Study On The Co-processing Of Waste Tire And FCC Slurry

The traditional pyrolysis method of waste tires has many problems such as high pyrolysis temperature and difficulty in large-scale continuous processing.The slurry of oil and tire powder was prepared by using the waste tire powder and FCC slurry,for the investigation of conversion effectiveness of co-processing system at nitrogen and hydrogen atmosphere respectively,with the method of evaluation in the autoclave.The reaction condition was studied to optimize the reaction effectiveness for the higher conversion efficiency of tire powder and the higher light oil yield in the liquid product.Multiple characterization method(GC,GC/MS,FT-IR,XRD,XPS,SEM,et al.)were used to analyze the composition,structure,and microscopic morphology of products.Besides,the role of FCC slurry during the co-processing of tire and FCC slurry was discussed.And the feasibility of selected co-processing method for waste tire powder and FCC slurry at hydrogen atmosphere was analyzed.The conversion efficiency of tire powder increased first and then decreased in the range of 230~350?,as the increasing of reaction temperature,for the co-processing of tire and FCC slurry at nitrogen atmosphere,whereas all the obtained conversion efficiency was beyond 82 wt%,with the highest value of 92.21 wt% at 330?.And the decrease of conversion efficiency should be due to the thermal condensation reaction of co-processing system.The influence of nitrogen pressure seemed to be little on the conversion efficiency of tire.The increase of reaction time promoted the conversion efficiency at relative lower temperature,while the conversion efficiency trended to be decrease as the increasing of reaction time at the temperature over 350?.The increase of proportion of FCC slurry in the co-processing system leaded to the promotion of tire conversion,and the conversionefficiency was relative low when the wt(FCC slurry: tire powder)was lower than 1:1;whereas the conversion efficiency of reaction system displayed little difference at the higher wt(FCC slurry:tire powder)beyond 1:1.To study the role of FCC slurry during the co-processing reaction,the strong swelling effect of FCC slurry on the tire powder was found.In addition,the comparison of thermogravimetric analysis result showed that the presence of FCC slurry significantly decreased the characteristic pyrolysis temperature of waste tire.The influence of solid particle in the FCC slurry on the conversion efficiency was also studied,exhibiting little variation.For the further improvement of conversion efficiency and light oil yield,the co-processing of waste tire powder and FCC slurry at hydrogen atmosphere was conducted,by investigating the influence of catalyst,reaction temperature,initial hydrogen pressure,and the wt(FCC slurry:tire powder).Results showed that the conversion efficiency of tire reached more than 95 wt% and the light oil yield was beyond 37 wt%,as the increasing of reaction temperature and initial hydrogen pressure,with the use of oil-soluble Mo-Ni catalyst.The increase of proportion of FCC slurry during the reaction could help to the improvement of tire conversion,whereas the light oil yield trended to be decrease.By the comparison of product analytical results between the co-processing method at nitrogen atmosphere and at hydrogen atmosphere,the saturated hydrocarbon content in the gas product for the co-processing reaction at hydrogen atmosphere was higher than that at nitrogen atmosphere.The reaction at hydrogen atmosphere resulted in the diesel and vacuum gas oil with a higher atomic ratio of H/C,a lower content of S and N,higher content of paraffin alkanes as well as cycloalkanes.but there existed lower content of resins and thiophenes in the vacuum gas oil.The higher conversion degree of tire leads to the decrease of H/C of resulted solid residue from co-processing at hydrogen atmosphere.The particle size of solid residue was quite small,with abundant organic groups on the surface of solid residue,mainly the groups of carbon and oxygen,which exhibited good dispersion in the liquid product.The co-processing of waste tire powder and FCC slurry displayed the advantage of achieving a high conversion efficiency at a relative lower temperature when compared to thetraditional pyrolysis techniques of tire powders.However,the obtained light oil yield was quite low.By adopting the co-processing method at the presence of hydrogen,a relative high conversion efficiency of tire and light oil yield could be achieved,so was the improvement of liquid oil properties,which exhibited apparent superiority in the upgrading of waste tire powders.Above all,experimental results proved a certain feasibility for the co-processing method of waste tire powder and FCC slurry at hydrogen atmosphere,and the further research was worthwhile.