Study On Hydrogen-donor Visbreaking Upgrading Of Oil Sands Bitumen

The high density and viscosity,low hydrogen carbon atom ratio of inferior ultra-heavy oil resources represented for oil sands bitumen carry severe challenge for its exploitation,transportation and processing.The conventional visbreaking technology has certain upgrading effect,but still has many disadvantages.The hydrogen-donating visbreaking technology developed from visbreaking has better upgrading effect for residue and can resolve above problems.To select fractions as hydrogen donors can promote economics of reaction process.Besides,the synergistic upgrading technology of hydrogen-donating fractions and asphaltene dispersants is a new technology of residue conversion to light fractions.In this paper,the best hydrogen donor was chosen from three different fractions HFB?200²80???HFC?280³50???HFD?350⁴20??by the chemical probe method,H¹-NMR and modified B-L method.The upgrading effect of hydrogen donor HFC was investigated under different reaction conditions and the upgrading effect of visbreaking products,hydrogen-donating visbreaking products and the reconcile upgrading oil of visbreaking products and fractions after reaction was coMPared.The storage stability and mechanism of conventional visbreaking and hydrogen-donating visbreaking products under different reaction conditions were studied.Specific results were as follows:the order of the relative hydrogen-donating ability is HFC>HFD>HFB and HFC is chosen as hydrogen donor.CoMPared to conventional visbreaking,the coke induction period of hydrogen-donating visbreaking extends 3⁵min under the same reaction conditions,the spot test rate reduces by 1² grades,the net viscosity reduction is 4.4¹2.5.The density of upgrading oil decreases significantly andoAPI increases,but not obvious.Besides,the?hydrogen ratio and H_A/H of hydrogen-donating visbreaking products is bigger and?hydrogen and?hydrogen ratio are smaller by coMParing three different oil products.The indication of colloidal stability is bigger and the stability of hydrogen-donating visbreaking is better.The upgrading effect of asphaltene dispersants in the process of hydrogen-donating visbreaking is good.By the analysis of products properties and optical microscope,the optimal ratio of asphaltene dispersants is 0.1%.CoMPared to hydrogen-donating visbreaking,the asphaltene content of products decreases,the spot test rates reduces NO.1 and the indication of colloidal stability increases 0.05⁰.12 g·g^-1.Besides,the dispersion effect of asphaltene dispersants on the asphaltene is revealed by the increase of mass fraction normalized conductivity.