Device for preventing coal dust in gas-solid separator of boiler for circulating fluidized bed from coking

Abstract

The invention relates to a method for preventing coal dust in a gas-solid separator of a boiler for a circulating fluidized bed from coking. According to the design provided by the invention, a low-temperature medium communicating pipe is arranged at the inlet of the gas-solid separator, and the low-temperature medium is derived from the intermediate extracted steam of a steam turbine or the outlet exhaust gas of a boiler induced draft; an electric butterfly valve is additionally arranged on the communicating valve; and temperature measuring devices are arranged at the inlet, outlet and discharge hole of the gas-solid separator. When the coal dust keeps burning and the exhaust gas rises in the gas-solid separator, the coal dust in the gas-solid separator is coked and the discharge hole isblocked, in order to prevent the coal dust in the gas-solid separator from coking, the electric butterfly valve can be switched on by an actuating mechanism according to the preset temperature of a controller and the low-temperature medium can be mixed into the high-temperature exhaust gas to reduce the temperature of the high-temperature exhaust gas. By using a low-temperature medium to reduce the temperature of the exhaust gas in the gas-solid separator, the invention has the advantages of high temperature regulating speed and high temperature regulating reliability.

Description

technical field [0001] The invention relates to a method for preventing coking of coal dust in a gas-solid separator of a circulating fluidized bed boiler, which is used for cooling flue gas in the gas-solid separator of a circulating fluidized bed boiler. Background technique [0002] Fluidized bed combustion is a clean coal-fired technology, and many of its unique advantages are beyond the reach of traditional boilers: the fuel has wide adaptability, and it can burn difficult-to-combustible coals and various low-calorific value, high-ash low-quality coals, as well as solid waste and other wastes; due to the multiple cycles of coal ash and fuel, it provides enough burnout time for the fuel, so that the carbon content of the fly ash is significantly reduced, so the combustion efficiency is high; the adjustment range of the boiler load is much larger than that of the pulverized coal furnace more; the combustion intensity of the boiler is high, and the ash and slag are easy to...

AI Technical Summary

Problems solved by technology

Especially when burning fuel with poor ignition performance and long burnout time, the fuel with small particles cannot be burned out in the dense phase area and dilute phase area of ​​the furnace, and is entrained by the flue gas into the gas-solid separator. Due to the oxygen in the flue gas These fuels continue to burn in the gas-solid separator, and the temperature of the flue gas in the gas-solid separator rises. When the temperature of the flue gas reaches the softening temperature of the coal ash, the coal dust in the gas-solid separator sticks to each other and cokes. Fall into the discharge port at the bottom of the gas separator and block the discharge port, preventing the coal dust collected by the gas-solid separator from returning to the boiler for combustion. At the same time, a large amount of coal dust accumulates in the gas-solid separator, which affects the separation of the gas-solid separator effect, endangering the safe and economical operation of the boiler

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