Novel sorbent achieves 90% carbon capture in DOE-sponsored test

22 August 2012

The successful bench-scale test of a novel carbon dioxide capturing sorbent promises to further advance the process as a possible technological option for reducing CO₂ emissions from coal-fired power plants.

The new sorbent, BrightBlack, was originally developed for a different application by Advanced Technology Materials Inc. (ATMI) , a subcontractor to SRI for the Department of Energy (DOE)-sponsored test at the University of Toledo. Through partnering with the Office of Fossil Energy’s National Energy Technology Laboratory (NETL) and others, SRI developed a method to use the ATMI sorbent to capture CO₂. The high-capacity sorbent is regenerated easily at moderate thermal temperatures, making the process less energy-intensive than typical, amine-based CO₂-capture processes.

Concern over the impact of greenhouse gas emissions and increasing CO2 concentrations in the atmosphere are driving the search for low-cost and efficient technologies to capture and store or utilize CO2 produced from sources such as power plants. Since a typical 500‑megawatt plant emits 2 to 3 million tons of CO₂ per year, capturing CO₂ from flue gas holds potential for reducing overall release of the greenhouse gas into the atmosphere.

NETL and hundreds of technology developers from industry and academia are working together to meet the challenge of devising low-cost, efficient CO₂ capture technologies for new and existing pulverized coal power plants.

In the SRI process, CO₂ is absorbed in a bed of sorbent pellets and desorbed in a separate reactor that regenerates the sorbent and cycles it back to the absorber. As the test run began, the observed CO₂‑capture efficiency was as high as 95% and the captured CO₂ purity was 95 to 100%. Through 7,000 absorption-regeneration cycles, and a total of 130 hours of operation, the sorbent showed little-to-no mechanical or chemical degradation.

SRI’s carbon capture process, which includes both the sorbent and unique process design, looks promising for future applications.

—Andrew O’Palko, the NETL project manager

As SRI nears completion of the project, they will analyze the test results in detail to determine total system performance and estimated economic benefits. This information will be used for the next steps in scaling-up the sorbent and process: designing a larger, pilot-scale unit of 0.5 megawatts or more in preparation for potential future testing at an operating pulverized-coal boiler.

In addition to researching and developing methods to capture CO₂, such as this new solvent, NETL researchers and their technology-development partners also are working on ways to safely and permanently store captured CO₂ in underground formations or use it in practical and economic ways, such as in enhanced oil recovery or the creation of products.