Preparation And Performance Optimization Of Mn-based High Temperature Desulfurization For SOFC

In this study, high temperature desulfurization researches which can be used for carbon-based Solid Oxide Fuel Cell were conducted. Manganese-based desulfurization has the high reactivity to hydrogen sulfide, thermal stability, and regeneration performance. Therefore, manganese-based desulfurization was carried on the study. The physical and chemical properties of desulfurization were analyzed by means of XRD, SEM and BET. The desulfurization activities of high temperature desulfurization sorbents were studied in a fixed bed reactor.Different Mn-based desulfurization was prepared by sol-gel method. Effect of different meshes, calcination temperature, sulfidation temperature, and regeneration temperature and sulfuridation-regeneration cycle performances were studied. It was found that the Mn-based desulfurization of 20-40 meshes calcinated at 850℃ which was sulfide at 850℃ and regenerated at 850℃ had the best average desulfurization accuracy and breakthrough time. Sulfidation–regeneration cycles were conducted to M2 which was prepared under the optimum operating conditions. It was found that after 5th successive sulfidation–regeneration cycles. Deactivation was detected in the M2 sorbent after regenerations. So it needs further optimization for M2.Different La-doped M2 desulfurizations were synthesized and evaluated to develop a highly active sorbent for H2 S removal. It is found that the average desulfurization accuracy and breakthrough time was improved. The sorbent of Mn: La mole ratio of 95:5 could remove H2 S from 1000 ug.g-1 to less than 4.9 ug.g-1 in the simulated gas, which breakthrough time could reach to 70 min.Different Mn La-Zr samples with different Mn La/Zr molar ratio have been prepared by precipitation combined with sol-gel method. It was found that the specific surface area, average desulfurization and breakthrough time of the manganese lanthanum desulfurization have been improved when the carrier was added. It shows the breakthrough time of MLZ4 can reach 156 min, which was selected as the best for subsequent research.Effects of the different calcination temperature on MLZ4 were studied. The results showed that MLZ4 after calcination at 850℃, had the biggest specific surface area and best desulfurization performance. Examines showed that the 1000 h- 1 space velocity was the best airspeed. After 6th successive sulfidation–regeneration cycles, no deactivation was detected in the MLZ4 sorbent after regenerations. The main conclusion here is that this sorbent had attractive regeneration abilities and H2 S sorption properties after successive sulfidation-regeneration runs with the MLZ4 sorbent synthesized in this work, which provide a powerful support to the application of direct carbon solid oxide fuel cells.The simulated gas after desulfurization was passed into the SOFC(Anode of Ni-YSZ, cathode of YSZ-LSM, is 8YSZ electrolyte support body, dry pressing method, 1450℃ sintering 3h) for the first time in order to verify the feasibility of the SOFC power generation. Sorbents loading quantity has been increased. It shows that no attenuation of SOFC life through 24 hours, also the performance of the cell is very stable. It provides a powerful support to the application of direct carbon solid oxide fuel cells.An equivalent pore model was proposed to describe the kinetic behavior of MLZ4 sorbent for hydrogen sulfide removal in hot coal gas.