Biogas production from various waste sources has gained considerable traction in recent years. With the focus on maximising gas yields and minimising process waste, hydrothermal treatment is considered a viable pre-treatment step enhance biogas yield. Hydrothermal treatment, with or without partial oxidation, can increase biogas yields by breaking bigger molecules into smaller, more-digestible organic molecules. SCFI is actively developing this pre-treatment step for a client that uses biomass sludge for biogas production.
The Application
The feasibility of using a hydrothermal partial oxidation step to increase the biogas yield from the feedstock material is being investigated. The main aim of this work is to develop a scalable process and to evaluate the system performance on pilot scale.
Feasibility Testing
The first step of the study was to investigate the feasibility of heating the specific lignin sludge stream while allowing for heat recovery to offer a more efficient pre-treatment step. The application required designing a lab-scale test rig to pump and heat the sludge to evaluate flow performance. SCFI designed the test unit and worked with sub-suppliers to fabricate the assembly. SCFI performed the work at its laboratory facilities in Cork, Ireland. The main finding from the current laboratory work is that heating the particular biomass results in an unstable suspension that causes blockages downstream of the heating step. This is valuable information for the development the pilot scale plant.
What’s Next
Based on the information gathered from the bench-scale testing, a continuous pilot scale unit was recommended to the client to further assess the business case for the full-scale pre-treatment step. The continuous pilot is to be operated on site to allow for optimisation with a real-time feedstock.
