WASHINGTON, DC - New ways to capture carbon dioxide from power plants and store it securely will be investigated in eight projects selected for funding by the Department of Energy's Office of Fossil Energy. Described as revolutionary and experimental, the new projects will explore innovative technologies that could lead to practical and cost-effective means of capturing and sequestering carbon dioxide, a greenhouse gas. The projects support the President's Global Climate Change Initiative, an aggressive strategy to cut U.S. greenhouse gas intensity by 18 percent by 2012.
The projects were selected under a solicitation announced in May 2003 by the National Energy Technology Laboratory, which will manage the projects for the Office of Fossil Energy. The solicitation called for proposals to conduct research in four technical areas: advanced separation techniques, advanced subsurface technologies, advanced geochemical methods for sequestering carbon, and novel niches.
These topics were identified in February 2003 during a workshop conducted for the Energy Department by a committee of the National Research Council. About 70 participants from the private sector, academia, government, and other institutions met to discuss new approaches for reducing the amount of carbon dioxide entering the atmosphere from fossil-fuel-based energy systems. The report generated from the workshop was considered in developing the solicitation.
Four of the newly selected projects will focus on advanced separation techniques to capture carbon dioxide and hydrogen from fossil-fueled power plants. Two of these will study high-temperature membranes, one will investigate a new carbon dioxide absorbent, and one will look at nanoscale materials-on a scale approximately 40,000 times smaller than the width of a human hair-as separation agents.
Three of the remaining projects will focus on advanced subsurface technologies and geochemical methods for sequestering carbon. Sequestration with these methods could offer permanent disposal of carbon dioxide by forming geologically stable rock-like structures called mineral carbonates. Carbonates are formed when minerals such as limestone, olivine, and serpentine react with carbon dioxide.
The eighth project falls under the technical area "novel niches," which includes novel concepts involving carbon dioxide recycling and products. For this project, biocatalysts-microorganisms and their enzymes-will cause chemical reactions that can potentially convert carbon dioxide to value-added products, and ensure permanent storage of carbon dioxide.
The new projects are outlined below.
- A New Concept for the Fabrication of Hydrogen Selective Silica Membranes
Researchers at the University of Minnesota's Department of Chemical Engineering and Materials Science will develop a new method for making extremely thin, high-temperature, hydrogen-selective silica membranes from by-product materials. The membranes, called molecular sieves, work like filters with uniquely designed, ultra-small pores that allow only hydrogen molecules to pass through, leaving a carbon-dioxide-rich gas behind for sequestration. These types of membranes will potentially be used in future fossil-fueled power plants that produce hydrogen under conditions of high temperatures and pressures.
This three year project has a total cost of $237,393.
- Novel Dual-Functional Membrane for Controlling Carbon Dioxide Emissions from Fossil Fuel Power Plants
Researchers at the University of New Mexico's Center for Micro-Engineered Materials, with collaboration from T3 Scientific in Arden Hills, Minnesota, will develop a new, dual-functional membrane that will use both the membrane pore structure, and an amine chemical adhered to the membrane, to increase the removal of carbon dioxide from fossil-fueled power plants. Researchers anticipate that the strong interactions between the carbon dioxide molecules and the amine-coated membrane pores will help spread the carbon dioxide on the pore walls and block other gases, such as oxygen, nitrogen and sulfur dioxides, that are also present in power plant stacks. The new membrane is expected to exhibit higher carbon dioxide selectivity than other types of silica-based membranes that separate carbon dioxide based only on the difference in pore size. This new membrane-based carbon dioxide capture process may be an attractive alternative to costly amine-based absorption processes currently available for carbon dioxide capture in power plants.
This three year project has a total cost of $871,997.
