The Element Majority Behavior During The Regeneration Of Fe₂O₃-based High Temperature Coal Gas Desulfurization Sorbent

The high temperature coal gas desulfurization is a gas soliduncatalyed reaction, the regeneration is a oxygen atom exchange sulfuratom process. The physical and chemical properties, the regenerationbehavior and the recovery of element sulfur has a close relationship withthe majority of the element, however until now it was not has a clearcognition. So investigate the element majority behavior reflect the crystaland element formation path of the iron oxide desulfurization sorbent andit will be further reveal the regeneration mechanism on the other hand itwill be helpful for us to research high temperature coal gasdesulfurization sorbent.The paper based on the national natural science fund projects（NO.21276172）,―The regeneration behavior of the high temperaturecoal gas desulfurization sorbent in SO2-O2mixtures atmosphere‖. In thefixed bed reactor investigate the element majority behavior during theregeneration of the iron oxide desulfurization sorbent. We typical use the XPS, SEM, EDS and XRD to characterize the element majority behaviorand the crystal component of the iron oxide desulfurization sorbent. Themain conclusion as follows:①In oxygen atmosphere, oxygen in the first place in the outer surfaceof the sorbent and Fe2O3is mainly generated accompanied by theformation of sulfate. Then regeneration gas gradually through the hole ofinternal diffusion and exchange of oxygen in the certain thickness area ofthe sorbent, outside this area oxygen exchange sulfur is completely, insidethere is no oxygen exchange sulfur, as the regeneration time goes on theoxygen exchange the sulfur completely in the whole sorbent.②In SO2atmosphere the element majority behavior is, firstly the SO2rapidly react with the FeS in the external surface of the sorbent andexchange the sulfur atom produce Fe3O4and few sulfate. Then the SO2diffuse to the thin film of the internal of the sorbent and exchange thesulfur atom. From the early research the react of SO2with FeS is fasterthan the transform of Fe3O4to Fe2O3, so in the outside area of oxygenexchange sulfur a thick area is the―Fe exchange O‖.As the time ofregeneration go on the oxygen exchange with the sulfur will be finished,finally the physical will be Fe2O3in the outside of the sorbent and theinside area is―Fe exchange O‖and finally the―Fe exchange O‖will befinished and physical of the sorbent will be Fe2O3.③In SO2-O2mixtures atmosphere the regeneration will first react with the FeS in the outside surface of the sorbent and produce Fe2O3, Fe3O4and a few sulfate. However the product Fe3O4will rapid react with O2andproduce Fe2O3, so in the outside layer of the sorbent is Fe2O3. With thetime go on the regeneration will diffuse to the internal of the sorbent andthe oxygen exchange sulfur,―Fe exchange O‖will go on and relay on thisregulation the oxygen exchange sulfur will be finished in the sorbent.④In the three regeneration the XPS and EDS result of Fe is not inaccordance. In the respect of theory, the reason may be,first in theregeneration gas atmosphere the Fe2+in the internal of the grain is moreeasy majority to the surface to oxidize to Fe3+, second the length of Fe2+S2-O2-, Fe2+is the shortest, so it will be more easier to majority in thegrain.⑤Because product layer and reaction layer in the volume of differentmaterial to make them a ditch between the gap, it is easy to causepulverization of sorbent, and the production of sulfate in the regenerationprocess is inevitable, the volume of sulfate is metal oxides and sulfidesseveral times, is easy to cause the volume expansion of the sorbent.