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CN-121993812-A - Dynamic combustion control method and control system for coal

CN121993812ACN 121993812 ACN121993812 ACN 121993812ACN-121993812-A

Abstract

A method for controlling dynamic combustion of coal includes such steps as obtaining input mass rate of coal powder, obtaining input air quantity of primary air and input air quantity of secondary air, inputting secondary air near to input position of primary air, and decreasing input air quantity of primary air and input air quantity of secondary air according to variation ratio when input mass rate of coal powder is varied. The application divides the secondary air into the secondary air and the main secondary air, the secondary air is partially supplemented with the primary air in practice, and the secondary air is regulated in a lagging way in the regulating process, so that the combustion can be better promoted, the integral combustion efficiency of the boiler is improved, and the capability of converting chemical energy into heat energy in the coal burning process is improved to a certain extent.

Inventors

  • BIAN YONGPING
  • MA LIN
  • WEI DAOJUN
  • BI ZHONGSI
  • YANG XIAOMING

Assignees

  • 华电国际电力股份有限公司莱城发电厂

Dates

Publication Date
20260508
Application Date
20260130

Claims (10)

  1. 1. A method for controlling dynamic combustion of coal is characterized by comprising the following steps: acquiring the input mass rate of coal dust; Acquiring the input air quantity of primary air and the input air quantity of secondary air; the secondary air comprises secondary air and main secondary air, and the secondary air is input near the input position of the primary air; when the input mass rate of the pulverized coal is changed, the input air quantity of the primary air and the input air quantity of the secondary air are reduced according to the change proportion, and the change proportion of the secondary air is lower than the integral change proportion of the secondary air in the process.
  2. 2. The method for controlling dynamic combustion of coal as set forth in claim 1, wherein the secondary air is introduced into the primary air at a position at which the secondary air is introduced, and is introduced into the primary air by means of lateral air, wherein the number of air passages through which the secondary air is introduced is not less than 3, and the air passages through which the secondary air is introduced are uniformly distributed.
  3. 3. The method for controlling dynamic combustion of coal according to claim 1, wherein the input air volume of the secondary air is obtained by: Acquiring a first temperature T 1i of a primary air input position, a second temperature T 2i of a secondary air input position, a third temperature T 3i of a first distance after the secondary air input position, a fourth temperature T 4i of the secondary air input position and a fifth temperature T 5i of a second distance after the secondary air input position; And correcting the change proportion of the secondary air according to the changes of the first temperature T 1i , the second temperature T 2i , the third temperature T 3i , the fourth temperature T 4i and the fifth temperature T 5i to obtain the input air quantity of the secondary air.
  4. 4. The method for controlling dynamic combustion of coal according to claim 3, wherein the total required air quantity F ti is calculated according to the input mass rate M i of the coal powder; Obtained according to the distribution proportion mu i , the input air quantity of the primary air is F 1i =μ i F ti the input air volume of the secondary air F 2i =（1-μ i ) F ti ; Air quantity F of secondary air c2i =λ i F 2i , the air volume of the primary and secondary air F m2i =（1-λ i ) F 2i ; The change coefficient of the coal powder input quality is T i ,M i +1=（1+T i M i ; F ti+1 =（1+T i ) M i ; F 1i+1 =（1+T i ) μ i F ti ; F 2i+1 =（1+T i ) (1-μ i ) F ti ; Verifying the change magnitudes of the first temperatures T 1i and T 1i+1 , the second temperatures T 2i and T 2i+1 , the third temperatures T 3i and T 3i+1 , the fourth temperatures T 4i and T 4i+1 , and the fifth temperatures T 5i and T 5i+1 , and if all do not exceed the change threshold, λ i+1 =λ i ; at the time T i <0, λ i+1 ={（|T 1i+1 -T 1i |+|T 2i+1 -T 2i |+|T 3i+1 -T 3i |)/ （|T 1i+1 -T 1i |+|T 2i+1 -T 2i |+|T 3i+1 -T 3i |+|T 4i+1 -T 4i |+|T 5i+1 -T 5i |）} λ i ; At T i > 0; λ i+1 ={（|T 1i+1 -T 1i |+|T 2i+1 -T 2i |+|T 3i+1 -T 3i |+|T 4i+1 -T 4i |+|T 5i+1 -T 5i |）/ (|T 1i+1 -T 1i |+|T 2i+1 -T 2i |+|T 3i+1 -T 3i |)} λ i ; Calculating to obtain the secondary air volume: F c2i+1 =λ i +1 F 2i+1 ; F m2i+1 =（1-λ i+1 ) F 2i+1 。
  5. 5. The method for dynamic combustion control of coal as set forth in claim 4, wherein μi has a value in the range of [0.25,0.35].
  6. 6. The method for controlling dynamic combustion of coal as set forth in claim 4, wherein the first distance is 200-400mm and the second distance is 500-700mm.
  7. 7. The method for controlling dynamic combustion of coal as set forth in claim 4, wherein the fuel of the coal-fired boiler is bituminous coal: F ti =α M i (1.05Xq/1000+0.278), where q is the calorific value of the fuel in kcal/kg; The alpha is an excess coefficient, and the value range is [1.1,1.2].
  8. 8. The method for dynamic combustion control of coal as set forth in claim 4, wherein the first temperature T 1i , the second temperature T 2i , the third temperature T 3i , the fourth temperature T 4i and the fifth temperature T 5i are temperatures of a center of a flue at the measuring position.
  9. 9. The method for dynamic combustion control of coal as set forth in claim 5, wherein the variation threshold is 5 ℃, and the sampling interval between i and i+1 is not less than 10s.
  10. 10. A control system for implementing the coal-fired dynamic combustion control method according to any one of claims 1 to 9, characterized by comprising the following modules: The monitoring module is used for acquiring the input mass rate of the pulverized coal; Acquiring the input air quantity of primary air and the input air quantity of secondary air; the secondary air comprises secondary air and main secondary air, and the secondary air is input near the input position of the primary air; And the control module is used for reducing the input air quantity of the primary air and the input air quantity of the secondary air according to the change proportion when the input mass rate of the pulverized coal is changed, and the change proportion of the secondary air is lower than the integral change proportion of the secondary air in the process.

