文摘
Water vapor in the furnace can be raised up to 45% during oxy-fuel combustion with wet flue gas recycle and will significantly affect the limestone sulfation process. In this paper, two limestone sorbents were used to investigate the effect of water vapor on indirect sulfation. Nitrogen adsorption analysis, scanning electron microscope, and X-ray diffraction (XRD) techniques were employed to analyze the products and investigate the sulfation mechanism in the presence of water vapor. Results indicate that the difference of calcium conversion in the atmosphere containing H2O(g) or not is indistinctive during the kinetic-controlled regime. However, the degradation of sulfation rate is delayed in the presence of H2O(g) and the calcium conversion is enhanced in the later stage. Solid-state diffusion is intensified in the presence of water vapor, and recrystallization and sintering are promoted. Pore size distribution obtained by nitrogen adsorption analysis indicates that the activity of gas鈥搒olid diffusion in the presence of H2O(g) diminishes, and the enhancement is mainly caused by solid-state diffusion. The maps of XRD analysis further validate the experiment results.