Automatic control method and system for scr denitrification and ammonia injection of thermal power units

Abstract

The invention discloses an automatic control method of thermal-power-unit SCR denitration ammonia spraying. The automatic control method includes the steps that the smoke flow and SCR-inlet-nitric-oxide concentration are obtained; the smoke flow is multiplied by the SCR-inlet-nitric-oxide concentration, and the basic-nitric-oxide content in smoke is obtained; the basic-nitric-oxide content is multiplied by the set denitration efficiency, and the basic-liquid-ammonia demanded quantity is obtained; the denitration-outlet-nitric-oxide content is obtained, the denitration-outlet-nitric-oxide content is compared with a denitration-outlet-nitric-oxide set value, an initial correction factor is obtained, a final correction factor is obtained in cooperation with further correction, and the liquid-ammonia demanded quantity is corrected. As the denitration-outlet-nitric-oxide set value is introduced, the denitration-outlet-nitric-oxide concentration serves as a final control target, the control target is specific, physical inspection and operation intervention intensity of operational persons are reduced, and the operational persons are liberated out of busy working. The invention also discloses an automatic control system of thermal-power-unit SCR denitration ammonia spraying.

Description

technical field [0001] The invention relates to the technical field of thermal power units, and more specifically, relates to an automatic control method for SCR denitrification and ammonia injection of thermal power units, and also relates to an automatic control system for SCR denitrification and ammonia injection of thermal power units. Background technique [0002] At present, most of the new large-scale thermal power generation units in my country adopt the SCR (Selective Catalytic Reduction) method. The SCR method generally sprays ammonia and other reducing agents into the flue gas, and uses catalysts to reduce the NO in the flue gas. X converted to N 2 and H 2 O. [0003] The classic SCR flue gas denitrification control system uses NH 3 / NO X The principle that the molar ratio is approximately equal to 1, using flue gas inlet NO X The product of concentration and flue gas flow yields the basic NO X content, which is the NO at the denitrification inlet X Total, ...

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Problems solved by technology

[0005] In view of this, the first object of the present invention is to provide an automatic control method for SCR denitrification and ammonia spraying of thermal power units, which can effectively solve the problem that operators need to go through complex monitoring and operations to make the concentration of nitrogen oxides at the desulfurization outlet reach the standard. problem, the second purpose of the present invention is to provide an automatic control system for thermal power unit SCR denitrification ammonia injection

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