Investigation of Petroleum Coke Gasification with CO/HO Mixtures and S/N Removal Mechanism via ReaxFF MD Simulation.

The removal of environmentally harmful S/N is crucial for utilization of high-S petroleum coke (petcoke) as fuels. Gasification of petcoke enables enhanced desulfurization and denitrification efficiency. Herein, petcoke gasification with the mixture of two effective gasifiers (CO and HO) was simulated via reactive force field molecular dynamics (ReaxFF MD). The synergistic effect of the mixed agents on gas production was revealed by altering the CO/HO ratio. It was determined that the rise in HO content could boost gas yield and accelerate desulfurization. Gas productivity reached 65.6% when the CO/HO ratio was 3:7. During the gasification, pyrolysis occurred first to facilitate the decomposition of petcoke particles and S/N removal. Desulfurization with the CO/HO gas mixture could be expressed as thiophene-S → S → COS → CHOS, thiophene-S → S → HS → HS. The N-containing components experienced complicated mutual reactions before being transferred into CON, HN, HCN, and NO. Simulating the gasification process on a molecular level is helpful in capturing the detailed S/N conversion path and reaction mechanism.