Hydrogen from Sewage Sludge
There are two subprojects in hydrogen generation from sewage.
1. Hydrogen Production from Sewage Sludge by Steam Gasification
Hydrogen from biomass steam gasification (SG) is a net zero greenhouse gas emission fuel. Sewage sludge (SS) has the potential to produce a hydrogen-rich gaseous fuel. Therefore, hydrogen production from sewage sludge may be a solution for cleaner fuel and the sewage sludge disposal problem. By using the Gibbs free energy minimisation (GFEM) method, the computer model for sewage sludge steam gasification (SSSG) showed hydrogen yield ranges from 135 to 70 g/kg of daf SS for equivalent ratios (ERs) 0 to 0.5. It was found that the higher the S/B, the higher the hydrogen yielded, however, heat energy requirements increased with S/B. Results from the simulations with or without heat loss showed that above ER 0.42, the SSSG can operate without external heat input with hydrogen production approximately 75 g/kg of daf SS. It should be noted that this optimum ER would change depending on the amount of heat loss and other operating parameters such as S/B and operating conditions. The aim is to develop and validate a computer model for predicting SSSG, to obtain the most economical conditions for producing hydrogen gas product from sewage sludge.
2. Supercritical Water Gasification of Sewage Sludge
Supercritical water gasification (SCWG) is a novel conversion method of sewage sludge for hydrogen production and its disposal method. Characterisation of the SCWG reaction has been undertaken through computer model development. Simulated results show that sewage sludge is the best suited wet waste biomass material for hydrogen production. Hydrogen rich production and complete utilisation can be achieved by the high temperature and low pressure SCWG operation with high water content in feed stream. Batch reactor system and optimisation method are required to characterise the transient SCWG reaction behaviour of sewage sludge. The objective is to develop computer models to characterise SCWG of sewage sludge.
Dr Lu Aye (Staff)
Department of Civil and Environmental Engineering - University of Melbourne
Pisuthi Klinkarjorn (Student)
Doki Yamaguchi (Student)