Simulation of chemical looping gasification of high-sulfur petroleum coke for syngas production coupled with recycling sulfur in 10 MWth system

The present work proposes a novel system which integrates high-sulfur petroleum coke chemical looping gasification (CLG) and sulfur recovery. Depending on the gas-solid reaction, CLG process has the ability to control the reaction pattern to obtain the mole ratio of H2S and SO2 as 2 in the syngas. The chemical chain gasification is combined with the catalytic conversion unit in the Claus process, and the high sulfur petroleum coke chemistry is proposed. Focusing on the core part of the system, CLG section, the simulation using the Aspen Plus was performed. The thermal input was designed as 10 MWth with high-sulfur petroleum coke as fuel. Iron ore and steam were used as oxygen carrier and gasification agent respectively. Effects of O/C, gasification temperature on the thermal balance during CLG process, syngas yield, effective gas content and sulfur conversion were investigated. Results indicated that increasing O/C leads to a decrease in the production yield of syngas, but the system gradually shifts from the endothermic to exothermic. When O/C is between 0.8669 and 0.9535, the system can maintain the heat balance without extra energy. Further, the increase of temperature is beneficial to syngas production. The CO concentration increases with increasing temperature and reaches 2.15 m3/kg at a gasification temperature of 975℃. A high ratio of O/C and gasification temperature can enhance H2S conversion during gasification process with a consequence of H2S concentration decreasing and SO2 concentration increasing. Furthermore, in the best case of the mole fraction of H2S to SO2 as 2, a negative correlation on the factors of O/C ratio and temperature was found. The cold gas efficiency is 64.09% at the conditions of the O/C ratio as 0.8669 and the gasification temperature of 900℃. © All Right Reserved.