19. ENERGY EFFICIENT MEMBRANES

Separation technologies recover, isolate, and purify products in virtually every industrial process. Pervasive throughout industrial operations, conventional separation processes are energy intensive and costly. Separation processes represent 40 to 70 percent of both capital and operating costs in industry. They also account for 45 percent of all the process energy used by the chemical and petroleum refining industries every year. Industrial efforts to increase cost-competitiveness, boost energy efficiency, increase productivity, and prevent pollution demand more efficient separation processes. In response to these needs, the Department of Energy supports the development of high-risk, innovative separation technologies. In particular, membrane technology offers a viable alternative to conventional energy intensive separations.

Successful membrane applications today include producing oxygen-enriched air for combustion, recovering and recycling hot wastewater, volatile organic carbon recovery, and hydrogen purification. Membranes also have been combined with conventional techniques such as distillation to deliver improved product purity at a reduced cost. Membrane separations promise to yield substantial economic, energy, and environmental benefits leading to enhanced competitiveness by reducing annual energy consumption, increasing capital productivity, and reducing waste streams and pollution abatement costs.

Despite the successes and advancements, many challenges must be overcome before membrane technology becomes more widely adapted. Technical barriers include fouling, instability, low flux, low separation factors, and poor durability. Advancements are needed that will lead to new generations of organic, inorganic, and ceramic membranes. These membranes require greater thermal and chemical stability, greater reliability, improved fouling and corrosion resistance, and higher selectivity. The objective is better performance in existing industrial applications, as well as opportunities for new applications. To advance the use of membrane separations, research is needed to develop new, more effective membrane materials and innovative ways to incorporate membranes in industrial processes. Grant applications must address the potential public benefits that the proposed technology would provide, both from reduced energy consumption and from the reduction in one or more of the following: materials consumption, water consumption, and toxic and pollutants dispersion. Grant applications also should include a plan for introducing the new technology into the manufacturing sector, in order to access capabilities for widespread technology dissemination. Grant applications are sought only in the following subtopics:

a. Membrane Materials with Improved Properties—Grant applications are sought to develop lower cost inorganic, organic, composite, and ceramic membrane materials in order to improve one or more of the following properties: (1) increased surface area per unit volume, (2) higher temperature operation (e.g., by using ceramic or metal membrane materials), and (3) suitability for separating hydrophilic compounds in dilute aqueous streams. Particular membrane materials of interest include nano-composites, mixed organic/inorganic composites, and chemically inert materials. Particular processes/systems of interest include membranes for the separation of biobased products, membranes for hydrogen separation and purification, and membranes for industrial applications.

For industrial applications, high temperature separations of hydrocarbons and other mixtures are of particular interest. For example, low molecular weight hydrocarbons are separated from natural gas by condensing them as a liquid, and the liquid is distilled to fractionate it, or the liquid is hydrocracked to olefins. However, chilling the natural gas in order to recover the condensable portion and then reheating it is inefficient, because the energy used to chill it cannot be recovered. Membranes, either as stand alone systems or hybridized with other separation technologies, may provide an energy efficient means of separating mixtures at the high temperatures at which these industrial processes are carried out.

For all membrane processes/systems, grant applications must be targeted toward the development of specific membrane materials for carefully defined commercial applications; efforts focused on generalized membrane material research are not of interest and will be declined. In order to assure the rapid commercialization of the technology, especially for use by U.S. manufacturers, applicants are strongly encouraged to engage in partnerships, so that the costs of the technology development and commercialization can be shared among manufacturers, suppliers, and end users.

b. Membranes for Separations of Biobased Products—Grant applications are sought to develop membrane technology to enhance the production of large volume, value-added chemical products using biomass feedstocks. These processes may use either enzymatic or chemical catalysis, and may be conducted in either aqueous reaction media or organic solvents. Grant applications must demonstrate a clear connection to a crop-based feedstock and a large volume chemical product (one that would be manufactured at greater than 500 million pounds). Of particular interest are (1) novel membrane processes that use reactive separation technology, which combines the reactive transformation with the separation; and (2) novel membrane materials with higher flux or selectivity, and with improved chemical and thermal membrane stability. Again, applicants are strongly encouraged to form partnerships involving manufactures, suppliers, and end users, in order to promote and ensure the rapid development and commercialization of the technology in the U.S.

c. Hydrogen Production—Hydrogen can be produced from coal, natural gas, biomass, and biomass derivatives through the use of gasification, pyrolysis, reforming, and shift technologies. In all cases, a hydrogen-rich producer gas or syngas results, from which the hydrogen must be separated and purified. The most common approach today involves the use of pressure swing adsorption (PSA) technology. The use of membranes holds the promise of reducing costs by combining the separation and purification with the shift reaction in a reactive separation operation. Therefore, grant applications are sought to develop improved hydrogen membrane separation and purification technology for use in the production of hydrogen; the focus of the research should be on low cost, high flux rate, durable membrane systems that can be integrated with the shift reaction. Membranes of interest include ceramic ionic transport membranes, micro-porous membranes, and palladium based membranes. Such membranes could be used for a wide range of production capacities, from large central production facilities (50,000-300,000 kgs/day of hydrogen) to small-distributed production units (50-1000 kgs/day of hydrogen). Grant applications must include a careful analysis of the overall hydrogen separation efficiency, to assure that the proposed membrane separation will maximize the hydrogen recovered by the proposed process. Technology partnerships with manufacturers, suppliers, and especially end users are encouraged, in order to assure rapid commercialization of the technology in the U.S.

