A method for adjusting the uniformity of ammonia injection in an SCR flue gas denitrification system

An adjustment method and uniformity technology, which is applied in the field of uniformity adjustment of ammonia injection in the SCR flue gas denitrification system, can solve the problems of different resistance along the process and different ammonia supply flow, and achieve high adjustment accuracy, improved safety and Stable, reliable results

Active Publication Date: 2016-07-13
STATE GRID CORP OF CHINA +2
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  • Description
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AI Technical Summary

Problems solved by technology

However, the number of ammonia injection grid valves at the inlet of the SCR reactor is 20 to 30. Due to the different positions of each ammonia injection branch pipe and the outlet main pipe of the mixer, the resistance along the route of the diluted ammonia gas passing through each ammonia injection branch pipe is different. , even if the openings of the ammonia injection grille valves of each channel are the same, the ammonia supply flow rate of each pipeline is also very different

Method used

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Embodiment Construction

[0030] The technical solutions of the present invention will be further described below in conjunction with specific embodiments.

[0031] Apply technical scheme of the present invention in concrete power plant:

[0032] The denitrification system of unit #2 of a power plant in Hebei includes two SCR reactors A and B. The ammonia injection grid at the inlet of each reactor contains 24 ammonia injection branch pipes. The ammonia injection amount of each ammonia injection branch pipe can be controlled by the valve opening. Make adjustments.

[0033] Before adjusting the uniformity of ammonia injection, the NOx concentrations at the outlets of SCR denitrification reaction systems A and B are shown in Table 1 and Table 2, respectively, and the average deviations are 34.60% and 22.55% respectively; the escape ammonia is 2.7ppm and 2.9ppm respectively. The formula for calculating the mean deviation is:

[0034] Formula Ⅴ

[0035] in: ——the average deviation of NOx concentrati...

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Abstract

The invention relates to an ammonia injection uniformity adjusting method for an SCR (Selective Catalytic Reduction) flue gas denitration system. The ammonia injection uniformity adjusting method comprises the following steps: (1) adjusting the valve opening degrees of an ammonia injection grid to make the valve opening degrees identical; (2) adjusting the inlet content of diluent air; (3) calculating the target diluent air quantity of each single branch pipe; (4) calculating the target differential pressure on the two sides of a throttle orifice plate; and (5) adjusting the opening degrees of the single branch pipes of the ammonia injection grid in sequence so as to reach the target differential pressure on the two sides of the throttle orifice plate in the step (4). The adjusting method disclosed by the invention is high in degree of accuracy, simple in structure and reliable in result; the uniformity of concentration of NOx at a denitration outlet can be effectively improved, the ammonia escape is alleviated, and thus the safety and stability in operation of the system are improved.

Description

technical field [0001] The invention relates to the field of SCR flue gas denitrification, in particular to a method for adjusting the uniformity of ammonia injection in an SCR flue gas denitrification system. Background technique [0002] Nitrogen oxides (NOx) are one of the main flue gas pollutants in thermal power plants. A large amount of emissions will not only cause acid rain and photochemical smog, but also cause great harm to human health. According to the "Emission of Air Pollutants from Thermal Power Plants" (GB13223-2011), the NOx concentration of coal-fired power plants will be 100mg / Nm 3 emission limits. According to this requirement, most power plants need to install selective catalytic reduction (selectivecatalyticreduction, SCR) denitrification devices. [0003] The principle of SCR technology is to spray a reducing agent (generally ammonia) into the flue gas at a lower temperature range (280~420°C) in the presence of catalyst and oxygen, and selectively bl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D53/90B01D53/56
Inventor 陈崇明宋国升陈秋李振海张杨
Owner STATE GRID CORP OF CHINA
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