Water condensation is a possible cause of membrane wetting in the operation of membrane contactors, especially under high-temperature conditions. In this study, water condensation in pores of polytetrafluoroethylene (PTFE) hollow fiber membranes was investigated during high-pressure CO₂ absorption around 70 °C. It was found that the liquid accumulation rate in the treated gas knock-out drum was constant during continuous operation for 24 h when all experimental conditions were fixed, indicating a stable degree of membrane wetting. However, as the operating parameters were changed, the equilibrium vapor pressure of water within membrane pores could change, which may result in a condensation-conducive environment. Water condensation in membrane pores was detected and proven indirectly through the increase in liquid accumulation rate in the treated gas knock-out drum. The Hagen–Poiseuille equation was used to correlate the liquid accumulation rate with the degree of membrane wetting. The degree of membrane wetting increased significantly from 1.8 × 10⁻¹⁵ m³ to 3.9 × 10⁻¹⁵ m³ when the feed gas flow rate was reduced from 1.45 kg/h to 0.40 kg/h in this study due to water condensation in membrane pores. The results of this study provide insights into potential operational limitations of membrane contactor for CO₂ absorption under high-temperature conditions.

Total Inorganic Carbon (TIC) is an analysis method to determine carbon content in a sample. In this paper, applicability of TIC method to determine carbon dioxide (CO₂) content in amine solvent is explored in detailed. Both commercial and self-blended amine solutions, consisting of MDEA and PZ, were used in this study and bubbled with CO2. TIC method was calibrated for both mid-level mode and high level mode. Difference in results were found when comparing TIC against the standard titration method; this is largely due to error in titration method during the methanol pH adjustment step. TIC method is considered to be better in terms of limit of detection, limit of quantification, recovery percentage, and susceptibility to error.

CO2 is one of the major contaminants in natural gas streams. Its removal from the natural gas stream is necessary prior to entering downstream units of the gas processing plants due to Health, Safety and Environment (HSE) concern, heating value specification, as well as plant and pipeline corrosion issues. CO2 is conventionally removed using acid gas absorption tower and membrane technologies. Application of these technologies in offshore facilities requires high capital and operating expenses, and large foot print. The potential reduction in both capital investment and equipment footprint has made membrane contactor technology a compelling solution for the removal of CO2 in natural gas. A membrane contactor is a device that allows gas-liquid mass transfer without direct contact of the two phases which flow at the different sides of the membrane. Recent findings have shown that membrane contactors have several advantages over those existing separation systems, which include smaller footprint, modular, not sensitive to flooding, channelling or back-mixing, and provide larger contact areas for increased mass transfer rate. Realizing its potential, PETRONAS and Dalian Institute of Chemical Physics (DICP) have successfully completed a development study on membrane contactor which can remove CO2 from feed gas containing a range of 70-10% of CO2 down to as low as 1% at the outlet gas stream. The technology could potentially further remove CO2 down to ppm level meeting LNG specifications. A pilot plant to demonstrate its performance on actual plant conditions will be commissioned at PETRONAS Gas Processing Plant in 2013.