内构件固定床反应器中不同水分煤的热解特性

通过在有无内构件(传热板和中心集气管)固定床反应器中研究不同水分含量煤的热解特性,考察了两反应器中煤料的升温特性、热解产物分布、焦油品质以及气体产物组成和半焦热值。结果表明,内构件可以强化传热和调节热解产物在反应器内的流动,相对无内构件反应器,有内构件反应器的反应时间缩短近一半。在有内构件反应器中,当煤水分增加,导致煤热解反应要求的时间延长,焦油中轻质组分(沸点低于360℃)含量明显升高,焦油收率先增加后降低,热解水和热解气产率升高,而无内构件反应器的热解产物无明显差异。当加热温度900℃时,煤水分从0.41%(本文中无特殊说明的均为质量分数) 增加至11.68%,焦油产率从9.21%增长到10.74%;当煤水分增加到15.93%,焦油产量下降到10.26%。两反应器气体平均组成随水分增加的变化趋势相似,气体热值均随水分增加呈下降趋势。

Pyrolysis of coal with different moisture contents in fixed-bed reactor with internals

The effects of coal moisture on heating rate and product distribution for pyrolysis of coal in a fixed-bed reactor with or without internals were investigated. The results showed that the reaction time in the reactor without internals is approximately twice of the time in the reactor with internals. With utilization of internals to enhance heat transfer and regulate the pyrolysis gas flow direction inside the reactor, increasing the coal moisture content prolonged the time that required to heat up the coal at the bed center to the preset temperature and increased the light tar content, whereas the tar yield tended to first increase and then decrease and the yields of pyrolysis gas and water tended to increase. In contrast, there was not dramatic difference in the reactor without internals when varying the coal moisture. At a heating furnace temperature of 900℃, the increase of coal moisture from 0.41% to 11.68% (mass) increased the tar yield from 9.21% to 10.74% (mass) for the reactor with internals, but when the coal moisture content increased further to 15.93% (mass) the tar yield decreased to 10.26% (mass). The variation trend with coal moisture content in the average pyrolysis gas composition was similar for both reactors, and the higher heating value (HHV) became lower when the coal moisture increased.