Preparation And Performance Of Oil-Affinity Catalysts For Diesel Oil Production From Waste Engine Oil Via Catalytic Pyrolysis

With the rapid development of transportation,mechanical processing and other industries,as a dangerous waste,the environmental pollution of waste engine oil has become increasingly prominent,and its treatment has become one of the key environmental issues that must be pay attention to.At the same time,the demand for diesel oil and gasoline in transportation industry is also increasing.Therefore,the pyrolysis of waste engine oil to produce high-quality diesel oil has become an important research direction with dual value of environmental protection and economy,while realizing the resource utilization of waste engine oil and alleviating the shortage of petroleum resources in China.In this paper,aiming at the hydrophobic characteristics of waste engine oil,the idea of oil-affinity modification of catalyst was innovatively put forward.The preparation of oil-affinity CeO₂/Al₂O₃ catalyst and the experimental study of catalytic pyrolysis of waste engine oil to produce high-quality diesel oil were carried out.The main contents and conclusions of the study are as follows:?1?NiO/Al₂O₃?NiO/SiO₂?CeO₂/Al₂O₃ and CeO₂/SiO₂ catalysts were prepared by sol-gel method.Through TG/DTG analysis and pyrolysis experiments,the catalysts for waste engine oil pyrolysis were screened based on the yield of pyrolysis oil.It was concluded that the effect of catalysts on yield of pyrolysis oil was in the following order:CeO₂/Al₂O₃>NiO/SiO₂>CeO₂/SiO₂>NiO/Al₂O₃.Based on TG/DTG analysis and pyrolysis experiment results,CeO₂/Al₂O₃ was selected as catalyst for catalytic pyrolysis of waste engine oil to diesel oil.?2?The effects of CeO₂ loading,catalyst dosage,reaction time and temperature on the catalytic pyrolysis of waste engine oil were studied using CeO₂/Al₂O₃ as catalyst.It was found that the highest yield of pyrolysis oil was 85.33%when the loading of CeO₂ was 25wt.%,the dosage was 1.8g/30.0g waste engine oil,reaction time was 60 min and reaction temperature was 330?.The results of oil analysis showed that the condensation point of pyrolysis oil obtained by catalytic pyrolysis with 25wt.%CeO₂/Al₂O₃ was maintained at-10?,the range of cetane number index is 31.28³7.30,the range of carbon atom is 6²6,the range of density is 0.876⁰.889 g/cm³.Besides the condensation point,there was a certain gap with the light diesel?Sixth National Standard?.?3?The oil-affinity of 25wt.%CeO₂/Al₂O₃ catalyst was modified by sodium lauryl benzene sulfonate,sodium stearate and titanate coupling agent.The effect of modified catalyst with greatest lipophilicity?69.7%?on catalytic pyrolysis of waste engine oil was studied.Through single factor and orthogonal experiment,it was found that the maximum yield of pyrolysis oil was 92.33%when the dosage of modified catalyst was 1.8g/30.0g waste engine oil,the reaction time was 50 min and the reaction temperature was 340?.?4?The condensation point of pyrolysis oil prepared by catalytic pyrolysis of waste engine oil with modified catalyst was reduced to-15?,the density was reduced to0.824⁰.836g/cm³,and the cetane number index was increased to 55.82⁶1.37.All the above indexes have reached the range stipulated by the Sixth National Standard of-10#Light Diesel Oil.In summary,according to the experimental results,using 25wt.%CeO₂/Al₂O₃ catalyst modified by lipophilicity,-10#light diesel oil meeting the Sixth National Standard was successfully prepared from waste engine oil,and the yield reached 92.33%.