Online detection system and method for ammonia gas concentration plane distribution at outlet of SCR

Abstract

The invention discloses an online detection system and method for ammonia gas concentration plane distribution at an outlet of SCR. The detection system comprises a sampling module, a flue gas pre-treatment module, a laser detection module and a data processing module; after the sampling module carries out lattice sampling in flues in more than two sides, the multiple channels of flue gas are introduced to the flue gas pre-treatment module for pre-treatment such as dedusting, the laser detection module detects the multiple channels of flue gas with laser at the same time, and NH3 concentrationvalues of the multiple channels of flue gas are calculated synchronously through processing the multiple channels of detection signals by the data processing module, and a plane distribution result of NH3 concentration is obtained. The system and method can accurately measure NH3 concentration at the outlet of the SCR denitrifying system. The detection signals of the multiple channels of flue gascan be generated at the same time. Data acquisition and processing can be carried out according to a set sequence. The time interval of acquisition and processing of two adjacent channels of data does not exceed 5s, so that the lattice detection period is shortened greatly, and the equipment cost and the maintenance cost are lowered obviously.

Description

technical field [0001] The invention relates to an operation optimization technology of a thermal power plant denitrification system in the field of environmental protection technology, in particular to an online detection system for the plane distribution of ammonia gas concentration at an SCR outlet. Background technique [0002] With the increasing pollution of NOx emissions, the state has put forward stricter requirements on NOx emissions. Selective catalytic reduction (SCR) technology is the flue gas denitrification technology currently used in most coal-fired power plants, and its main principle is NH 3 As a reducing agent, it reacts with the pollutant NOx in the flue gas to generate non-toxic and non-polluting N 2 and H 2 O, so as to meet the national requirements for smoke emissions. The control of the amount of ammonia injection during the operation of the flue gas denitrification device should not only ensure the maximum removal of NOx, but also reduce the amoun...

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Problems solved by technology

[0005] The purpose of the present invention is to solve the problems of low efficiency, high cost, large maintenance and unrepresentative single-point measurement results of TDLAS concentration online single-point measurement of escaped ammonia in the SCR denitrification device of a coal-fired power plant, and provide a plane distribution of ammonia concentration On-line detection system, realizing a set of detection system to simultaneously detect NH in flue gas with grid-type multi-point sampling 3 Concentration, to obtain the concentration distribution of escaped ammonia in the SCR denitrification device, improve the efficiency of gas concentration detection, and reduce the equipment cost and maintenance cost required for gas concentration detection

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