Deep Hydroconversion of Heavy Oil Residues with Dispersed Catalysts: Analysis of the Transformation

Effectiveness of Different Transition Metal Dispersed Catalysts for In Situ Heavy Oil Upgrading

“…It was observed that the asphaltene content in feed oil is the main factor responsible for shot-type coke versus sponge-type coke formation in delayed cokers. ,, Moreover, Picon-Hernandez et al observed sponge-type coke from coking processes of feed oil, which moderated asphaltene and metal (Ni + V) content. It can therefore be confirmed that the active metal (Ni, Mo, or Fe) actually helped in controlling the rate of addition reactions between free radicals during heavy oil upgrading by promoting hydrogen uptake by the cracked active hydrocarbon fragments. , This stabilizes the asphaltene in the oil mixture and explains the formation of sponge-type coke during catalytic upgrading with MoS 2 and Fe 2 O 3 . Furthermore, sponge-type cokes are porous lumps that are surrounded by relatively thin walls with no interconnection between pores. , In the reservoir, the flow of upgraded oil could crack and convey sponge-type coke to the production well and to the surface because of its physical appearance.…”

“…Zhang et al reported that coke yield is significantly inhibited using dispersed nickel catalysts at 425 °C, 6 MPa, Ni loading of 300 μg/g, and a reaction time of 1 h during residue hydrocracking. This is because the active metals (Ni, Mo, or Fe) help to moderate the rate of free radical propagation via β-scission reactions by incorporating hydrogen to the cracked active hydrocarbon fragments during heavy oil upgrading. , This would explain the decrease in coke formation as well as the increase in liquid amount during hydroconversion in the presence of unsupported metal catalysts. , The distillate fractions of the produced oil after upgrading with unsupported Ni catalyst were 21 wt % (light naphtha), 49 wt % (middle distillate), and 30 wt % (gas oil). These results are in agreement with the literature. , …”

“…It can therefore be confirmed that the active metal (Ni, Mo or Fe) actually helped in controlling the rate of addition reactions between free radicals during heavy oil upgrading by promoting hydrogen uptake by the cracked active hydrocarbon fragments 60, 80 . This stabilizes the asphaltene in the oil mixture, and explains the formation of sponge-type coke during catalytic upgrading with MoS 2 and Fe 2 O 3 .…”