CCS and Power Systems
Carbon Capture - Post-Combustion Capture
Novel Inorganic/Polymer Composite Membranes for CO2 Capture
Project No: FE0007632
The Ohio State University (OSU), along with its partners, will develop a cost-effective design and manufacturing process for novel membrane modules that efficiently captures CO2 from power plant flue gas. The innovative membrane design combines the selectivity and stability of inorganic microporous membranes and the cost and flexibility of polymer materials. This design will result in hybrid membranes with exceptionally high CO2 permeance, high selectivity of CO2 over nitrogen (N2), and the full operational stability needed for energy-efficient CO2 capture. The membranes will be implemented in a two-stage CO2 capture process with the potential to meet the DOE goals of 90 percent CO2 capture with less than a 35 percent increase in the cost of electricity (COE).
An important cost driver of current CO2 capture technologies is the parasitic power required to maintain the driving force for membrane separation. Initial OSU research found that parasitic power needs can be sufficiently reduced in a two-stage CO2 capture process. In the first stage (see Figure 1) CO2 is removed from flue gas by evacuation; in the second stage the remaining CO2 is removed using an air sweep. This process has the potential to meet DOE targets with membranes that can achieve a CO2/N2 selectivity of around 200, a permeance above 3,000 gas permeation units (GPU), and can remain stable in the presence of flue gas contaminants. This combination cannot be achieved with fully polymeric membranes. Fully inorganic microporous membranes are sufficiently selective and stable but are generally too expensive due to high manufacturing costs. Hence, the OSU design combines favorable inorganic membrane selectivity with the cost-effectiveness of polymer processing in continuous mode.
OSU will conduct bench-scale development and testing of the process for new membrane modules for CO2 capture during the three-year project. The membrane will consist of a thin selective inorganic layer embedded in a polymer structure that allows it to be manufactured in a continuous process. It will be incorporated in spiral-wound modules for bench-scale tests at actual conditions. The membranes that are developed should achieve the performance requirements by using a cost-effective nanoporous polysulfone support; depositing a very thin, highly selective yet permeable inorganic membrane; and applying a polydimethylsiloxane (PDMS) or amorphous fluoride polymer top layer for defect abatement. The multi-layer support provides strength, a smooth deposition surface, and high permeance. OSU will scale up the optimized membrane to a width of at least 14 inches and a length of at least 50 feet using their in-house continuous fabrication machine. Three pilot/prototype membrane modules will be fabricated and tested to demonstrate the membrane’s performance. Technical and economic feasibility studies will be completed, as well as an environmental, health, and safety (EH&S) assessment.