CO2 Capture from Power Plant Flue Gas By PolarisTM Membranes: Update on Field Demonstration Tests

To mitigate the harmful effects of global climate change, CO₂ in power plant flue gas must be captured and sequestered. Membrane technology is considered as an option for CO₂ capture because of advantages such as energy-efficient passive operation, tolerance to acid gases and oxygen, a small footprint, no use of hazardous chemicals, no additional use of water, and no steam use requiring modifications to the existing boiler and steam turbine.

Working with DOE, MTR has developed new membranes and process designs to recover CO₂ from power plant flue gas.  MTR Polaris membranes have CO₂ permeances ten times higher than standard commercial membranes, which greatly reduces the cost of a membrane capture system.  These membranes are combined with a novel process design that uses incoming combustion air to sweep membranes and recycle CO₂ to the boiler.  Design calculations estimate that this membrane process can capture 90% of the CO₂ in flue gas as a supercritical fluid using approximately 25% of the plant power, at a cost of $40-$50/ton of CO₂ captured.  This translates to an increase in the levelized cost of electricity of about 50%. 

In 2010, MTR completed a three-month field demonstration of the membrane CO₂ capture process with Arizona Public Service (APS) at their Cholla coal-fired power plant. The pilot system used commercial-scale membrane modules, and removed 90% CO₂ from a post-FGD flue gas slipstream containing 1 ton CO₂/day. In late 2011, the system was moved to National Carbon Capture Center (NCCC) operated by Southern Company in Birmingham, AL, for further demonstration. Overall, the system has an accumulated run time of over 10,000 hours, and the membrane modules have exhibited stable performance. With experience learned from these tests, MTR has designed a scale-up small pilot unit to capture 20 ton CO₂/day from a power plant slipstream (equivalent to 1 MW_e-scale power generation). The system was initially commissioned in August 2014 and testing concluded in June 2015.  During testing, advanced modules demonstrating higher packing density, lower pressure drop, and cost savings were validated.  Technical results to date for the field tests, and future plans on technical development will be discussed in this presentation.