Separation of H2S from CH4 by polymeric membranes at different H2S concentrations

• Published in: International journal of environmental science and technology (Tehran) 2017-02, Vol.14 (2), p.375-384
• Main Authors: Niknejad, S. M. S., Savoji, H., Pourafshari Chenar, M., Soltanieh, M.
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Science and Engineering; Original Paper; Soil Science & Conservation; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 1735-1472; 1735-2630
• DOI: 10.1007/s13762-016-1156-3

In this work, permeation of mixed gases H 2 S/CH 4 through commercial polyphenylene oxide (PPO) hollow fiber and poly (ester urethane) urea (PEUU) flat membranes was studied at pressures of 345–689 kPa, at ambient temperature and at 313.15 K. Various H 2 S concentrations of about 100–5000 ppm in CH 4 binary synthetic gas mixtures as well as a real natural gas sample obtained from a gas refinery containing 0.3360 mol.% H 2 S (equivalent to 3360 ppm) were tested. It was observed that the permeance of components was affected by the balance between competitive sorption and plasticization effects. Separation factors of H 2 S/CH 4 were in the range of 1.3–2.9, 1.8–3.1 and 2.2–4.3 at pressures of 345, 517 and 689 kPa, respectively. In the range of 101–5008 ppm of H 2 S in CH 4 , the effect of temperature on the separation factor was nearly negligible; however, permeances of both components of the mixtures increased with temperature. Additionally, the results obtained by PEUU membrane indicated that it was a better choice for hydrogen sulfide separation from H 2 S/CH 4 mixtures than PPO. For PPO membrane, removal of hydrogen sulfide from high-concentration (up to 5008 ppm) binary mixtures of H 2 S/CH 4 was compared with that of low concentration (as low as 101 ppm) through PPO. At concentrations of 101–968 ppm, plasticization was dominant compared with the competitive sorption, while for the H 2 S feed concentrations of 3048 ppm, the competitive sorption effect was dominant. For H 2 S concentration of 5008 ppm, the balance between these two effects played an important role for explanation of its trend.