Intelligent Adjustment Control System and Method for Cooler Based on Feedforward Temperature Change Rate

Abstract

The present invention belongs to the technical field of intelligent control of slag coolers, and specifically relates to an intelligent regulation control system and method for slag coolers based on the feedforward temperature change rate; the automatic control PID output instruction of the slag cooler is connected to the first input end i1 of the adder, and the change rate of the incoming slag temperature per minute is fitted into a signal of the frequency increase and decrease action amount of the slag cooler through the function generator M3 and then connected to the second input end i7 of the adder after being filtered by the lead-lag generator M4; the change rate of the outgoing slag temperature per minute is fitted into a signal of the frequency increase and decrease action amount of the slag cooler through the function generator M7 and then connected to the third input end i 13 of the adder after being filtered by the lead-lag generator M8; the change rate of the return water temperature per minute is fitted into a signal of the frequency increase and decrease action amount of the slag cooler through the function generator M11 and then connected to the fourth input end i 19 of the adder after being filtered by the lead-lag generator M12, and the adder outputs an automatic control output instruction for the slag cooler. The present invention ensures the continuous and reliable operation of the slag cooling system of the circulating fluidized bed boiler and the safe and stable operation of the unit.

Description

Technical Field

[0001] The invention belongs to the technical field of intelligent control of slag coolers, and particularly relates to an intelligent regulation control system and method for a slag cooler based on a feedforward temperature change rate. Background Art

[0002] During the combustion process of a circulating fluidized bed boiler, while maintaining a certain amount of bed material, it is also necessary to discharge the burned ash and debris to keep the coal feeding amount and the slag discharging amount in a balanced state to ensure the bed material temperature and normal fluidization. For different operating conditions of the boiler, the on-duty operator needs to timely adjust the balance point where the output of the slag cooler is adapted to the coal feeding amount. The operation of the slag cooler is a very frequent operation in the circulating fluidized bed boiler and is also a device most prone to abnormalities. During the boiler slag discharging operation, abnormal phenomena such as slag blocking, slag flowing, and over-temperature of slag discharging often occur in the slag cooler. Due to the relatively slow rotation speed of the slag cooler, these abnormal states are relatively lagging and not easily detected in the early stage. Although there are staff arranged to handle them when discovered, the working environment is dangerous, and factors such as high temperature, dust, noise, and large labor intensity greatly affect the work efficiency. If these abnormal phenomena are not handled in time and cause the slag cooler to trip, it is very likely to cause the bed layer pressure to exceed the limit and the over-current protection of the primary fan to act, and then the boiler trips, triggering a non-stop accident, resulting in huge economic losses, seriously affecting personal safety and unit safety. The conventional automatic control strategy of the slag cooler is relatively single and cannot timely detect and adjust the occurrence of abnormal operation of the slag cooler. Ensuring the safe and stable operation of the slag cooler is the premise for the reliable operation of the circulating fluidized bed boiler. Therefore, it is necessary to seek an intelligent regulation control strategy for the slag cooler to solve the above problems. Summary of the Invention

[0003] The invention overcomes the deficiencies existing in the prior art and provides an intelligent regulation control system and method for a slag cooler based on a feedforward temperature change rate.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is as follows: During the production operation of the circulating fluidized bed boiler slag cooler, through the analysis and research of various parameters of the slag cooler, it is found that after the slag cooler is blocked by slag, the incoming slag temperature, the slag discharge temperature, and the return water temperature all decrease; after the slag cooler discharges slag, the incoming slag temperature, the slag discharge temperature, and the return water temperature all increase; when the slag discharge of the slag cooler is overheated, the return water temperature also increases accordingly. Therefore, by introducing feedforward quantity control, the per-minute change rates of the incoming slag temperature, the slag discharge temperature, and the return water temperature of the slag cooler are respectively fitted into the slag cooler frequency increase and decrease action quantity signals through a function generator, and after being filtered by a lead-lag generator, they are respectively superimposed on the PID automatic control loop of the slag cooler. The dynamic feedforward technology is used to instantaneously increase or decrease the slag cooler frequency adjustment, so that the slag cooler frequency changes synchronously with the per-minute change rates of the incoming slag temperature, the slag discharge temperature, and the return water temperature, timely increasing or decreasing the slag cooler frequency, better stabilizing parameters such as the incoming slag temperature, the slag discharge temperature, the return water temperature, and the bed pressure, preventing abnormal phenomena such as slag cooler slag blockage, slag discharge, and overheated slag discharge, and ensuring the continuous and reliable operation of the circulating fluidized bed boiler slag cooling system, thus guaranteeing the safe and stable operation of the unit.

