简约型660MW超超临界循环流化床锅炉设计开发

Conceptual Design of a Simplified 660 MW Ultra-supercritical Circulating Fluidized Bed Boiler

分析了660 MW超超临界CFB锅炉的设计原则和依据,提出了简约型660 MW超超临界CFB锅炉方案。采用单布风,消除翻床现象;不设置外置式换热器,能够满足性能要求。前水冷壁采用锯齿形结构,在截面积不变的条件下扩大周界长度,确保一次上升水冷壁的面积,炉膛高度仅为48.2 m;二次风在齿凹处给入,降低了二次风处炉膛实际深度,利于改善炉膛中心区的供氧。后墙水冷壁在两个分离器之间设置一个锯齿,将炉膛大体上分为4个单元,形成单元设计。根据目前的运行实践,随着分离器直径的增加,飞灰的中位径基本上没有上升趋势,说明分离器直径放大并不能引起分离效率的显著下降,因此布置4个直径为10.85 m的分离器是完全可行的。介绍了简约型660 MW超超临界循环流化床锅炉结构,并对其性能进行了预测。

The design consideration of a 660 MW ultra-supercritical circulating fluidized bed （CFB） boiler was discussed. The conceptual design of simplified 660 MW ultra-supercritical CFB boiler was suggested. In this boiler, there is only one distributor to avoid the bed inventory overturn between pant-legs. All the heating surface in the loop are located in the uppers of the furnace instead of external heat exchanger. The front water wall is embattlement shape, the water wall surface is enlarged compared with that the normal one because the length of the wall is expended for the same furnace sectional area. And the height of the furnace is only 48.2 m. The secondary air nozzles are located in the trough to the furnace of the embattlement shape wall, the distance between the front wall and rear wall is decreased to improve the Oxygen diffusion in the gas solid two phase flow. There is an embattlement in the rear wall between the adjacent cyclones. And the furnace alone the width direction is divided into four units. Thus this design is unit design. The operation practices shows that the cut size of the fly ash is not upward trend when the cyclone diameter increases. This indicates that the collection efficiency of the cyclone does not decrease when the cyclone diameter increases, which proves the feasibility of the cyclone with 10.85 m diameter in this design. The structure of the simplified 660 MW supercritical CFB boiler was described, and the performance was also predicted.