In a study financed by the Swedish Energy Agency and the industrial gasification group at the Swedish Gas Technology Centre (SGC) Renewtec has reviewed promising gasification techniques for small and medium scale (5-30 MWth) biomethane production.
Small plants are normally associated with a high specific investment cost but by changing to a gasification and gas cleaning technique adopted for smaller plants this problem may be circumvented.
Even if small plants often are associated with a somewhat lower conversion efficiency there are several advantages to build plants in the smaller scale. The economic risk is lower, it’s easier to secure the feedstock supply and to integrate excess process heat with the local heat demand.
On the gas cleaning side techniques related to catalytic tar reforming are under development which implies that the rather costly tar separation based on wet scrubbing techniques can be avoided. When it comes to carbon dioxide separation the thermo-chemical biomethane route based on gasifcation and methanation profits from the development within the anaerobic digestion sector.
The report can be downloaded through the following link Small and medium scale technologies for bio-SNG production
In the report the specific investment cost is investigated.