Method and system for reducing disturbance of start and stop of double-inlet and double-outlet coal mill to denitration system

A double-in, double-out, coal mill technology, applied in the combustion method, regulating fuel supply, block/powder supply/distribution, etc., can solve the disturbance of nitrogen oxide concentration, the fluctuation of nitrogen oxide in flue gas, Measurement data lag and other problems, to achieve the effect of reducing large fluctuations, reducing disturbance intensity, and facilitating stable operation

Active Publication Date: 2020-07-17
国家能源(山东)工程技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the double-inlet and double-outlet coal mill starts and stops, it also produces a very large disturbance to the concentration of nitrogen oxides in the flue gas, and no specific solution is given; at the same time, for starting the coal feeder and coal mill The process of establishing the capacity air volume during the transition period of the normal coal level is estimated by the simulation method without considering the actual change process of the coal level. This method will cause a large deviation between the estimated capacity air volume and the actual fuel volume entering the furnace, resulting in Parameters such as the main steam pressure of the unit and the concentration of nitrogen oxides in the flue gas produce large disturbances
There are also researchers who have proposed a medium-speed coal mill start-stop control method based on coal online compensation. The amount of coal in the boiler remains unchanged, and in view of the different characteristics of the influence of the start and stop of coal mills in different layers on boiler combustion, the coal amount compensated online during the start and stop of coal mills in different layers is corrected to reduce the impact of coal mill start and stop on boilers. Combustion disturbance, but it only compensates the amount of coal that enters the boiler during the start and stop of the coal mill, improves the calculation accuracy of the coal

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  • Method and system for reducing disturbance of start and stop of double-inlet and double-outlet coal mill to denitration system
  • Method and system for reducing disturbance of start and stop of double-inlet and double-outlet coal mill to denitration system
  • Method and system for reducing disturbance of start and stop of double-inlet and double-outlet coal mill to denitration system

Examples

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Effect test

Example Embodiment

[0032] Example 1:

[0033] Embodiment 1 of the present disclosure provides a control method for reducing the disturbance to the denitration system caused by the start and stop of the double-inlet and double-outlet coal mill. The double-inlet and double-outlet coal mill A, the coal distributor A1 (left side) and A2 (right side) ). After mixing the powder from both sides of the coal mill, the left and right side burners and the left and right secondary air baffles are separately controlled as an example, including the following steps:

[0034] (1) Determine the volumetric air volume calculation formula after coal level correction

[0035] Take mill A as an example:

[0036] F A =f(L A )·F A

[0037] Among them, F A -The air volume of mill A after the coal level is corrected, namely figure 1 The product of the sum of the left and right volume air volume of the middle A mill multiplied by the function f(x);

[0038] L A —A coal grinding level;

[0039] f(L A )—The capacity air volume correct...

Example Embodiment

[0075] Example 2:

[0076] Embodiment 2 of the present disclosure provides a system for reducing the disturbance to the denitration system caused by the start and stop of the double-in and double-out coal mill, including:

[0077] The capacity air volume acquisition module after the coal level correction is configured to obtain the corrected coal level volume air volume according to the corrected coal level of the double-in and double-out coal mill;

[0078] The ratio function obtaining module is configured to obtain the ratio function of the combustion-supporting air volume and the capacity air volume after the coal level correction according to the capacity air volume after the coal level correction;

[0079] The control module is configured to: when the double-inlet and double-outlet coal mill and the corresponding coal feeder start, control the coal feeder's coal volume according to the preset maximum initial coal feed volume and increase rate of the coal feeder, and the maximum ai...

Example Embodiment

[0091] Example 3:

[0092] The third embodiment of the present disclosure provides a medium on which a program is stored. When the program is executed by a processor, the method for reducing the disturbance of the denitration system caused by the start and stop of the double-inlet and double-outlet coal mill as described in the first embodiment of the present disclosure is realized Steps in.

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Abstract

The invention provides a method and system for reducing disturbance of start and stop of a double-inlet and double-outlet coal mill to a denitration system, and belongs to the technical field of automatic control of coal-fired power plants. The influence of coal level change of the coal mill on the capacity air volume is corrected, so that the measurement precision of the capacity air volume is improved, the capacity air volume can better represent the real fuel quantity during start and stop of the coal mill, stable operation of a unit combustion system is facilitated, and fluctuation of theconcentration of nitrogen oxides in flue gas is reduced; the change range and the change rate of the capacity air volume and the secondary air volume during start and stop of the double-inlet and double-outlet coal mill are reasonably controlled, so that the disturbance intensity of fluctuation of the combustion-supporting air volume and the fuel quantity to the combustion working condition is reduced; and the ratio of the capacity air volume to the secondary air volume is reasonably controlled, so that good matching of the combustion-supporting air and the fuel quantity is realized, large fluctuation of the oxygen content in the flue gas is reduced, the concentration fluctuation range of the nitrogen oxides generated in the flue gas is small, the change is gentle, and stable operation ofthe denitration system is facilitated.

Description

technical field [0001] The disclosure relates to the technical field of automatic control of coal-fired power plants, and in particular to a method and system for reducing the disturbance to the denitrification system caused by the start and stop of double-inlet and double-outlet coal mills. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. [0003] The units using the double-inlet and double-outlet pulverizer direct blowing pulverization system need to start and stop the coal mill frequently to change the amount of fuel entering the furnace when operating in a wide range of variable loads. During the start and stop of the coal mill, due to the large fluctuations and fast fluctuations of the volumetric air volume (or called the primary air volume carrying pulverized coal) and the combustion air volume (or called the secondary air volume) entering t...

Claims

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Application Information

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IPC IPC(8): F23K3/02F23N1/02B02C25/00
CPCF23N1/02F23K3/02B02C25/00F23K2203/201
Inventor 王景华宋益纯戚兴坤赵建新何刚赵培山韩敏王纪东孙华伟
Owner 国家能源(山东)工程技术有限公司
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