PVC熔融盐气化制备低氯富氢可燃气试验

Experimental study on preparation of low hydrogen chloride content and hydrogen-rich combustible gas by molten salt gasification of PVC

为了研究新型的医疗废物无害化与资源化利用方式,在立式管式炉反应器中研究NaOH熔融盐对医疗废物主要组分——PVC(聚氯乙烯)气化产物的影响。结果表明:PVC熔融盐气化最适温度为750℃;气化反应中添加O_(2)能明显提高H_(2)与CH_(4)产气量,且加入O_(2)流量为40 mL/min时产气量最高;熔融盐与PVC的相关反应发生较为迅速,所需时间较短,且反应时间对产物影响不显著;气化过程中加入NaOH熔融盐后,产出的有效气体以H_(2)为主。750℃下,H_(2)体积分数在有效气体组分中占38.3%,显著高于不添加熔融盐时的常规气化。加入熔融盐后,产出气体中HCl的质量浓度由1.17×10^(5) mg/m^(3)下降至46 mg/m^(3),降低效果显著。

As the main component of medical waste,polyvinyl chloride(PVC)causes some environmental problems.To deal with PVC,we investigate the effect of NaOH molten salt on the gasification process of PVC in a vertical tube furnace reactor.In this paper,the gaseous and solid products from the gasification of PVC are collected by aluminum foil bags and gas-washing bottles.The collected products are analyzed by GC,IC,and XRD.The nitrogen equilibrium method is used to calculate the gas production.The results show that the volume percentage of H_(2)reaches up to 38.3%when the temperature of molten salt gasification of the PVC increases to 750℃.Meanwhile,when the temperature further increases,the volume percentage of H_(2)increases.However,the NaOH molten salt is evaporated drastically,which is harmful to the gasification of PVC.Therefore,750℃ is selected as the appropriate temperature.Besides,he addition of oxygen in the PVC gasification process significantly increases the gas yields of H_(2)and CH_(4),and the optimal oxygen flow is 40 mL/min.Compared with the reaction time,the amount of oxygen is more significant for gaseous products.Besides,the components of the gaseous products of molten salt gasification of PVC are quite different from those of the conventional gasification.The main product from PVC gasification with the molten salt is H_(2),while the main products from the conventional gasification of PVC are CO_(2)and CO.With the addition of NaOH molten salt,the concentration of HCl in the gaseous product significantly reduces from 1.17×10^(5)mg/m^(3)to 46 mg/m^(3).Based on the research results,it can be concluded that molten salt-assisted gasification promotes disposing of the Polyvinyl chloride(PVC).This work is significant for the harmless treatment and resource utilization of the organic components of medical waste.