磷钨酸催化氧化吸附脱除模拟油中氮化物研究

Removal of nitrogen-containing compounds from model fuels with oxidative adsorption catalyzed by phosphotungstic acid

将磷钨酸、质量分数30%双氧水负载于介孔硅胶吸附剂孔中制备成脱氮剂,脱氮剂中硅胶与磷钨酸、质量分数30%双氧水的质量比为50%∶26.7%∶23.3%。以喹啉、吲哚和咔唑为模型氮化物,二甲苯及二甲苯和十二烷的混合溶液作溶剂,配制成含氮模拟油。在间歇反应器中,对磷钨酸、氧化剂的作用进行了研究,考察了温度、氮化物质量浓度和性质对脱氮反应速率的影响。结果显示:磷钨酸可以深度脱除碱性氮化物和低浓度非碱性氮化物,氧化剂能强化脱氮速率和吸附剂对氮化物的选择性。脱氮剂在温度50℃,脱氮剂与喹啉、吲哚模拟油质量比在3∶30,脱氮剂与咔唑模拟油质量比在3∶25条件下,模拟油中的氮化物90 min内被深度脱除。脱氮剂具有良好的再生性能,再生后脱氮剂的脱氮能力下降很小。

An oxidative adsorbent used to effectively remove nitrogen-containing compounds from model fuels was prepared,which was composed of 50% silica gel,26.7% phosphotungstic acid and 23.3% hydrogen peroxide,in which the mass fraction of hydrogen peroxide was 30%.Quinoline,indole and carbazole were used to represent the nitrogen-containing compounds in model fuels with xylene or the mixture of xylene and dodecane as solvents.In the batch test,the roles of phosphotungstic acid and oxidant played in deep denitrogenation of model fuel were investigated and the effect of temperature,the mass concentration and characterization of nitrogen-containing compounds on the reaction rate were also studied.The results show that the basic nitrogen-containing compounds and non-basic compounds with low-concentration in model fuels can be deeply removed by adsorbent without loading oxidant.The selectivity of the adsorbent in the removal of nitrogen-containing compounds and the reaction rate can benefit from the existence of oxidant in the pores.Ultra-low nitrogen model fuels were obtained within 90 min at 50 ℃ when the mass proportions between adsorbent and model fuels were set to 3 ∶ 30 and 3 ∶ 25 for quinoline,indole and carbazole model fuels,respectively.The oxidative adsorbent can be almost totally recovered and it still has high efficiency in the removal of nitrogen-containing compounds from model fuels after regeneration.