Research On Coking Control For SOFC With Microwave Pyrolysis Gas Of Sludge As Fuel

Aiming at increasingly tense energy situation, to solve the problems of inefficiency in sewage sludge treatment and disposal, this paper is about the research on solid oxide fuel cell(SOFC) fueled with biogas produced by technology of microwave pyrolysis, which will realize the high-efficiency utilization of biomass. SOFC is highly efficient power generation device, which can directly convers chemical energy into electrical supply. Now carbon deposition is a real pitfall in popularization and application for SOFC. Carbon deposition is produced when SOFC fueled by carbon fuel gas, resulting in structural failure, obstruction of gas transmission, and finally affects discharge stability, shortens the battery life. Ni-YSZ-SOFC was used for this research. This research was based on two main aspects, which were optimization of operating conditions and electrode material properties. Operation status, reformation of biogas and modification anode material were tested. The behavior of coking was discussed, while the stability was enhanced under improvement. SOFC fueled with biogas produced by technology of microwave pyrolysis operated with less carbon deposition.When fueled with simulate biogas produced by microwave pyrolysis, there was less coking with higher temperature and current density, which lead to stability. In comparison, when operated with lower temperature and current density, SOFC operated undulately, which indicated that more carbon was produced. Meanwhile, SOFC fueled by H2 or simulate biogas was prominently influenced by temperature. The max power density(MPD) increased with temperature remarkably.When it came to the research of biogas reformation, the effect of eliminating carbon of CO2 was investigated. Fueled with CO2/CH4, the discharge performance and behavior of coking was discussed. The data indicated that to add CO2 in CH4 enhanced the stability of SOFC while operating. When CO2/CH4 equaled 2, SOFC was operating most stably.Fueled with simulate biogas, to enhance the concentration of CO2 lowered the MPD, but SOFC operated more stably. The performance of SOFC was best when the concentration came to 20%. At this point, the output voltage was stable. Adding H2 O to biogas enhanced not only the stability of operation but also the MPD slightly. The performance of biogas with 7% H2 O was better than biogas with 3% H2 O.Mn Fe2O4 was prepared by the method of sol-gel self-propagating combustion, then Mn Fe2O4 anode barrier layer was made with the technique of screen printing. The microstructure of anode barrier layer was observed by SEM and to discuss the electrochemical performance via electrochemical test. The result indicated that compared with SOFC without barrier, SOFC with Mn Fe2O4 anode barrier layer operated more stably while the MPD declined slightly. The performance of 24 hours operation, the MPD test after operation and SEM pictures showed that 16 wt%-C anode barrier layer behaved the best with a slight decrease of voltage.