Process simulation for mass balance of continuous biomass hydrothermal liquefaction with reaction kinetics

Hydrothermal Liquefaction (HTL) process has been investigated for biomass conversion to bio-crude and other valuable materials. However, this process modeling remains a challenge due to the high complexity of its feedstock and product compositions and the numerous chemical reactions occurring simultaneously. Here, we investigate the mass balance of the HTL reaction using a process simulation with a kinetic model previously developed for the HTL of microalgae. This model was implemented in UniSim-Design software, and the simulation's performance was validated against published experimental results for various feedstocks, including microalgae, macroalgae, food waste, and model protein. Bio-crude had the best performance for predicting the products' yields from HTL of microalgae, and aqueous-phase had the poorest. For predicting the bio-crude yield from HTL of different feedstock categories, microalgae had the best performance, and model proteins had the poorest. Insights are suggested for improved modeling towards a more robust system-design-oriented approach for process simulations.