Carbon Negative Platform Chemicals from Waste Using Enhanced Geothermal Systems

Abstract

Australia has ample geothermal resource, however, it is of low-grade heat and requires Enhanced Geothermal Systems (EGS). Integrating heat recovered via EGS into a lignocellulosic biorefinery opens the avenue for countless opportunities in biomass to products industries. In this study, a biorefinery is modelled that uses heat from a supercritical CO2 (scCO2) based EGS to convert waste biomass into platform chemicals. Additionally, CO2 is consumed by the microbes during the production of these chemicals. Simulation shows 60 t/h of scCO2 at 75 atm pressure and 120 °C is able to fulfil 438.23 kW/h of heat demand of the biorefinery. Overall, the biorefinery consumes 416.67 kg/h of biomass and 191 kg/h of CO2 to produce 113 kg/h of succinic acid and 50 kg/h of acetic acid.

Keywords: CO2 use for production of algae or chemicals, GHGT-14, EGS, biorefinery, renewable energy, CO2 utilisation