Abstract:
The Claus process is effective for acid-gas processing and sulfur recovery. For industrial applications, combustion-supporting gas is needed to ensure flame stability when processing low-concentration acid gases, which can cause problems in terms of the increase in harmful substances such as polycyclic aromatic hydrocarbons and organic sulfur. The use of pure oxygen for combustion can not only increase the temperature in the furnace and improve the removal rate of hydrocarbon impurities, but also overcome the problems caused by the presence of combustion-supporting gas. In this paper, a full Claus-process model was constructed using the Aspen Plus software, and the theoretical result was validated by experimental data. The influences of the inlet acid gas composition, oxygen concentration, oxygen preheating temperature, furnace pressure, oxygen gas intake and the temperature of the second catalytic stage reactor on the Clause process were systematically examined. Optimized Aspen Plus was used to calculate the optimal operating parameters. The results showed that the sulfur recovery efficiency was enhanced from 98.31% to 99.08%, and the emission of SO
2, which was the main pollutant in the tail gas, was reduced from 0.350 kmol/h to 0.278 kmol/h; the reduction rate reached 20.6%. In addition, a heat of 9 133.38 J/mol (acid gas) was less consumed for the preheating of the acid gas and air.