Gasification Characteristics of Sewage Sludge in Water under Subcritical Conditions

Abstract

Gasification of sewage sludge in sub-critical water was investigated in a continuous flow reactor at temperatures of 300 and 350 C and residence time in the range of 5−30 s under the fix pressure of 25 MPa. The effect of temperature and residence time on the composition of the product gas were investigated. The gaseous products were analyzed by using a gas chromatograph (GC) equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID). H2 was detected by GC-TCD with N2 as the carrier gas; CO2 and CO were detected by GC-TCD with He as the carrier gas, and CH4, C2H4, and C2H6 were detected by GC-FID with He as the carrier gas. The results showed that the gaseous product mainly contained H2 and CO2 with less amount of CH4 and C2H4, and no CO was found. Temperature did not affected carbon gas efficiency