Sean Plasynski

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.

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.

CCS Activities Being Performed by the U.S. DOE

The United States Department of Energy (DOE) is the lead federal agency for the development and deployment of carbon sequestration technologies. Its mission includes promoting scientific and technological innovations and transfer of knowledge for safe and permanent storage of CO2 in the subsurface. To accomplish its mission, DOE is characterizing and classifying potential geologic storage reservoirs in basins throughout the U.S. and Canada, and developing best practices for project developers, to help ensure the safety of future geologic storage projects. DOE’s Carbon Sequestration Program, Regional Carbon Sequestration Partnership (RCSP) Initiative, administered by the National Energy Technology Laboratory (NETL), is identifying, characterizing, and testing potential injection formations. The RCSP Initiative consists of collaborations among government, industry, universities, and international organizations. Through this collaborative effort, a series of integrated knowledge-based tools have been developed to help potential sequestration project developers. They are the Carbon Sequestration Atlas of the United States and Canada, National Carbon Sequestration Database and Geographic System (NATCARB), and best practice manuals for CCS including Depositional Reservoir Classification for CO2; Public Outreach and Education for Carbon Storage Projects; Monitoring, Verification, and Accounting of CO2 Stored in Deep Geologic Formation; Site Screening, Site Selection, and Initial Characterization of CO2 Storage in Deep Geologic Formations. DOE’s future research will help with refinement of these tools and additional best practice manuals (BPM) which focus on other technical aspects of project development.

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.

Carbon dioxide mitigation via combustion modification: An overview of U.S. Department of energy's power systems technology R&D program

Publisher Summary The US Department of Energy (DOE), in partnership with United Technologies Research Center (UTRC) and Foster Wheeler Development Corporation (FWDC), is focusing on its Combustion 2000 Program aimed at developing inherently low-polluting high-performance power system (HIPPS). The UTRC concept is the development of an inherently low CO 2 emitting coal-fired power plant based on thermodynamic optimization of indirectly fired combined cycle configurations using a topping Brayton cycle and a bottoming Rankine cycle. The UTRC HIPPS technology embodiment allows a baseline efficiency of 47%, and efficiencies approaching 55% are realizable using advanced cycles. FWDC is developing an all coal-fired system utilizing a pyrolyzer to convert coal to fuel gas and char. The fuel gas is sent to a turbine combustor, and the char is burned in FWDCs version of the high temperature advanced furnace. This chapter also reviews noncryogenic oxygen production technology, which is based on a class of dense ceramic materials that conduct oxygen ion at high temperatures.