Coal economizer water temperature adjusting system for denitration input in unit starting process

Abstract

The invention discloses a coal economizer water temperature adjusting system for denitration input in the unit starting process. The system comprises a platen superheater, a high-pressure main steam valve, a high-pressure regulating valve, a high-pressure cylinder, a high-pressure bypass, a low-temperature reheater, a regulating valve, a second electric valve, a first high-pressure heater, a high-pressure cylinder steam exhaust check valve, a low-temperature reheater, a second-section steam extraction check valve, a first electric valve, a second high-pressure heater, a first-section steam extraction check valve, a first-section steam extraction electric valve, a high-temperature reheater, a medium-pressure main steam valve, a medium-pressure cylinder, a low-pressure bypass, a condenser, athree-section steam extraction check valve, a three-section steam extraction electric valve, a third high-pressure heater, a four-section steam extraction check valve, a four-section steam extractionelectric valve, an auxiliary steam header, a secondary economizer and a denitration reactor. The system can reduce nitrogen oxide emission in the starting stage.

Description

technical field [0001] The invention relates to a water temperature regulating system for an economizer, in particular to a water temperature regulating system for an economizer with denitrification input in the start-up process of a unit. Background technique [0002] At present, domestic thermal power plants widely use SCR (Selective Catalytic Reduction) to control NOx emissions. Different catalysts have different suitable reaction temperatures, and the inlet flue gas temperature varies with the boiler load. When the boiler load drops to 40% to 50% of the unit load, the inlet temperature of the reactor is low, on the one hand, the catalyst activity is low, on the other hand, the reducing agent ammonia and the SO in the flue gas 3 The ammonia bisulfate produced by the reaction will be deposited on the catalyst, further reducing the activity of the catalyst, and even causing an irreversible reduction in the activity of the catalyst. At present, most SCR systems at home and...

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Problems solved by technology

The above five divisions have their own advantages and disadvantages, and they all have a lot of engineering application practice. After the transformation, they can basically realize the minimum stable combustion load of the boiler (about 35% BMCR) and start to put it into operation.

[0004] However, even after the wide-load denitrification transformation, the unit still cannot be put into normal operation for a long period of time from the start of coal commissioning to normal operation, and the nitrogen oxide emission of the boiler exceeds the standard. The release time will be longer

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