Toward carbon neutral fuels: process analysis of integrated biomass conversion routes for sustainable biofuels production

Bioenergy is a significant aid in transport sector decarbonization. To design integrated biomass energy conversion processes for fuel production, comprehensive evaluation tools like energy analysis and Life Cycle Assessment are essential to assess technical feasibility and environmental impact. This study introduces a methodology for early-stage process design optimization, integrating energy optimization and environmental criteria within the design phase using Multi-Criteria Decision-Making principles and the Technique for Order Preference by Similarity to Ideal Solution ranking tool to identify optimum choices. A case study on lignocellulosic biomass conversion into hydrogen and drop-in fuels is used to test the methodology. The case optimizes four parameters: pyrolysis temperature, Steam-to-Char ratio in the Sorption Enhanced Gasification reactor, process layout, and plant capacity. Simulations using Aspen Plus and Well-to-Tank and Well-to-Wheel approaches assessed energy and environmental performance. The results demonstrate the methodology's usefulness in multi-objective optimization. Optimal design parameters shift based on evaluation criteria: for energy efficiency, the pyrolysis temperature is optimal at 400 °C and the steam-to-carbon ratio at 1.6; for environmental criteria, these values shift to 350 °C and 1.6, and further to 350 °C and 1.2 when prioritizing carbon dioxide reduction. For full utilization, the optimal values are 300 °C and 1.2. This integrated approach ensures process design aligns with decarbonization and transportation efficiency objectives.