Effect of polyoxyethylene laurate series surfactants on HCFC-141b hydrate formation.

[Display omitted] • The hydrophilic chain length of surfactant affects the kinetics of hydrate formation. • Surfactants improve the scatter of the induction time of hydrate formation and hydrate production. • The emulsion stability affects the promoting effect of surfactants on hydrate formation. • LAE-9 has the most effective on improving hydrate formation. To address the problems of slow crystallization and nucleation in two-phase miscibility in the application of refrigerant hydrates, adding surfactants can be taken as an effective way to promote hydrate formation. Three kinds of polyoxyethylene laurate (LAE) surfactant with different hydrophilic chain lengths (LAE-4, LAE-9 and LAE-24) were selected as accelerators to study their effects on hydrate formation. LAE series surfactants significantly reduce hydrate nucleation induction time. The hydrate induction time of the system with 4.0 wt% LAE-9 is shortest (98 min). The hydrate formation with 4.0 wt% LAE-9 has small randomness and is more stable. Micelles formed by LAE surfactants provide more nucleation sites and accelerate hydrate growth. The hydrate cold storage density is related to the hydrophilic chain length of surfactant. The system with 4.0 wt% LAE-9, which has a suitable hydrophilic chain length, achieves the largest hydrate cold storage density (246.10 kJ·kg−1). Hydrate has the fastest growth rate of 4.80 kJ·kg−1·min−1 in the system with 2.0 wt% LAE-24. There is a "memory" effect during hydrate formation and dissociation cycle, eliminating the need for induction time during hydrate re-formation. Hydrate can be re-formed quickly. [ABSTRACT FROM AUTHOR]