Is subcooling the right driving force for testing low-dosage hydrate inhibitors?

Mosayyeb Arjmandi, Bahman Tohidi, Ali Danesh, Adrian C. Todd

Research output: Contribution to journalArticle

Abstract

The degree of subcooling is usually used as the driving force for hydrate formation; however, it does not encompass the effect of pressure. A comprehensive driving force for hydrate formation is a function of pressure, temperature, and gas composition; however, its calculation is not as simple as that of subcooling. In this work, by application of the two latest driving force expressions for hydrate formation, the relationships between subcooling and the true driving force at different conditions for pure gas-water and natural gas-water systems are analysed. The effect of pressure on the induction time in the presence and absence of a kinetic inhibitor have been tested at similar degrees of subcooling. The results show that for pure gas-water systems subcooling is proportional to the driving force, with a good approximation over a wide pressure range at isothermal conditions. However, for multicomponent systems (e.g., natural gases), the driving force is more than that suggested by subcooling at some pressures. Changes of driving force with pressure at a constant degree of subcooling for the above systems have been presented. The results show that the pressure has no significant effect on the driving force (at a constant degree of subcooling) above a certain pressure range. The experimental results show that in a natural gas-water system at constant degree of subcooling the induction time is not significantly affected by pressure. However, in the presence of the kinetic inhibitor tested in this study, high-pressure conditions decreased the induction time. © 2004 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)1313-1321
Number of pages9
JournalChemical Engineering Science
Volume60
Issue number5
DOIs
Publication statusPublished - Mar 2005

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Hydrates
Testing
Natural gas
Water
Gases
Kinetics

Keywords

  • Crystallization
  • Gas hydrates
  • Isothermal
  • Kinetic inhibitors
  • Kinetics
  • Nucleation

Cite this

Arjmandi, Mosayyeb ; Tohidi, Bahman ; Danesh, Ali ; Todd, Adrian C. / Is subcooling the right driving force for testing low-dosage hydrate inhibitors?. In: Chemical Engineering Science. 2005 ; Vol. 60, No. 5. pp. 1313-1321.
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Is subcooling the right driving force for testing low-dosage hydrate inhibitors? / Arjmandi, Mosayyeb; Tohidi, Bahman; Danesh, Ali; Todd, Adrian C.

In: Chemical Engineering Science, Vol. 60, No. 5, 03.2005, p. 1313-1321.

Research output: Contribution to journalArticle

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