Elementary sulfur recovery by H2-regeneration of SO2-adsorbed CuO/Al2O3—Effect of operation parameters

CuO/Al2O3 is capable of removing SO2 and NOX from flue gas simultaneously at around 400 °C. After the SO2 removal, the SO2-adsorbed CuO/Al2O3 needs to be treated to regenerate its SO2 removal capacity and to recover the removed sulfur. This paper reports recent research on direct formation of elementary sulfur during H2-regeneration of the SO2-adsorbed CuO/Al2O3 through recycling of the regeneration tail gas. In such a way, the SO2 removal, the sorbent-catalyst's regeneration and elementary sulfur recovery can be carried out in a single reactor. The operating parameters studied include the amounts of H2 fed into the reactor, H2 feed strategy and O2 treatment of the H2-regenerated CuO/Al2O3. An intermittent H2 feeding mode is found to give a higher elementary sulfur yield (91%), less residual sulfur-compounds in the system after the regeneration, and higher SO2 capacity in the subsequent SO2 removal process. An O2 treatment after the H2-regeneration improves the elementary sulfur yield further and results in a number of other advantages.