Preparation Of Sorbents For Hot Coal Gas Desulfurization And Performance Of Sorbents Under Different Reaction Conditions

The mesoporous silica was selected as supports,a series of sorbents with high sulfur capacity,high utilization and regeneration capacity was prepared.Besides,the influence of different preparation process,various silica supports and adding different rare earth oxide were explored.It has three parts:1.Performance of Zn-Fe-Mn/MCM-48 sorbents for high temperature H₂ S removal and analysis of regeneration process.A series of 50%Zn-Fe-Mn/MCM-48 sorbents were prepared and their performance of hot coal gas desulfurization was investigated.High breakthrough sulfur capacity?13.2 g S/100 g sorbent?and utilization?66.1%?of 50%1Zn2Fe2Mn/MCM-48 sorbent at 550 ? was achieved.MCM-48 had excellent thermal stability at less than 700 ?.MCM-48 mesoporous structure remained intact after eight successive desulfurization/regeneration cycles.The regeneration process of 50%1Zn2Fe2Mn/MCM-48 sorbent was analyzed,it indicated that the breakthrough sulfur capacity decline of sorbent was due to the migration of Zn onto the sorbent surface and Zn accumulated on the surface and vaporized to the exterior from the surface.The TPO test revealed that the temperature of regeneration for ZnO sorbent should be higher than 700 ?.2.Different preparation process versus performance of Mn_xO_y/MCM-48 sorbents for hot coal gas desulfurization.A series of 50% Mn/MCM-48 sorbents with different synthesis methods,precursor compounds,calcination temperature and heating rate in the calcination step were prepared.The synthesis methods and precursor solutions influenced the dispersion while the calcination temperature and heating rate in the calcination step influenced the dispersion and structure of MCM-48 support in the sorbents,which were the dominant parameters influencing their desulfurization efficiency.The more dispersing of active species and integrity of MCM-48 support structure,the better the desulfurization performance of sorbent.Thus,the best sorbent was prepared with a sol-gel method using Mn?Ac?2 solution as precursor and calcined at 550 ? with a heating rate of 2 o/min.3.Performance of rare earth oxide doped Mn-based sorbent on various silica supports for hot coal gas desulfurization.A Mn-based sorbent with high desulfurization efficiency were fabricated using various mesoporous silica as support and doping rare earth oxides.The results indicated that Mn/MCF exhibited the highestdesulfurization performance among Mn/MCM-41,Mn/SBA-15,Mn/MCM-48 and Mn/MCF due to the 3-D ultra-large mesopores and excellent thermal stability of MCF at 700 ?.Doping rare earth oxides into Mn/MCF can make the high dispersion of active particles.But the breakthrough sulfur capacities over 95Mn5Ce/MCF,95Mn5La/MCF and 95Mn5Sm/MCF sorbents are lower than Mn/MCF sorbent.The desulfurization efficiency and precision further declined with increasing steam content for Mn/MCF sorbent.The high sulfur capacity over the Mn/MCF sorbent was maintained during the five consecutive desulfurization/regeneration cycles.