燃准东煤锅炉辐射受热面的灰沉积特性

Ash Deposition Characteristics on Radiant Heating Surface of Zhundong Coal Boiler

建立了与气固两相流动燃烧模型相耦合的飞灰沉积模型,对一台660 MW超临界锅炉燃用准东五彩湾煤时的飞灰沉积特性进行了数值模拟,并且讨论了烟气流速和灰颗粒粒径对飞灰沉积速率的影响规律.结果表明:在BMCR工况下,炉膛辐射受热面上的飞灰颗粒沉积分布主要集中在高度为30~45 m处的区域,且各墙的沉积分布规律呈现出相似性;烟气流速为9.5~12.5 m/s时,辐射受热面上的飞灰沉积速率与烟气流速成正比;烟气流速大于12.5 m/s时,辐射受热面上的飞灰沉积速率与烟气流速成反比;辐射受热面上飞灰颗粒的沉积速率的整体变化趋势是随灰颗粒粒径的增大而增大的.

A fly ash deposition model coupled with a gas-solid two-phase flow combustion model was established.The fly ash deposition characteristics of a 660 MW supercritical boiler burning Zhundong Wucaiwan coal were numerically simulated,and the influence of flue gas flow velocity and ash particle size on the deposition rate of fly ash was discussed.The results show that under the BMCR operating condition,the sedimentary distribution of fly ash particles on the heated surface of the furnace is mainly concentrated in the area of 30—45 m,and a similar distribution is shown on each wall.The fly ash deposition rate on the radiant heating surface is proportional to the velocity of flue gas when the gas flow velocity is within the range from 9.5 m/s to 12.5 m/s.However,when the flue gas flow velocity is beyond 12.5 m/s,the fly ash deposition rate is inversely proportional to the velocity of flue gas.The deposition rate of fly ash on the radiation heating surface increases with the increase of ash particle size.