Developing efficient gasification technology for high-sulfur petroleum coke to hydrogen-rich syngas production

Abstract

Gasification technology can convert high-sulfur petroleum coke (petcoke) to high-value syngas (CO + H2) for hydrogen generation and chemical products via synthesis routes. Moreover, it provides superior environmental performance in comparison to combustion since the sulfur inherent in petcoke can be converted into H2S, and then can be recovered as S by Claus process. Petcoke has superior properties of high heating value and low ash content, however, its high sulfur, vanadium and nickel content, and low reactivity make it a challenging feedstock for gasification. The present work aims to develop an advanced petcoke gasification technology with higher carbon conversion, higher thermal efficiency and lower operating cost. Based on extensive investigation of petcoke gasification reactivity and ash fusion characteristics, the pilot-scale dry-feed pressurized entrained-flow gasifier (24 t/d, 3.0 MPa) is developed for efficient high-sulfur petcoke gasification. The pilot tests show a superior gasification performance. The carbon conversion is higher than 97%. The maximal cold gas efficiency is about 79%. The content of H2 is more than 32% in raw product gas. The oxygen consumption is ~15% lower than current commercial slurry entrained-flow gasification technologies. The scale-up principle and operation optimization are also discussed based on the pilot testing results. The pressure scale-up factor of 0.5–0.7 is empirically recommended for the gasifier capacity. The ratios of O2/coke and H2O/coke are in the range of 0.68–0.73 Nm3/kg and 0.20–0.30 kg/kg.