As one of the top contributors to energy-related CO2 emissions, coal has been both a reliable power source and a target for reduced consumption as countries across the globe work to combat air pollution.
But huge steps are being made toward cleaning its dirty image. The term “clean coal” remains an oxymoron, for the most part; however, carbon capture-EOR projects—like the one being built by NRG Energy and JX Nippon Oil & Gas Exploration’s Petra Nova Holdings—could go a long way in making the term a reality by preventing most of the power plant CO2 from entering the atmosphere, instead delivering it via pipeline to oil fields for EOR projects.
“Using proven technology, the [Petra Nova] project will be a commercial-scale carbon capture system that captures 90% of the carbon dioxide [CO2] in the processed flue gas from an existing unit at the WA Parish power plant in Fort Bend County, southwest of Houston,” according to a Business Wire news release. Construction on the project has started, and when complete, “the project is expected to be the world’s largest post-combustion carbon capture facility on an existing coal plant.”
The captured CO2, anticipated to be about 1.6 million tons annually, will be compressed and delivered via a 132-km (82-mile) pipeline to the West Ranch oil field, which is co-owned by Petro Nova (NRG, 50% interest; and JX Nippon, 50% interest) and Hilcorp Energy.
“EOR is expected to boost oil production at the field from around 500 [bbl/d] to approximately 15,000 [bbl/d],” the release said. “The West Ranch oil field is currently estimated to hold approximately 60 [MMbbl] of oil recoverable from EOR operations.”
Technology and processes developed by Mitsubishi Heavy Industries and Kansai Electric Power Co. are making the project, which was also a recipient of a U.S. Department of Energy’s (DOE) Clean Coal Power Initiative Program grant, possible. The release stated that the process will use the KM-CDR Process and proprietary KS-1 high-performance solvent for CO2 absorption and desorption.
The project is one of several that illustrate how technology is making coal cleaner.
Another project is already making an impact.
Air Products and Chemicals Inc. has captured more than 1 million metric tons of CO2 at its facility in Port Arthur, Texas, according to the DOE. The company is using a technology called vacuum swing adsorption, enabling it to capture more than 90% of the CO2 from onsite steam methane reformers (SMR).
“Vacuum swing adsorption works by feeding the SMR product gas—a synthesis gas consisting predominantly of hydrogen and CO2 —into ‘adsorber vessels’ where the CO2 adheres to a solid sorbent while the remainder of the stream, primarily hydrogen, passes through the vessels,” according to an article posted June 27 on the DOE’s website. The hydrogen is purified for use in an adjacent refinery, while the CO2 is removed from the solid sorbent through a number of pressure adjustments inside the vessels.
Like the Petra Nova project, this one also pipes gas to an oil field for EOR—the West Hastings Field in southeast Texas. The DOE said the field could produce between 60 MMbbl and 90 MMbbl more of oil with the CO2 injection.
“This process is a promising approach that, if retrofitted to every steam methane reforming facility in the U.S., could reduce our CO2 emissions by about 56 million metric tons a year,” the DOE said.
Now, that would be a huge transformation indeed.
So far, the DOE said its projects have already captured and stored nearly 7.5 million metric tons of CO2 emissions. That, according to the agency, is the equivalent of removing more than 1.5 million vehicles from roads for a year.
Contact the author, Velda Addison, at firstname.lastname@example.org.