An innovative system that produces cost-effective potable water and hydrogen from seawater and renewable photovoltaic energy

PAX Scientific (PAX) has developed a low-temperature process that purifies water and provides for its reuse in a simplified and cost-effective process, regardless of the salinity content and contamination level. Our technology is mobile, modular and easily scalable with variable throughput handling abilities. The water purification system can use secondary energy sources, such as low-grade heat and solar thermal, and remove multiple water contaminants in one step, including minerals, salts, hydrocarbons, suspended solids, metals, microplastics, etc. PAX offers a cost-efficient solution for seawater that reduces electrical energy use by 50% or more compared to competing technologies and allows water recovery rates of at least 80%. PAX’s technology avoids key issues commonly associated with high total dissolved solids thermal purification such as source variability, corrosion effects, limited access to energy sources, high capital expenses and high operating and maintenance costs (O&M). Its lower operating temperatures allow an all-plastic system for many applications, avoiding corrosion and fouling, and eliminating the need for expensive materials, such as titanium. In addition, the system can handle highly variable water sources without the need to replace membranes, filters or add chemicals, minimizing O&M costs. PAX’s distillation method simplifies the process by removing many steps in the treatment train. During Phase I, PAX simulated the combination of its distillation technology with a solar photovoltaic-powered hydrogen electrolyzer, to co-produce hydrogen and water from seawater in a cost-effective, rugged, and scalable way. PAX tested the potential for this novel system through extensive thermo-economic modeling based on analysis of academic and market research. PAX purified seawater into potable water in a prototype unit and tested the water to prove it met requirements to be utilized by the electrolyzer without further pre-treatment. In Phase II, PAX will implement and validate a 10-kW potable water and hydrogen co-production prototype fed with seawater and powered by solar PV. The system validation will be performed in two steps, starting with the testing of an integrated prototype single effect system in a laboratory environment in Phase II Base, followed by a demonstration in operational environment (TRL7) of a multiple effect distillation (MED) unit in Phase II Option, potentially at a NAVFAC facility. In addition to a successful demonstration, PAX will define a four to 16 effect MED system that, integrated with a larger electrolyzer, meets ambitious water and hydrogen cost production goals of $.80/m3 and $2.30/kg respectively.