Decomposition Of Tar From The Gasification Of Municipal Solid Waste By Rotating Gliding Arc Plasma

Gasification technology can convert municipal solid waste(MSW)into syngas and achieve the resource utilization of MSW.Compared with the traditional MSW disposal technologies,i.e.,landfill,compost and incineration,the gasification technology exhibits advantages of small secondary pollution and remarkable capacity reduction effect,and thus is considered as one of the most promising waste treatment technologies.However,the waste gasification process generates tar,which easily condenses into black viscous oil.The formed tar can block the downstream equipment and pipelines,and seriously affect the stability and safe operation of the gasification equipment.In this study,a novel rotating gliding arc(RGA)plasma co-driven by a magnetic field and a tangential gas flow was used for tar decomposition,aiming to solve the technical problems that plague the development of gasification technology.In this paper,a representative sample of tar produced by a biomass gasifier was chosen and tested by a gas chromatography-mass spectrometry(GC/MS)for composition analysis.46 kinds of organic substances were detected in the tar sample,mainly benzene derivatives and benzene-like structures.In addition,the content and chemical structure of these 46 tar components were analyzed.Naphthalene and toluene were chosen as the simulated tar components in the tar degradation experiments.The effects of tar concentration,gas flow rate,preheating temperature,load resistance,water vapor concentration and CO2 concentration on tar degradation were investigated.In addition,the gas products and liquid products generated from tar degradation were characterized by gas chromatography-mass spectrometry.The results showed that under the same experimental conditions,the degradation efficiency of toluene was always higher than that of naphthalene.The optimal toluene degradation rate was 95.8%and the optimal naphthalene degradation rate was 95.0%.A lower tar concentration,a lower gas flow rate or a smaller load resistance were conducive to the degradation of tar.The tar degradation rate increased with increasing temperature,and the degradation rate of toluene was more sensitive to temperature changes.The pyrolysis of toluene only starts when the temperature was higher than 700 ℃,while for naphthalene,the pyrolysis would not occur under 900 ℃.The addition of an appropriate amount of water vapor was advantageous for the degradation of tar and in the mean time increased the concentration of H2 and CO in the gas product.However,the addition of CO2 had a negative effect on the degradation of both toluene and naphthalene,but showed a greater negative impact on naphthalene degradation rate.H2 and C2H2,together with small amounts of CH4,C2H4 and C2H6 were detected in the gas product.After adding water vapor,the gas product also contained CO and CO2.The liquid product of the mixed tar degradation experiments were benzene derivatives of monocyclic to tetracyclic structures which still belonged to the tar category,however,the content of liquid products was small.In addition,the paper also carried out an extensive study on the wet reforming of ethanol to hydrogen by rotating gliding arc plasma.An optimal hydrogen production energy of 25.8KJ/L was obtained with a hydrogen production rate of 606ml/min.At the end of the paper,the reaction mechanism of ethanol wet-reforming hydrogen was discussed.