超临界水中聚乙烯油化的研究

采用125mL间歇式高压釜反应器，在超临界水条件下考察了反应温度、反应时间、水/聚乙烯比和水填充率对聚乙烯降解油化的影响。实验结果表明,聚乙烯在超临界水中迅速降解，油收率可达90%以上；随温度从450℃提高到480℃，油收率从91.4％下降到61.7％，气体收率从1.9％提高到27.7％；在450 ℃反应时间从1 min延长到30 min时，油收率略有下降，油品中C7-11组分所占比例增大一倍。水/聚乙烯比和水填充率的增加在一定程度上对聚乙烯的降解起抑制作用。

Investigation on degradation of PE to oils in supercritical water

To get basic knowledge about the degradation of polyethylene (PE) to oils in supercritical water (SCW), the effects of reaction temperature, reaction time, water to PE ratio and water fill rate on the degradation of PE to oils were investigated in supercritical water with a 125mL autoclave. Reaction conditions were in the range of temperature 450℃~480℃, time 1min~30min, water/PE ratio 2/1~10/1 and water fill rate 25%~40%. The experiment results show that PE can be highly converted to liquid fuel and the temperature is the main factor effecting the decomposition of PE in SCW. The yield of oil decreases from 91.4% to 61.7% and that of gas increases from 1.9% to 27.7% with the increase of temperature from 450℃ to 480℃. A twofold increase of the yield of C7-11 hydrocarbons with the increase of reaction time from 10min to 30min is observed. The decomposition of PE is retarded to a certain extent due to the high water/PE ratio or high water fill rate. For increasing the productivity of the unit volume of reactor, keeping H2O/PE ratio at 2-4 is reasonable.