Energy, exergy, exergoeconomic, and environmental assessment of different technologies in the production of bio-jet fuel by palm oil biorefineries

Abstract

This work explores palm oil and the residual biomass from oil palm extraction to obtain valuable products via sustainable routes in integrated biorefineries, which were separated into three scenarios: Baseline Scenario is the current Brazilian application of palm in the energy sector using a biodiesel plant with a cogeneration system; Scenario 1 integrates a Hydrotreatment of Esters and Fatty Acids unit to produce bio-jet fuel into the previous case; and Scenario 2, integrates a second-generation ethanol plant and an Alcohol-to-Jet process in order to obtain bio-jet fuel from the second generation. Taking into account that the selection and integration of processes carried out in a biorefinery would impact the overall efficiency of the system, the production costs and the impacts on the environment of the plant make it is necessary to carry out a comprehensive evaluation of the system that allows characterizing and quantify the energy, economic and environmental aspects related to the biomass energy conversion. A methodology of analysis was proposed to address all of these aspects and to provide results that allow for a decision-making guide in technology selection. It was identified that the main need for improvement in the biorefineries relies on cogeneration, which exergy destruction rate ranged from 167.99 to 213.63 MW. The unit exergoeconomic costs founded for glycerol, biodiesel, and electricity were all lower than the market costs, the bio-jet fuel costs, from hydrotreatment, were nearly the same as those from the Brazilian market 0.49 and 0.46 USD/L, respectively. However, the costs of upgrading ethanol were the highest found and way higher than the market rate at 5.15 USD/L. Environmentally, the selected configuration of biorefineries provides all produced biofuel environmental gains compared to conventional non-renewable fuels. Biodiesel and bio-jet fuels would avoid emission of 324.65 kgCO2eq/t and 3092.45 kgCO2eq/t, respectively.