A modelling approach to the techno-economics of Biomass-to-SNG/Methanol systems: Standalone vs Integrated topologies

Chile accounts for one of the most important forest areas in Latin America; nevertheless, both Chilean energy and chemical infrastructures heavily relies on imported fossil fuels. This study focuses on the analysis of several scenarios contributing to change this status quo by producing biomass-based Methanol and Synthetic Natural Gas (SNG). A comprehensive flowsheeting model, including such technologies, is developed and validated. The plants are assembled in a general superstructure to perform their energy integration and economic evaluation. For the studied scenarios, the energy efficiency of gasifier was 74%; Methanol and SNG yields were 0.59 kgMeOH/kgDry-biomass and 0.33 kgSNG/kgDry-biomass, respectively. The biomass-derived SNG has an average of 88% mol of methane and a Lower Heating Value of 41 MJ/kg. The unit energy cost ($/GJ) via SNG and Methanol were 18.41 $/GJ and 29.54 $/GJ for standalone operation, and both can be reduced by 12.7% and 9.5%, respectively, by using an integrated process scheme. Finally, near 25% of sensitivity on unit cost of products (energy based) was found when the feedstock price varied between 1 and 60 US$/tonne.