A Method of Regulating the Load of Circulating Fluidized Bed Boiler

Abstract

The invention discloses a method for regulating load of a circulating fluidized bed boiler. The method is characterized in that an ash conditioning step refers to introducing ash in an ash returner into a furnace hearth while opening an ash returning valve on the air returner, enabling high-temperature ash to enter an ash conditioner by an ash discharge pipe which is connected on the ash returning valve, cooling the high-temperature ash by a cold ash chamber in the ash conditioner, introducing fluidizing air, which carries out secondary cooling on high-temperature ash, into a venture fluidizing air chamber of the ash conditioner to form fluidizing air with high pressure flow velocity, opening an isolating valve on the ash returning pipe and blowing low-temperature ash with temperature regulated by the ash conditioner into the ash returning pipe; an ash introducing step refers to enabling ash mixture obtained by mixing ash in the ash returning pipe with low-temperature ash into the furnace hearth; and an ash discharge step refers to directly enabling cooled ash which passes through the ash conditioner to enter a bottom ash cooler through the ash discharge pipe for being discharged. According to the method disclosed by the invention, circulating ash can be flexibly introduced into a boiler and load in the boiler is regulated within a large range, so that combustion efficiency of fuels in the boiler is improved, and steam output of the boiler is increased in a facilitated mode.

Description

technical field [0001] The invention relates to the technical field of circulating fluidized bed boilers, in particular to a method for adjusting the load of circulating fluidized bed boilers. Background technique [0002] The early circulating fluidized bed boiler had a relatively high fluidization velocity, so it was called a fast circulating fluidized bed boiler. The basic theory of fast circulating bed boiler can also be used in circulating fluidized bed boiler. The circulating fluidized bed boiler adopts a single drum and natural circulation mode, and is generally divided into two shafts at the front and the rear. The front shaft is a general suspension structure, surrounded by membrane water cooling walls. From bottom to top, it is the primary air chamber, dense phase area, and dilute phase area, and the tail flue is from top to bottom: high temperature superheater, low temperature superheater, economizer, and air preheater. The tail shaft adopts a supporting struct...

AI Technical Summary

Problems solved by technology

The load of the boiler needs to be adjusted and changed depending on the situation. The existing technology can only rely on the input of wind and coal to adjust the boiler load. This traditional adjustment method has two defects: one is slow speed; the other is load adjustment. The range is small, only 65%-105%

However, when the load adjustment of the boiler is completed, two problems are brought about during stable operation: one is that at low load, the amount of ash in the furnace is too much compared to the low load, the bed temperature is low, and the combustion efficiency is low , large wear; second, when the load is high, the amount of ash in the furnace is relatively small relative to the load, and the bed temperature is high, so the load cannot be raised too high

[0007] The device for adjusting the circulating ash flow rate of circulating fluidized bed boilers disclosed in this patent document can make the circulating ash after heat exchange smoothly flow into the ash discharge pipe through the fly ash flow controller and the heat exchanger, and it is easy to control the amount of ash discharge and the amount of ash discharge. Ash speed; however, the load in the boiler cannot be adjusted by circulating ash, the concentration of particles in the boiler is not easy to control, and the load adjustment range of the boiler is narrow, resulting in low fuel combustion efficiency in the boiler, which is not conducive to increasing the steam production of the boiler

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