Research On Utilization Of Used Tire Pyrolysis Oil

Large amount of used tires have been produced due to the rapidly growing global economics and automobile industry. To figure out an economic and practical manner on utilization of used tires has come into a stringent task for researches. It is widely known that to pyrolysis used tires is a high value-added and environmentally friendly recycling route. However, the most critical issue during used tires pyrolysis is how to intelligently utilize the specific pyrolysis oil. In this dissertation, used tires pyrolysis oil from industrial unit was used as the starting material. Characterization, utilization and application of used tire pyrolysis oil were studied. The results are expected to provide a principle valuable option for the utilization of used tires. This dissertation mainly consists of the following contents.A detail analysis and evaluation were conducted on compositions of the used tire pyrolysis oil, including fractions and narrow fractions of the oil. The results showed that pyrolysis oil was low metal content with high sulfur and nitrogen, and high aromatic. The content of light and medium fractions was high up to 62.9% of pyrolysis oil, and the characteristics and compositions were much closed to those of FCC gasoline and FCC (Fluid Catalytic Cracking) diesel, respectively. On the other hand, the characteristics and compositions of heavy fraction were similar to those of petroleum asphalt. The regular pattern of the distribution of hydrocarbon compounds and non-hydrocarbon compounds in narrow fractions were ascertained as well. In the characteristics component analysis of the pyrolysis oil, it was found that the main acidic compounds in the pyrolysis oil were fatty acids which are seldom seen in crude oils.Pyrolysis oil contained light and medium fractions of 62.9%, which was an important point for utilization of pyrolysis oil. Since the characteristics and compositions of pyrolysis oil were similar to those of crude oil, it is potential to use oil processing methods to process and turn the pyrolysis oil into petroleum products or additive particles. In this dissertation, a distinctive utilization route for the pyrolysis oil was present, which the pyrolysis oil would be incorporated in oil processing plants in consideration of the features of pyrolytic device being small scale and large dispersion.Light fraction in the pyrolysis oil was used as a model fraction to blend with FCC gasoline, and then the hydrotreating process of the mixture oil was studied. With the method of orthogonal experiment, the hydrotreating operation parameters (including the blending ratio of light fraction to FCC gasoline) on desulphurization and denitrogeneration rate were optimized in the laboratory fixed bed micro-reactor. The results showed that hydrotreating temperature was the most significant factor. Furthermore, the feasibility of hydrotreating of FCC light gasoline blending with light fraction was investigated under industrial operating conditions. The results showed that density, sulfur content and distillation range of the hydrotreating product achieved the standards of gasoline fuels for vehicles under the following conditions:the ratio of hydrogen to oil at 512, the liquid hourly space velocity at 1.65 h-1, reaction temperature at 353?, reaction pressure at 3 MPa, and blending ratio at 10%. In the three kinetic study models of hydrotreating reaction of FCC gasoline blending with light fraction, the first-order reaction kinetic model was found to describe the HDS and HDN reactions. The analysis of relative error and F statistical analysis showed that the multiple correlation indexes were 0.9248 and 0.9794, and the average relative errors were 4.33% and 0.87%, respectively.The investigation of heavy fraction composition showed that heavy fraction was potential to produce road asphalt. The feasibility of heavy fraction to produce road asphalt was studied by distillation and blending methods, respectively. The distillation results showed that penetration, softening point, and ductility of straight asphalt of cutting point temperature at 420?,430?and 440?could meet with the major technical index of road asphalt's standards, except for substandard performance after aging. Therefore, heavy fraction producing road asphalt by distillation method was infeasible. On the other hand, under conditions of different mixing temperature, stirring time, stirring speed, and the feasibility of AH-70 road asphalts blending with heavy fraction were discussed. The results showed that the aged ductility of the blending asphalt was greatly enhanced, which can basically match the standard of AH-70 road asphalt. The optimum conditions were mixed at 160?, stirred at 2500 r-min-1 for 10 min with the blending ratio of 1%.These results open up a novel route for utilization of used tire pyrolysis oil, and have not only significant academic value but also application value.