污泥微波高温热解条件下富氢气体生成特性研究

分别采用单模微波炉和电加热管式炉对污泥热解过程进行了实验研究,分析了污泥粒径、含水率、热解温度和微波吸收剂形态等参数对热解产物分布特性和气体组分浓度的影响规律和机理。结果表明,在粒径0~5.00 mm,污泥粒径大小对污泥微波热解产物分布无明显影响,但粒径减小可以提高H₂和CO浓度,当粒径从2.50~5.00 mm减小至小于0.45 mm,H₂和CO体积分数分别从31%和17%上升至34%和22%;污泥含水率和微波热解温度对热解产物分布和热解气组分浓度分布都有显著影响,提高污泥含水率或微波热解温度都可以显著提高H₂和CO浓度,当污泥含水率从0上升至83%,H₂和CO体积分数分别从32%和20%上升至42%和31%;相比粉末态吸波剂,固定形态的微波吸收器可以提高挥发分向热解气的转化,提高热解气产量,同时还能略微提高H₂和CO产率,但效果并不明显。

Hydrogen-rich gas formation characteristics during microwave-induced high temperature pyrolysis of sewage sludge

Pyrolysis of sewage sludge was conducted in a single-mode microwave reactor and an electric-heated tube furnace, respectively. The effects of particle size, moisture content, pyrolysis temperature, and structure of microwave receptor on the yield and composition of hydrogen-rich gas were studied. The results indicate that the sludge particle size within 0~5.00 mm has no obvious effect on the mass distribution of pyrolysis products. However, H₂ and CO concentrations increase with decreasing of particle size. When the size decreases from 2.50~5.00 mm to <0.45 mm, the H₂ concentration increases from 31% to 34%, and that of CO increases from 17% to 22%. Both the sludge moisture content and the pyrolysis temperature have great influences on distribution of the pyrolysis products. Higher moisture content or pyrolysis temperature will lead to markedly higher concentrations of H₂ and CO. When the sludge moisture content increases from 0 to 83%, H₂ concentration increases from 32% to 42%, and CO concentration increases from 20% to 31%. Microwave absorber in powder phase can transform more volatile compounds into incondensable gas than that in fixed phase, and the concentrations of H₂ and CO also increase slightly.