Robustness of PTFE membrane in the presence of impurities and heavy hydrocarbons: article

The presence of heavy hydrocarbons such as toluene, and n-hexane are a problem in carbon dioxide separation which causes loss of flux and selectivity of the membranes. Moreover, small amounts of condensable heavy hydrocarbons also can cause membrane failure and premature aging. Thus, these impurities and heavy hydrocarbons need to be removed before natural gas undergoes carbon dioxide separation in acid gas removal process. Most studies on membrane contactor in separation of gas has focused on polymeric membrane. PTFE is used in this study because of its hydrophobicity and delivers the best performance with high efficiency compared to other materials that have been studied, due to its stability and structure. The PTFE hollow fibre membrane was obtained from PETRONAS Research Sdn Bhd. This research aim is to study the effect of such hydrocarbons and impurities to carbon dioxide separation based on chemical and physical characteristic. The hydrocarbons and impurities include toluene, pentane, n-heptane, hexane, and amine solvent. The data is analysed based on membrane characterization such as Fourier Transform Infrared (FTIR) Spectroscopy, Thermogravimetric Analysis (TGA), digital microscope, mercury porosimeter and tensile strength. Based on this study’s findings, for TGA, rapid weight loss for the PTFE hollow fiber membrane happened starting the temperature 600oC to 650oC and the weigh loss decreases as the period of exposure increases. The wall thickness of the membrane also decreases as the period of exposure increases. The porosity and tensile strength of the membrane also shows a decrease trends which is validated by the thinning of the membrane wall. For second objective, the same trends as the first objective is shown. For TGA, rapid weight loss for the PTFE hollow fiber membrane happened starting the temperature 600oC to 620oC and the weight loss decreases as the temperature of exposure increases. The porosity and tensile strength of the membrane decreases as the temperature of exposure increases. The thickness of the membrane wall does not show any changes which may be due to short time of heating process. From the findings, the exposure of the membrane material to heavy hydrocarbons decreases the thermal, morphology, porosity, and mechanical properties of the hollow fibre membrane but did not show any changes in chemical stability.