Hossein Rahideh

Using metallic pipes in gas transmission lines brings some major problems such as corrosion, coating dissociation, sedimentation and consequently leakage, low lifetime, and environmental issues. Nowadays, innovative polymeric pipes and conjunctions (like: polyethylene, polyester, vinyl ester and epoxy, and composite) reduce tackle the issues of using metallic pipes; however, the gas leakage from composite pipes is a possible problem that should be considered. According to the polymers’ structure and their morphology, mass transfer plays a significant role if leakage exists in composites. Soloubility and diffusion are major phenomena in mass transfer of gas transfer from porous media. In this study, diffusion and solubility cells were designed to investigate ethane diffusion coefficient from gas nutrition composite lines by considering pressure reduction through the experiment and time lag method. A sample from gas nutrition composite lines with 5.95 mm diameter was devised in diffusion cell. Moreover, powdery sample was prepared to calculate the solubility of ethane in composite. The experiments were performed from 25 to 40 ℃. The results showed that diffusion coefficient increased by increasing temperature; however, solubility decreased. The minimum and maximum diffusion coefficients were observed at 40 ℃ (2.86E-11) and 25 ℃ (7.94E-11), respectively. Finally, ethane concentration around the pipe was reported below than 0.1 ppm.