Method for widening SCR denitration low-load operation potential based on ammonium bisulfate poisoning recovery characteristics of catalyst

Abstract

The invention relates to a method for widening SCR denitration low-load operation potential based on ammonium bisulfate poisoning recovery characteristics of a catalyst. The method includes determining the lowest continuous ammonia injection temperature of the catalyst; enabling the catalyst to continuously operate at the temperature T1, wherein T1 is lower than the lowest continuous ammonia injection temperature, the continuous operation time is t1, the unit load corresponding to T1 is W1; and after the continuous operation time of the catalyst at the temperature T1 exceeds t1, enabling the operation temperature of the catalyst to be increased to T2 for continuous operation, wherein T2 is not lower than the minimum continuous ammonia injection temperature, the continuous operation time ist2, the unit load corresponding to T2 is W2, and the difference value between W1 and W2 is the percentage or potential that the SCR denitration low-load operation of the unit can be widened. The method does not need to preform temperature raising transformation on on-site equipment, fully utilizes the low-load adaptability of the catalyst to realize the wide-load operation of the denitration system, reduces transformation investment, avoids the shutdown from affecting the power generation of the unit, and reduces the risk of affecting the normal operation of the unit due to the equipment transformation.

Description

technical field [0001] The invention relates to a method for widening the potential of SCR denitrification and low-load operation based on the recovery characteristics of catalyst ammonium bisulfate poisoning. Background technique [0002] In view of the current strict environmental protection emission standards, flue gas SCR denitrification technology is widely used in coal-fired power plants. SCR denitration is the use of reducing agents (such as NH 3 , urea) under the action of catalyst, selectively with NO x N 2 and H 2 O. [0003] Flue gas from coal-fired power plants contains SO 3 Gas, because the nano-scale microporous structure of the catalyst itself is prone to capillary condensation, when the temperature of the flue gas is lower than the minimum continuous ammonia injection temperature (MOT) of the catalyst, there is SO in the flue gas 3 、H 2 O will react with reducing agent NH 3 The action generates ammonium bisulfate, which will block the micropore struct...

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Problems solved by technology

[0003] Flue gas from coal-fired power plants contains SO 3 Gas, because the nano-scale microporous structure of the catalyst itself is prone to capillary condensation, when the temperature of the flue gas is lower than the minimum continuous ammonia injection temperature (MOT) of the catalyst, there is SO in the flue gas 3 、H 2 O will react with reducing agent NH 3 The action produces ammonium bisulfate, which will block the micropore structure of the catalyst and cause the risk of poisoning

[0004] In order to reduce nitrogen oxide emissions under lower unit loads, most coal-fired power plants have adopted schemes such as flue gas temperature adjustment bypass modification, water bypass modification, and heating surface classification modification, so as to increase the inlet of flue gas denitrification system under low load. The flue gas temperature is above the minimum continuous ammonia injection temperature (MOT), but these equipment transformation schemes have the risk of large investment, unit shutdown affecting power generation, and equipment failure during operation

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