Device for preventing ash deposition at bypass flue inlet horizontal section of coal-fired boiler economizer

Abstract

The invention provides a device for preventing ash deposition at a bypass flue inlet horizontal section of a coal-fired boiler economizer. The device can effectively solve the problems of ash deposition at the bypass flue horizontal section and mechanical jamming of a baffle door, ensure the catalyst efficiency and meet the denitration commissioning requirements. The device comprises a boiler hearth, wherein the boiler hearth is sequentially connected with a low-temperature superheater, the boiler economizer and an SCR denitration reactor after passing through an outlet flue of the boiler hearth, and a boiler bypass flue is arranged between an outlet of the outlet flue of the boiler hearth and an inlet of the SCR denitration reactor; a bypass flue baffle door is installed at an inlet of the boiler bypass flue and arranged on a bypass flue inlet horizontal flue of the boiler bypass flue; and a communicated bypass flue ash conveying channel is arranged between the bypass flue inlet horizontal flue in front of the bypass flue baffle door and the outlet flue of the boiler hearth.

Description

technical field [0001] The invention relates to the technical field of an economizer bypass flue, in particular to a device for preventing ash accumulation at a horizontal section of an inlet of a coal-fired boiler economizer bypass flue. Background technique [0002] At present, it has become an inevitable trend for thermal power plants to participate in flexible peak shaving, and its primary goal is to reduce the minimum technical output of units. The existing widely used flue gas denitrification technology (SCR technology), due to catalyst activity and other reasons, its working temperature is generally 310 ℃ ~ 420 ℃, and under low load (generally below 50% of the rated load), the flue gas temperature cannot meet , in order to increase the inlet flue gas temperature of the flue gas denitrification system under low load, and realize full-load operation of the SCR flue gas denitrification device, most coal-fired power plants adopt the economizer bypass transformation plan, ...

AI Technical Summary

Problems solved by technology

The existing widely used flue gas denitrification technology (SCR technology), due to catalyst activity and other reasons, its working temperature is generally 310 ℃ ~ 420 ℃, and under low load (generally below 50% of the rated load), the flue gas temperature cannot meet , in order to increase the inlet flue gas temperature of the flue gas denitrification system under low load, and realize full-load operation of the SCR flue gas denitrification device, most coal-fired power plants adopt the economizer bypass transformation plan, that is, install the economizer bypass flue There is a baffle door to adjust the high-temperature flue gas volume at the inlet of the SCR device. Generally, under the high-load condition of the boiler, the economizer bypass baffle door is closed; When the ammonia temperature is high, the baffle door is opened, but in the actual operation process, when the economizer bypass flue baffle door is closed, a "dead zone" will be formed at the front end of the baffle door, resulting in the bypass flue inlet level Severe dust accumulation at the position of the flue. If the horizontal section of the economizer bypass flue accumulates dust for a long time, it will easily cause the mechanical jamming of the damper door, so that the damper door cannot be closed completely when the unit is under high load. Strictly speaking, the high-temperature flue gas will enter the SCR denitrification reactor through the bypass flue of the economizer, causing local overheating of the flue gas and affecting the catalyst efficiency; Severe dust accumulation causes the resistance of the bypass flue to increase, and an effective pressure difference cannot be formed, so that the high-temperature flue gas entering the SCR denitrification reactor is relatively small, and the flue gas temperature cannot meet the denitrification requirements for operation

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