Improved Energy Efficiency of Power-to-X Processes Using Heat Pumps Towards Mobility Sector Defossilization

Abstract

Combining Power-to-X (PtX) processes with high temperature heat pumps (HTHP) can significantly increase their energy efficiency. Evaluating the example of oxymethylene ethers (OME) production from H2 via H2O electrolysis and captured CO2 from air shows that by upgrading waste heat streams using HTHP, a process overall energy efficiency of higher than 61 % can be achieved compared to 30 % in conventional integrated processes. Thereby, the waste heat stream from H2O electrolysis already covers the low temperature heat demand for CO2 capture via direct air capture, not only for OME but also for various PtX products. Importantly, a significant lever for the energy efficiency enhancement is the consideration of other low temperature heat-demanding sectors. High overall process energy efficiencies and the electrification of the industry are key aspects towards a sustainable mobility sector.