System and method for reducing boiler NOx emission by tertiary air concentrated-diluted separation

A technology of thick-thin separation and thick-thin separator, which is applied in the system field of tertiary air thick-thin separation to reduce boiler NOx emissions, can solve the problems of high carbon content in fly ash, high NOx emission of boiler tertiary air, and low burnout rate, and achieve reduction Effect of NOx emission, guarantee of burnout rate, reduction of NOx emission

Active Publication Date: 2016-04-20
SHANGHAI BOILER WORKS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The invention aims to solve the technical problems of excessive NOx emission in the tertiary air of the boiler, high carbon content in fly ash and low burnout rate

Method used

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  • System and method for reducing boiler NOx emission by tertiary air concentrated-diluted separation
  • System and method for reducing boiler NOx emission by tertiary air concentrated-diluted separation
  • System and method for reducing boiler NOx emission by tertiary air concentrated-diluted separation

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Embodiment 1

[0042] image 3 The burner arrangement provided for this embodiment. combine figure 2 , image 3 , the concentrated powder (accounting for 70% powder amount of former tertiary wind) that the tertiary air separates, sprays into the middle part of main combustion zone through two layers of tertiary air dense powder spouts 7, and arranges separately, replaces two layers of secondary air spouts 2 respectively, reduces The amount of oxygen in the main combustion zone is increased, so that the main combustion zone is in an oxygen-deficient reducing atmosphere, which is beneficial to the reduction of NOx produced by combustion. Concentrated coal powder has an average particle size of 18 μm. As a fine coal powder, it ignites quickly, gasifies quickly, and has fast response ability. It can form a large number of reducing particles in a short period of time and maintain a certain concentration. The effect of reducing NOx is remarkable. The light powder separated by the tertiary air ...

Embodiment 2

[0044] Figure 4 The burner arrangement provided for this embodiment. combine figure 2 , Figure 4 , the thick powder (accounting for 70% powder amount of former tertiary wind) that the tertiary wind separates, sprays into the middle and lower part of the main combustion zone through two layers of tertiary wind thick powder nozzles 7, and one layer of tertiary wind thick powder nozzles 7 sprays into the main combustion zone at the end In the lower part, another layer of tertiary air dense powder nozzles 7 is sprayed into the middle of the main combustion zone, replacing two layers of secondary air nozzles 2, which reduces the amount of oxygen in the main combustion zone and makes the main combustion zone in an oxygen-deficient reducing atmosphere, which is conducive to combustion. NOx reduction. Concentrated coal powder has an average particle size of 18 μm. As a fine coal powder, it ignites quickly, gasifies quickly, and has fast response ability. It can form a large numb...

Embodiment 3

[0046] Figure 5 The burner arrangement provided for this embodiment. combine figure 2 , Figure 5 , the concentrated powder (accounting for 70% powder amount of the original tertiary air) separated by the tertiary air is sprayed into the middle part of the main combustion zone through two layers of tertiary air dense powder nozzles 7, and arranged adjacently, replacing the two layers of secondary air nozzles 2, reducing The amount of oxygen in the main combustion zone is increased, so that the main combustion zone is in an oxygen-deficient reducing atmosphere, which is beneficial to the reduction of NOx produced by combustion. Concentrated coal powder has an average particle size of 18 μm. As a fine coal powder, it ignites quickly, gasifies quickly, and has fast response ability. It can form a large number of reducing particles in a short period of time and maintain a certain concentration. The effect of reducing NOx is remarkable. The light powder (accounting for 30% pow...

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Abstract

The invention provides a system for reducing boiler NOx emission by tertiary air concentrated-diluted separation. An outlet of a tertiary air powder exhaust fan is connected with a coal powder concentrated-diluted separator; a separation blade for adjusting a separation quantity of concentrated-diluted coal powder is arranged on an inlet section of the coal powder concentrated-diluted separator, and a concentrated coal powder pipe and a diluted coal powder pipe are arranged on an outlet section; the concentrated coal powder pipe is connected with at least one layer of hearth main combustion area middle lower nozzles; and the diluted coal powder pipe is connected with at least one layer of hearth main combustion area upper nozzles. The invention further provides a method for reducing boiler NOx emission by tertiary air concentrated-diluted separation; tertiary air containing thin coal powder is separated as concentrated and diluted two parts of coal powder air currents; and the concentrated and diluted two parts of coal powder air currents are respectively sprayed into the middle lower part and the upper part of a hearth main combustion area. The concentrated coal powder current replaces one part of secondary air to form an oxygen debt environment in the main combustion area so as to enhance the reducibility of the main combustion area; the diluted coal powder current is quickly burnt to consume oxygen so as to enhance the reducibility of NOx in a boiler; and the secondary air quantity reduced in the main combustion area is replenished to high-level burnt air so as to guarantee the burn-off rate of the coal powder in the boiler.

Description

technical field [0001] The invention relates to a system and method for reducing boiler NOx emissions, in particular to a system and method for reducing boiler NOx emissions by separating thick and thin tertiary air. Background technique [0002] For lean coal and anthracite with low volatile content, my country's coal-fired power plants use more intermediate storage-type pulverized coal boilers, mainly because the hot air powder delivery system can improve the ignition performance of pulverized coal. After passing through the fine powder separator, most of the coal powder is stored in the powder bin, and the hot air heated by the air preheater is used as the primary air to be transported to the furnace to participate in combustion, and the exhaust gas separated and discharged by the fine powder separator carries part of the fine powder. Pulverized coal is input into the furnace as tertiary air for combustion. Due to the high humidity of the tertiary wind, low temperature, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F23K3/02F23C7/00
CPCF23C7/00F23C2201/101F23C2201/30F23C2900/06041F23K3/02F23K2201/30F23K2203/201
Inventor 韩志江易祖耀李江涛张建文龚丽颖马先良
Owner SHANGHAI BOILER WORKS
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