Catalytic vacuum residue upgrading under methane: Evaluation of process feasibility, stability and versatility

Abstract The better utilization of low-quality oil resources is becoming more and more crucial for sustainable development due to the depletion of conventional petroleum resources and continuously increasing energy demand. Vacuum residue (VR) is the heaviest part of crude oil accounting for a large proportion in modern refineries, while its utilization routes are generally of low efficiency and high energy intensity, and thus economically and environmentally unfavorable. Methane, as a main component of natural gas, is naturally available with abundant reserve, and the direct use of methane demonstrates unique advantages over hydrogen for the upgrading of a wide spectrum of oils due to the avoidance of natural gas steam reforming step, leading to significantly reduced operational cost and CO2 emission. In this work, a 60-day continuous VR upgrading process under a methane environment was evaluated in a fixed bed reactor with the processing capacity of 20 L/day to validate the feasibility of treating the challenging feedstock and the stability for long-term operation. The feedstock and products collected on day 7, 30 and 60 were selected for comprehensive analysis. The quality indexes of these oil samples were compared in terms of the basic properties including density, viscosity, freezing point, pour point and flash point, the compositional information including characterization K factor, water content, salt content, organochlorine content, ash content, water and sediment volume fraction, total acid number, carbon residue, and asphaltene content, the elemental contents of sulfur, nitrogen and metal impurities, as well as a simulated distillation analysis. All results indicated significantly improved oil qualities and stable operation were maintained for 60 days. Moreover, a Merey heavy crude oil was also upgraded by the same process and favorable product qualities were also observed after a 30-day run, indicating the process was also capable of dealing with other heavy feedstocks. This novel technology with high feasibility, stability and applicability is anticipated to exhibit huge commercial potential for heavy oil valorization in the oil & gas industries.