Techno-economic and environmental comparison of processes for the production of grape oil

Abstract

A systematic techno-economic analysis for the comparison of different routes for grape seed oil extraction was performed, which included hexane extraction as benchmark process, and the use of supercritical fluids (SC), specifically SC-CO2 and SC-CO2+ethanol as co-solvent. The processes have been modeled rigorously using Aspen Plus. The results show that the use of hexane is the most efficient (13.06 % recovery) and, only by using a co-solvent together with SC-CO2, the yield is similar (12.98 %). However, the cost increases from 6.31 USD/kg of extracted grape oil to 8.61 USD/kg of oil extracted, even though it is cheaper than the use of SC-CO2 alone. The investment cost is almost twice using the co-solvent compared to the traditional one ($9.72 MM vs $4.95 MM). SimaPro has been used to perform the lifecycle assessment (LCA). Similar results are found when the LCA analysis is performed as long as the energy mix is the current one. The high energy consumption of SC based systems results in high carbon emissions. However, combining electrification and renewable energy allowed the SC-CO2+ethanol system to reduce by 25 % the CO2 emissions per kg of oil produced by the hexane system. The economic evaluation performed provides the estimation of the CAPEX and OPEX for each alternative.