Investigations on the interaction mechanisms of hydrogen donor and non-hydrogen donor on hydrogenation behaviors of asphaltene

Abstract

In the manuscript, the effects of temperature, H2/N2 atmosphere, ratio of hydrogen donor (HD)/non-hydrogen donor (NHDs) and non-hydrogen donor (NHDs) components on product distributions and hydrogen consumption during asphaltene hydrogenation process were investigated. Besides, the structure of asphaltenes were analyzed. The results showed that increasing temperature can significantly promote the dehydrogenation of THN. The oil-water yields in binary solvents were 16.21 % - 22.54 % lower than that in pure THN (48.20 %)，which may be due to the hydrogenation of NHDs components competing for active hydrogen with free radicals cracked by AS. In N2 atmosphere, the amount of hydrogen transfer from THN was higher than that in H2 atmosphere, and the presence of anthracene promoted the dehydrogenation of THN from 2.70 wt% in pure THN to 2.98 wt% in binary solvents, while the addition of phenanthrene and pyrene inhibited the dehydrogenation of THN. Anthracene and pyrene were susceptible to be hydrogenated to generate hydrogenated aromatics, while phenanthrene was more prone to ring-opening and isomerization reactions in N2 atmosphere, leading to opposite trends of oil-water yield in H2/N2 atmospheres. The H2/N2 atmospheres had a modest effect on oil-water yields in THN/1-MN mixtures, but CH4 yield (4.49 %) in N2 atmosphere were significantly higher than that (1.42 %) in H2 atmosphere, indicating that 1-MN facilitated hydrogen transfer from THN to naphthalene and CH4. The XPS results showed that in H2 atmosphere, C-O-C of asphaltenes was almost removed, and pyrene and 1-MN inhibited the cleavage of ether bond to some extent in N2 atmosphere.