(373x) Circular Economy Approach to Monetize Palm Oil Agricultural Residues

We recreate via mathematical programming a palm oil value chain comprising land cultivation, biomass gathering, pretreatment, transportation, and gasification to convert the palm oil agricultural residues such as palm kernel shells (PKS), empty fruit bunch (EFB), and fiber (F) into biohydrogen. Mass and energy balances for the biomass drying, grinding, torrefaction, and pelletization are adapted from empirical correlations from literature. As a result, we obtain an EFB-B pellet, which has a higher energy density and a lower moisture content than the EFB and B independently. In addition, pellets can enhance the performance of the gasification process and minimize transportation costs. We consider the possibility of energy hubs for centralized biomass pretreatment, where the PKS, EFB and F can be storage for further transformation into pellets or decentralized pellets production in each palm oil extraction plant. Moreover, truck transportation from/to each energy hub or extraction plant is considered. The pellets gasification is modelled using Aspen Plus and a series of surrogate models for this process are built using ALAMO. These models are integrated into the value chain optimization framework. In terms of sustainability, we estimate the carbon footprint for the whole value chain using OpenLCA. The results indicate that the LCOH is about 6.6 USD/Kg H₂ with a carbon intensity of 0.48 Kg CO₂-eq/Kg H₂.