Solid Phase Supports for Flue Gas CO2 Separation with Molten Electrolytes

There are increasingly greater legislative, social, and environmental factors motivating the use of clean energy technologies that reduce carbon dioxide and other greenhouse gas emissions, with fossil fuel power plants collectively producing the largest fraction of carbon dioxide. The high costs associated with separation are prohibiting the application of carbon capture due to high energy and infrastructure costs and potentially double the cost of electricity ($/kWh) extended to consumers. A new approach is needed to retrofit existing fossil fuel power plants for cost effective CC&S. The solution: An energy efficient approach to carbon capture will separate CO2 from flue gases while it is still at high temperatures and pressures. Carbon dioxide separation in these conditions has recently emerged with the use of dual phase separation membranes using novel molten electrolyte formulations embedded in a solid phase support. While continued research into appropriate chemistries for the liquid phase is underway, the feasibility of solid phase support materials and their scale up has to larger membrane modules has yet to be addressed. The proposed work addresses the materials, optimization, design and scale up of new dual phase membrane modules that sustainably operate in the heat recovery steam generators (HRSG) cycle power plants. The work: In Phase I, the Luna team targeted solid phase support materials with high strength, increased CO2 separation capabilities, and stability in the presence of the new molten electrolyte formulations. It was critical that these materials were evaluated in context of the HRSG operational conditions to demonstrate their mechanical, thermal, and chemical stability, and their scale up to larger membrane systems. Numerous successes were achieved during this effort, including the scale up of high strength, high stability solid phase support materials with precision manufactured tubular membranes and the demonstration of the highest separation rates recorded for a CO2 membrane. Related fields of research have continually focused on solid and liquid phase materials in dual phase membranes, without consideration of their practical implementation in fossil fuel power plants. Luna Innovations is demonstrating the technical feasibility of a new membrane technology that has the potential to enable cost effective carbon capture from flue gases while integrating directly with HRSGs. In Phase II, Luna will design a multi-tube membrane module that demonstrates both the scalability and performance of the technology. Additional work in optimizing CO2 separation, CFD modeling, and a systems level approach will help to optimize separation performance and integration of the technology in relevant HRSG environments. The benefits: The proposed design and scale up of Luna’s dual phase separation membranes has the potential to facilitate a reduction in the United States’ carbon dioxide emissions by 10-20 % by avoiding tens of billions $US per year in separation costs. A significant reduction in carbon dioxide emissions is expected to have a positive effect on the environment.