Cost-Effective Centrifugal Reverse Osmosis

Opportunity

The increase in demand for freshwater during the 20th century has led to a global water-scarcity crisis affecting 40% of the world’s population. The situation is exacerbated by the contamination of freshwater resources, global climate change, industrialisation and rapid population growth. Less than 0.008% of the water on Earth is available for its current population of 7.7 billion people. One effective way to increase available freshwater supply is through seawater desalination. Desalination via reverse osmosis (RO) membrane technology now dominates the world market. However, a longstanding problem of RO desalination is its high cost relative to freshwater sources. A major contributor to this disparity is the high-pressure pumping cost for RO.

Technology

This invention presents a centrifugal reverse osmosis (CRO) technology that can significantly reduce the pumping cost for RO - as it operates close to the minimum energy required for separating freshwater from saltwater. This is achieved by rotating a membrane module to create a centrifugal pressure that increases with distance from the axis of rotation. As a result, the local pressure is only slightly higher than the minimum required for RO. In contrast, conventional RO desalination employs a high-pressure pump to operate the entire membrane module at the maximum pressure. This novel CRO technology can reduce the energy required for a 50% recovery of freshwater from a typical seawater feed by over 30%. Collaborations with companies interested in licensing this technology for pilot-scale testing and commercial application are welcome.

Applications & Advantages

Main application areas include seawater desalination as well as brackish and inland water resources. It is also applicable for solute concentration, such as concentrating ethanol from dilute aqueous biomass solutions, and resource recovery, such as the recovery of lithium and rubidium from concentrated brine products.

Advantages:

• Significantly reduces the cost of producing freshwater from seawater and other saline resources
• Significantly reduces the cost of producing ethanol from dilute aqueous biomass solutions
• Cost-effective way to increase the world’s freshwater resources
• Reduces the cost of producing renewable energy sources, such as ethanol
• Enhances the recovery of valuable solutes, such as lithium and rubidium from seawater