Intelligent regulation control system and method for slag 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 feedforward temperature change rate; the PID output instruction of the automatic control of the slag cooler is connected to the first input terminal i of the adder 1 The rate of change of the slag inlet temperature per minute is fitted into the frequency increase and decrease action signal of the slag cooler through the function generator M3, and then filtered by the lead-lag generator M4 and connected to the second input terminal i of the adder. 7 The rate of change of the slag temperature per minute is fitted into the frequency increase and decrease action signal of the slag cooler through the function generator M7, and then filtered by the lead-lag generator M8 and connected to the third input terminal i of the adder 13 The return water temperature change rate per minute is fitted into the frequency increase and decrease action signal of the slag cooler through the function generator M11, and then filtered by the lead-lag generator M12 and connected to the fourth input terminal i of the adder. 19 The adder outputs the automatic control output instruction of the slag cooler. The invention ensures the continuous and reliable operation of the circulating fluidized bed boiler slag cooling system and the safe and stable operation of the unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent control of slag coolers, and in particular relates to an intelligent regulating 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 material in the bed, it is also necessary to discharge the burnt ash and debris so that the coal feed and slag discharge are in a balanced state to ensure the bed material temperature and normal fluidization. According to the different operating conditions of the boiler, the operating staff on duty need to timely adjust the balance point between the output of the slag cooler and the coal feed. The slag cooler operation is a very frequent operation of the circulating fluidized bed boiler and is also the equipment most prone to abnormalities. During the boiler slag discharge operation, abnormal phenomena such as slag cooler blockage, slag flow, and slag overheating often occur. Due to the slow rotation speed of the slag cooler, these abnormal conditions are relatively delayed and difficult to be discovered in the early stages. Although staff are arranged to deal with them when they are discovered, the dangerous working environment, high temperature, dust, noise, and high labor intensity greatly affect the operation. The work efficiency is affected. If these abnormal phenomena are not handled in time and the slag cooler trips, it is very likely to cause the bed pressure to exceed the limit, the primary fan overcurrent protection to be activated, and then the boiler trips, causing an unstoppable accident, resulting in huge economic losses and serious impact on personal safety and unit safety. The conventional slag cooler automatic control strategy is relatively simple and cannot detect and adjust the abnormal operation of the slag cooler in time. Ensuring the safe and stable operation of the slag cooler is the prerequisite for the reliable operation of the circulating fluidized bed boiler. Therefore, it becomes necessary to seek an intelligent adjustment and control strategy for the slag cooler to solve the above problems. Summary of the invention

[0003] The present invention overcomes the shortcomings of the prior art and provides a slag cooler intelligent adjustment control system and method based on a feedforward temperature change rate.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: during the production and operation of the circulating fluidized bed boiler slag cooler, various parameters of the slag cooler are analyzed and studied, and it is found that the slag inlet temperature, slag discharge temperature and return water temperature of the slag cooler all decrease after slag blockage, the slag inlet temperature, slag discharge temperature and return water temperature of the slag cooler all increase after slag flow, and the return water temperature of the slag cooler also increases after the slag discharge is over-temperature. Therefore, by introducing feedforward control, the minute change rates of the slag inlet temperature, slag discharge temperature and return water temperature of the slag cooler are respectively fitted into the frequency increase and decrease action of the slag cooler through a function generator. The quantity signal is filtered by the lead-lag generator and superimposed on the PID automatic control loop of the slag cooler. The dynamic feedforward technology is used to instantaneously increase or decrease the frequency adjustment of the slag cooler, so that the frequency of the slag cooler changes synchronously with the per-minute change rate of the slag inlet temperature, slag outlet temperature and return water temperature. The slag cooler frequency is increased or decreased in time to better stabilize the parameters such as the slag inlet temperature, slag outlet temperature, return water temperature and bed pressure, and prevent abnormal phenomena such as slag blockage, slag flow and slag over-temperature in the slag cooler, ensuring the continuous and reliable operation of the circulating fluidized bed boiler slag cooling system and ensuring the safe and stable operation of the unit.

[0005] The intelligent regulating control system of a slag cooler based on the feedforward temperature change rate comprises an automatic control output instruction PT1, a plurality of branch lines and an adder unit M13, wherein the output ports of the automatic control output instruction PT1 and the plurality of 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 PT1 of the slag cooler. 13 ;

[0006] The plurality of 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 respectively connected to the input end of the pure delay generator M1 and the input end i3 of the subtractor unit M2, the output end of the pure delay generator M1 is connected to the input end i4 of the subtractor unit M2, 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, 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 a slag inlet temperature parameter transmitter PT2, the transmitter unit in the second branch line is a slag outlet temperature parameter transmitter PT3, and the transmitter unit in the third branch line is a return water temperature parameter transmitter PT4.

