| An important step in processing of coal-derived liquids is N removal. One pathway toward more active HDN (hydrodenitrogenation) catalysts is the development of polymetallic catalysts. In this regard, the effects of Pt, Ru, and Ir promotion on three commercial catalysts (NiMo, CoMo, and NiW) have been examined. For sulfided forms of NiMo, all the noble metals tested improved the pyridine HDN activity. The activity of CoMo was improved by Pt and Ir, while NiW was not improved by noble metals promotion. In contrast with the pyridine HDN study, only Pt promotion gave increased HDN activity with the actual coal-derived materials. For naphthalene hydrogenation, the activities of both original and Pt promoted catalysts were similar in the sulfided forms. However the Pt promoted catalysts exhibited a distinct advantage for hydrogenation in the presence of N. In another study, alumina-aluminum phosphate (AAP) was considered. On a unit surface area basis, the NiMo/AAP catalysts had comparable initial HDN activities to that of a commercial P promoted NiMo/Al{dollar}sb2{dollar}O{dollar}sb3{dollar} catalyst. The AAP supports demonstrated the possibility of tailoring the catalyst pore size by variation of the Al/P ratio which may offer advantages when dealing with macromolecular feedstocks where hindered diffusion may slow reaction rates.; The upgrading potential of a residual plastics pyrolysis liquid and a coal-wastes coprocessing liquid has been investigated using hydrocracking with NiMo/zeolite-alumina catalyst. A simplified three-lump sequential reaction pathway (gas oil {dollar}to{dollar} naphtha {dollar}to{dollar} gas) was applied to upgrading of the gas oil fraction. The kinetic model considered the variation in H{dollar}sb2{dollar} partial pressure and satisfactorily simulated the experimental data. This batch upgrading study generally indicated a positive potential for upgrading of the plastics-derived liquids to naphtha range materials, suitable for inclusion in the clean transportation fuels pool. Based on these results, a residual plastics pyrolysis liquid was upgraded to a gasoline range product using a three-step sequential process consisting of hydrotreating, hydrocracking, and distillation in nominal 100 hr continuous runs using a fixed bed reactor. The gasoline range product, compared to a commercial gasoline, was characterized by lower aromatics, olefins, and N, with comparable research octane number indicating an environmentally favorable properties. |
