洗涤塔内相变脱除燃煤超细颗粒的试验研究

Removal of fine particles from coal combustion in scrubber by heterogeneous condensation

为研究洗涤塔内相变对燃煤超细颗粒的脱除,在洗涤塔液相进口上方注入蒸汽使烟气达到过饱和,由高效除雾器脱除凝并长大的含尘液滴。系统研究了蒸汽添加量、洗涤塔入口气液温差、液气体积比、烟气在相变区域的停留时间等操作参数对燃煤超细颗粒脱除效率的影响规律。结果表明:在塔内添加少量蒸汽,可显著促进燃煤超细颗粒的脱除,蒸汽添加质量浓度为0.03 kg/m3时,数量浓度脱除效率由10%增至60%以上;液气体积比的提高有利于燃煤超细颗粒的脱除,特别是当洗涤塔入口气液温差较大时。研究结果表明利用洗涤塔内相变脱除燃煤细颗粒是一种有应用前景的新方法。

In order to investigate the removal of fine particles from coal combustion in the scrubber, the grown particles were removed by highly efficient mist eliminator through injecting the proper amount of water vapor to the top of scrubber so as to make flue-gas approach supersaturation. The influence of operating parameters on the removal of fine particles was investigated, such as steam injection amount, the temperature difference between gas and liquid in scrubber inlet, the volume ratio of liquid to gas and the residence time of flue gas in the condensation growth region. The results show that a small amount of steam injection in scrubber can promote the removal of fine particles from coal combustion, and the number concentration removal efficiency can be enhanced from 10% to 60% with a steam injection mass concentration of 0.03 kg/m^3. Increasing the ratio of liquid to gas can promote the removal of fine particles, especially when the difference of the temperature of gas and liquid at the inlet of scrubber is big. The results indicate that removing fine particles from coal combustion by heterogeneous condensation in the scrubber is a useful-foreground method.