[0005] The intelligent regulation control system of the slag cooler based on the feedforward temperature change rate includes an automatic control output instruction PT1, several branch lines, and an adder unit M13. The output ports of the automatic control output instruction PT1 and several branch lines are connected to the input port of the adder unit M13, and the output port of the adder unit M13 outputs the final automatic control instruction o of the slag cooler. 13 ;

[0006] Several branch lines include a first branch line, a second branch line, and a third branch line. The first branch line includes a transmitter unit, a pure delay generator M1, and a lead-lag generator M4. The output end of the transmitter unit is divided into two lines and is respectively connected to the input end of the pure delay generator M1 and the input end i of the subtractor unit M2. 3 The output end of the pure delay generator M1 is connected to the input end i of the subtractor unit M2. 4 After processing the received data information, the subtractor unit M2 outputs it to the function generator M3. The output port of the function generator M3 is connected to the input port of the lead-lag generator M4, and the output port of the lead-lag generator M4 is connected to the adder unit M13.

[0007] The second branch line and the third branch line have the same structure as the first branch line.

[0008] Preferably, the transmitter unit in the first branch line is the incoming slag temperature parameter transmitter PT2, the transmitter unit in the second branch line is the slag discharge temperature parameter transmitter PT3, and the transmitter unit in the third branch line is the return water temperature parameter transmitter PT4.

[0009] Preferably, the dead time of the dead time generator M1 is 60 s.

[0010] Preferably, the lead time S1 of the lead-lag generator M4 is 0 s, and the lag time S2 of the lead-lag generator M4 is 5 s.

[0011] According to the above method of the intelligent control system for the slag cooler based on the feedforward temperature change rate, the method specifically includes the following steps:

[0012] S1: The automatic control output instruction PT1 inputs the original slag cooler data information i 1 into the adder unit M13;

[0013] S2: The slag inlet temperature parameter transmitter in the first branch line acquires the data information i 2 and transmits it to the dead time generator M1 and the subtractor unit M2;

[0014] S3: The dead time generator M1 processes the received data information i 2 to obtain the value o 2 after a 60 s dead time, and the dead time generator M1 inputs the data o 1 into the subtractor unit M2; 1 1

[0015] S4: The subtractor unit M2 analyzes and processes the data o 1 and i 3 to determine the change rate o 2 of the slag inlet temperature of the slag cooler per minute;

[0016] S5: The change rate o 2 of the slag inlet temperature per minute is fitted into the slag cooler frequency increase and decrease action amount signal o 3 through the function generator M3;

[0017] S6: The slag cooler frequency increase and decrease action amount signal o 3 is filtered by the lead-lag generator M4 to determine the filtered value o 4 , and the filtered value o 4 is input into the adder unit M13;

[0018] S7: The second branch line and the third branch line repeat steps S2-S6, and the change rate of the slag outlet temperature per minute and the change rate of the return water temperature per minute are respectively fitted into the slag cooler frequency increase and decrease action amount signals through the function generator, and then input into the adder unit M13 after being filtered by the lead-lag generator;

[0019] ​S8: The adder unit M13 integrates the data in steps S1, S6, and S7 to obtain the final automatic control output instruction o of the slag cooler. 13 。

[0020] The beneficial effects of the present invention compared with the prior art are as follows:

[0021] The present invention solves the technical problems that the slag cooler adjustment is not timely and intelligent, resulting in abnormal conditions such as slag blockage, slag flow, and over-temperature of slag discharge in the slag cooler, which in turn affect the safe operation of the unit. The present invention is based on the proportional relationship between abnormal conditions such as slag blockage, slag flow, and over-temperature of slag discharge in the slag cooler and various parameters of the slag cooler, such as inlet slag temperature, outlet slag temperature, and return water temperature. On the basis of the conventional PID control strategy of the slag cooler, by introducing feedforward control, the minute change rates of the inlet slag temperature, outlet slag temperature, and return water temperature of the slag cooler are respectively fitted into the slag cooler frequency increase and decrease action signals through a function generator and then superimposed on the original PID automatic control loop of the slag cooler after being filtered by a lead-lag generator, so as to adjust the bed pressure, inlet slag temperature, outlet slag temperature, and return water temperature more timely and intelligently, reduce the risk of burns and scalds caused by manual handling of slag cooler abnormalities, reduce the manual labor intensity, ensure the safe, continuous, and stable operation of the slag cooler, and at the same time ensure the safe and stable operation of the unit. Brief Description of the Drawings

[0022] The following further describes the present invention with reference to the drawings.

