Influence of Pyrolysis Temperature and Pellet Size on Syngas Production from Sewage Sludge: towards Energy Recovery

摘要

The energy recovery from sewage sludge has been turned out to be vital solution to the sludge problem. This study focused on the conversion of sewage sludge into syngas production. The effects of pyrolysis temperature and pellet size on syngas yield and composition were studied. The influence of operation mode on syngas yield was also investigated. Results showed that when the pyrolysis temperature increased from 450°C to 850°C, the yield of syngas increased and the energy recovery of syngas reached maximum value of 5194.3 J·g~(-1). Besides, the maximum lower heating value (LHV) of syngas reached 31.5 MJ·m~(-3) at 550°C because the CH_4 mole percentage in the total gas reached maximum value. The smaller pellet size was demonstrated to favour the production of H_2, CO and CH_4. The maximum CO and H_2 yield can be achieved at pyrolysis temperature of 850°C for smaller particle size. The syngas yield obtained in continuous operation reactor was evidently lower than that in sequencing batch reactor at pyrolysis temperature of 450 and 550°C. The difference of syngas yield in the two operation modes decreased with increasing pyrolysis temperature.