A Negative-Carbon Footprint Process with Mixed Biomass Feedstock Maximizes Conversion Efficiency, Product Value and Co2 Mitigation

Spent mushroom substrate and bagasse were processed in a designed process to achieve negative CO2 emission yet produce value-added products. Specifically, biomass was processed into activated carbon and biofuel in a process that includes pyrolysis, activation, water-gas shift, Fischer-Tropsch synthesis and distillation. By integrating experimental characterization, this work uses process simulation, techno-economic analysis and life cycle assessment to evaluate the techno-economic viability and CO2 footprint of processes with single or dual-/mixed-biomass feedstocks. The combination of biomass species provides unique match of the production of flue gas and primary carbon that is critical for the optimization of mass and energy flow. Such combination has been demonstrated effective to improve product yield and energy efficiency. Results show that mixed biomass feedstock offers favourable figures such as high carbon efficiency of 66.74%, short payback period of 3.16 years, considerable net present value of 80.48 million dollars, and low GWP of -2.37 kg CO2-eq