凝结洗涤塔脱除燃煤超细颗粒实验研究

对洗涤塔内相变促进燃煤细颗粒凝结长大与脱除进行了实验研究。通过在洗涤塔入口和洗涤塔内注入适量蒸汽，使其在塔内不同区域形成细颗粒凝结长大所需的过饱和环境。探讨了2种情况下，不同操作参数对燃煤超细颗粒脱除效率的影响规律。结果表明2种蒸汽添加方式均可显著促进燃煤超细颗粒的脱除，蒸汽添加量为0.03 kg/m3时，颗粒数浓度脱除效率分别提高了50%和60%；对于塔前添加蒸汽，气液温差的提高有利于细颗粒的脱除，而塔内添加蒸汽则正好相反；此外，对于气液温差较大的情况，增大液气比可有效提高脱除效率；燃煤细颗粒的脱除效率随烟气在塔内停留时间的增加而提高，特别是塔内添加蒸汽的情况，当停留时间为1.5 s时，塔前和塔内添加蒸汽脱除效率可分别达到60%和65%以上，而未添加蒸汽时脱除效率几乎不受停留时间的影响。

Experimental Study on Removal of Ultrafine Particles From Coal Combustion Using Condensation Wet Scrubber

The removal of ultrafine particles from coal combustion was investigated experimentally based on condensational enlargement of supersaturated vapor in wet scrubber. Supersaturation required for fine particles growth was achieved in different regions of the scrubber by adding adequate steam before the inlet of scrubber and in the scrubber. The influence of operating parameters on ultrafine particles removal efficiency was demonstrated for both cases. The results show that the removal of submicron particles from coal combustion can be significantly improved for both steam addition methods. The collection efficiencies of over 50% and 60% are obtained with steam addition amount of 0.03 kg/m3. The removal efficiency increases with the temperature difference between the gas and water in the inlet of scrubber for steam addition before scrubber, but it is opposite for steam addition in scrubber. In addition, removal efficiency can be effectively promoted by increasing the ratio of liquid to gas for higher temperature difference. Furthermore, fine particles removal efficiency increases with the gas residence time in the scrubber, especially with steam addition in the scrubber. With residence time of 1.5 s, both removal efficiencies of more than 60% and 65% are obtained for steam addition before and in the scrubber, respectively, but it is independent on the residence time without steam addition.