Description

Dynamic combustion control method and control system for coal Technical Field The application relates to a method and a system for controlling dynamic combustion of coal. Background The coal-fired boiler is a device for mixed combustion of coal and combustion-supporting gas (generally air), and chemical energy is converted into heat energy during combustion and then is used for heating water or steam to play a role of a heat source. In order to improve the combustion efficiency, a pulverized coal boiler is adopted at present, the pulverized coal boiler is a boiler taking pulverized coal as a raw material, the pulverized coal is mixed with primary air during combustion, the state of the pulverized coal, the state of the primary air and the state of combustion in the boiler need to be considered, and a control strategy of a higher university is obtained based on the state of the primary air. The existing primary air adjustment is generally controlled based on the supply proportion and the carrying speed, and the effect of the primary air on the combustion of the pulverized coal boiler is not fully exerted in practice, and the control method is required to be adjusted to achieve the effect of dynamic combustion control of the coal. Disclosure of Invention In order to solve the problems, the application provides a coal dynamic combustion control method, which comprises the following steps of obtaining the input mass rate of coal dust; The secondary air comprises secondary air and main secondary air, the secondary air is input near the input position of the primary air, when the input quality rate of pulverized coal is changed, the input air quantity of the primary air and the input air quantity of the secondary air are reduced according to the change proportion, and the change proportion of the secondary air is lower than the integral change proportion of the secondary air in the process. The application divides the secondary air into the secondary air and the main secondary air, the secondary air is partially supplemented with the primary air in practice, and the secondary air is regulated in a lagging way in the regulating process, so that the combustion can be better promoted, the integral combustion efficiency of the boiler is improved, and the capability of converting chemical energy into heat energy in the coal burning process is improved to a certain extent. Preferably, the input position of the secondary air is arranged at the input position of the primary air and is guided in a lateral air guiding mode, the number of air channels guided in the lateral direction of the secondary air is not less than 3, and the air channels guided in the lateral direction of the secondary air are uniformly distributed. The secondary air is guided laterally and matched with the primary air, and the secondary layer is supplied in a split mode, so that disturbance to a combustion flame body can be reduced, air can be provided, and out-of-control of local temperature can be avoided. Preferably, the input air volume of the secondary air is obtained as follows: Acquiring a first temperature T 1i of a primary air input position, a second temperature T 2i of a secondary air input position, a third temperature T 3i of a first distance after the secondary air input position, a fourth temperature T 4i of the secondary air input position and a fifth temperature T 5i of a second distance after the secondary air input position; And correcting the change proportion of the secondary air according to the changes of the first temperature T 1i, the second temperature T 2i, the third temperature T 3i, the fourth temperature T 4i and the fifth temperature T 5i to obtain the input air quantity of the secondary air. Preferably, the total required air quantity F ti is calculated according to the input mass rate M i of the pulverized coal; Obtained according to the distribution proportion mu i, the input air quantity of the primary air is F 1i=μiF ti the input air volume of the secondary air F 2i=（1-μi)Fti; Air quantity F of secondary air c2i=λiF 2i, the air volume of the primary and secondary air F m2i=（1-λi)F2i; The change coefficient of the coal powder input quality is T i,Mi+1=（1+TiMi; Fti+1=（1+Ti)Mi; F1i+1=（1+Ti)μiFti; F2i+1=（1+Ti)(1-μi)Fti; Verifying the change magnitudes of the first temperatures T 1i and T 1i+1, the second temperatures T 2i and T 2i+1, the third temperatures T 3i and T 3i+1, the fourth temperatures T 4i and T 4i+1, and the fifth temperatures T 5i and T 5i+1, and if all do not exceed the change threshold, λ i+1=λi; at the time T i <0, λi+1={（|T1i+1-T1i|+|T2i+1-T2i|+|T3i+1-T3i|)/ （|T1i+1-T1i|+|T2i+1-T2i|+|T3i+1-T3i|+|T4i+1-T4i|+|T5i+1-T5i|）}λi; At T i > 0; λi+1={（|T1i+1-T1i|+|T2i+1-T2i|+|T3i+1-T3i|+|T4i+1-T4i|+|T5i+1-T5i|）/ (|T1i+1-T1i|+|T2i+1-T2i|+|T3i+1-T3i|)}λi; Calculating to obtain the secondary air volume: Fc2i+1=λi+1F2i+1; Fm2i+1=（1-λi+1) F 2i+1. According to the application, lambda i is regulated and controlled acc