(496c) CO2 Pipeline Integrity Modelling Challenges

Pressurised pipelines are widely considered to be the most practical, and in the case of fossil fuel power generation plant, the only option for transporting captured CO2 for subsequent sequestration. Typically, such pipelines may be several hundred kilometres long, transporting enormous amounts of CO2 under supercritical conditions.

Given the large quantities involved and the hazardous nature of CO2 (at concentrations greater than 10% the gas is instantly fatal [1] the understanding of the hazards that may undermine the mechanical integrity of such pipelines is central to the success of CCS as an effective means for combating the effects of global warming.

It is widely acknowledged [2] that existing experience with the use of pressurised CO2 pipelines is simply too limited to draw any meaningful conclusions. Additionally, the widely different hazard profile of CO2 as compared to hydrocarbons means that any confidence that existing experience with operating hydrocarbon pipelines can be wholly extended to CO2 pipelines is dangerously misplaced [3].

This paper presents an overview of some of the most important hazards affecting CO2 pipeline safety that can be mitigated using robust mathematical modelling through informed operating conditions and pipeline materials selection. These include consideration from the molecular level, such as the impact of impurities on thermodynamics and phase behaviour of CO2, corrosion resistance and hydrate formation to macroscopic failures such as fast running ductile or brittle fracture propagation.

References

1.http://www.energyinst.org.uk/content/files/hseinfopaper.pdf

2. Intergovernmental Panel on Climate Change, IPCC, Carbon Capture & Storage ISBN 92-9169-119, 2005.

3. Mahgerefteh, H., Denton, G., Rykov, Y., CO2 Pipeline Rupture, HAZARDS XX Process Safety and Environmental Protection, IChemE Sympsium Series No. 154, 869 -879, 2008.