Low-temperature (below 150°C (300°F)) and coproduced geothermal resources represent a growing sector of development in to produce power as well as recover mineral resources. Southern Research Institute developed an innovative Geothermal ThermoElectric Generation (G-TEG) system specially designed to both generate electricity and extract high-value lithium (Li) from low-temperature geothermal brines. The process combined five modular technologies including: silica removal, nanofiltration (NF), membrane distillation (MD), Mn-oxide sorbent for Li recovery, and TEG.

350Solutions staff served as the technoeconomic evaluation and commercial plant design leads for the innovative Li G-TEG process, developing ASPEN process models of the technology at commercial scales  (500 GPM brine at 150 ppm Li) based on experimental results, including specification and costing of all primary and balance of plant equipment. Economic analysis was completed using US DOE Pro Forma tools. Our staff demonstrated the potential of the technology to provide positive economic returns at lithium brine concentrations above 300 mg/l. For applications with concentrations of 150mg/l, analysis indicated a need for over 25% reduction in capital costs.