Composition Analysis Of Fushun Shale Oil And Hydrodenitrogenation Of Quinoline Over NiW/γ-Al₂O₃ Catalysts

The more and more requirement of clean fuel oil by the developing of modern society, interest in the development of new substitute energy has been spurred because of the drying up of petroleum feedstock in the range of world day by day.Oil shale has been identified as an altemative source for production of crude oil substitutes.The upgrading process of shale oil is difficult from that of crude oil for the higher content of hetero-atoms.On the basis of analyzing the composition of shale oil,we also studied the hydrodenitrogenation(HDN) of quinoline and mutual influence with dibenzothiophene(DBT).In this work,Fushun shale oil was fractionated using HC1 and NaOH washing,chemical solvent extraction and liquid chromatography on a silica gel column,and analysis by Ultimate analysis and GC/MS.The results show that there were about 360 compounds had been identified in this work,including 97 aliphatic compounds,90 aromatics,60 oxide compounds and 115 nitrogen compounds,which included 85 basic nitrogen compounds and 30 nonbasic nitrogen compounds,and quinolines is the most important basic compound and nitriles is the most important nonbasic compound.The HDN of quinoline and its intermediates were studied over the commercial NiW/γ-Al₂O₃ catalyst in a continuous fixed-bed reactor.The results show that:The HDN of quinoline increased drastically with the increase of reaction pressure,reaction temperature and hydrogen/oil ratio.However,at the high hydrogen pressure and high volume ratios of hydrogen/oil,the conversion of quinoline was almost unaltered.There are two ways in which the nitrogen atom can be removed:one path is via aromatic intermediates THQ1 and OPA, and the other is via the saturated intermediates DHQ and PCHA.The HDN via the pathway of DHQ is much easier than OPA over the sulfided NiW/γ-Al₂O₃.The HDN of OPA was suppressed by the presence of Q,THQ1,THQ5 and DHQ,maybe due to their stronger adsorption on the catalyst.H₂S inhibits the hydrogenation of quinoline and inhibites the pathway of OPA hydrogenolysis while promotes C-N bond cleavage to PCHA in the THQ5 -DHQ pathway.The mutual influence of hydrodesulfurization(HDS) of DBT and HDN of quinoline or THQ1 were also studied in the simultaneous hydroprocessing of feedstock.The results show that:Even of the presence of small amount of quinline lead to a drastic inhibiting effect in the HDS of DBT,and the HYD pathway of the HDS of DBT is suppressed stronger than the DDS pathway,this suggests that the hydrogenolysis and hydrogenation of DBT proceed on different catalytic sites.The inhibiting effect of quinline on the on the HDS of DBT is due to the competitive adsorption of quinoline and its intermediates.However,a small amount of quinline has a promoting effect on the DDS pathway,due to the absence of the HYD pathway, and more DBT could go through the DDS pathway.It is found that the inhibiting effect of THQ1 is weaker than quioline on the HDS of DBT for its lower adsorption constant.Likewise, in the presence of DBT on the HDN of quinline and THQ1,DBT had a negative effect on the hydrogenation,but did not influence the C-N bond cleavage,suggesting that C-N bond and C-S bond breaking takes place at different active sites.