An anti-overheating device and control method for a CFB boiler after burning peat

Abstract

The invention discloses an over-temperature prevention device for a CFB (circulating fluid bed) boiler after addition and burning of peat and a control method of the over-temperature prevention device; the device comprises a secondary air fan (7), a low temperature overheater, a lower temperature reheater (6), pasty fluid pumps (4) and peat spouts (2); the pasty fluid pumps (4) and the peat spouts (2) are connected by peat feeding pipelines; a peat pipeline air exhaust valve (3) is installed on each of the peat feeding pipelines; the air of the peat pipeline air exhaust valve (3) is exhausted every 3h for 3-5min, so that the output of the secondary air fan (7) is reduced and the oxygen content in a hearth is kept between 1.5% and 2.0%. According to the device and the method disclosed by the invention, the problems of the prior art that when the peat is added and is combusted in the CFB boiler, the combustion conditions are easily deviated from a design standard greatly if the peat exceeds the standard, the heating surfaces inside the boiler and on the tail part of the boiler are over-temperature, the safety operation of the boiler is affected or the machine set is in non-planned outage in a severe case, and the like are solved.

Description

technical field [0001] The invention belongs to boiler combustion control technology, in particular to a device for preventing overheating of a CFB boiler after burning peat and a control method thereof. Background technique [0002] At present, the amount of peat fired in CFB boilers designed by major boiler factories is generally between 10% and 30% of the designed fuel volume of the boiler. In this range, the peat fired system can operate normally, and the boiler can basically achieve stable and safe combustion. Because peat is the waste after coal washing in coal mines, except for CFB power plant boilers, other boilers and industrial applications are rarely used. my country produces more than 300 million tons of low calorific value coal resources such as coal gangue, coal slime, and washed coal that can be used for power generation every year. The built low calorific value coal power generation units can only consume more than 100 million tons of low calorific value coal ...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide an anti-overheating device and its control method after the CFB boiler burns peat, so as to solve the problem that when the CFB boiler burns peat in the prior art, the peat exceeding the standard will easily lead to boiler combustion failure. The condition greatly deviates from the design standard, resulting in overheating of the heating surface in the furnace and at the rear, which will affect the safe operation of the boiler in serious cases and cause problems such as unplanned shutdown of the unit

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