Effects of process variables on the initial gas hydrate formation rate: The case of ethane hydrate formation in the absence or presence of SDS kinetic promoter

摘要

The ethane (C_2) gas hydrate formation kinetic at the onset of solution turbidity in the absence or presence of sodium dodecyl sulfate (SDS) kinetic promoter is experimentally and theoretically investigated. The time dependent heterogeneous nucleation and growth kinetics are simultaneously employed for the determination of the initial rate of gas hydrate formation. It is shown that the effective diffusion coefficient of ethane in the solution is one of the most important influencing physical properties regarding gas hydrate growth process. At the SDS concentration of 500 ppm, the maximum ethane effective diffusion coefficient and the highest conversion rate are obtained. The C_2 hydrate-liquid interfacial tension according to the suggested heterogeneous nucleation mechanism is about 17.3 mJm~(-2) for all cases. The overall average absolute deviations between predicted and measured C_2 consumption rates are about 0.63% and 0.75% regarding non-promoted and promoted gas hydrate formation processes respectively.