The Study On Desulfurization Performance Of ZnO/MCM-41 Sorbent Prepared By Microwave Assisted In-Situ Method For Hot Coal Gas

As one of the three largest fossil energy sources,coal plays the important role in the basic energy in China,and it's position will not shakable in the economic development.However,the environmental problems arising from the direct combustion of coal have to be noticed by people.Integrated Gasification Combined Cycle technology?IGCC?is based on the comprehensive utilization of coal,and uses coal gas as power to generate electricity,which is a clean and efficient green technology.But,the coal gas contains large amounts of sulfides and more than 90%of hydrogen sulfide,which will not only cause corrosion damage to the equipments,but also make the catalyst poisoned,what's more,is a threat to people's health.Therefore,we must remove the hydrogen sulfide from the coal gas before entering the fan.Then,how to prepare hot coal gas desulfurizers with high efficiency and easy using in industry has become the focus of research.This paper from the perspective of reduceing desulfurizer preparation technology and improving the desulfurization performance,using zinc acetate and thioacetamide as raw materials,prepared ZnO/MCM-41 sorbents via microwave assisted in-situ regeneration method successfully.First,prepared Zn S/MCM-41desulfurizer precursor through one step Synthesis assisted microwave,then getting fresh Zn O/MCM-41 sorbents by in-situ regeneration method.To getting the best preparation conditions,optimized the selection of desulfurizer precursor preparation technology in the experiments;then gets the best active components loads in in-situ regeneration stage and gets the best regeneration condition;finally,on this basis,the five sulfide-recycling experiments was carried out,to test the stability of the desulfurizer.In the experiments,various samples in every stages was characterized by XRD,BET,SEM-EDS,TEM and FTIR,and the following main conclusions were drawn:?1?Zinc acetate and thioacetamide were selected for the the zinc and sulfur sources of the precursor ZnS/MCM41,and further get the best preparation conditions:microwave power 400 W,microwave reaction time 2.5 h,and the molar ratio of raw materials?zinc acetate:thioacetamide?1:3.?2?Do the tests of sulfurization performance with different loads,the fresh desulfurizer with 40%active components obtained by microwave assisted in-situ regeneration method have the largest sulfur capacity and the longest breakthrough time,which is the best loads.The BET specific surface area reached 527.64m²/g and characterized by SEM and TEM for fresh samples,found that sorbents particles can be dispersed evenly by microwave assisted in-situ regeneration method,and the molecular sieve pore structure of MCM-41 was not damaged,which have the whole two-dimensional hexagonal phase mesoporous structure.?3?Desulfurizer regeneration condition was investigated,the results shows that the best regeneration condition is:regeneration temperature 650?,regeneration space velocity 5000 h^-1 and regenerative oxygen concentration 6%.The regeneration rate of desulfurizer in this condition was 91.85%,indicating that the desulfurizer regenerated relatively complete.?4?Do five times desulfurization-regeneration recycling experiments,the results shows that after five times sulfuration,sorbents can still keep the initial sulfur capacity above 60%,and the first sulfide has best performance with the sulfur capacity of 11.27 g S/100 g sorbent and breakthrough time of 705 min,more importantly,the sorbents remains whole structure in the process of five sulfide desulfurization,does not appear pulverization cracking phenomenon.?5?The desulfurizer in the process of five desulfurization-regeneration recycling was characterized by XRD,the results shows that the regenerated samples contain Zn₂SiO₄,and part of the regeneration of samples also contain ZnS.Through the analysis of the pore structure and morphology of sulfide,BET surface area has decreased,and partial pore structure is blocked,which may be the reason for the decrease of sulfurization performance.