title: Multiscale approach to CO2 hydrate formation in aqueous solution: phase field theory and molecular dynamics. Nucleation and growth.
abstract: A phase field theory with model parameters evaluated from atomistic simulations/experiments is applied to predict the nucleation and growth rates of solid CO(2) hydrate in aqueous solutions under conditions typical to underwater natural gas hydrate reservoirs. It is shown that under practical conditions a homogeneous nucleation of the hydrate phase can be ruled out. The growth rate of CO(2) hydrate dendrites has been determined from phase field simulations as a function of composition while using a physical interface thickness (0.85+/-0.07 nm) evaluated from molecular dynamics simulations. The growth rate extrapolated to realistic supersaturations is about three orders of magnitude larger than the respective experimental observation. A possible origin of the discrepancy is discussed. It is suggested that a kinetic barrier reflecting the difficulties in building the complex crystal structure is the most probable source of the deviations.
authors.affiliation: Research Institute for Solid State Physics and Optics, P.O. Box 49, H-1525 Budapest, Hungary. turpi@szfki.hu
authors.forename: György
authors.initials: G
authors.lastname: Tegze
authors.forename: Tamás
authors.initials: T
authors.lastname: Pusztai
authors.forename: Gyula
authors.initials: G
authors.lastname: Tóth
authors.forename: László
authors.initials: L
authors.lastname: Gránásy
authors.forename: Atle
authors.initials: A
authors.lastname: Svandal
authors.forename: Trygve
authors.initials: T
authors.lastname: Buanes
authors.forename: Tatyana
authors.initials: T
authors.lastname: Kuznetsova
authors.forename: Bjorn
authors.initials: B
authors.lastname: Kvamme