Full-load precise ammonia spraying system with functions of online speed field leveling and concentration field measuring

Abstract

The invention discloses a full-load precise ammonia spraying system with functions of online speed field leveling and concentration field measuring. The full-load precise ammonia spraying system comprises a zone flue gas speed measuring device and a zone NOx (oxynitride) concentration measuring device corresponding to a vertical flue zone between a first corner fixed flow guide plate and a primaryammonia spraying grid, and a secondary micro-ammonia spraying and supplementing system, a zone speed measuring device, and a zone ammonia and nitrogen integrated concentration measuring device whichare arranged from top to bottom corresponding to each zone between a flow equalizer and a catalyst layer; a zone ammonia and nitrogen integrated concentration measuring device is arranged corresponding to each zone between the catalyst layer and an exit flue; a zone flue gas speed measuring device, a zone NOx concentration measuring device, a zone speed measuring device and the zone ammonia and nitrogen integrated concentration measuring device are used for respectively transmitting the measuring data to an input port of a control unit, and the control unit is used for generating a control adjusting signal, and sending to a primary ammonia spraying grid, a dynamic flow field leveling flow guide device, and a secondary micro-ammonia spraying and supplementing system via an output end. The full-load precise ammonia spraying system has the advantages that the speed field in front of the catalyst can be flexibly leveled according to the characteristics of the flue gas flow field formed bythe combination of different coal types, different loads and different combustors.

Description

technical field [0001] The invention relates to a full-load precise ammonia injection system for online velocity field leveling and concentration field measurement, and belongs to the technical field of environmental treatment. Background technique [0002] The newly revised "Emission Standards of Air Pollutants for Thermal Power Plants" has set very strict requirements on NOx emissions, requiring NOx emission standards to be within 50 mg / Nm3. Only relying on low-nitrogen combustion cannot meet the emission target requirements. Therefore, controlling NOx after combustion, That is, installing a denitrification device at the tail of the flue has become an inevitable choice for coal-fired power plants. Among denitrification technologies, SCR has become the main choice for coal-fired power plants due to its high denitrification efficiency and mature technology. However, due to the strong nonlinearity and large hysteresis of the existing SCR system itself, there is a problem tha...

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Problems solved by technology

[0008] Purpose of the invention: The purpose of the invention is to address the deficiencies of the prior art, to provide a full-load precision ammonia injection system for online velocity field leveling and concentration field measurement, and to solve the problem that the existing SCR denitrification system cannot be based on the concentration and flow rate of NOx at the inlet of the catalyst layer. The problem of on-demand ammonia injection, under the demand of frequent peak shaving in power plants, can reduce the amount of ammonia injection and ammonia slip rate as much as possible under full load conditions, and can make the NOx concentration at the tail of the flue reach the standard smart ammonia injection system

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