Integrated Process Of Yulin Coal Pyrolysis With Carbon Dioxide Reforming Of Ethane For Tar Production

With the development of coal intensive processing and coal-to-liquid technologies,requirements on cleaner production,energy saving and emission reduction are raised by industry successively.Coal grading transformation based on coal pyrolysis attracts extensive attention recently.In order to improve tar yield,taking advantage of the coupled process of coal pyrolysis with carbon dioxide reforming of ethane?CP-CRE?presented in our research group,study on process of Yulin coal pyrolysis in the atmosphere of C₂H₆ and CO₂ for tar production is carried outFixed bed reactor was employed,meanwhile Ni/Al₂O₃ was adopted as catalyst of reforming reaction.Based on these,impacts on products yield of different reaction conditions,such as temperature,atmosphere,flow rate of C₂H₆ and flow rate ratio of CO₂ to C₂H₆ were researched.The results show that the highest yield of tar occurs at 650?,and the yield of tar by CP-CRE is 17.4%and 6.6%better compared with that by CP-N₂ and CP-CRM under the same reaction temperature respectively.For CP-CRE,by appropriately increasing the flow rate of C₂H₆ and flow rate ratio of CO₂ to C₂H₆,the yield of tar can be improved.When the flow rate of C₂H₆ is 100 m L/min and the flow rate ratio of CO₂ to C₂H₆ is 3,the maximum yield of tar,14.01%,is reached.In addition,the yield of char by CP-CRE is lower than that by CP-CRM and CP-N₂,while the yield of water by CP-CRE is higher than that by CP-CRM and CP-N₂.Through the simulated distillation,GC/MS and GC analysis of tar produced by CP-CRE,CP-CRM and CP-N₂,the content of light oil,phenol oil and naphthalene oil in tar by CP-CRE is discovered to be improved compared with that by CP-N₂ and CP-CRM.About 133components are detected in tar,where the yield of toluene,xylene,methylphenol,xylenol and naphthalene by CP-CRE are 1.94,2.07,2.87,2.42 and 1.73 times of that by CP-N₂respectively.The reasons of those experiment results may be that,the optimum reaction condition can improve the concentration of active radical generated by reforming reaction so that the reaction of combination with active radical generated by coal pyrolysis is improved,which makes more active radical stabilized as tar.During the integrated process,active radical generated by reforming reaction will combine with active radical generated by coal pyrolysis to generate tar.Ultimately,the yield of tar by CP-CRE is increased,meanwhile the yield of char is decreased.