Phase equilibrium properties aspects of CO2 and acid gases transportation

Antonin Chapoy*, Christophe Coquelet

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter


Acid gases can be present in non-negligible quantity in natural gas. They are typically removed during gas processing operations and acid gases cleaning by chemical absorption with aqueous alkanolamine solution, for example. CO2 and other impurities are also present in combustion products of power stations. Carbon dioxide Capture transport and storage (CCS) is one solution to reduce emission of CO2 attributed to human activities. It exists in several technologies more or less mature which can be used for CO2 capture. These technologies depend on the composition of the flue gas (the stream after combustion is mainly composed of N2 and CO2) and the processes used, (post-, pre- or oxy-combustion processes). CO2 can be transported via ship or pipeline (mainly by pipelines for acid gases). The required compression pressure can be 100-300 bar, depending on the distance between the place of CO2 removal and the place of its utilization but also the composition of CO2 rich gas stream. The CO2 rich stream can contain a lot of impurities which can modify the phase diagram. It is of great importance to know the phase behavior of CO2 rich streams [1]. Indeed, along with carbon dioxide, a great number of compounds such as water, O2, N2, Ar, SOx, NOx, H2, CO and H2S can be present at different levels of concentration. The presence of these impurities combined with potentially long-distance transportation could lead to challenging engineering and flow assurance issues. During transportation by pipeline, if the pipe suffers a major fracture due to an accidental release or a failure, CO2 can rapidly expand and cool: Vapor cloud followed by solid formation of CO2 may appear. The impurities could change the characteristics of the leak and change the conditions and compositions of CO2 clouds and solid. The presence of water in the stream may also result in corrosion, ice and/or gas hydrate formation and pipeline blockage, so the fluid system should meet certain dehydration requirements. Comparisons of the results obtained using different equations of state are also reported.

Original languageEnglish
Title of host publicationCutting Edge for Carbon Capture Utilization and Storage
PublisherScrivener Publishing
Number of pages21
ISBN (Electronic)9781119363804
ISBN (Print)9781119363484
Publication statusPublished - 2018


  • Acid gas
  • Correlation
  • Measurements
  • Phase equilibrium

ASJC Scopus subject areas

  • General Energy


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