Methane from biomass: process-integration aspects

The production of synthetic natural gas (SNG) via biomass gasification constitutes a promising option for biofuel manufacture due to its high conversion efficiency and diversity of end-use opportunities in different sectors. This paper presents a critical review of possible feedstock conversion paths from biomass to SNG via gasification. Similarities with research and development issues for coal gasification projects for SNG production are identified and the state of the art for the bottleneck stages of the conversion is discussed. The need for tools to improve process efficiency is clearly shown; the pinch methodology is a powerful tool for process integration and is of particular interest in this regard. Biofuel production processes often deliver multiple products and services such as heat, electricity and other by-products and are often referred to as polygeneration or biorefinery concepts. To take into account the multiple possible products and services resulting from SNG production, it is necessary to carefully define appropriate process performance indicators. For a sound assessment of the future potential of biomass-based SNG production, an evaluation of the most promising process alternatives against a background of possible future energy market scenarios is necessary.