[0023] Figure 1 It is a schematic structural diagram of the present invention. Detailed Embodiment

[0024] As shown in the figure, the intelligent adjustment control system of the slag cooler based on the feedforward temperature change rate includes an automatic control output instruction PT1, several branch lines, and an adder unit M13. The output ports of the automatic control output instruction PT1 and several branch lines are connected to the input port of the adder unit M13, and the output port of the adder unit M13 outputs the final automatic control instruction o of the slag cooler. 13 。

[0025] Several branch lines include a first branch line, a second branch line, and a third branch line. The first branch line includes an inlet slag temperature parameter transmitter PT2, a pure delay generator M1, and a lead-lag generator M4. The output end of the inlet slag temperature parameter transmitter PT2 is divided into two lines and respectively connected to the input end of the pure delay generator M1 and the input end i of the subtractor unit M2. 3 , the pure delay time of the pure delay generator M1 is 60 s, and the output end of the pure delay generator M1 is connected to the input end i of the subtractor unit M2. 4connected, the subtractor unit M2 processes the received data information and outputs it to the function generator M3. The output port of the function generator M3 is connected to the input port of the lead-lag generator M4. The output port of the lead-lag generator M4 is connected to the adder unit M13. The lead time S1 of the lead-lag generator M4 is 0 s, and the lag time S2 of the lead-lag generator M4 is 5 s;

[0026] The second branch line includes a slag discharge temperature parameter transmitter PT3, a pure delay generator M5, and a lead-lag generator M8. The output end of the slag discharge temperature parameter transmitter PT3 is divided into two lines and respectively connected to the input end of the pure delay generator M5 and the input end i of the subtractor unit M6 9 , the pure delay time of the pure delay generator M5 is 60 s, and the output end of the pure delay generator M5 is connected to the input end i of the subtractor unit M6 10 connected, the subtractor unit M6 processes the received data information and outputs it to the function generator M7. The output port of the function generator M7 is connected to the input port of the lead-lag generator M8. The output port of the lead-lag generator M8 is connected to the adder unit M13.

[0027] The third branch line includes a return water temperature parameter transmitter PT4, a pure delay generator M9, and a lead-lag generator M12. The output end of the return water temperature parameter transmitter PT4 is divided into two lines and respectively connected to the input end of the pure delay generator M9 and the input end i of the subtractor unit M10 15 , the pure delay time of the pure delay generator M9 is 60 s, and the output end of the pure delay generator M9 is connected to the input end i of the subtractor unit M10 16 connected, the subtractor unit M10 processes the received data information and outputs it to the function generator M11. The output port of the function generator M11 is connected to the input port of the lead-lag generator M12. The output port of the lead-lag generator M12 is connected to the adder unit M13.

[0028] According to the above method of the intelligent control system for a slag cooler based on the feedforward temperature change rate, it specifically includes the following steps:

[0029] S1: The automatic control output command PT1 inputs the original slag cooler data information i 1 into the adder unit M13;

[0030] S2: The slag inlet temperature parameter transmitter in the first branch line acquires data information i 2 and transmits it to the pure delay generator M1 and the subtractor unit M2;

[0031] S3: The pure delay generator M1 processes the received data information i 2 to obtain i 2 the value o after a pure delay of 60 s 1 , and the pure delay generator M1 inputs the data o 1 to the subtractor unit M2;

[0032] S4: The subtractor unit M2 analyzes and processes the data o 1 and i 3 to determine the change rate of the slag cooler's incoming slag temperature per minute o 2 ;

[0033] S5: The change rate of the incoming slag temperature per minute o 2 is fitted into the cold slag cooler frequency increase / decrease action amount signal o 3 by the function generator M3; In the function generator M3, the functional relationship between the abscissa x and the ordinate y is shown in Table 1:

[0034] Table 1 Change situation of the functional relationship of the function generator M3

[0035] Rate of change of slag inlet temperature °C / min -20 -1 1 20 Output value of the fitted curve Hz 10 0 0 -10

[0036] S6: The cold slag cooler frequency increase / decrease action amount signal o 3 is filtered by the lead-lag generator M4 to determine the filtered value o 4 , and the filtered value o 4 is input to the adder unit M13;

