利用纳米粒子强化微乳液体系HCFC141b 水合物的生成

Abstract

Accelerating the formation of gas hydrate is of great significance for the application of gas hydrate technology in the area of cooling storage. To promote the rapid formation and growth of HCFC141b gas hydrate, the thermodynamically stable HCFC141b microemulsion was successfully prepared with aid of Tween 20/lecithin compound surfactants for increasing interface and compatibility between the refrigerant and water. The hydration process of HCFC141b in the microemulsion system was investigated in terms of induction time and supercooling degree and was compared to that in coarse HCFC141b/water mixture systems with or without surfactant in them. The characteristics of hydrate formation in the different systems were revealed. It is indicated that HCFC141b hydrate can form rapidly and uniformly in the microemulsion system. The induction time of HCFC141b hydration in the microemulsion system was shortened by 36% and 52% compared to that in coarse HCFC141b/water mixture with 1wt% Tween 20 and without any surfactant in it, respectively. Then, considering the characteristics of nano-particles in the enhancement of heat transfer, different amount of nano-Cu particles or nano-Al2O3 particles was added to HCFC141b/water microemulsion system and coarse mixture systems aiming to facilitate HCFC141b hydration process. The addition of nano-Cu to the microemulsion system further shortened the induction time and led to reduced supercooling degree of hydration in the microemulsion system, while it did not function in the coarse mixtures. The promotion degree of nano-Cu on decreasing the induction time as welll as the supercooling degree of hydration was increased with an increase in the amount of nano-particles in the system. By adding 0.1wt% nano-Cu in the microemulsion system, the induction time was shortened by 29% and the supercooling degree was reduced by 39%. In all, combining the characteristics of large interfacial area of microemulsion with that of enhanced mass and heat transfer of nano-fluid by adding nano-particles can be an effective way to promote the formation of gas hydrate.