Membrane Technology and Research (MTR), along with the University of Toledo, will develop new large-area membrane contactor modules to significantly increase the feasibility of using membrane technology to separate CO2 from the high-flow, low-pressure, dilute flue gas streams of coal-fired power plants. Current membrane-based CO2 separation modules use a spiral-wound geometry which limits their size. Given the large volumes of flue gas produced by a coal-fired power plant, many of these modules would be required, resulting in a very complex, expensive piping arrangement and large space requirements. Such complex piping arrangements often result in difficult control and larger pressure drops. MTR estimates that a 500 megawatt (MW) power plant would require 0.5 to 1.0 million square meters (m2) of membrane area. This project will apply an alternative approach to membrane packing to develop plate and frame modules with a membrane area 20 to 25 times that of existing modules. The new membrane modules will each contain 500 m2 of membrane and will be optimized for low-pressure, countercurrent sweep operation. These mega-modules can dramatically reduce the manifolding complexity, footprint, and cost of the very large membrane plants required for flue gas treatment. Additionally, the modules have potential for use in synergistic CO2 capture combinations of a membrane pre-concentration step and a second final concentration step such as absorption, adsorption, or cryogenic separation. The feasibility of these combined or hybrid processes will also be evaluated during this project.
The proposed optimized membrane module will utilize CO2 separation membrane technology developed by MTR through previous and current DOE/NETL projects, and will be useful for current membranes as well as any next-generation CO2 capture membrane that is produced. Development of the module will proceed in stages through small, intermediate, and full size prototype modules to determine the optimum module geometry and materials. Bench-scale testing will be carried out to evaluate the module performance and integrity, and computational fluid dynamics (CFD) modeling will be used to guide module development.
The mission of the U.S. Department of Energy/National Energy Technology Laboratory (DOE/NETL) Carbon Capture Research & Development (R&D) Program is to develop innovative environmental control technologies to enable full use of the nation’s vast coal reserves, while at the same time allowing the current fleet of coal-fired power plants to comply with existing and emerging environmental regulations. The Carbon Capture R&D Program portfolio of carbon dioxide (CO2) emissions control technologies and CO2 compression is focused on advancing technological options for new and existing coalfired power plants in the event of carbon constraints.
Post-combustion separation and capture of CO2 is a challenging application due to the low pressure and dilute concentration of CO2 in the waste stream, trace impurities in the flue gas that affect removal processes, and the parasitic energy cost associated with the capture and compression of CO2. Membrane-based CO2 control technologies utilize permeable or semi-permeable materials that permit the selective separation of CO2 from flue gas and have the potential to effectively reduce the energy penalties and costs associated with post-combustion CO2 capture for both new and existing pulverized coal (PC)-fired power plants.
Development of this new type of very large area membrane contactor module can increase the feasibility of using membrane technology to separate CO2 from the low-pressure, dilute flue gas from coal-fired power plants. The cost and complexity of manifolding membrane modules and the footprint of the membrane system for commercial power plants can be considerably reduced by development of the new mega-modules. Energy savings resulting from the reduced pressure drop of gases circulating through the modules, as well as improved countercurrent flow, are additional benefits. The availability of this type of module also opens up the possibility of creating synergistic hybrid combinations of CO2 capture technologies capable of meeting DOE performance goals.
Primary Project Goal
The primary project goal is to build and operate a 500 m2 prototype low-pressure countercurrent flow sweep membrane module and evaluate its potential—in an all-membrane process and in hybrid processes—to significantly contribute to the DOE goal of capturing at least 90 percent of the CO2 from coal-fired power plant flue gas with less than a 35 percent increase in the cost of electricity.
The project objectives are to (1) prepare modules with an effective membrane area of 500 m2, (2) perform parametric testing with synthetic flue gas, (3) validate that module pressure drop is less than 1.5 psi, (4) analyze the cost and efficiency of the modules for an all-membrane process and for hybrid processes, (5) determine strategies to maximize CO2 enrichment for the membrane unit, and (6) develop a plan to integrate the technology for potential field testing.
Construct and evaluate several small prototype membrane modules (20 m2).
Select the best design for further development.
Select module components and sealing techniques.
Construct and evaluate intermediate size modules (100 m2).
Select the final geometry.
Refine CFD process simulation of module.
Construct and test a full-size module (500 m2).
Complete design and feasibility evaluations incorporating the new module design with other CO2 capture systems.
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