Molybdenum carbide nanocatalyst for activation of water and hydrogen towards upgrading of low-quality hydrocarbons

Abstract

Molybdenum carbide catalyst is proposed to be used in a novel downhole upgrading method, called in-situ upgrading technology (ISUT). In this work, this catalyst is assessed for its activity and stability for this process. In an attempt to partially replace hydrogen with steam, as a carbon free source of hydrogen, several experiments under hybrid environments of steam and hydrogen were carried out. A systematic approach was also followed to replace either of the two gases with an inert gas like nitrogen. The presence of steam and its potential impact on the activity and stability of the catalyst is essential to be studied as water is often present in downhole heavy oil producing environments. Molybdenum carbide shows great activity and selectivity under different environments including co-presence of hydrogen and water. As well, this catalyst shows capability of water activation towards upgrading of products. Compared to the hybrid case of co-presence of hydrogen and nitrogen, co-incorporation of water with hydrogen improved the H/C ratio, tendency to form coke, asphaltene removal and desulphurization. In addition, the hydrogenation capability of the catalyst in a reservoir simulated environment was confirmed to be stable by quantifying hydrogenation of two polyaromatic model molecules under the co-presence of steam and hydrogen. Upon removal of steam and switching back to hydrogen-only environment, the activity of the catalyst was restored, highlighting its tolerance to water in terms of hydrogenation and hydroprocessing activities, making molybdenum carbide a promising catalyst for in-reservoir upgrading methods to partially replace hydrogen that in turn may improve the economics of the process.