Chemical energy storage via methanol synthesis in a tubular steam electrolyser-reactor
Due to the extensive expansion and utilization of wind and solar energy in Germany, the demand for technologies for temporal and spatial decoupling of energy provision and consumption is continuously increasing. As a consequence, the integration of large amounts of energy from intermittently regenerative energy sources into the existing power grid leads to fundamentally new requirements related to the current, base-load oriented power economy and its corresponding energy infrastructure. Furthermore, the lack of applicable technologies for the direct storage of electricity in relevant orders of magnitude shifts the scope of interest of ongoing research activities towards technologies for the conversion of excess power into chemical energy carriers, such as liquid hydrocarbons. Liquid hydrocarbons can be used as synthetic liquid fuels as well as for the synthesis of a diversity of downstream products with higher added value, thus providing an interesting economic alternative for the power economy and the chemical industry.
A promising opportunity for chemical energy storage and the production of valuable chemicals can be found in the decentralized production of methanol or longer-chain liquid hydrocarbons from carbon dioxide and electrolytic hydrogen, gained from intermittently regenerative energy sources. Combined with an appropriate coupling of stationary carbon dioxide emitters and consumers, carbon dioxide can be used in a closed loop, thus providing a forward-looking method for the recycling of carbon dioxide (CCU – Carbon Capture and Usage).
The goal of research project DELTA is the development of an economically and technically flexible device for the electrochemical production of hydrogen with an integrated, heterogeneously catalyzed hydrocarbon synthesis based on carbon dioxide and steam. The device, based on a tubular and proton-conducting ceramic high temperature electrolysis cell (SOEC) and a synthesis unit with ideal system integration, represents the basic module which then can be combined with further identical modules forming a flexible plant capable of decentralized operation for future technical applications. The high degree of system integration allows for an efficient energy and material-flow management as well as a compact design. The usage of proton-conducting ceramic membranes represents an innovative development since high-purity hydrogen can be supplied within the targeted temperature range without the need for complex and energy-intensive downstream processes for hydrogen refinement. The aim of the overall project is the practical demonstration of an integral reactor system which is characterized by low system costs, low energy losses, high system efficiencies, high reliability and an excellent load change behavior.
The sub-project of the HZDR contributes to the development of the overall system with computer-aided analysis of the ideal flow behavior by means of CFD and FEM methods which take into account thermodynamics, mass transport and chemical reactions inside the DELTA reactor. Another work package is concept development for the measurement of key process parameters and the development of suitable control technologies and strategies. In particular, the consideration of the process behavior of the overall system in the case of a highly fluctuating electricity supply caused by intermittently regenerative energy sources and the development of suitable process control strategies are of primary importance. Furthermore, system analyses for the application of the presented technology to decentralized production of further chemical energy carriers and basic chemicals (e.g. ammonia) are conducted.
Funded by the European Union
- European Regional Development Fund (EFRE)
- Promoter: Sächsische Aufbaubank (SAB)
- Project title: Development of a tubular steam electrolyzer with integrated hydrocarbon synthesis (DELTA)
- Project duration: 09/2016 – 08/2019
- Technische Universität Dresden, Institute of Power Engineering
- Technische Universität Bergakademie Freiberg, Institute of Ceramic, Glass and Construction Materials
- Technische Universität Bergakademie Freiberg, Institute of Chemical Engineering
- Fraunhofer Institute for Ceramic Technologies and Systems IKTS