Lithium, the renewable coal
Lithium can be used for chemically storing electricity as part of a cycle in which it is first generated electrochemically using surplus electricity and then combusted as required in a power plant-compatible process to release the energy again. In the “LiKohle” project, researchers are investigating and assessing the possible reaction processes, for example in a carbon dioxide or nitrogen atmosphere. Valuable chemical raw materials can be generated as a by-product of the energy conversion.
|Project status||Project completed|
|Project duration||June 2012 until September 2015|
With the exception of the battery technology, the potential of lithium to store overproduction electricity from renewable energy sources has not been studied. The fundamental aspects of the lithium combustion in a power plant relevant process, as well as concepts for the energy efficient possibility for the recycling of the solid reaction products are to be examined within the project. The project consortium includes the following partners: Siemens AG, as project leader and industrial partner, the research group of professor Scherer (Ruhr-Universität Bochum, specialists in combustion processes) and the research group of professor Katharina Kohse-Höinghaus and professor Andreas Brockhinke (Universität Bielefeld) with an extensive experience in the analysis of reaction kinetics and flame characterization.
The target of the present project consortium is the study and evaluation of the potential of a closed energy loop on the basis of electropostive metals and in particular lithium as high density, seasonal, energy storage material. Thereby lithium is produced using an electrochemical process (electrolysis of lithium chloride) by use of stranded, overproduction electricity from renewable energy sources. The conversion / release of the stored renewable energy in to thermal energy by use of a power plant compatible combustion process in a carbon dioxide or nitrogen atmosphere is to be examined. According to its position in the standard reduction potential table, lithium can reduce even very low reactive gases. The strongly exothermic reaction of lithium with CO2 and nitrogen (N2) yields thermal energy comparable to the combustion of coal in an oxygen atmosphere. Furthermore lithium can reduce thereby CO2 to valuable carbon monoxide (CO), which can be further converted with hydrogen (H2) from renewable sources to methanol or gasoline. The lithium nitride, as product of the combustion in nitrogen, can offer in an exothermic reaction with water an energy efficient access to ammonia, an important chemical product obtained otherwise with a large energy comsumption.
Key aspects of research
- Reaction mechanism and reaction kinetics of the exothermic reaction of lithium with carbon dioxide, nitrogen and gas mixture
- Combustion parameters (ignition characteristics, particle temperature, flame characteristics)
- Reaction products in dependence of the reaction parameters
- The present project is not to be seen as an alternative to hydrogen as energy storage material, but as an addition to the energy storage materials topic
At the current stage of the project (first project year) the partners are developing reactors with lithium particles, lithium spray as well as low pressure reactors for the caracterisation of the combustion in carbon dioxide or nitrogen atmosphere. Up to the present date no study on lithium combustion reactors for energy conversion and usage in an power plant relevant process was published. The reactor design activities are supported by experiments in order to determine relevant material properties of electroposite metals and numerical simulation. The fundamentals of the lithium combustion in carbon dioxide and nitrogen will be determined as part of the activities of the second and third project year: single particle raction, ignition, flame and particle temperature, reaction kinetics and mechanism, reaction products in dependence of the reaction paramters. Technical relevant lithium combustion concepts will be developed based on the experimental results. The investigation of the lithium availableness, enviromental impact and effciency of the energy storage concept based on litium (electropositive metals) complete the presented study.
The first project milestone was successfully completed. The fulfillment of the other defined milestones is not at risk.