On-line cyclic detection device and control method for NOx concentration of SCR (Selective Catalytic Reduction) reaction chamber

Abstract

The invention discloses an on-line cyclic detection device and a control method for NOx concentration of an SCR (Selective Catalytic Reduction) reaction chamber. The on-line cyclic detection device comprises a sampling module, a cyclic control module and a flue gas analysis module, wherein the sampling module comprises multiple groups of sampling guns, sampling boxes, multiple pipelines and suction pumps, each group of sampling guns extend into the SCR reaction chamber in correspondence to ammonia spraying partitions, and multiple sampling guns with different lengths are distributed along theflue depth direction according to a grid method; the cyclic control module comprises a logical control cabinet, detection electromagnetic valves and emptying electromagnetic valves; and the flue gas analysis module comprises a flue gas pretreatment unit and a flue gas analyzer. Cyclic detection is performed according to 'previous measurement and next preparation' by taking the ammonia spraying partitions as units, thereby greatly shortening the cyclic detection period; and simultaneously, each ammonia spraying partition has a plurality of sampling points with different depths, each sampling point is sampled by the corresponding sampling gun, and the sampled flue gases of multiple sampling guns in one ammonia spraying partition are mixed, averaged and then detected, so that the representativeness of the detection result can be improved.

Description

technical field [0001] The invention relates to the technical field of denitrification in thermal power plants, in particular to an online roving detection device for NOx concentration in an SCR reaction chamber and a control method thereof. Background technique [0002] Flue gas NOx concentration is an important indicator required by the Ministry of Environmental Protection of China to monitor the flue gas of thermal power plants. GB13223-2011 "Emission Standards of Air Pollutants for Thermal Power Plants" puts forward stricter requirements for the concentration of NOx in the flue gas emitted by thermal power plants. At present, most thermal power plants use Selective Catalytic Reduction (SCR) for denitrification, and the amount of ammonia injection in the SCR denitrification system has an important impact on the denitrification efficiency. The amount of ammonia injection is too small, the denitrification efficiency is low, and the NOx concentration of the exhaust flue gas ...

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and provide an online roving detection device for NOx concentration in the SCR reaction chamber, which solves the problem that the prior art NOx concentration roving detection cycle is long and the detection results cannot reflect the average level of NOx concentration in the ammonia injection zone , It is difficult to provide a reasonable basis for the SCR denitrification system to adjust the amount of ammonia injection

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