Flue gas backward-flow preventing coal feeding device of CFB boiler and flue gas backward-flow preventing method of device

Abstract

The invention discloses a flue gas backward-flow preventing coal feeding device of a CFB boiler and a flue gas backward-flow preventing method of the device, and belongs to the technical fields of coal feeding devices, and aims at solving the problems of overhaul inconvenience and environment pollution caused by flue gas backward flowing and operation difficulty caused by in-furnace negative pressure suction during the shutdown of the conventional coal feeder. The process of the flue gas backward-flow preventing coal feeding device is as follows: a, when a coal feeder operates normally, a gate valve is opened, an isolating valve is closed, the fire coal passes through a belt, a scraper coal feeder and a Venturi coal falling pipe in sequence and then falls to a material returning leg of a material returning device, and the fire coal and recycle materials at the bottom outlet of a cyclone separator together enter the hearth; b, when the coal feeder is shutdown and overhauled, the gate valve is closed, the isolating valve is opened, sealing air in a sealing air pipe forms a downward inclined jet flow through a dip angle alpha formed between the air outlet of the sealing air pipe and the wall surface of the straight pipe section, above the contraction section, of the Venturi coal falling pipe; c, through the suction force of the Venturi coal falling pipe, the downward inclined jet flow formed by the sealing air is sucked to the material returning leg of the material returning device and the hearth. The flue gas backward-flow preventing coal feeding device is convenient to operate and maintain and low in investment, and can be used for effectively solving the problems of flue gas backward flowing, device corrosion, overhaul and operation difficulty and environment pollution during the shutdown of the coal feeder.

Description

technical field [0001] The invention belongs to the technical field of coal feeding devices for boilers, and in particular relates to a coal feeding device and a method for preventing flue gas reverse channeling of a CFB boiler. Background technique [0002] At present, when the coal feeder of the boiler is out of service, the flue gas in the furnace will flow back, and the coal feeder and its connected devices will be corroded, which will cause inconvenient maintenance of the coal feeder and related equipment, environmental pollution, and increase the maintenance workload of the system and equipment. Large, increasing the operation and maintenance costs of the coal feeding system. At the same time, in order to avoid the backflow of flue gas when the coal feeder is out of service, the operator needs to carry out the negative pressure work of the boiler, which will bring certain dangers to the work of the operator, and the negative pressure will also cause the output of the i...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a CFB boiler anti-corrosion boiler for the shortcomings of coal feeding devices such as inconvenient maintenance, environmental pollution, and operational difficulties caused by negative pressure in the furnace caused by the outage of the coal feeder of the CFB boiler. Coal feeding device for flue gas reverse channeling

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