Coal economizer water temperature adjusting system under full-load denitration working condition

Abstract

The invention discloses a coal economizer water temperature adjusting system under the full-load denitration working condition. The coal economizer water temperature adjusting system comprises a turbine high pressure cylinder, a first high pressure heater, a coal economizer, a boiler and a steam increasing machine, wherein the first-section steam extracting pipeline of the turbine high pressure cylinder is connected with the steam side of the first high pressure heater; the high pressure steam inlet of the steam increasing machine is connected with the high temperature steam pipeline of the boiler; the low pressure steam inlet of the steam increasing machine is connected with the first-section steam extracting pipeline of the turbine high pressure cylinder; the mixed steam outlet of the steam increasing machine is connected with the steam side of the first high pressure heater; and boiler feedwater passes through the first high pressure heater and enters the coal economizer after beingheated and warmed by steam. The coal economizer water temperature adjusting system is small in transforming workload and low in cost; and under high load or low load of a unit, an SCR denitration device effectively runs.

Description

technical field [0001] The invention belongs to the field of environmental protection, and in particular relates to a water temperature regulating system for an economizer under full-load denitrification working conditions. Background technique [0002] In recent years, the low annual average utilization hours of thermal power units in my country is a serious problem faced by thermal power plants. The load rate of most units is less than 70%, or even lower. Under low-load working conditions, the inlet water temperature of the economizer will be relatively low, and the feed water entering the economizer will absorb too much heat, which will cause the flue gas temperature at the outlet of the economizer to be too low. [0003] The SCR denitration device is arranged after the economizer, and the catalyst will fail when the working environment is lower than 290 ° C. Therefore, when the unit is running at low load, the SCR denitrification device will not be able to operate normal...

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Problems solved by technology

However, this method needs to add a new high-pressure heater to the heat recovery system, and it is usually difficult to renovate the pipeline of the heat recovery system and add a No. 0 high-pressure heater in the turbine room of the power plant.

[0008] The above three methods have disadvantages, and it is difficult to implement them, especially in the renovation project for existing operating units.

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