SURFACE-AREA DEVELOPMENT OF SEWAGE-SLUDGE DURING PYROLYSIS

Experimental studies on surface area and pore structure development during pyrolysis of digested sewage sludge were carried out. Surface area and pore structure characterization of the resultant chars was evaluated using an accelerated surface area and porosimetry system (ASAP 2000). The effects of process parameters, temperature and hold time were found to be significant. Generally, the surface area of the resultant char increases with temperature and hold time. However, the surface area is reduced for chars obtained at 550-650 degrees C, possibly owing to the pore enlargement phenomenon as a result of loss of volatiles in the intermediate thermoplastic phase. Reduction in mesopore volume due to sintering at high temperatures and prolonged times was also observed. In this study, the optimum temperature and hold time for maximum surface area development of the resultant char were found to be 850 degrees C and 2 h, respectively.