Simulation And Optimization Of Waste Tire Pyrolysis Process

With the rapid growth of modern transportation and the automobile industry,coupled with the rapid increase in the number of waste tires,the disposal of waste tires has become one of the world's environmental problems.As one of the most promising methods for the treatment of waste tires,pyrolysis gas,pyrolysis oil,pyrolysis carbon and steel wire can be produced,which has attracted more and more attention.However,the traditional pyrolysis method has the disadvantages of high energy consumption,high pollution and low added value.Therefore,it is of great practical significance to optimize the pyrolysis reaction process and study the pyrolysis oil desulfurization process and pyrolysis carbon activation process to increase the added value of pyrolysis products.Based on the pyrolysis process of waste tires with an annual processing capacity of100,000 tons,a simulation process was established using Aspen plus software.And using the literature reaction kinetic model,the effect of different temperatures on the pyrolysis products and energy balance was studied to optimize the pyrolysis process.The simulation results show that:with the increase of pyrolysis temperature,the yield of pyrolytic carbon was gradually decreased;the output of ASH?metal?was not changed with the change of pyrolysis temperature;pyrolysis gas production was gradually increased;the yield of pyrolysis oil was first decreased and then increased slightly.For the process with pyrolysis oil as the target product,as the temperature increases,the yields of C₇,C₈,and C₉ were increased,and the yields of C₁₀ to C₁₅ were reduced as the temperature increases.When the pyrolysis temperature was 400?600?,energy self-sufficiency could be achieved,and with the increase of temperature,the remaining energy was more and more.For the process with pyrolysis oil and pyrolysis carbon as the target products,400?was the optimal pyrolysis temperature.In the process of simulated hydrodesulfurization,the effects of reaction parameters on desulfurization and energy were studied:with the increase of catalyst concentration,initial hydrogen pressure,temperature and reaction time,the desulfurization efficiency was gradually increased;with the increase of catalyst concentration and initial hydrogen pressure,the increase of reaction time and the decrease of temperature,the energy released by hydrodesulfurization reactor was gradually increased.In the process of simulated oxidation desulfurization,the effect of oxidant dosage on desulfurization and energy was simulated:with the increase of the added oxidant,the sulfur content was gradually reduced,and the energy released by the oxidative dechlorination reactor was gradually increased.In order to optimize the desulfurization treatment scheme of pyrolysis oil of waste tires,the hydrogenation-metallic metal oxide desulfurization process of pyrolysis oil was simulated.The simulation results show that:the pyrolysis oil with a mass flow rate of 7975.10 kg/h was generated with GLF with a mass flow rate of 1581.87 kg/h and DLF with a mass flow rate of 5975.34 kg/h.The energy consumption of oxidation desulfurization process was 259.39 kW.The income of undesulfurized pyrolysis oil is 23925.3 yuan/h,and the income after desulfurization is41953.01 yuan/h.The income after desulfurization is 1.75 times that of undesulfurized.Therefore,it is very promising for the hydrogenation of waste tire pyrolysis oil and the desulfurization of metal oxides.In the simulated hydrochloric acid-steam activation process,the effect of activation parameters on activation was studied:with the increase of temperature and the increase of reaction time,the burnout rate was gradually increased;with the increase of burnout rate,the specific surface area was increased first and then decreased;with the increase of activation time,the specific surface area was gradually increased;with the decrease of the yield and the increase of the specific surface area,the energy consumption of the activated reactor is increasing.In order to obtain the best activated carbon,the process of hydrochloric acid-steam-nitric acid activation was simulated.The simulation results show that:pyrolysis carbon with a mass flow rate of 2763.41 kg/h is activated by hydrochloric acid-steam-nitric acid,and activated carbon with a mass flow rate of528.56 kg/h is generated.The energy consumption of pyrolysis carbon for hydrochloric acid-steam-nitric acid activation process was 8196.60 kW.The income of pyrolytic carbon is 829.02 yuan/h,and the income of activated carbon is 1714.09 yuan/h.The income of activated carbon is 2.07 times that of pyrolytic carbon.Therefore,it is very promising to activate the pyrolytic carbon of waste tire by hydrochloric acid water vapor nitric acid.