CFB boiler tertiary air center cylinder

Abstract

A CFB boiler tertiary air center cylinder is a hollow cylinder wall, and includes a center cylinder body, an outlet end first air bellow connected to the top end of the center cylinder body and an inlet end air bellow connected to the bottom end of the center cylinder body, the center cylinder body comprises an inner wall and an outer wall, an air supply cavity which is through up and down is arranged between the inner wall and the outer wall, the top end and the bottom end of the air supply cavity are sealed, the outlet end first air bellow is connected with an induction air duct and providesfirst-level over fire air, an air guiding branch tube is arranged on the inner wall of the inlet end air bellow to form an eddy flow, the eddy flow is mixed with flue gas, the upper end of the outletend first air bellow is connected with an outlet end second air bellow, and the outlet end second air bellow is connected with an induction air duct charged with second-level over fire air and an airblast branch tube for blasting air to a flue. The first-level over fire air and the second-level over fire air are introduced to the flue, and are fully mixed with unburnt carbon particles and CO inthe flue gas to burn the unburnt carbon particles and CO, so the burning efficiency of a boiler is improved.

Description

technical field [0001] The invention relates to a central cylinder of a CFB boiler, in particular to a central cylinder through which tertiary air is introduced. Background technique [0002] One of the main disadvantages of CFB boilers compared with pulverized coal boilers is that the fly ash has a high carbon content, and some coal types even reach as high as 20%, so the incomplete combustion heat loss q4 of the boiler machinery is much higher than that of pulverized coal boilers. [0003] First, the division of the combustion zone of the CFB boiler. [0004] Referring to the division of the combustion area of ​​the pulverized coal boiler, the combustion area of ​​the CFB boiler is also divided into three parts: the main combustion area, the reburning area, and the burnout area. However, unlike the pulverized coal furnace, the three combustion areas of the pulverized coal furnace are all located in the furnace. , and the boundaries of the three zones of the CFB boiler are...

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Problems solved by technology

[0015] For pulverized coal boilers, since the fuel has been burned in the furnace, the excess air coefficient at the furnace outlet can accurately reflect the air required for the fuel to be burned. For CFB boilers, there are still a lot of combustibles in the flue gas at the furnace outlet. It is obviously inappropriate to choose the same excess air coefficient as the outlet of the pulverized coal furnace for design and operation.

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