UnLimited-Newsletter 21-1 | May 5, 2021

we are glad to send you our first UnLimited Newsletter with actual information about the development of the scientific project. The newsletter is published quarterly. In this first issue you find a presentation about the research project and an overview about the latest activities.

Enjoy reading! We looking forward to your feedback and any questions. If you like it please forward it to your colleagues. On the Information Site Tiefe Geothermie you find the web-version.

Best regards your

UnLimited Communication Team

Topics UnLimted Newsletter 2021-1 | May 5, 2021

Kick-off session UnLimited: Investigations into lithium production from hot deep waters in Germany
With the start of UnLimited, the project partners BESTEC, EnBW, HYDROSION, KIT and Göttingen-University are working together on the development and implementation of a process that will enable lithium production from extracted deep waters to accompany their geothermal energy use. The research project is funded by the German Federal Ministry of Economic Affairs and Energy.

The UnLimited project aims at developing the necessary basis for lithium production from hot geothermal waters in Germany. The investigations are being held in the Upper Rhine Graben and North German Basin, where high lithium concentrations in geothermal waters have already been proven. For this purpose, the sustainability of lithium production will be examined and evaluated site-specifically and regionally, and various adsorbents will be tested in a demonstration plant under the conditions of an operating geothermal plant. Regarding sustainable management, not only the origin of the dissolved lithium is important, but also the understanding of essential reservoir processes. In this context, topics such as resource analyses, technically possible extraction rate and change in concentration of dissolved lithium over time are included in the research project UnLimited. All results generated in the project are an integral part of a lifecycle assessment, which optimizes and evaluates the sustainable and environmentally friendly use of adsorbents for lithium production. The necessary techno-economic and techno-ecological analyses are hence part of UnLimited.

The duration of the project, coordinated by EnBW, is 48 months and it was kicked off on December 1, 2020. For further information please visit the Unlimited website https://www.geothermal-lithium.org/en/unlimited.

Deep water analysis should provide information about the origin of lithium
The first sampling took place at the geothermal plant in Bruchsal as part of the UnLimited project on February 25, 2021. The campaign was supported by the team of EnBW.  During sampling, HYDROSION uses cooled samples, gas as well as water samples under operating pressure and temperature with appropriate high-pressure hoses and fittings. The aim of these investigations is to characterize the deep water and reservoir using hydrochemical and different isotope methods. Along with the results information on the origin and host rocks of lithium, as well as other interesting elements and their sustainable production shall be provided.

Webinar presentation available: “Over ten years in operation - experience with the Bruchsal geothermal plant”
On March 5, 2021, Dr. Thomas Kölbel of EnBW Energie Baden-Württemberg AG gave a presentation on the Bruchsal geothermal plant, which was initially envisioned as a research facility but is now in commercial operation. In addition to the experiences in operating the Bruchsal geothermal plant for the past 10 years, Dr Thomas Kölbel also addressed the UnLimited research project, which focuses on the recovery of lithium from geothermal brines.

Here you find the ink to the recording of the webinar.

3D process animation explaining the basic process of lithium recovery from geothermal waters
An animation about the lithium recovery process designed for the Bruchsal geothermal site was created by EnBW. The video depicts a faithful reproduction of the site conditions at Bruchsal and in a simplified form shows the extraction of lithium via adsorption and desorption processes using lithium-selective adsorbents. The English version of the process animation can be seen here.

Assessment of the sustainability of the lithium yield from the geothermal brine at the Bruchsal site
In order to quantify the fluid residence times in the reservoir under the production-relevant flow regimes, a tracer test will be conducted at the Bruchsal site. 'Spike' slug injection and 'outflow' sampling design is based on the artificial-tracer signals from the ongoing long-term monitoring campaign, which indicates the fluid turnover volumes in the range of ~1 to ~8 million m³ for the precursor flow regimes (according to the conservative estimations by a team of modelers at University of Goettingen). On-site monitoring and fluid sampling is secured by BESTEC and HYDROSION together with the operator's well-site team (EnBW), whereas the laboratory-instrumental metering of tracer signals is performed by Hydroisotop.

Research on global lithium production
The lithium market situation and current technological developments - such as developments in the recycling of lithium-ion batteries or technical alternatives in a post-lithium phase are being searched. The focus of the research is on resources/reserves, production quantities and the specific production costs and thus the buildability (cut-off grade). Data on the local environmental impact of lithium production and resource use - such as water consumption and energy use - are also collected and analyzed. The key data determined here will be an essential part of the Life Cycle Assessment.

Testing of lithium-selective sorbents on a lab-scale
Based on literature study and laboratory experiments, we determine a potentially suitable Mn-oxide sorbent for direct lithium extraction from geothermal brines. The sorbent shows fast reaction kinetics at the elevated temperatures of the geothermal brine (60 °C), a high adsorption capacity and only low sorption of competing ions. The strong sorbent stability indicates high reusability for many extraction cycles. In future steps, further laboratory experiments will be conducted in order (1) to verify the initial results; and (2) to investigate different ways of sorbent application into extraction chambers.

First design of a prototype for lithium recover
Based on the nominal lithium production rate in the produced geothermal brines in Bruchsal a first set of lithium extraction chambers has been designed for the planned lithium extraction bypass. The first design includes geometrical fluid flow parameters and is based on the results of the first successful performed laboratory tests. The brine produced in Bruchsal contains liquid and partly non liquid CO₂. Therefore, the pressure in the lithium extraction chambers needs to be controlled and potentially released CO₂ needs to be led back to the reinjected brine. Additional laboratory tests are planned to optimize the lithium recovery within the extraction chambers and to modify and adapt the design of the prototype.

UnLimited im Focus on Geothermal Webinar
The scientific project UnLimited will be introduced by Elif Kaymakci, the project manager at the EnBW, in the Focus on Geothermal Webinar. The presentation is scheduled for Friday, May 21, 2021 at 14.00 (CEST). Registration will soon be possible on the IGC.Events website.

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