分散型镍、铁催化剂用于重油-煤的加氢共炼研究

将硝酸镍和硝酸铁分别溶于水、甲醇或N,N二甲基甲酰胺(DMF),然后通过高速剪切分散在重油中,脱除溶剂后在350℃下采用升华硫预硫化成为分散型镍、铁催化剂,用于重油-煤加氢共炼。结果表明:与水溶性镍、铁催化剂相比,有机溶剂化的镍、铁催化剂前体在重油中由于黏度较小和相容性较好而具有更好的分散性,并且DMF做溶剂的性能优于甲醇;预硫化后甲醇化的镍、铁催化剂颗粒分别可达50和120 nm,而采用DMF相应的催化剂颗粒为10～40和30～50 nm,并且催化剂粒径均匀;在420℃、1 h、冷氢压8.0 MPa和煤与重油质量比1∶3的反应条件下,与以水为溶剂相比,采用甲醇或DMF为溶剂,尤其是DMF制备的镍、铁催化剂更能明显改善轮古常压渣油、Du-84特稠油与神华烟煤以及内蒙褐煤的加氢共炼效果;有机溶剂化制备的镍、铁催化剂在硫化和共炼条件下不容易聚结失活,并且DMF作溶剂的性能优于甲醇。

Study on dispersed Ni and Fe catalysts for coal-heavy oil co-processing

The dispersed nickel or ferric sulfide catalyst were prepared from nickel or ferric nitrate by dissolving in H2O,methanol or N-N dimethyl foramide(DMF) and then dispersing in heavy oil and presulfurizing with sulfur at 350 ℃.The results show that the particles sizes of the nickel and ferric sulfides from organic-soluble catalysts precursors are smaller and more symmetrical than those of the traditional water solution.The particles sizes of nickel and ferric sulfides from DMF-soluble catalysts precursors are about 10-40 nm and 30-50 nm,exhibiting the advantage of DMF on methanol for the corresponding particles size from methanol-soluble respectively about 50 nm and 120 nm,which resulted from the lower viscosity and good compatibility of the preparing system.In the two heavy oils(LGAR,Du-84) and two coals(Shenhua bitumite or Neimeng brown coal) co-processing system at 420 ℃,1 h,8.0 MPa H2(cold) and the mass ratio of coal to oil 1∶3,the catalysts prepared from the organic solution could greatly improve the co-processing effect compared with the catalysts prepared from the water solution.XRD analysis shows that the aggregation and deactivity of the organic-soluble nickel and ferric catalysts are slower than that of corresponding water-soluble catalysts,especially with the DMF-soluble catalysts.