Synergetic Effect on Syngas Yield and Energy Yield during Co-pyrolysis of Sewage Sludge and Rice Straw

Abstract

This study focused on the co-pyrolysis of sewage sludge and rice straw in order to improve syngas yield and energy recovery potential. The singular pyrolysis of sewage sludge and rice straw was firstly investigated under varying operating temperatures. Then the synergetic effect on yield of combustible gas and energy yield during co-pyrolysis was studied. Results showed that the syngas yield increased with operating temperature from pyrolysis of sewage sludge, meanwhile, the energy recovery reached maximum value of 5194.3 J · g -1 at 850°C. The yields of combustible gases were found to first increase and then decrease with increasing pyrolysis temperature from pyrolysis of rice straw. The synergetic effect of co-pyrolysis on gas yield was different at different operating temperature. There was a beneficial synergetic effect on yields of CO and H2 at 850°C, while it was shown an unfavorable influence on CO and H2 yields during co-pyrolysis at 650°C. The maximum conversion of energy reached 8098.4 J·g -1 at 850°C when the weight ratio of rice straw was 15%. In this case, it was indicated that an energy recovery of approximately 60% was achieved with the energy potential of parent stock.