Demonstrating the CCU-Chain and Sector Coupling as Part of ALIGN-CCUS - Dimethyl Ether from CO2 as Chemical Energy Storage, Fuel and Feedstock for Industries

In the ALIGN-CCUS project a full CCU-chain will be demonstrated as an element for large-scale energy storage together with CO2 conversion and CCU-fuel usage as a promising blue print for sector coupling. The demonstration comprises: amine-based CO2 post-combustion capture, liquefaction and storage processes at the lignite fired power plant at Niederaussem (liquefied CO2 pressure 16.5 bar(a) - 17.5 bar(a), temperature -26.5 °C), an alkaline water-electrolysis unit (140 kWel, specific power consumption 4.5 kWh/mN³ H2 at 1.0 A/cm²), to split water into hydrogen and oxygen and an one-step methanol/dimethyl ether (DME) synthesis unit (approx. 50 kg DME/day from 180 kg CO2/day). A diesel engine of a stationary power generator (240 kWel) will be adapted to the use of DME to demonstrate peak and back-up power production in the energy sector. Additionally a passenger car will be modified for the utilization of oxymethylen dimethyl ether (OMEn), a diesel substitute for the transport sector that could be produced out of the CCU base chemicals methanol and DME. Based on real data from the demonstration plant the integration costs and environmental benefits of the CCU-chain technology are evaluated and optimised by a techno-economic-ecological assessment. A promising optimization measure for the synthesis process is the in-situ removal of water in the reversed water-gas shift reaction to increase efficiency and yield. For the application of DME as a fuel for peak- and back-up power production an optimised concept for the integration of the power generator into the existing power plant infrastructure will be developed.