| As an alternative, the pyrolysis of sewage sludge is receiving increasing attention as an economic and environmentally acceptable route to waste disposal. This process has the high ability to convert sewage sludge to renewable resource. In this paper, the pyrolysis of sewage sludge was systematically investigated under inert conditions in a fixed-bed batch pyrolyzing furnace which can simulate the engineering practice with obvious temperature grads and reaction time segments. The characteristics of products were detected by calorimeter, element analyzer, scanning electronic microscope (SEM) and gas phase chromatography and the thermogravimetric analysis techniques were used in the research of the pyrolytic decomposition kinetics mechanics.The effects of final pyrolysis temperature, heating rate, reaction time and material moisture on the product distribution and composition were researched also. It was found that the final pyrolysis temperature was the most important influencing factor during the process. When the final temperature was above 450℃, liquid phase(oil) achieved higher yield and the highest yields were achieved at 550℃.The maximum value was 43%. The analytical experiments and evaluation results of oil approved that vaporized hydrocarbons content in the liquid phase were higher than crude oil and the compositions were similar to diesel oil. So the pyrolysis oil has potential quality to instead of diesel oil. The liquid phase production could become the succedaneum of mineral fuel if they were disposed properly. The characteristics of solid phase under moderate final pyrolysis temperatures varied from 250℃~700℃were analyzed. It was found that volatile matter content in semi-coke reduced but ash and fixed carbon contents raised with the increasing of final pyrolysis temperature. Because the solid phase at high final temperature has higher porosity, the semi-coke can adsorb harmful ingredient chlorine and sulfur in NCG. According to the analysis of NCG, the yield of CO2 was maximum at lower pyrolysis temperature but the yields of H2,CO,CH4 were higher than other gases at elevated pyrolysis temperature and the caloric value were higher also.According to the study of the thermogravimetric curve, differential thermal analysis curve and differential thermogravimetric curve, the pyrolysis of sewage... |
