August 12, 2019 — Southwest Research Institute has been selected by the U.S. Department of Energy (DOE) to design a large-scale flameless pressurized oxy-fuel combustion pilot plant. DOE is providing nearly $3 million in funding, with an additional $760,658 from industry collaborators Itea, Sargent & Lundy, Electric Power Research Institute, General Electric Global Research and the University of Wyoming.
Oxy-fuel combustion is a fairly new approach to power generation. The process uses air that is stripped of other elements like argon and nitrogen until it’s pure oxygen. It is then combined with a fuel, usually either coal or natural gas, into a stream of carbon dioxide (CO2) and water inside a combustor. The fuel and oxygen chemically react, and the hot gas can be used to boil steam, which pushes a turbine that generates power. Pressurized oxy-fuel combustion has the potential to push on a turbine directly, potentially improving the overall cycle efficiency.
A major benefit of the oxygen-rich combustion is also that it results in pure CO2 that can be easily captured and stored or reused rather than released into the atmosphere as a pollutant. The captured CO2 has many possible applications in a number of areas—it could be used in refrigeration and cooling or to create carbonation in soft drinks in addition to a number of uses in the oil and gas industry.
While natural gas and coal are both frequently used as fuels in oxy-fuel combustion, the proposed pilot plant will use coal. Both fuels primarily produce water and CO2 during the combustion process, but when coal is used the incombustible ash is trapped by a mechanism in the novel combustor design, emerging as small, manageable pellets. Other undesirable elements, such as sulfur and mercury, are removed prior to CO2 purification in a standard emission control process.
“One of the most exciting aspects of oxy-fuel combustion is its potential for power generation with almost no CO2 emissions in the atmosphere,” said Joshua Schmitt, the SwRI research engineer leading the project. “Burning coal is often associated with harmful emissions, but this is a way to utilize it for power generation with very limited emissions.”
Schmitt’s proposed plant is one of six projects selected by the DOE as part of a larger effort to support innovative energy technology that supports the coal industry. He and his colleagues have already completed conceptual designs for the plant and chose a host site near the University of Wyoming.
“This will be a completely new type of power plant,” Schmitt said. “Oxy-fuel combustion plants generally don’t exist on this scale because the technology is so new.”
Over the next year, Schmitt and his collaborators will now proceed with a front-end engineering design study that involves the basic engineering, full design, cost analysis and schedule metrics for building the large-scale pilot plant. After completion in August 2020, the DOE will select the most promising pilot plant projects to move forward with construction and operation.