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

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

[0011] According to the above-mentioned method of intelligent regulation and control system of slag cooler based on 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 i1 into the adder unit M13;

[0013] S2: the slag inlet temperature parameter transmitter in the first branch line obtains data information i2 and transmits it to the pure delay generator M1 and the subtractor unit M2;

[0014] S3: the pure delay generator M1 processes the received data information i2 to obtain the value o1 of i2 after a pure delay of 60s, and the pure delay generator M1 inputs the data o1 to the subtractor unit M2;

[0015] S4: the subtractor unit M2 analyzes and processes the data o1 and i3 to determine the minute change rate o2 of the slag cooler inlet slag temperature;

[0016] S5: The minute change rate o2 of the slag inlet temperature is fitted into the slag cooler frequency increase / decrease action signal o3 through the function generator M3;

[0017] S6: The frequency increase / decrease action signal o3 of the slag cooler is filtered by the lead-lag generator M4 to determine the filter value o4, and the filter value o4 is input to the adder unit M13;

[0018] S7: the second branch line and the third branch line repeat steps S2-S6, determine the change rate of the slag discharge temperature per minute and the change rate of the return water temperature per minute, respectively, fit them into the frequency increase and decrease action amount signal of the slag cooler through the function generator, and then filter them through the lead-lag generator and input them into the adder unit M13;

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

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention solves the technical problem that the untimely and unintelligent adjustment of the slag cooler causes abnormal conditions such as slag blockage, slag flow, and slag discharge overtemperature of the slag cooler, which then 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 slag discharge overtemperature of the slag cooler and various parameters of the slag cooler, such as slag inlet temperature, slag discharge temperature, and return water temperature. On the basis of a conventional slag cooler PID control strategy, the present invention introduces feedforward control, and the minute change rates of the slag inlet temperature, slag discharge temperature, and return water temperature of the slag cooler are respectively fitted into slag cooler frequency increase and decrease action quantity signals through a function generator, and are filtered by a lead-lag generator and then superimposed on the original slag cooler PID automatic control loop, so as to more timely and intelligently adjust the bed pressure, slag inlet temperature, slag discharge temperature, and return water temperature, reduce the risk of burns and scalds caused by manual handling of slag cooler abnormalities, reduce manual labor intensity, ensure the safe, continuous, and stable operation of the slag cooler, and also ensure the safe and stable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings.

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

[0024] As shown in the figure, the intelligent regulation and control system of the slag cooler based on the feedforward temperature change rate includes an automatic control output instruction PT1, a plurality of branch lines and an adder unit M13, wherein the output ports of the automatic control output instruction PT1 and the plurality of 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 slag cooler automatic control instruction 0 13 .

[0025] The plurality of branch lines include a first branch line, a second branch line and a third branch line, the first branch line includes a slag inlet temperature parameter transmitter PT2, a pure delay generator M1 and a lead-lag generator M4, the output end of the slag inlet temperature parameter transmitter PT2 is divided into two lines respectively connected to the input end of the pure delay generator M1 and the input end i3 of the subtractor unit M2, the pure delay time of the pure delay generator M1 is 60s, the output end of the pure delay generator M1 is connected to the input end i4 of the subtractor unit M2, 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 0s, and the lag time S2 of the lead-lag generator M4 is 5s;

[0026] The second branch line includes a slag temperature parameter transmitter PT3, a pure delay generator M5 and a lead-lag generator M8. The output end of the slag temperature parameter transmitter PT3 is divided into two lines, which are respectively connected to the input end of the pure delay generator M5 and the input end i9 of the subtractor unit M6. The pure delay time of the pure delay generator M5 is 60s. The output end of the pure delay generator M5 is connected to the input end i9 of the subtractor unit M6. 10 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, which are respectively connected to the input end of the pure delay generator M9 and the input end of the subtractor unit M10. 15 The pure delay time of the pure delay generator M9 is 60s, and the output end of the pure delay generator M9 is connected to the input end i of the subtractor unit M10. 16 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-mentioned method of intelligent regulation and control system of slag cooler based on feedforward temperature change rate, the method specifically includes the following steps:

[0029] S1: The automatic control output instruction PT1 inputs the original slag cooler data information i1 into the adder unit M13;

[0030] S2: the slag inlet temperature parameter transmitter in the first branch line obtains data information i2 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 i2 to obtain the value o1 of i2 after a pure delay of 60s, and the pure delay generator M1 inputs the data o1 to the subtractor unit M2;

[0032] S4: the subtractor unit M2 analyzes and processes the data o1 and i3 to determine the minute change rate o2 of the slag cooler inlet slag temperature;

[0033] S5: The minute change rate o2 of the slag inlet temperature is fitted into the frequency increase / decrease action signal o3 of the slag cooler through 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 Changes in the function relationship of function generator M3

[0035] Slag inlet temperature change rate ℃ / min -20 -1 1 20 Fitting curve output value Hz 10 0 0 -10

[0036] S6: The frequency increase / decrease action signal o3 of the slag cooler is filtered by the lead-lag generator M4 to determine the filter value o4, and the filter value o4 is input to the adder unit M13;

[0037] S7: the second branch line and the third branch line repeat steps S2-S6, determine the change rate of the slag discharge temperature per minute and the change rate of the return water temperature per minute, respectively, fit them into the frequency increase and decrease action amount signal of the slag cooler through the function generator, and then filter them through the lead-lag generator and input them into the adder unit M13;

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

[0039] Table 2 Changes in the function relationship of function generator M7

[0040] Slag temperature change rate ℃ / min -20 -1 1 20 Fitting curve output value Hz 6 0 0 -20

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

[0042] Table 3 Changes in the function relationship of function generator M11

[0043]

[0044]

[0045] S8: The adder unit M13 integrates the data in steps S1, S6 and S7 to obtain the final slag cooler automatic control output instruction o 13 .

[0046] The calculation expression of the lead-lag generator in the present invention is: The scanning time dt = 250ms.

[0047] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Those familiar with the technology may modify or improve the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made 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. Intelligent regulation and control system for slag cooler based on feedforward temperature change rate, characterized in that: The system comprises an automatic control output instruction PT1, a plurality of branch lines and an adder unit M13, wherein the output ports of the automatic control output instruction PT1 and the plurality of 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 slag cooler automatic control instruction 0 13 ; The plurality of 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 respectively connected to the input end of the pure delay generator M1 and the input end i3 of the subtractor unit M2, the output end of the pure delay generator M1 is connected to the input end i4 of the subtractor unit M2, 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, 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.

2. The intelligent regulation and control system for slag cooler based on feedforward temperature change rate according to claim 1 is characterized in that: The transmitter unit in the first branch line is a slag inlet temperature parameter transmitter PT2, the transmitter unit in the second branch line is a slag outlet temperature parameter transmitter PT3, and the transmitter unit in the third branch line is a return water temperature parameter transmitter PT4.

3. The intelligent regulation and control system for slag cooler based on feedforward temperature change rate according to claim 2 is characterized in that: The pure delay time of the pure delay generator M1 is 60s.

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

5. The method for intelligent regulation and control of slag cooler based on feedforward temperature change rate according to claim 4 is characterized in that: The specific steps include: S1: The automatic control output instruction PT1 inputs the original slag cooler data information i1 into the adder unit M13; S2: the slag inlet temperature parameter transmitter in the first branch line obtains data information i2 and transmits it to the pure delay generator M1 and the subtractor unit M2; S3: the pure delay generator M1 processes the received data information i2 to obtain the value o1 of i2 after a pure delay of 60s, and the pure delay generator M1 inputs the data o1 to the subtractor unit M2; S4: the subtractor unit M2 analyzes and processes the data o1 and i3 to determine the minute change rate o2 of the slag cooler inlet slag temperature; S5: The minute change rate o2 of the slag inlet temperature is fitted into the slag cooler frequency increase / decrease action signal o3 through the function generator M3; S6: The frequency increase / decrease action signal o3 of the slag cooler is filtered by the lead-lag generator M4 to determine the filter value o4, and the filter value o4 is input to the adder unit M13; S7: the second branch line and the third branch line repeat steps S2-S6, determine the change rate of the slag discharge temperature per minute and the change rate of the return water temperature per minute, respectively, fit them into the frequency increase and decrease action amount signal of the slag cooler through the function generator, and then filter them through the lead-lag generator and input them into the adder unit M13; S8: The adder unit M13 integrates the data in steps S1, S6 and S7 to obtain the final slag cooler automatic control output instruction o 13 .

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