HCFC141b气体水合物水平换热管外生长特性研究

通过自建的可视化气体水合物反应实验台,对质量分数为0.2%的SDS(十二烷基硫酸钠,分子式为C12H25SO3Na)水溶液和HCFC141b在单根水平换热管外生成气体水合物的过程进行了可视化观测,通过照片和采集的温度值对水合反应的过程特性进行了描述,发现气体水合物和冰的生长形态完全不同,它不是围绕着换热管生长,而是沿着固体表面(换热管表面)渗透到制冷剂相中生长.采用表面自由能理论进行机理分析表明,其原因在于水溶液在表面张力的作用下可以沿着换热管表面自发渗透到制冷剂相中.据此可以认为,在间接接触换热式气体水合物蓄冷系统中,如果在换热器外增加垂直金属翅片,将有利于改进气体水合物的生长过程.

Characteristics research on HCFC141b gas hydrate formation process outside of a horizontal heat transfer tube

An observation of gas hydrate growth process outside of a horizontal heat transfer tube in the reaction system of 0.2% SDS water solution and HCFC141b is carried out in a transparent apparatus of gas hydrate indirect-contact heat transfer mode reactor. The morphology of gas hydrate growth process is described according to the recorded photos and temperatures. It is found that the gas hydrate grows mainly in the liquid HCFC141b phase, which is different from the growth morphology of icearound the heat transfer tube. In the light of the mechanism analysis using the theory of surface free energy, the cause lies in that the water solution can permeate spontaneously into the liquid HCFC141b phase along the surface of heat transfer tube under the effect of surface tension, so it is reasonable that the gas hydrate growth process can be improved if vertical metal fins are added to the heat exchanger in the indirect-contact heat transfer model of gas hydrate cool storage vessel.