Experimental and numerical investigation on sulfur transformation in pressurized oxy-fuel combustion of pulverized coal

Abstract Pressurized oxy-fuel combustion, as a novel and promising technology for CO 2 capture from power plants, has attracted worldwide attentions. The high partial pressure of CO 2 induces significant changes to the SO x release characteristic. Properly addressing these fundamental issues and technological challenges is beneficial for reducing SO x emissions and complementing pressurized oxy-fuel combustion technology. In this study, experimental and numerical investigations are carried out to explore the sulfur transformation mechanism under different operation parameters in the pressurized oxy-fuel combustion of pulverized coal. The experimental results reveal an obvious decline of 50% in SO 2 emissions as the operating pressure increased from 0.1 MPa to 1.6 MPa, which is ascribed to the enhanced oxidation from SO 2 to SO 3 and the reduction of SO 2 to elemental sulfur. As the operation temperature increased from 700 °C to 1100 °C, the SO 2 concentration first decreased and then increased, and the minimum SO 2 emission was observed at 900 °C. Additionally, when the oxygen concentration increased from 10% to 60%, the SO 2 emissions were significantly reduced by 74%. The simulation results show great agreement with experimental data and indicate that SO 2 emissions were synergistically affected by seven elementary reactions in which HSO, SO, SH and other intermediate species were involved. The key reaction paths from fuel-S to different S products were revealed, where SO and HSO act as the major precursors to form SO 2 , and SH is an important intermediate product that participates in the sulfur transformation of both H 2 S and COS.