Techno-economic barriers of an industrial-scale methanol CCU-plant

Abstract

Global anthropogenic CO2 emissions are expected to peak to 40 Gt in 2020. If these emissions are not mitigated climate change and global warming will further aggregate. Meanwhile, demand for products and fuels produced from fossil raw materials are increasing. CO2, however, can be considered as feedstock for certain materials and processes. If CO2 is catalytically synthesised with H2 it can form a variety of hydrocarbons, such as methane, methanol (MeOH), higher alcohols, and liquid fuels. In this paper, a simulation model of a MeOH plant using CO2 and H2 as feedstock was developed in Aspen Plus™. This is the first plant studied at an industrial-scale comparable with fossil MeOH plant units. The plant produces 5 kt chemical-grade MeOH daily that can be used as raw material for the chemical industry or as a fuel. The kinetic model, considering both CO and CO2 as the source of carbon, accomplished high overall CO2 conversion rate and close to stoichiometric raw material utilisation. Under the current market conditions, the MeOH plant is not feasible even at this scale. The most significant cost parameter making the plant non-viable is attributed to the high cost of H2 produced by water electrolysis. A series of sensitivity analyses revealed that co-selling of O2 by-product from the electrolyser and lowering the H2 cost price have a significant factor in achieving a more competitive levelised cost of MeOH. These economic results are analysed in-depth with previous studies to reveal the effect of different economic assumptions.