Rheology of cyclopentane hydrate slurry in a model oil-continuous emulsion

• Published in: Rheologica acta Vol. 55; no. 3; pp. 235 - 243
• Main Authors: Karanjkar, Prasad U., Ahuja, Amit, Zylyftari, Genti, Lee, Jae W., F. Morris, Jeffrey
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-03-2016; Springer Nature B.V
• Subjects: Agglomeration; Characterization and Evaluation of Materials; Chemistry and Materials Science; Complex Fluids and Microfluidics; Cooling effects; Dependence; Dispersion; Food Science; Liquid bridges; Materials Science; Mechanical Engineering; Original Contribution; Polymer Sciences; Porosity; Quenching; Rheological properties; Rheology; Shear rate; Shear thinning (liquids); Slurries; Soft and Granular Matter; Thixotropy; Viscosity; Water drops; Water film; Gas hydrates; Emulsion; Cyclopentane; Rheology; Flow assurance
• ISSN: 0035-4511; 1435-1528
• DOI: 10.1007/s00397-016-0911-1

Liquid cyclopentane (CP)-based hydrate slurry is prepared at atmospheric pressure from a density-matched water-in-oil emulsion by quenching it to a lower temperature at a fixed shear rate. Viscosity increases by several orders of magnitude and is indicative of hydrate formation on the dispersed water droplets and subsequent agglomeration. A mechanism in which the hairy and porous hydrate growth combined with enhanced agglomeration due to liquid bridges formed by wetted water films leads to the development of a porosity, resulting in greater effective dispersed phase fraction, is proposed. This is supported by experiments performed for water volume fractions ranging from 10 to 45 % at variable shear rates, temperatures, and surfactant (Span 80) concentrations. The observed dependence on the degree of sub-cooling, with lower slurry viscosity obtained at higher sub-cooling, and the possible anti-agglomerant like effect of high Span 80 concentrations, support our proposed mechanism. The hydrate slurries are found to exhibit shear-thinning and a small degree of thixotropy.