Separation of greenhouse gases (SF6, CF4 and CO2) in an industrial flue gas using pilot-scale membrane

Abstract

The separation of greenhouse gases, such as sulfur hexafluoride (SF6), tetrafluoromethane (CF4) and carbon dioxide (CO2), from the flue gas that originated from a display manufacturing plant was investigated using the membrane technology. Permeation experiments were performed on single gases (N-2 and SF6) and flue gas to demonstrate the applicability of membrane technology for the mitigation of greenhouse gas emissions. The gas separation experiments were performed using a pilot-scale membrane apparatus composed of a commercial PSf hollow fiber membrane under various conditions of feed pressure and stage cut. The flue gas was composed mostly of N-2 and O-2 and included less than 1% greenhouse gases such as SF6 (800-1000 ppm), CF4 (50-100 ppm) and CO2 (600 ppm above the atmospheric level). In the flue gas separation experiment, SF6 and CF4 were enriched in the retentate. By increasing the stage cut, the enrichment ratio was increased, and the recovery was decreased. An increase in the feed pressure can enhance the efficiency by increasing the capacity without a significant decrease in the enrichment ratio and recovery at the pilot scale. The recovery and enrichment of SF6 was lower than expected based on the ideal selectivity due to the mixture effect. The enrichment ratio of CF4 was lower than that of SF6 due the higher permeance of SF6. Because the selectivity is not high, this membrane is not appropriate for the purification of SF6. CO2 was included in the retentate below the level in the atmosphere due to its high permeability. The result provided realistic information about the performance of membrane technology for the mitigation of greenhouse gas emissions. (C) 2015 Elsevier B.V. All rights reserved.