Arrangement structure of all levels of superheaters of circulating fluidized bed boiler

Abstract

The invention relates to an arrangement structure of all levels of superheaters of a circulating fluidized bed boiler. The arrangement structure comprises a coal economizer, a steam pocket, a hearth water cooled wall, and a plurality of tail-cladding superheaters, low-temperature superheaters and high-temperature superheaters, wherein the coal economizer is arranged in a convection flue on the tail part of the boiler; the steam pocket is connected with the coal economizer through a pipeline; the hearth water cooled wall is connected with the steam pocket through a pipeline; the plurality of the tail-cladding superheaters, the low-temperature superheaters and the high-temperature superheaters are connected with one another through pipelines to form a closed loop; the high-temperature superheaters are arranged in the hearth of the boiler; and the heat absorption capacity of the high-temperature superheaters is in an amount of 48 to 58 percent based on the heat absorption capacity of an overall superheater system. By using the arrangement structure, the steam temperature and wall temperature properties of all levels of the superheaters of the boiler under various loads are greatly improved; the operating safety of the boiler is improved; and the service life of the boiler is prolonged.

Description

[0001] technical field [0002] The invention relates to a circulating fluidized bed boiler, in particular to an arrangement structure of superheaters at various stages of a circulating fluidized bed boiler. Background technique [0003] Circulating fluidized bed combustion technology originated from catalytic cracking in the chemical industry. Its purpose is to control the combustion temperature, keep the catalyst in the optimal reaction temperature range, and improve the utilization rate of the catalyst. Lurgi Company of Germany first introduced this technology Coal-fired boilers have been used to develop circulating fluidized bed boiler combustion technology widely used in industry. [0004] The main feature of the circulating fluidized bed boiler is that the boiler furnace contains a large amount of materials. During the combustion process, a large amount of materials are carried to the upper part of the furnace by the flue gas, and the materials are separated from the f...

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Problems solved by technology

Therefore, in the layout of the heating surface of the superheater of the fluidized bed boiler, the distribution of the heat absorption share of the furnace superheater and the tail superheater has a great influence on the steam temperature and tube wall temperature characteristics of the superheaters at all levels of the CFB boiler. The design of the fluidized bed boiler is not enough to grasp the dynamic heat transfer characteristics of the circulating fluidized bed boiler during the load change process, resulting in the frequent occurrence of overheating of the superheater system pipes or excessive water injection of the CFB boiler during the variable load operation phenomenon, seriously affecting the safe and stable operation of the boiler

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