Techno-economic Modelling of Carbon Dioxide Utilisation Pathways at Refineries for the Production of Methanol

Abstract

The decarbonisation of carbon-intensive sectors is a fundamental task for the achievement of future environmental goals. Within the challenge of industrial decarbonisation, oil refining represents a hard-to-abate sector, considering that it is characterised by CO2 emissions deriving from multiple units and at different levels of concentration and flow rate. Therefore, pathways for the separation and conversion of such CO2 into products (e.g., synthetic fuels) may cover an important role in the reduction of CO2 emissions from refineries. The objective of this study is the technical design and economic evaluation of a conversion pathway for the production of CO2 and green H2-based e-Fuel methanol (i.e., based on conventional electrolysis), as juxtaposed to an alternative process concept based on electrified reforming er-Fuel methanol. Such plants are modelled in terms of mass and energy balances in Aspen Plus® software to produce methanol. Then, an economic assessment is carried out to highlight the best design configurations and compare the production costs. Optimal plants configurations are determined by fine-tuning the level of light products recycles, to minimise the feed of green H2 and maximise the performance indicators. Results demonstrate how the er-Fuel configuration allows better conversion efficiencies and lower production costs, in the order of 30-40 % reduction with respect to the e-Fuel design.