Brief description:
Absorption refrigeration systems are the best ecological and economic solution for many applications in refrigeration and air conditioning technology. This is particularly true when previously unused heat sources can be utilized. Absorption refrigeration is generated by utilizing the temperature dependence of the physical solubility of two substances. The water/lithium bromide working fluid pair is very widely used. In each system, fill quantities ranging from a few hundred kilograms to several tons of a 54 % lithium bromide solution are common. The systems consist primarily of steel and copper, which are in direct contact with this solution. To suppress the resulting corrosion of the metallic materials, corrosion inhibitors are added to the absorption solution. Since corrosion cannot be completely prevented even with the addition of inhibitors, corrosion products accumulate in the solution over time. To date, used materials have been sent for disposal at the end of such systems’ lifespans or following repairs; the raw material lithium bromide is thus removed from the cycle. This also results in the loss of lithium, a metal of strategic value for various future technologies. Compounding this issue is the fact that the demand for lithium bromide solution in Germany must currently be met entirely through imports.
Project Objective:
The goal of this project is to develop an environmentally friendly, economically viable, and ready-to-use process for the treatment of used, highly concentrated lithium bromide solutions in order to initiate a lithium recycling cycle from lithium bromide solutions derived from absorption refrigeration systems, thereby contributing to resource efficiency. The project aims to demonstrate that a 54% brine solution intended for disposal—which contains inhibitors and is contaminated with corrosion products—can be converted into a regenerated stock solution. A batch process with a capacity of approximately 1 m³ per day is planned, which will generate a marketable new lithium bromide solution from waste solutions in accordance with the required specifications.
Partner:
Project Manager: LuxChemtech GmbH
Industry Partner: Johnson Controls
Project completion:
The project is scheduled to end on April 30, 2021. Initial results were presented in 2019 at the DKV conference in Ulm. Do you have absorption refrigeration solution that needs to be disposed of or recycled? If so, please contact our project partner LuxChemtech. Do you have general questions about chemistry, corrosion, and corrosion inhibition in absorption solutions? If so, we are the right people to contact.
Awards & Nominees
In 2021, ILK Dresden, in collaboration with LuxChemtech GmbH, was awarded the eku - FUTURE PRIZE for Energy, Climate, and Environment in Saxony. The award recognized the development of a recycling process for lithium bromide solutions from absorption refrigeration systems. In doing so, the project made an important contribution to resource conservation and the sustainable use of working fluids in refrigeration and energy technology.
The following year, the project was nominated for the German Raw Material Efficiency Award. In connection with this, a video was also produced that provides an insight into the project:
