Progress in Development of Electrochemical Membrane Technology for Post-Combustion Carbon Capture
Carbon Management Technology Conference
2015
2015 Carbon Management Technology Conference
CO2 Capture for Fossil Energy Power Plant
CO2 Capture for Fossil Energy Power Plants 2
Thursday, November 19, 2015 - 1:10pm to 1:35pm
To address the concerns about climate change resulting from emission of CO2 by natural gas and coal-fueled power plants and industrial facilities, FuelCell Energy, Inc. (FCE) has developed the Combined Electric Power and Carbon-dioxide Separation (CEPACS) system. The CEPACS system utilizes Electrochemical Membrane (ECM) technology derived from the Company’s molten carbonate fuel cell-based Direct FuelCell® products. The system separates CO2 from the flue gas of other plants and produces electric power using a supplementary fuel. FCE is currently evaluating the use of ECM to cost effectively separate CO2 from the flue gas of Pulverized Coal (PC) power plants under a U.S. Department of Energy contract. The overarching objective of the project is to verify that the ECM can achieve at least 90% CO2 capture from the flue gas with no more than 35% increase in the cost of electricity (COE).
The potential of ECM for separating greater than 90% of carbon dioxide from the flue gas of a PC power plant have been experimentally verified. ECM materials tolerance levels to various contaminates in the flue gas including sulfur, chlorine, mercury and selenium, specifically SO2, HCl, Hg, and SeO2, have been identified. The contaminant levels expected from the flue gas clean-up subsystem were also estimated and compared with the ECM tolerance levels. The analysis showed that the ECM tolerance levels are well above the contaminant levels expected in the ECM cathode feed gas (treated flue gas). Additionally, the ability of ECM to destroy NOx components in the flue gas were confirmed in the laboratory tests. Testing showed that 70-80% of all NOx was destroyed at high inlet NOx concentrations of over 200 ppm. This significant finding may result in further reduction of the incremental COE associated with the CEPACS system, if credits are given to elimination of the selective catalytic reduction (or other) process step for NOx control in the PC plant.
The Technical and Economic Feasibility studies were conducted including the assessments of performance and cost of an ECM-based CO2 capture system for retrofitting a 550 MW (net AC) PC plant. The CEPACS system generates 421 MW of additional power after compensating for the auxiliary power requirements of CO2 capture and compression. The economic analysis included estimation of the CEPACS plant cost and the incremental cost of electricity for ECM-based CO2 capture. The CEPACS technology has the potential to meet DOE’s goal of ≤35% increase in COE for post-combustion CO2 capture. The cost of CO2 avoided for a PC plant equipped with CEPACS system was estimated to be $30/tonne (2011 US dollars) which is significantly lower than $78/tonne for a PC plant equipped with an amine-based scrubbing system. The CEPACS system can also meet the DOE’s target cost of <$40/tonne CO2 captured.
A bench-scale ECM-based CO2 capture system was designed and fabricated. The objective of the demonstration is to show the capability of full-size ECM cells to separate >90% of CO2 from a simulated PC plant flue gas stream during extended operation (> 1 year). The system utilizes an ECM stack containing 14 full-area cells with a total electrochemical membrane area of 11.7 m2. Peak gross DC output is ~10 kW, with capability for high-purity liquid CO2 production of ~100 tons/year. The stack has been operating for more than 6,500 hours and has demonstrated a very stable electric power generation while separating 93% of carbon from flue gas at a constant CO2 flux of 116 cc/s/m2.
In this presentation, the status of the ECM technology and its application for carbon capture will be reviewed. The results of trace contaminants experiments, characterization of ECM tolerance to key flue gas contaminants, ECM technology NOx removal capabilities, bench scale full-area ECM stack testing, and the techno-economic studies of CEPACS systems will be discussed. Finally, the benefits and commercialization activities of the ECM technology will be presented.