应用蒸汽相变机理脱除燃煤可吸入颗粒物实验研究

应用蒸汽相变机理促进细颗粒凝结长大，然后用湿式洗涤塔脱除长大后的含尘液滴，对燃煤可吸入颗粒物作为凝结核在过饱和蒸汽中凝结长大及湿式洗涤塔对凝结长大颗粒的脱除效果进行了实验研究，考察了蒸汽添加量、颗粒粒径及洗涤塔操作条件的影响。用电称低压冲击器(ELPI)实时测量凝结洗涤脱除前后的颗粒数量浓度和粒径分布。实验结果表明：蒸汽添加量的增加，能够迅速提高小粒径颗粒的脱除效率，蒸汽添加量为0.17kg/m3时，对平均粒径为0.3μm的颗粒的脱除效率超过80%；随着颗粒粒径增大，脱除效率提高；此外，洗涤塔液气比的增加，有利于燃煤可吸入颗粒物的脱除。研究表明蒸汽相变是脱除燃煤可吸入颗粒物的重要预调节措施之一。

Experimental Study on Separation of Inhalable Particles From Coal Combustion by Heterogeneous Condensation Enlargement

A novel process to separate inhalable particles from coal combustion with high efficiency using wet scrubber was presented. The process was based on the vapor heterogeneous condensation with PM2.5 particles acting as nucleation centers. Water vapor was injected into the flue gas to achieve supersaturation and cause particles to grow in size by vapor condensation in front of the scrubber. The grown particles were then removed efficiently in wet scrubber. The influence of steam addition amount, initial particle size distribution, liquid to gas ratio on the separation of the particles were investigated experimentally. The particle size distribution and concentration were measured in real time by electrical low pressure impactor (ELPI). Experimental results show that the separation efficiency rises sharply with the addition amount of water vapor for fine particles which can reach to 80% for the particles with a size of 0.3μm at the vapor mass flow rate of 0.17kg/m3. Additionally, the separation efficiency increases with increasing particle size and liquid to gas ratio at the same addition amount of water vapor. The present study indicates that wet scrubber with heterogeneous condensation of water vapor as a preconditioning technique is a highly efficient process for separating inhalable particles from coal combustion.