Effect of operating parameters on thermochemical liquefaction of sewage sludge

Abstract

To determine the optimum combination of operating parameters for direct thermochemical liquefaction of sewage sludge, dewatered materials (raw mixed sludges) were treated over a temperature range of 150-300°C, a holding time of 0-180min and a catalyst (sodium carbonate) loading of 0-5wt% using a batch reactor. By variance analysis, the lower limit of reaction temperature for the production of heavy oils was found to be 250°C. At that temperature, however, organic concentrations in the aqueous phase were still high. From the viewpoint of oil production and wastewater treatment, the optimum combination of operating parameters was a reaction temperature of 275-300°C, a holding time of 60 min and operation without catalyst. © 1990, The Society of Chemical Engineers, Japan. All rights reserved.