Real-time online prediction and control method for ammonia escape concentration

Abstract

The invention discloses a real-time online prediction and control method for ammonia escape concentration. The real-time online prediction and control method disclosed by the invention comprises the following steps: S1, testing the NOx concentration at the inlet and / or the outlet of an SCR reactor, the NH3 / NOx molar ratio, the denitration efficiency and the ammonia escape concentration on site; S2, by utilizing data acquired by the step S1, calculating the current potential of a reactor under the real unit load, and predicting the ammonia escape concentration in real time according to the NOx concentration at the inlet of the reactor and the denitration efficiency which are displayed by a DCS dial plate; and S3, according to the predicted ammonia escape concentration value and a pre-designed upper limit value of the ammonia escape concentration, predicting the ammonia escape concentration in a period of time in the future, and controlling the amount of sprayed ammonia in a manual or automated way. The real-time online prediction and control method disclosed by the invention has the advantages that the actual ammonia escape concentration can be predicted according to flue gas conditions at the inlet of the SCR reactor and the operation denitration efficiency, the ammonia spraying flow and the denitration efficiency are reasonably controlled, denitration performance efficiency improvement is timely and early warned, the ammonia escape concentration is controlled and lowered, and influence on blockage of a downstream air preheater is reduced.

Description

Technical field [0001] The invention belongs to the field of ammonia escape concentration control during the operation of SCR flue gas denitrification equipment in thermal power plants, and specifically relates to a real-time online prediction and control method of ammonia escape concentration. Background technique [0002] Selective Catalytic Reduction (SCR) is the main denitrification process widely used in large-scale coal-fired units at home and abroad. SCR denitration process uses ammonia (NH 3 ) Is the reducing agent. The ammonia gas is sprayed into the flue through the ammonia injection grid, fully mixed with the flue gas, and enters the SCR reactor. Under the action of the multilayer catalyst, the NO in the flue gas is removed x Reduce to N 2 And H 2 O, complete NO X The removal. Among them, the denitrification efficiency and ammonia escape concentration are the two most important performance indicators for the interdependence of denitrification equipment. For a given de...

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Problems solved by technology

[0005] Aiming at the problem of serious clogging of ammonium bisulfate in the air preheater caused by unreliable online CEMS detection of ammonia escape concentration in SCR flue gas denitrification, the present invention provides a real-time online prediction and control method for ammonia escape concentration

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