Life Cycle Assessment of Methanol Production by Gasification using Biomass Residues

Abstract

A Python script was developed for automated life cycle assessment (LCA), able to evaluate different impact categories. The automation of LCA, will allow to identify the most and least polluting process steps from our overall process. The script functions include importing simulation values, linking emission data, calculating environmental impacts and visualizing of LCA results. In this study, two models have been conceptualized for process operation: pure biomass alone mode or electrolysis assisted mode. Aspen inputs parameters were changed based on the Aspen Plus simulation in order to investigate different process conditions and decide which is the most environmentally friendly option. The various process parameters include the H2/C ratio (hydrogen to carbon), that means additional H2 is used for methanol synthesis. Also, the extra oxygen is used for the autothermal reforming. Both are provided by the water electrolysis, when it is switched on. Furthermore, the type of biomass used for gasification was varied between bark and straw. In addition, two LCA cases were considered. In the first case, the electricity mix was switched to wind energy and in the second case, wind energy and potential sustainable biomass (organic straw and debarking in wood) were selected.