Bio-SNG Production via Gasification - Process Integration Aspects for Improving Process Performance

Paper in proceeding, 2013

This paper presents results from a comprehensive process integration study of different process alternatives for Bio-SNG production based on biomass gasification. The influence of the different conversion steps in the process chain – drying, gasification, gas cleaning, methanation, and gas upgrade – on the overall process performance is investigated. Process bottlenecks as well as heat and material integration aspects are highlighted. Using future energy market scenarios, the energetic, economic, and carbon footprint performance of different process configurations are evaluated from a system perspective. About 63 MLHV of Bio-SNG can be produced from a process converting 100 MWth,LHV (20 wt-% moisture) of forestry residues. Drying of the feedstock from a natural moisture content of 50 wt-% using internal process heat recovery is shown to be important for increasing the process energy efficiency, while the choice of gasification and methanation technology is shown to be of minor importance from a process integration perspective. Amine-based CO2 separation for gas upgrade is shown to be preferable to membrane or pressure-swing adsorption based options both from an economic and Bio-SNG yield perspective. Production cost estimates in the range of 103–112 €2010/MWhSNG indicate that price parity with fossil natural gas would require specific and significant support policies.