Ohio Coal Development Office

Determining the Corrosive Potential of Transporting CO₂ with Impurities and Development of Mitigation Strategies (OCDO)

Emissions from coal-fired power plants represent a significant source of carbon dioxide emissions, a known greenhouse gas. To eliminate CO₂ emissions from coal plants, CO₂ must be captured and compressed to a supercritical liquid, and then transported to a sequestration site, such as an oil field for enhanced oil recovery, by pipeline, which is generally the cheapest form of transport available. Such pipelines for CO₂ transport are usually made of carbon steel. For CO₂ transport systems, water and other impurities from combustion of coal (SO₂, O₂, N₂, NO_x, volatile organic acids, hydrocarbons, etc) are in the bulk CO₂ liquid. Dry carbon dioxide does not corrode the carbon steels; however, corrosion rates are much higher if free water is present because of formation of H₂CO₃. In addition, these impurities make the high pressure CO₂ corrosion process more complicated. How these confounding factors affect corrosion at very high CO₂ pressures is completely speculative. No published information about the effects of various impurities on high CO₂ pressure corrosion has been reported.

AIMS

The main goal of this work is to improve the understanding of potential problems that utilities and pipeline companies will face in transporting CO₂ over long distances to remote sequestration sites.

• Quantifying the effects of various impurities on the corrosive potential of high pressure CO₂ (supercritical condition) on conventional pipeline and compressor materials.
• Developing mitigation strategies, including the possibility of using corrosion resistant alloys for pipeline or compressor construction and/or reducing the levels of contamination by trace species.

DELIVERABLES

• An improved understanding of the phenomena of corrosion under supercritical CO₂ conditions with impurities such as SO₂, O₂, N₂, and H₂O.
• A predictive model for the thermodynamic properties of supercritical CO₂ with impurities validated over experimental data.
• An experimental database of corrosive potential for pipeline by examining the electrochemical and surface properties in supercritical CO₂ with impurities.
• A test matrix for the flow loop system developed from the modeling and the coupon testing.
• Mitigation strategies for corrosive potential of CO₂ transporting pipeline.

TIMELINE

The OCDO project was initiated in September 2007 and is scheduled to end in August 2009.

Please contact Yoon-Seok Choi or Xiu Jiang for more information