Abstract
Clathrate hydrates are complex molecules formed by the contact between water and gas at high pressure and low temperatures. One of the important aims of gas hydrate technology is to enhance the formation of hydrate and reduction the induction time for clathrate formation. Effect of the different promoters (nonionic surfactant Tween80) on R-134a gas hydrate formation has been investigated in the isochoric system experiment. It is noted that the surfactants have a significant effect of increasing the speed of nucleation as well as improving the growth of hydrate. In the experiment, the effect of Tween80 surfactant was studied to determine its effect on the composition and cooling capacity of 134 hydrates. From kinetic models, many objective functions such as the amount of gas consumed (Δn), the growth rate (r (t)), the apparent rate constant (Kapp) and conversion of the water to hydrate were obtined. The improvement of hydrate growth is marked by the addition of surfactants, which in turn increase the solubility of hydrate gas and reduce the contact angle. In addition, surfactants positively the contact with the gas through the increase of the gas diffusion in the water and this increases the rate of formation of hydrate. Best value achieved at a surfactant concentration of 100 ppm with maximum gas consumed amount (0.16 mol) and less indction time 32 min.
