DO signals include valve opening signal and valve closing signal; 6 DI signals include open position signal, close position signal, open over torque signal, close over torque signal, fault signal and remote signal; The AI ​​simulates a 4-20mA signal as a drum liquid level signal, and the full scale of the liquid level is 20mA, which indicates the type of card, and the full scale of the liquid level is 20mA; The relationship between the drum liquid level and the blowdown stop valve is: when the liquid level is lower than 36% of the liquid level, all electric blowdown stop valves are closed; when the blowdown stop valve is fully opened or a fault signal or over-torque signal is issued, all electric blowdown stop valves are closed; Remote signal means there is a switch on site, which can be controlled on site; All signals are transmitted to PLC for sewage control; The sewage control is divided into the following five parts: (1) Automatic program The automatic program enters the start state after the PLC is powered on. To execute the boiler scheduled discharge, the equipment must first enter the automatic execution permission state; if the process requirements are met, the system has no total faults, no emergency stop button is triggered, all valves are in remote state, and all valves are selected as automatic state on the touch screen, the program considers that the system has entered the automatic program execution permission state; if the conditions are not met at any time during system operation, the system will exit the automatic program; (2) Automatic cycle program of electric stop valve 1 to electric stop valve 8 When the automatic program is allowed to be executed, manually press the automatic cycle button of electric stop valve 1 to electric stop valve 8, and the button light will light up; after pressing, the program will enter the automatic cycle logic of electric stop valve 1 to electric stop valve 8; electric stop valve 1 will automatically open, and after opening to the full extent, it will automatically close after a time delay, and after closing to the full extent, it will automatically open electric stop valve 2 after a time delay, and then complete the process in sequence until 8# valve is closed and then electric stop valve 1 is opened, and the cycle is executed; when it is necessary to stop, press the automatic cycle button of electric stop valve 1 to electric stop valve 8 again, the button light will go out, and the program will close all valves; (3) Automatic cycle program of electric stop valve 1 to electric stop valve 12 When the automatic program is allowed to be executed, manually press the automatic cycle button of electric stop valve 1 to electric stop valve 12, and the button light will light up; after pressing it, the program will enter the automatic cycle logic of electric stop valve 1 to electric stop valve 12; electric stop valve 1 will automatically open, and after opening to the full extent, it will automatically close with an interval delay, and after closing to the full extent, it will automatically open electric stop valve 2 with an interval delay, and then complete the process until electric stop valve 12 is closed and then electric stop valve 1 is opened, and the cycle will be executed; when it is necessary to stop, press the automatic cycle button of electric stop valve 1 to electric stop valve 12 again, the button light will go out, and the program will close all valves; (4) Fault judgment logic The system monitors the status of fault points in real time during operation. Any abnormality at any point will trigger a total fault. There are 12 valve over-torque fault points, 24 valve switch timeout fault points, 1 liquid level lower than the set value fault point, and 1 fan non-operation fault point in the system. After the total fault is triggered, the system leaves the automatic cycle working mode. (5) Automatic valve closing protection operation under fault and emergency stop conditions The total fault and emergency stop signals are abnormal signals of the system. When any of the two signals is triggered, the system will enter the valve closing protection logic, first exit the automatic circulation logic, and close all valves at the same time to prevent steam leakage; The electric stop valve 1 to the electric stop valve 12 receive a valve opening instruction and a valve closing instruction; The valve opening command is executed by a one-touch start button to execute the PLC internal program cycle. When the opening command is issued, the sewage stop valve is implemented. The PLC receives the feedback signal and issues the valve closing command according to the preset time. The signal time is received at the opening position and the closing position to prevent over-delay or closing delay. There are 12 electric stop valves in the system, and a valve control block is called to complete the switch control of a single valve; A / M is the manual and automatic state of the valve, DI_Remote / local is the remote state feedback signal of the on-site valve, DI_Fault is the on-site valve over-torque feedback signal, DI_open_position is the on-site valve open position feedback signal, DI_close_position is the on-site valve closed position feedback signal, open is the manual valve opening command, close is the manual valve closing command, Auto_open is the automatic valve opening command, Auto_close is the automatic valve closing command, DQ_open is the valve opening output, DQ_close is the valve closing output; when the external signal has no over-torque and is in the remote state, the PLC program controls the valve opening and closing through the valve opening and closing output; when the A / M signal is 1, it means that the manual mode controls the valve opening and closing through the manual valve opening and closing command, and when the A / M signal is 0, it means that the automatic mode controls the valve opening and closing through the automatic valve opening and closing command; introduce the valve opening and closing time, open_time is the valve opening time, open_time_set is the maximum setting time when the valve is open output, when the valve opening time is greater than the maximum setting time, the program determines the valve opening timeout fault open_fault, similarly close_time is the valve closing time, close_time_set is the maximum setting time when the valve is closed output, when the valve closing time is greater than the maximum setting time, the program determines the valve closing timeout fault close_fault, any one of the valve opening and closing timeout fault and the valve over-torque fault triggers the valve fault fault output; The automatic operation conditions are that there is no total system failure, no emergency stop button is triggered, all valves are in remote state, and all valves are selected as automatic state on the touch screen; After the system starts the automatic cycle logic, it first triggers the first position to start the automatic operation; the program uses the displacement transfer instruction to complete the transfer of each step; Each time the valve is switched into place, the displacement instruction is executed and the next logic is entered; After the automatic opening instruction of the electric stop valve 1 is set, wait for the valve opening signal of the electric stop valve 1, close the automatic opening instruction after the interval delay, open the automatic closing instruction, and so on until the last valve is closed and then jump back to the opening of the electric stop valve 1 to complete a large cycle; Fault judgment: There are 12 single valve faults in total, and any one of them can trigger a total fault; There are 12 single valve over-torque faults in total, and any one of them triggers the total fault; The boiler liquid level is less than the set value and there is no fan running signal, which triggers a general fault.

2. According to claim 1, a power generation boiler automatic setting and modification control system, Features: The model of the centralized sewage pipeline is The model of sewage stop valve is DN256.3MPa.

3. According to claim 1, a power generation boiler automatic setting and modification control system, Features: The electric stop valve 1 to the electric stop valve 12 are also respectively connected with a valve opening indicator light and a valve closing indicator light.

4. According to claim 1, a power generation boiler automatic setting and modification control system, Features: The electric stop valve 1 to the electric stop valve 12 are also respectively connected with automatic sewage discharge indicator lights.

5. According to claim 4, a power generation boiler automatic setting and modification control system, Features: The modified control system also includes a remote indicator light and a fault indicator light.

6. The automatic setting and modification control system for power generation boiler according to claim 5, Features: The electric stop valve 1 to the electric stop valve 12 are also respectively connected with an open position signal light, a closed position signal light, an open torque signal light, a closed torque signal light, a fault signal light and a remote signal light.

7. The automatic setting and modification control system for power generation boiler according to claim 1, Features: The modified control system also includes a socket, which is connected to a live wire U and a neutral wire N; The modified control system also includes a switching power supply, which is connected to a live wire U and a neutral wire N; The modified control system also includes a backup power supply, which is connected to the live wire U and the neutral wire N; The PLC cabinet also includes an in-cabinet lighting fan, which is connected to a live wire U and a neutral wire N.

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