Dimethyl ether synthesis via captured CO2 hydrogenation within the power to liquids concept: A techno-economic assessment

The necessity to decarbonise the transportation sector has triggered the exploration of alternative cleaner fuels that can successfully substitute fossil derived fuels. Dimethyl ether (DME) poses as a promising candidate due to excellent combustion properties and low greenhouse gas emissions. Recently, the power to liquids (PtL) concept in conjunction with the carbon capture and utilisation (CCU) scenario have emerged as sustainable ways to produce carbon based material and contribute into satisfying the ever growing energy demand. In view of these, the goal of the present study is to determine the technical performance and economic viability of a novel di methyl ether (DME) production route via captured CO2 hydrogenation within a power to liquid context. Mass and energy balances were solved and integrated by means of simulations using Aspen Plus V10 and Matlab R2017b software. Based on a plant that produces roughly 740 tonnes of DME per day, the global energy efficiency of the proposed process configuration is equal to 44.4% while the overall achieved CO2 conversion to DME is 82.3%. A typical discounted cash flow analysis revealed that the deterministic minimum DME selling price (MDSP) is 2193 (sic) t(-1) (or equally 75.62 (sic) GJ(-1)); this figure is approximately 5-fold greater than the gate price of conventional diesel. The factors that mostly affect the MDSP are associated with the electrolysis unit, i.e. electricity price as well as electrolyser efficiency and capital cost. Changes in the renewable energy price cause wide fluctuations in the DME market price of -70% to + 21%. Finally, stochastic uncertainty analysis, based on Monte Carlo simulations, exposed a 95% confidence interval for the MDSP to be within the range of 1828-2322(sci) t(-1).