摘要
循环流化床(CFB)燃烧技术正朝着高参数大型化方向发展,分离器个数相应增加。采用多分离器并联布置的结构会出现气固分布不均的偏流现象,非对称结构下分离器系统的流量分配不均问题与结构非对称性有很大关系,为了解M型布置的660 MW高效超超临界CFB锅炉多分离器并联引起的气固偏流现象,采用欧拉双流体模型进行热循环回路内气固流动特性数值分析,获得了系统的压力分布、炉膛以及分离器内的气固流动特性,分析了M型布置的超超临界CFB锅炉多分离器并联引起的气固偏流形成的原因。模拟结果表明,循环流化床的循环回路整体压力分布呈现斜“8”字分布的方式,4个循环回路在炉膛内的压力分布基本一致;4个分离器间的气体流量分布较为均匀,但固体流量却呈现中间低、两边高的分布状态。这与4个出口烟窗的位置布置以及分离器的入口烟道角度、长度等设计条件有关。结构对称的分离器表现基本一致,但由于炉内气固流场的波动性,瞬时运行过程中分离器较容易处在偏流运行工况下,不利于分离工作。床料在炉膛内分布较为均匀,但炉内气固流场的波动性易造成分离器瞬时处于偏流工况下,不利于分离工作。
Circulating Fluidized Bed(CFB)combustion technology is developing towards higher parameters and larger size,and the number of the separator is increasing accordingly.The structure with multiple separators arranged in parallel can lead to uneven gas-solid distribution and bias flow phenomenon.The uneven flow distribution problem of the separator system under an asymmetric structure is closely related to the structural asymmetry.In order to understand the gas-solid partial flow phenomenon caused by the parallel connection of multiple separators in M-type arrangement of 660 MW high efficiency ultra-supercritical CFB boiler,Eulerian two-fluid model was used to numerically analyze the gas-solid flow characteristics in the thermal circulation loop,and the pressure distribution,furnace chamber and gas-solid flow characteristics in the separator were obtain.The reason for the formation of gas-solid bias flow caused by the parallel connection of multiple separators in M-type arrangement of the ultra-supercritical CFB boiler was analyzed.The simulation results show that the overall pressure distribution of the circulating circuit of circulating fluidized bed presents an oblique"8"distribution,and the pressure distribution of the four circulating circuits in the furnace chamber is basically the same.The gas flow distribution among the four separators is relatively uniform,but the solid flow shows a distribution state of low in the middle and high on both sides.This is related to the location arrangement of the four exit flue windows and the design conditions such as the angle and length of the separator inlet flue.The structural symmetry of the separator is basically the same.However,due to the volatility of the gas-solid flow field in the furnace,the separator is more likely to be under bias flow operating conditions during transient operation,which is not conducive to the separation work.The bed material is distributed more uniformly in the furnace chamber,but the volatility of the gas-solid flow field in the furnace is easy to cause the separator to be in the partial flow condition instantaneously,which is not conducive to the separation work.
作者
韩平
张东旺
谢国威
辛胜伟
郑伟佳
顾从阳
张缦
HAN Ping;ZHANG Dongwang;XIE Guowei;XIN Shengwei;ZHENG Weijia;GU Congyang;ZHANG Man(CHN Energy Guoyuan Electric Power Co.,Ltd.,Beijing 100033,China;Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China;School of Energy and Environmental Engineering,University of Science&Technology Beijing,Beijing 100083,China)
出处
《洁净煤技术》
CAS
北大核心
2021年第6期85-92,共8页
Clean Coal Technology
基金
国家重点研发计划资助项目(2016YFB0600204)
国家能源集团国源电力有限公司科技项目(GSKJ-19-03)。
关键词
超超临界
循环流化床
气固均匀性
分离器
压力分布
ultra-supercritical
circulating fluidized bed
gas-solid uniformity
separator
pressure distribution
