SBIR Phase I: High-Salinity Produced Water Management by Recovering Solid Waste with Low Grade Thermal Energy

The broader impact/commercial potential of this SBIR Phase I project is to develop a desalination system powered by solar energy. Water is used for lithium and rare metal mining, requiring energy-efficient water treatment to produce fresh water and concentrated brines. This type of water treatment in mineral recovery systems can yield valuable critical materials as byproducts. Many lithium and rare metal mining fields are located in regions in the US where solar energy is abundant. Energy efficiency in traditional distillation processes must be significantly improved to make water treatment economical. The use of solar energy to power the proposed system also reduces or eliminates the need for transporting fuel for deployments of the process in remote areas. The proposed Phase I project will develop a system using solar energy to treat salty tailing waters through thermal desalination by an integrated system of lithium bromide (LiBr) multi-effect distillation (MED) dryer. The system also includes a second MED with mechanical vapor compression (MVC) and a LiBr regenerator. All the electrical and thermal energy used in the system are converted from solar heat. The water treatment process includes lithium and rare metal recovery as well. The design incorporates a distillation system with mechanical vapor compression. Comparing to traditional MED, our unique design enables our system to be 10-20 times more compact than traditional MEDs. During the Phase I project, the company will develop physics-based models to analyze the technology, as well as build and evaluate small prototypes to confirm the feasibility. The proposed integrated, enhanced and compact MED plus MVC equipment can intensify the heat and mass transfer processes and reduce heat losses. By integrating multi-cylinder configurations in one single cylinder or similar configurations, our equipment designs will exceed those of traditional MED systems. Modeling and simulation of the proposed distillation system show up to 10-fold improvement in energy efficiency. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.