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Growth Kinetics of Single Crystal sII Hydrates: Elimination of Mass and Heat Transfer Effects
Author(s) -
BOLLAVARAM P.,
DEVARAKONDA S.,
SELIM M. S.,
SLOAN E. D.
Publication year - 2000
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2000.tb06808.x
Subject(s) - subcooling , mass transfer , thermodynamics , chemistry , kinetics , hydrate , heat transfer , crystal growth , crystal (programming language) , kinetic energy , materials science , crystallography , chromatography , organic chemistry , physics , quantum mechanics , computer science , programming language
A bstract : This work presents the results from experiments and modeling of tetrahydrofuran single crystal hydrate growth. The purpose was to study growth kinetics, independent of mass transfer and heat transfer. We used a single crystal apparatus, at stoichiometric concentrations of tetrahydrofuran and water, varying the fluid shear to decrease the boundary layer at the crystal surface. We found that with extreme precautions to totally eliminate mass transfer and to minimize heat transfer via high shear, it is very difficult to obtain reliable kinetic constants for the single hydrate crystal growth system. We eliminated mass transfer, but were only able to reduce the heat transfer resistance to a value of about 10% of the total resistance (i.e., 90% kinetic resistance) at the lowest value of subcooling. We found that growth rate increased with the driving force (i.e., subcooling) and established that the growth process occurred by a step mechanism. We only measured the fluid phases in order to obtain hydrate phase kinetics. The results of this work suggest that assessment of heat transfer, previously ignored in crystal growth kinetic studies is vital for accurate hydrate kinetics.