Air Products & Chemicals, Inc. (Air Products) has signed a cooperative agreement with the US Department of Energy (DOE) to design and construct a carbon dioxide (CO2) purification system in support of an oxyfuel technology development project. The project is being conducted in association with a separate cooperative agreement between DOE and Alstom Power, Inc. The project will use Alstom’s boiler simulation facility in Windsor, Connecticut.
The CO2 purification is essential to the compression, transport and potential sequestration of greenhouse gas emissions from power plants. The development project at the 15 megawatt thermal equivalent facility, to be conducted over two years beginning in mid-2009, is part of DOE’s furthering development of new and cost-effective technologies for the capture of CO2 from the existing fleet of U.S. coal-fired power plants.
In the project, Air Products will purify a portion of the CO2 from flue gas, or waste gas, coming from Alstom’s tangentially-fired (T-fired) coal combustion unit operated in oxy-combustion mode. T-fired boilers are the most prevalent pulverized boilers used to burn coal and make steam at coal-fired power plants, and make up over 40% of the installed base of utility boilers in the U.S. and around the world. Air Products’ technology is designed to purify the CO2 by targeting removal of up to 95% of the impurities in the waste gas including sulfur oxides (SOX), hydrogen chloride, and nitrogen oxides (NOX). These acidic impurities must be removed from the CO2 stream to prevent corrosion before the purified CO2 is introduced into a pipeline. Air Products’ CO2 purification and compression system is targeted to achieve over 90% CO2 capture, while improving cost savings over other technology such as amine-scrubbing, or more expensive and complex flue gas de-sulfurization units and de-NOx units.
“It’s now time to advance the technology from study and bench level testing to the next scale evaluation. Air Products’ oxyfuel technology has optimized the compression process to remove impurities to an acceptable level in the gas to make carbon sequestration possible. The ability to achieve this at lower costs is encouraging to industries with large scale CO2 emissions. We look forward to the results of this project and applaud DOE for its dedicated efforts on this important technology,” said Steve Carney, business development manager at Air Products.
This project is part of DOE’s Office of Fossil Energy’s Existing Plants – Emissions & Capture program (EPEC), which is managed by the National Energy Technology Laboratory. The EPEC program maintains a portfolio of research projects to address these and other environmental challenges faced by America’s existing fleet of coal-fired power plants.
Air Products’ oxyfuel technology can reduce the cost of capturing CO2 for the power industry. The company has specifically focused on the purification of the resulting oxyfuel combustion flue gas, developing a robust process for the efficient removal of trace impurities. Air Products’ proprietary sour compression technology uses a staged compression process to optimize pressure, hold-up, and residence time to allow removal of impurities during the compression process. This allows cost savings in the oxyfuel combustion process and minimizes the content of these components in the sequestered CO2.