- Design and Evaluation of Ionic Liquids as Novel Carbon Dioxide Absorbents
This project, to be conducted by the Department of Chemical and Biomolecular Engineering at the University of Notre Dame, will focus on the development of liquid absorbents that fall within a relatively new class of compounds called ionic liquids. Ionic liquids are typically organic salts that, in their pure state, are liquid under atmospheric conditions at room temperature. They have unusual properties that suggest they could be extremely effective as carbon dioxide absorbents, possibly replacing current amine-based technology to capture carbon dioxide from power plants stacks. Unlike amines, which are corrosive and costly to operate, organic salts are typically benign, and can be disposed of in landfills. Building upon and extending their previous work with other chemicals, the researchers will use computer modeling to design and evaluate ionic liquids to determine their affinity for capturing carbon dioxide. They will also assess the economics of different ionic liquids against conventional absorbents.
This three year project has a total cost of $399,409.
- Carbon Dioxide Separation with Novel Microporous Metal Organic Frameworks
This project will be a collaborative effort among UOP LLC, in Des Plaines, Illinois, the University of Michigan, and Northwestern University to discover novel microporous metal organic frameworks (MOFs) suitable for carbon dioxide separation. MOFs are hybrid organic/inorganic structures at the nanoscale to which carbon dioxide will stick. Researchers plan to use molecular modeling on computers to design, tailor, and assess MOFs with the best properties for adsorbing carbon dioxide, and to predict structures of new MOFs. Successful completion of this project will lead to a low-cost, novel sorbent to remove carbon dioxide from the gases emitted from power plant stacks.
This three year project has a total cost of $900,000.
- Carbon Dioxide Sequestration in Carbonate Sediments Below the Sea Floor
Scientists from Harvard University will collaborate with scientists from Columbia University, Carnegie-Mellon University, and the University of California at Santa Cruz to investigate the feasibility of sequestering carbon dioxide by injecting it below the sea floor in calcium carbonate sediments. These sediments could act as absorbents for the carbon dioxide, but they need study because the chemistry, temperature, and pressure below the sea floor are different than in underground sequestration on land. Pressurized tanks in a laboratory will be used as a modeling tool to simulate the conditions below the sea floor. The researchers will seek to understand the mechanical and chemical behavior of carbon dioxide and carbon-dioxide/water mixtures injected into carbonate sediments under a range of pressures and temperatures, and with a range of sediment compositions.
This three year project has a total cost of $797,210.
- A Novel Approach to Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost
This project, to be conducted by researchers at the Center for Solid State Science at Arizona State University, will study the chemistry and kinetics of carbonation using commonly occurring minerals such as olivine as the geochemical method for sequestering carbon dioxide. The approaches taken by the researchers will include using sonic frequencies to increase the exfoliation and particle cracking of the minerals to enhance carbon dioxide sequestration. They will also perform chemical and fluid studies to determine optimal exfoliation of the mineral and the kinetics involved. Using modeling and experimental investigations, the scientists will attempt to speed up, control, and tailor the carbonation process. As the result of this research, the scientists should discover whether or not carbon dioxide sequestered underground in this manner will be permanently stored.
This two year project has a total cost of $558,663.
- A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics
This project, an experimental study incorporating modeling and bench-scale testing, will study geological sequestration of carbon dioxide using the carbonation process. Scientists from the Department of Geology and Planetary Science at the University of Pittsburgh will try to store carbon dioxide with sulfur dioxide in redbed sandstones containing feldspar and iron oxides. They will use an electron microscope to determine what reactions have occurred at the molecular and atomic levels, and will seek to answer such questions as: What happens to the carbon dioxide and the minerals when they come into contact? Are iron carbonates developed? Will the porosity of the minerals change, and, 50 years later, will the carbon dioxide leak out over a large area?
This three year project has a total cost of $426,701.
- Process Design for the Biocatalysis of Value-Added Chemicals from Carbon Dioxide
Researchers from the Faculty of Engineering at the University of Georgia Research Foundation will conduct the most novel of all the newly selected projects. They will perform metabolic engineering to create strains of microbes that feed off carbon dioxide and produce by-products such as succinic, malic, and fumeric acids, all of which have commercial uses. The advantage of the proposed process is that microbial strains will be placed in direct contact with the gases emitted from power plants, thereby avoiding the cost of commercial carbon dioxide capture systems.
This three year project has a total cost of $384,275.