[0037] S7: The second branch line and the third branch line repeat steps S2 - S6, and the change rate of the outgoing slag temperature per minute and the change rate of the return water temperature per minute are respectively fitted into the cold slag cooler frequency increase / decrease action amount signal by the function generator, and then input to the adder unit M13 after being filtered by the lead-lag generator;

[0038] In the second branch line, for the function generator M7, the functional relationship between the abscissa x and the ordinate y is shown in Table 2:

[0039] Table 2 Change situation of the functional relationship of the function generator M7

[0040] Rate of change of slag outlet temperature °C / min -20 -1 1 20 Output value of the fitted curve Hz 6 0 0 -20

[0041] In the third branch line, for the function generator M11, the functional relationship between the abscissa x and the ordinate y is shown in Table 3:

[0042] Table 3 Change situation of the functional relationship of the function generator M11

[0043]

[0044] S8: The adder unit M13 integrates the data in steps S1, S6, and S7 to obtain the final automatic control output instruction o of the slag cooler. 13 .

[0045] The calculation expression of the lead-lag generator in the present invention is: where the scan time dt = 250 ms.

[0046] The above embodiments are only used to exemplarily illustrate the principles and effects of the present invention, rather than to limit the present invention. Those who are familiar with this technology can modify or improve the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. An intelligent control system for a slag cooler based on the feed-forward temperature change rate, characterized in that, It includes an automatic control output instruction PT1, several branch lines, and an adder unit M13. The output ports of the automatic control output instruction PT1 and several branch lines are connected to the input ports of the adder unit M13, and the output port of the adder unit M13 outputs the final automatic control instruction o for the slag cooler 13 ; A plurality of the branch circuits include a first branch circuit, a second branch circuit, and a third branch circuit. The first branch circuit includes a transmitter unit, a pure delay generator M1, and a lead-lag generator M4. The output end of the transmitter unit is divided into two lines and respectively connected to the input end of the pure delay generator M1 and the input end i of the subtractor unit M2 3 , the output end of the pure delay generator M1 is connected to the input end i of the subtractor unit M2 4 ; the subtractor unit M2 processes the received data information and then outputs it to the function generator M3. The output port of the function generator M3 is connected to the input port of the lead-lag generator M4, and the output port of the lead-lag generator M4 is connected to the adder unit M13; the second branch line and the third branch line have the same structure as the first branch line; the transmitter unit in the first branch line is the incoming slag temperature parameter transmitter PT2, the transmitter unit in the second branch line is the outgoing slag temperature parameter transmitter PT3, and the transmitter unit in the third branch line is the return water temperature parameter transmitter PT4.

2. The intelligent control system for a slag cooler based on the feed-forward temperature change rate according to claim 1, characterized in that, the pure delay time of the pure delay generator M1 is 60 s.

3. The intelligent control system for a slag cooler based on the feed-forward temperature change rate according to claim 2, characterized in that, the lead time S1 of the lead-lag generator M4 is 0 s, and the lag time S2 of the lead-lag generator M4 is 5 s.

4. The method of the intelligent control system for a slag cooler based on the feed-forward temperature change rate according to claim 3, characterized in that, specifically includes the following steps: S1: The automatic control output instruction PT1 inputs the original cooler data information i 1 into the adder unit M13; S2: The slag inlet temperature parameter transmitter in the first branch line obtains the data information i 2 and transmits it to the pure time-delay generator M1 and the subtractor unit M2; S3: The pure delay generator M1 processes the received data information i 2 to obtain i 2 The value o after a pure delay of 60 s 1 , and the pure delay generator M1 inputs the data o 1 into the subtractor unit M2; S4: The subtractor unit M2 analyzes and processes the data o 1 and i 3 to determine the change rate of the slag cooler's incoming slag temperature per minute o 2 ; S5: Rate of change of slag inlet temperature per minute o 2 The signal of the amount of increase or decrease in the cooler frequency is fitted through the function generator M3 o 3 ; S6: Signal of the action amount of increasing or decreasing the frequency of the slag cooler o 3 After being filtered by the lead-lag generator M4, the filtered value is determined o 4 , and the filtered value o 4 is input to the adder unit M13; S7: The second branch line and the third branch line repeat steps S2 - S6, fit the change rate per minute of the outgoing slag temperature and the change rate per minute of the return water temperature into the slag cooler frequency increase and decrease action amount signals respectively through the function generator, and then input them to the adder unit M13 after being filtered by the lead-lag generator; S8: The adder unit M13 integrates the data in steps S1, S6, and S7 to obtain the final automatic control output instruction o of the slag cooler 13 .

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