Gasification of a Dried Sewage Sludge in a Laboratory Scale Fixed Bed Reactor

The paper present study on the air gasification process of dried sewage sludge. Parameters such as air ratio λ=0.12÷0.27, air temperature t=50oC÷250oC and molar fraction of O2 in gasification agent zO2=0.21 and zO2>0.2) were found to influence on the syngas parameters: Lower Heating Value (LHV) and composition. The results indicate that the syngas LHV was found to decrease with increase air ratio for all analyzed cases. Increasing O2 concentration in gasification agent increased the temperature, which tended to favour the formation of smaller molecular components in the gas mixture. Thus, the enriched air medium produced a gas with a higher LHV. In contrast to conventional gasification, a process with a preheated gasification agent causes that the flux of heat necessary to support endothermic gasification reactions is producing more effective. As a result, H2 and CO production is promoted.