Investigation of Petroleum Coke Gasification with CO2/H2O 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 (CO2 and H2O) 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 CO2/H2O ratio. It was determined that the rise in H2O content could boost gas yield and accelerate desulfurization. Gas productivity reached 65.6% when the CO2/H2O ratio was 3:7. During the gasification, pyrolysis occurred first to facilitate the decomposition of petcoke particles and S/N removal. Desulfurization with the CO2/H2O gas mixture could be expressed as thiophene-S-* S-* COS-* CHOS, thiophene-S-* S-* HS-* H2S. The N-containing components experienced complicated mutual reactions before being transferred into CON, H2N, HCN, and NO. Simulating the gasification process on a molecular level is helpful in capturing the detailed S/N conversion path and reaction mechanism.

Automated summary

The removal of environmentally harmful sulfur and nitrogen is crucial for using high-sulfur petroleum coke (petcoke) as fuel. Simulating petcoke gasification with a mixture of two effective gasifiers (CO2 and H2O) revealed the synergistic effect of the mixed agents on gas production. Increasing the content of H2O can boost gas yield and accelerate desulfurization. The gas productivity reached 65.6% when the CO2/H2O ratio was 3:7. Detailed sulfur and nitrogen conversion paths and reaction mechanisms can be captured by simulating the gasification process on a molecular level.