d. Industrial Membrane Process Systems—Grant applications are sought to enhance the separation capabilities of membranes used in industrial process streams. Proposed research should be aimed at developing and commercializing innovative membrane systems, using new or currently existing membranes, that can be robust when integrated within real-world processes (e.g., inert gas removal, isomer separation, aromatic/non-aromatic separations, sulfur removal, and removal of trace metals). Grant applications should seek to address one or more of the following needs: (1) techniques for overcoming scale-up problems related to contaminants in industrial streams (fouling, oil misting, etc.), (2) manufacturing technologies that would reduce the cost of membrane modules, (3) anti-fouling and anti-flux schemes to improve the long-term operability of membrane systems, and (4) methods to regenerate membrane performance and lower membrane maintenance costs. Also of interest is the integration of membranes with other technologies (such as the integration of membranes with distillation systems, or with adsorption or extraction processes), in order to address specific process issues. For all grant applications, the overriding goal is to enhance U.S. industrial process efficiency to the maximum possible extent by increasing the separation process efficiency. Therefore, priority will be given to applications that carefully examine the efficiency of the proposed membrane technology within the targeted application. Grant applications also should include a process evaluation and an economic analysis along with the R&D effort. Lastly, technology partnerships involving U.S. manufacturers, suppliers, and end users are strongly encouraged.

References:

1. Humphrey, J. L. and Keller, G. E., II, Separation Process Technology, McGraw-Hill, 1997. (ISBN: 0-07-031173-0)

2. Sirkar, K. K., “Membrane Separation Technologies: Current Developments,” Chemical Engineering Communications, 157:145-184, 1996. (ISSN: 0098-6445)

3. Technology Vision 2020: The U.S. Chemical Industry, Washington, DC: American Chemical Society, 1996. (Available from the Council for Chemistry Research. Web site: http://www.ccrhq.org. Select “Vision 2020.”)

4. McLaren, J., The Technology Roadmap for Plant/Crop-Based Renewable Resources 2020, National Renewable Energy Laboratory, February 22, 1999. (Report No. NREL/BK-570-25942) (Available at: http://www.osti.gov/energycitations/. Using “Basic Search,” search “Identifier Numbers” for “NREL/BK-570-25942.”)

5. Vision 2020: 2000 Separations Roadmap, New York: AIChE, Waste Reduction Technologies, 2000. (ISBN 0-8169-0832-X) (Available at http://www.oit.doe.gov/chemicals/. On menu at left, select “Vision & Roadmaps.” Scroll down to center of page & select “Separations 2000.”)

6. Vision 2020: 1998 Separations Roadmap, New York: AIChE, Waste Reduction Technologies, October 1998. (ISBN: 0816907870)

7. Vision 2020: Reaction Engineering Roadmap, New York: AIChE, Waste Reduction Technologies, 2001. (ISBN: 0-8169-0833-8) (Available at: http://www.oit.doe.gov/chemicals/. On menu at left, select “Vision & Roadmaps.” Scroll down to center of page & select “Reaction Engineering.”)

8. Nanomaterials and the Chemical Industry R&D Roadmap Workshop: Preliminary Results, sponsored by Vision 2020, NNI, and U.S. DOE Industrial Materials and Chemicals Program, October 2002. (Full text available at: http://www.energetics.com/download/chemvision2020/nanomaterialsroadmap/nano_workshop_results_report.pdf)

9. Biobased Industrial Products: Research and Commercialization Priorities, National Research Council Commission on Life Sciences, 2000. (Available at: http://books.nap.edu/books/0309053927/html/2.html#pagetop)

10. Vision for Bioenergy and Biobased Products in the United States, U.S. Biomass Research and Development Advisory Committee, October 2002. (Available at: http://www.bioproducts-bioenergy.gov/pdfs/BioVision_03_Web.pdf)

11. Roadmap for Biomass Technologies in the United States, U.S. Biomass Research and Development Advisory Committee, December 2002. (Available at: http://www.bioproducts-bioenergy.gov/pdfs/FinalBiomassRoadmap.pdf)

12. Developing and Promoting Biobased Products and Bioenergy: Report to the President of the United States in Response to Executive Order 13134, U.S. DOE and U.S. Department of Agriculture, February 14, 2000. (Available at: http://www.bioproducts-bioenergy.gov/pdfs/presidentsreport.pdf)

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