Howard G. McIlvried

Advances in CO2 capture technology—The U.S. Department of Energy's Carbon Sequestration Program

There is growing concern that anthropogenic carbon dioxide (CO2) emissions are contribut- ing to global climate change. Therefore, it is critical to develop technologies to mitigate this problem. One very promising approach to reducing CO2 emissions is CO2 capture at a power plant, transport to an injection site, and sequestration for long-term storage in any of a variety of suitable geologic formations. However, if the promise of this approach is to come to fruition, capture costs will have to be reduced. The Department of Energys Carbon Sequestration Program is actively pursuing this goal. CO2 capture from coal-derived power generation can be achieved by various approaches: post-combustion capture, pre-combus- tion capture, and oxy-combustion. All three of these pathways are under investigation, some at an early stage of development. A wide variety of separation techniques is being pursued, including gas phase separation, absorption into a liquid, and adsorption on a solid, as well as hybrid processes, such as adsorption/membrane systems. Current efforts cover not only improvements to state-of-the-art technologies but also development of several innovative concepts, such as metal organic frameworks, ionic liquids, and enzyme-based systems. This paper discusses the current status of the development of CO2 capture technology.

Integrated collaborative technology development program for CO2 sequestration in geologic formations––United States Department of Energy R&D

A major contributor to increased atmospheric CO2 levels is fossil fuel combustion. Roughly one third of the carbon emissions in the United States comes from power plants. Since electric generation is expected to grow and fossil fuels will continue to be the dominant fuel source, there is growing recognition that the energy industry can be part of the solution to reducing greenhouse gas emissions by capturing and permanently sequestering CO2. Consequently, an important component of the United States Department of Energy’s (DOE) research and development program is dedicated to reducing CO2 emissions from power plants by developing technologies for capturing CO2 and for subsequent utilization and/or sequestration. Injection of CO2 into geologic formations is being practiced today by the petroleum industry for enhanced oil recovery, but it is not yet possible to predict with confidence storage volumes, formation integrity and permanence over long time periods. Many important issues dealing with geologic storage, monitoring and verification of fluids (including CO2) in underground oil and gas reservoirs, coal beds and saline formations must be addressed. Field demonstrations are needed to confirm practical considerations, such as economics, safety, stability, permanence and public acceptance. This paper presents an overview of DOE’s research program in the area of CO2 sequestration and storage in geologic formations and specifically addresses the status of new knowledge, improved tools and enhanced technology for cost optimization, monitoring, modeling and capacity estimation. This paper also highlights those fundamental and applied studies, including field tests, sponsored by DOE that are measuring the degree to which CO2 can be injected and remain safely and permanently sequestered in geologic formations while concurrently assuring no adverse long term ecological impacts.

Progress and new developments in carbon capture and storage.

Growing concern over the impact on global climate change of the buildup of greenhouse gases (GHGs) in the atmosphere has resulted in proposals to capture carbon dioxide (CO 2 ) at large point sources and store it in geologic formations, such as oil and gas reservoirs, unmineable coal seams, and saline formations, referred to as carbon capture and storage (CCS). There are three options for capturing CO 2 from point sources: post-combustion capture, pre-combustion capture, and oxy-combustion. Several processes are available to capture CO 2 , and new or improved processes are under development. However, CO 2 capture is the most expensive part of CCS, typically accounting for 75% of overall cost. CCS will benefit significantly from the development of a lower cost post-combustion CO 2 capture process that can be retrofitted to existing power plants. Once captured, the CO 2 is compressed to about 150 atm and pipelined at supercritical conditions to a suitable storage site. Oil and gas reservoirs, because they have assured seals and are well characterized, are promising early opportunity sites. Saline formations are much more extensive and have a huge potential storage capacity, but are much less characterized. Several commercial and a number of pilot CCS projects are underway around the world. Information from these projects will form the basis for the development of CCS as a climate change mitigation strategy. These projects are contributing to the development of suitable regulations, determining best operating practices, improving mathematical models, and providing information to the public and other stakeholders. Based on current knowledge, CCS appears to be a promising option for reducing GHG emissions.

BLAST FURNACE GRANULAR COAL INJECTION AT BETHLEHEM STEEL'S BURNS HARBOR PLANT

This paper discusses the demonstration of the British Steel/CPC-Macawber Blast Furnace Granular Coal Injection (BFGCI) technology that was installed on the blast furnaces at Bethlehem Steels Burns Harbor Plant in Indiana as a highly successful Clean Coal Technology project, cofunded by the U.S. Department of Energy. In the BFGCI process, granular coal (10%–30% through a 200-mesh screen) is injected into a blast furnace as a fuel supplement to decrease coke requirements, thus reducing costs. Tests run to determine the effect of process variables on furnace operations showed that granular coal works as well as pulverized coal and is easier to handle and cheaper to produce because of reduced grinding costs.

Considerations for monitoring, verification, and accounting for geologic storage of CO2

Growing concern over the impact of increasing concentrations of greenhouse gases (GHGs), especially carbon dioxide (CO 2 ), in the atmosphere has led to suggested mitigation techniques. One proposal that is attracting widespread attention is carbon capture and storage (CCS). This mitigation approach involves capture of CO 2 and permanent storage in geologic formations, such as oil and gas reservoirs, deep saline formations, and unmineable coal seams. Critical to the successful implementation of this approach is the development of a robust monitoring, verification, and accounting (MVA) program. Defining the site characteristics of a proposed geologic storage project is the first step in developing a monitoring program. Following site characterization, the second step involves developing hypothetical models describing important mechanisms that control the behavior of injected CO 2 . A wide array of advanced monitoring technologies is currently being evaluated by the Weyburn―Midale Project, the Frio Project, and the U.S. Department of Energys Regional Carbon Sequestration Partnerships Program. These efforts are evaluating and determining which monitoring techniques are most effective and economic for specific geologic situations, information that will be vital in guiding future projects. Although monitoring costs can run into millions of dollars, they are typically only a small part of the overall cost of a CO 2 storage project. Ultimately, a robust MVA program will be critical in establishing CCS as a viable GHG mitigation strategy.