Evaluation of processing route alternatives for accessing the integration of algae-based biorefinery with palm oil mill

Abstract

Algae biomass has gained attention as a potential feedstock for renewable energy production in a biorefinery due to its capability to assist on carbon sequestration and wastewater remediation. Since algae can be grown using CO2 and wastewater, the integration the algae-based biorefinery with other industry that produced CO2 and discharge water as wastes may improve the economic and environmental aspects of the biorefinery. In this study, the economic potentials of five processing route alternatives for algae processing (1000 t/y of dry algae feed basis) in an integrated algae-based biorefinery with palm oil mill were assessed. The alternatives evaluated were: (A1) Combustion of residual algae, (A2) Production of biogas from the Palm Oil Mill Effluents (POME), (A3) Production of biochar and bio-oil, (A4) Production of biogas and bio-oil, (A5) Production of green diesel. The economic assessments of the processing route alternatives were compared with the baseline scenario, which was the processing of algae into biodiesel and glycerol without the palm oil mill integration. Depending on the alternatives, the algae could be processed to produce up to 20.6 GWh/y of electricity, 100 t/y of biodiesel, 139 t/y of bio-oil, and 13.9 t/y of green diesel. The capital costs (CAPEX), operating costs (OPEX), revenue (REV), and energy demand (ED) for the baseline scenario and alternatives were calculated. The CAPEX for the baseline scenario and all of the integrated biorefinery alternatives evaluated varied between 9.239 × 105 USD/y to 9.526 × 105 USD/y while the OPEX varies between 7.765 × 106 USD/y to 8.474 × 106 USD/y. Based on the specific case study, all alternatives were not economically feasible since evaluation on all alternatives resulted in loss. Palm oil mill integrated algae-based biorefinery for biogas production was the alternative with least loss of −6.240 × 106 USD/y.