Experimental and modeling investigation on structure H hydrate formation kinetics

•Applying affinity model for the formation kinetics of sH hydrate and two stage kinetics.•Performing the experiments of hydrate formation of sH with MCP.•A unique path for the SH hydrate formation.

In this work, the kinetics of crystal H hydrate and two stage kinetics formation is modeled by using the chemical affinity model for the first time. The basic idea is that there is a unique path for each experiment by which the crystallization process decays the affinity. The experiments were performed at constant temperatures of 274.15, 275.15, 275.65, 276.15 and 277.15 K. The initial pressure of each experiment is up to 25 bar above equilibrium pressure of sI. Methylcyclohexane (MCH), methylcyclopentane (MCP) and tert-butyl methyl ether (TBME) are used as sH former and methane is used as a help gas. The parameters of the affinity model (Ar and tk  ) are determined and the results show that the parameter of ArRT has not a constant value when temperature changes in each group of experiments. The results indicate that this model can predict experimental data very well at several conditions.