| Energy has become a mainstay of the national economy with the development of social economy. Coal resources play an important role in China’s energy consumption which occupies about 68%.It is very important to improve the utilization rate of coal, develop and use clean coal technology andpersist in sustainable development strategy when the coal resources were used. Technologies, like IGCC, CPG, FC, etc,which have high power generation efficiency, low pollution emissions, good economic results, have been the key projects among the solving clean coal conversion projects in the development of the current research of coal gasification technology and efficient coal technology. It is very important among these technologies to achieve the removal of sulfur containing gases and the recovery of sulfur in different forms. This requires the desulfurizer has the desulfurization performance of clean and efficient, but also to ensure that can withstand hundreds of sulfidation/regeneration cycle and its performance is not much change.The research of desulfurizer regeneration must consider the key problem of operating conditions and the sulfur resource recycling. Therefore, the research of regeneration behavior for high temperature coal gas desulfurization sorbent in SO2-O2 atmosphere which can achieve sulfur recycling has important theoretical significance and value in use.This paper adopted self-made Mn2O3 metal oxide made by co-precipitation method as high temperature coal gas desulfurizer and studied the influence of the different regeneration atmosphere under different regeneration temperature, regeneration gas concentration and regeneration space velocity on the regeneration performance of desulfurizerseparately in the differential and integral fixed bed reactor.The phase composition, mechanical strength, microstructure, element distribution of the sorbent before or after regeneration were characterized by XRD, strength tester, ESM, XPS and other characterization methods, on account of that, the reaction mechanism of desulfurizer in different regeneration atmosphere were inferred and elemental sulfur selectivity were counted.The results show that the major regeneration products for Mn2O3 high temperature coal gas desulfurizer are Mn3O4、SO2 and sulfur in O2 atmosphere. Improve the regeneration temperature and concentration of O2 portion of the Mn3O4 will be oxidized into Mn2O3. If temperature and O2 concentration is too high, it will cause sintering of the desulfurizer. The rate of the regeneration is slow at 400℃ andthe desulfurizer cannot be regenerated completely. With the increaseof temperature, regeneration rate of desulfurizer gets higher, therefore selectivity of elemental sulfur is elevated. Regeneration rate of desulfurizer indifferential bed under low concentrations of O2 is slower, with low selectivity of sulfate. However, growth rate of desulfurizer indifferential bed under high concentrations of O2 and integral bed increases as concentration of O2 grows, with high selectivity of sulfate. Increasing space velocity assists to cut down accumulation ofSO2 in the bed and slow down generation of sulfate.The major regeneration products for Mn2O3 high temperature coal gas desulfurizer are Mn3O4, MnSO4 and little sulfurin SO2 atmosphere. After thermal processing of the regeneration sample in high N2 atmosphere under 800℃, sulfate is decomposed into Mn3O4 and little M2O3. Desulfurizercan hardly be regenerated in differential bed under 800℃and 1.68% SO2. Increasing temperature or concentrations of SO2 enhancing regeneration performance of desulfurizer, whereas regeneration rate is far below that in O2 atmosphere; desulfurizercannot be regenerated in integral bed under 800℃,2.1% SO2(high temperature and high concentration of SO2), which may be caused by the fact that bed layer is large and particle size of intense desulfurizer is large either, and regeneration of desulfurizer and SO2is rather slow.Thus, the desulfurizercannot be regeneratedin SO2 atmospherein integral bed.The major regeneration products for Mn2O3 high temperature coal gas desulfurizerare Mn3O4, MnS04, SO2 and little elemental sulfurin SO2-O2cooperating atmosphere. O2 regeneration mainly controls the reaction rate and inlet SO2 has an increasing influence on regeneration reactionwith the increase of temperature. When concentration of SO2 is constant, increasing concentration of O2 promotes the generation of sulfate. After the regeneration sample is thermally processed in high N2 atmosphere under 800℃, it can be recycled with no evident decay of desulfurization performance.From the perspective of elemental sulfur selectivity and sulfur resource recycling, in spite of good regeneration effects of mono-metal Mn2O3 high temperature coal gas desulfurizer in O2 atmosphere, regeneration in SO2 atmosphere or SO2-O2 cooperating atmosphere not applicable. |
PDF Full Text Request