Recirculating fluidized bed boiler

Abstract

The invention discloses a recirculating fluidized bed boiler which comprises a hearth, wherein the hearth comprises an inner wall and an outer wall, wherein the outer wall surrounds outside the inner wall, and an annular space between the inner wall and the outer wall forms a hearth inside. When the area of the hearth is enlarged, sizes of all directions of the recirculating fluidized bed boiler can be simultaneously increased, thus, the problem caused by imbalance of width to depth ratio due to the size increase of the single direction of the traditional hearth is effectively overcome. Meanwhile, the annular hearth is completely through the integral hearth space without risks of pressure imbalance and pressure drastic fluctuation bed tilting during the operation of the boiler.

Description

technical field [0001] The invention relates to a circulating fluidized bed boiler, in particular to a super large circulating fluidized bed boiler suitable for 660MW, 1000MW and above. Background technique [0002] Circulating fluidized bed (CFB) combustion technology is a clean combustion technology with good fuel adaptability, high efficiency, and less pollutant emissions. In recent years, CFB boiler technology has developed rapidly and is constantly developing towards large scale. With the development of large-scale, CFB boilers face the problem of increasing capacity. [0003] The increase of boiler capacity is mainly achieved through the increase of the heating surface, but due to the mismatch between the increase of the heating area of ​​the boiler furnace and the increase of the boiler capacity, the layout of the heating area of ​​the circulating fluidized bed boiler is very large in the process of enlargement. A problem that is difficult to solve, or even if it is...

AI Technical Summary

Problems solved by technology

This brings about two problems: (1) The boiler's width-to-depth ratio is out of balance, causing the boiler to occupy an excessively large area, the fuel feeding system arranged along the width of the furnace is difficult to cooperate, and the boiler's economy is poor; increase, the average mass flow rate of the water wall decreases, reducing the safety of the boiler; (3) the size of the furnace is too large in one direction, causing uneven temperature field and flow field in the furnace, reducing the performance of the boiler

Moreover, the air distribution device of the single air distribution plate is limited by the oxygen supply in the center of the air distribution plate and the aspect ratio, so the area cannot be too large, so it is difficult to meet the needs of the large-scale development of fluidized combustion boilers

[0005] In order to solve this problem, the prior art provides a furnace with double air-distributing panels, the cross-section of which is as follows figure 2 As shown, the double-cloth air-panel furnace 1 has a middle partition wall 4 in the furnace, and the auxiliary system is located on the periphery of the furnace. 16m, but the above-mentioned limitations still exist when the boiler capacity needs to be further expanded, and there are still the following problems: (1) The lower part of the furnace is divided into two independent parts, and the pressure of the two parts is not balanced when the boiler is running. (2) The periphery of the furnace is occupied by the flue opening of the separation device, and the radiation heating surface in the furnace can only be arranged between the openings of the flue, which makes it difficult to increase the radiation heating surface in the furnace

The existing double cloth air plate furnace boiler technology usually increases the heat exchange area by adding an external heat exchanger, but adding an external heat exchanger will bring about the complexity of the entire boiler system, difficulty in controlling the operation of the boiler, and poor reliability of the boiler

Moreover, the air distribution device of the double air distribution board is divided into two independent parts, and the pressure of the two air distribution devices cannot be naturally balanced during operation, which brings difficulties to the stable and safe operation of the boiler

The air distribution device with double air distribution boards that has been disclosed must adopt complex adjustment methods to meet the requirements of boiler operation.

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