Coal-fired boiler SCR (Selective Catalytic Reduction) denitration control method and system

A technology of coal-fired boilers and control methods, applied in various fluid ratio control, separation methods, chemical instruments and methods, etc., can solve problems such as excessive, extensive control, and insufficient ammonia injection, so as to reduce standard deviation and extend service life The effect of life, safety and stability improvement

Active Publication Date: 2014-12-24
河南合众电力技术有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to provide a control method and control system for SCR denitrification of a coal-fired boiler,

Method used

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  • Coal-fired boiler SCR (Selective Catalytic Reduction) denitration control method and system
  • Coal-fired boiler SCR (Selective Catalytic Reduction) denitration control method and system
  • Coal-fired boiler SCR (Selective Catalytic Reduction) denitration control method and system

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Embodiment 1

[0027] As a control method, the present invention is different from the existing control methods. The molar ratio of ammonia nitrogen before the catalyst is selected as the feedforward amount, and the molar ratio of ammonia nitrogen is preset as the target, and the regulating valve of the ammonia injection device is controlled by an automatic control algorithm such as PID control. To control the amount of ammonia injection.

[0028] Specifically, the ammonia nitrogen molar ratio before the catalyst is the product of the ratio between the NOx concentration and the ammonia concentration before the catalyst and the ratio of the corresponding molar value; Ratio of former NOx concentration.

[0029] The control introduces the preset NOx concentration, the NOx concentration before the catalyst and the ammonia concentration, which can ensure that there will be no excessive or insufficient ammonia injection to the greatest extent, and then reduce the ammonia consumption while ensuring...

Embodiment 2

[0031] Such as figure 1 Shown is a coal-fired boiler SCR denitrification system according to an embodiment of the present invention, including a flue gas inlet chamber, a catalyst chamber, and a flue gas outlet chamber connected in sequence. The vertical section of the coal-fired boiler SCR denitrification system in the flue gas advancement The upper part is divided into several areas, and the flue gas inlet chamber corresponding to each area is equipped with a corresponding ammonia injection device, a NOx concentration detection device 2 before the catalyst, and an ammonia concentration detection device 3 before the catalyst, and the ammonia concentration detection device 3 before the catalyst is installed Downstream of the ammonia plant.

[0032] The ammonia injection device includes several nozzles, the nozzles are connected to the ammonia injection main pipe 5, and a regulating valve 4 is arranged on the ammonia injection branch between the ammonia injection main pipe and ...

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Abstract

The invention relates to a coal-fired boiler SCR denitration control method and system. The method includes the steps of monitoring the molar ratio of ammonia and nitrogen in each section in real time before flue gas enters a catalyst, regulating ammonia injection branch pipe remote electric control regulating valves corresponding to each section to control ammonia supply amount of each section in real time according to a preset molar ratio of ammonia and nitrogen, and keeping the actually measured molar ratio of ammonia and nitrogen to be identical to the preset molar ratio of ammonia and nitrogen so as to prevent excessive ammonia injection and ensure even concentration distribution of nitric oxides at a denitration system outlet.

Description

technical field [0001] The invention relates to the field of coal-fired boiler pollutant emission treatment, in particular to a coal-fired boiler SCR denitrification control system. Background technique [0002] With the increasingly stringent emission standards of thermal power plants, Selective Catalytic Reduction (SCR) has become an essential part of coal-fired boilers. SCR uses liquid ammonia or urea as a reducing agent to reduce NOx into N 2 and H 2 O, unreacted NH during the reaction 3 It is discharged with the flue gas in the form of escape ammonia, and a small amount of SO will be produced during the combustion process of the coal-fired boiler 3 , unreacted NH 3 and SO 3 And the water in the flue gas undergoes a chemical reaction to generate ammonium bisulfate (ABS). The chemical reaction equation is: It can be seen from the equation that the reaction rate of ammonium bisulfate is mainly related to the flue gas temperature and the escaped NH in the flue gas. 3...

Claims

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Application Information

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IPC IPC(8): B01D53/90B01D53/56G05D11/13
Inventor 谢慧朱红涛
Owner 河南合众电力技术有限公司
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