Flue gas extraction analysis and ammonia spraying control system

Abstract

The invention relates to a flue gas extraction analysis and ammonia injection control system, which comprises a sampling detection device and an ammonia injection device, the sampling detection device comprises a plurality of sampling branch pipes, a sampling header pipe and a NOx analyzer, one end of each sampling branch pipe is provided with a sampling port, and the other end of each sampling branch pipe is communicated with one end of the sampling header pipe; the plurality of sampling ports are formed in the cross section, below the lower catalyst layer, of the denitration reactor at intervals, and the sampling header pipe is communicated with a third pipe section between the air pre-heater and the smoke exhaust outlet; the ammonia spraying device comprises an ammonia spraying grid provided with a plurality of ammonia spraying subareas, one or more nozzles and ammonia spraying branch pipes communicated with the one or more nozzles are arranged on each ammonia spraying subarea, and each ammonia spraying subarea corresponds to one or more sampling openings in the flowing direction of the flue gas. Through the technical scheme, the flue gas extraction analysis and ammonia injection control system provided by the invention can accurately inject ammonia, reduce ammonia escape, improve the denitration efficiency and improve the safety and stability of boiler operation.

Description

technical field [0001] The present disclosure relates to the field of environmental protection measurement and control in the power industry, in particular to a flue gas extraction analysis and control ammonia injection system. Background technique [0002] In recent years, environmental pollution caused by energy utilization has become increasingly serious. Among them, nitrogen oxides (NOx) emitted from the combustion of fossil fuels have become an important aspect of environmental pollution. Traditional low-nitrogen combustion technology can no longer meet the requirements. Gas denitrification technology has become a key technology for nitrogen oxide control, among which selective catalytic reduction (SCR) has been widely used in large coal-fired power plants. However, there are many problems after the application of low nitrogen combustion + SCR (selective catalytic reduction) denitration technology. For example, the complexity of the arrangement of the heating surface o...

AI Technical Summary

Problems solved by technology

However, there are many problems in the application of low-nitrogen combustion + SCR (selective catalytic reduction) denitrification technology.

For example, the complexity of the arrangement of the heating surface of the tail flue and the dynamic characteristics of the flow field make the distribution of the flow field at the SCR inlet uneven, and the flow state is unsteady; in order to meet the NOx emission requirements under various conditions, it is necessary to add Large ammonia injection volume; the increase of ammonia injection volume not only increases the cost of ammonia injection, but also corrodes downstream equipment and causes new environmental pollution

Usually there is only one automatic ammonia volume regulating valve for each flue. In the case of uneven distribution of NOx concentration in the inlet flue gas and large deviation of catalyst performance, the distribution of NOx at the outlet is greatly deviated, which further increases the slip of ammonia and cannot adapt to the industrial environment. change of situation

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