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TDA Research, Inc (TDA) has developed a highly efficient integrated WGS pre-combustion carbon capture technology and demonstrated its techno-economic viability for use in the Integrated Gasification Combined Cycle (IGCC) power plants that process coal. The new system uses a warm gas CO2 scrubber integrated with a Water-Gas-Shift (WGS) catalyst to capture greater than 90% of the carbon emissions, which does not increase the cost of electricity (COE) as much as conventional carbon capture technologies.<
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The integrated WGS/CO2 removal reactor contains both a high temperature physical adsorbent capable of removing CO2 above the dew point of the synthesis gas and a commercial WGS catalyst to convert CO and H2O into H2 and CO2. The integrated operation of the WGS catalyst and the CO2 sorbent in a single process step drives the equilibrium-limited WGS reaction towards hydrogen without the need to add large amounts of water to the synthesis gas. When coupled to an IGCC the reduced steam input greatly increases the power cycle efficiency and reduces the cost of carbon capture. Our preliminary system analysis results suggested that maintaining the H2O:CO molar ratio close to that required by the reaction stoichiometry (i.e., H2O:CO = 1.0) rather than using an excess of steam (e.g., 2.0 is commonly used as the basis of various DOE analyses) will improve the absolute process efficiency by more than 2% (over a current efficiency of 34%). The process intensification provided by combining the two unit operations in the same reactor will also reduce the capital cost and improve the process economics.<
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In this project we demonstrated the techno-economic viability of the new process by: 1) demonstrating it in field tests, and 2) carrying out a high-fidelity engineering design and an economic analysis. We fabricated an 8-bed high temperature PSA system to run the full cycle sequence and demonstrated the integrated WGS pre-combustion carbon capture process, including the thermal management subsystems. We completed over 30,000 adsorption desorption cycles, showing stable catalyst and sorbent performance and completed a techno-economic analysis showing the merits of the integrated WGS carbon capture process.<
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In collaboration UCI, we also completed a high-fidelity process design and economic analysis for the combined WGS based pre-combustion CO2 capture system integrated with IGCC power plants operating on coal based E-GasTM and GE gasification systems. This analysis was completed on the basis of the DOE Rev 2a baseline study, operating on Illinois No. 6 bituminous coal integrated with regular state-of-the-art cold gas and TDA?s warm gas clean-up based CO2 capture system (without integration with WGS). We see that the net plant efficiency was the highest for TDA?s warm gas capture system when integrated with the last water gas shift stage at 34.7% vs 34.1% for the warm gas capture based system when it is not integrated with the WGS step. The increase in heat rate for the integrated WGS carbon capture system is about 12% over the cold gas cleanup based carbon system (SelexolTM). The cost of carbon capture including TS&M is estimated to be $35.8 per tonne ($25.8 per tonne when excluding the TS&M costs) for integrated WGS based capture system. This is much lower than DOE?s target for transformational carbon capture technologies of $30 per tonne excluding TS&M costs.<
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