Life cycle GHG emission reduction of hydrotreated vegetable oil integration in an industrial petroleum refinery

Abstract

The purpose of this paper is to perform a comprehensive Life Cycle Assessment to evaluate the environmental performance, in terms of GHG emissions, of co-processing Used Cooking Oil (UCO) with fossil light gas oil into a current diesel hydrotreater unit at an industrial refinery, located in Northern Greece. Two scenarios have been defined and compared, considering: (i) the hydrodesulphurization process of light gas oil for the production of conventional ultralow sulphur diesel fuel (reference scenario), and (ii) the integration of pre-treated UCO along with conventional fossil feed at 5/95% volume ratio, for the production of Hydrotreated Vegetable Oil (HVO) (retrofit scenario). The results of the LCA analysis show that the net life cycle GHG emissions associated with fossil diesel production amount to 103.41 gCO${}_{\mathrm{2eq}}$/MJ, while the relevant ones related to the HVO/blended diesel production are 95.42 gCO${}_{\mathrm{2eq}}$/MJ. A considerable GHG emissions reduction (about 7.7%) will be incurred by the substitution of conventional fossil diesel fuel with the HVO blended diesel one. A newbuild refining facility using exclusively used cooking oil as feedstock could further increase the GHG emission savings up to 93%, indicating that additional research is required regarding the environmental performance of sustainable fuel production processes. Furthermore, alternative sources of biomass feedstock need to be investigated, because of the maximum cap on used cooking oil set in the Renewable Energy Directive (RED II) legislation.