Preparation And Desulfurization Performance Of Zinc Oxide Load In MCM-41 Sorbent For Hot Coal Gas

In recent years,environmental problems,especially the fog haze weather get more and more attention of people,however,the direct combustion and indirect use of coal is the main cause of this problem.Integrated Gasification Combined Cycle（IGCC）technology as the most efficient and clean coal utilization technology in the word is particularly important.Hot coal gas desulfurizer which used in gas purification was widely researched by scholars.A good desulfurizer should not only have higher sulfurization and regeneration performance,also need simply preparation technology,which is conductive to industrial applications.This paper use the sodium silicate as silicon source,single metal oxide ZnO as active component,through a novel one step hydrothermal synthesis method,get the high temperature coal gas desulfurizer of zinc oxide locad in MCM-41 mesoporous molecular sieve.In experiment,to get the optimum preparation conditions and the best regeneration conditions,the preparation process of the desulfurizer and regeneration condition was investigated respectively.Subsequently,the six times desulfurization-regeneration cycles of sorbent was carried out,various samples was characterized by XRD、BET、SEM and XPS methods.The conclusions are as follows:（1）The main influence factors in the process of the desulfurizer was investaged through the orthogonal experiment,the optimum preparation conditions of the sorbent is: keep the pH value of solution system as 10,adding zinc source at room temperature,the add status of zinc source is Zn（OH）deposits,the delay time of add zinc source is 4 h,adjust system pH value by 1mol/L sulphuric acid.（2）According to the sulfurization performance test,the sorbent 35%ZnO/M41 with 35% active component was the best sorbent,which exhibit the highestsulfur capacity and the longest breakthrough time,reached 11.0089（g S/100 g sorbent）and 390 min,respectively.The SEM and TEM analysis of the fresh sample found that metal oxide ZnO was evenly dispersed on the surface of molecular sieve with very regular lamellar structure,and hexagonal phase structure of the molecular sieve MCM-41 was not damaged.（3）The best regeneration conditions of desulfurization are as follows: regeneration airspeed 3000 h-1,regeneration temperature 650 ℃,oxygen concentration of regeneration is 6%,and the regeneration rate was the largest at this regeneration conditions,reached 95.61%,which indicted that the desulfurizer can regenerate completely under this best regeneration conditions.（4）The experiments of the sample 35%Zn O/M41 six times desulfurization-regeneration cycles showed that the desulfurization efficiency of six times sulfide remained above 70%,which indicted that the sorbent have relatively stable desulfurization performance,and the mechanical strength also remain stable in the process of six times desulfurization-regeneration cycles,no pulverization and tensile crack phenomenon.（5）The samples of desulfurizer 35%ZnO/M41 at six times desulfurization-regeneration cycles was characterized by various characterization methods,the results of XRD shows that in the process of desulfurization-regeneration cycles,ZnO active componed gradually shift to Zn₂SiO₄,and the morphology of desulfurizer shift to uniform small spheres by original sheet structure in the SEM figure,which leads to the special surface area and pore volume of desulfurizer has decreased.