H2S absorption at high pressure using hollow fibre membrane contactors

• H2S removal from natural gas at high pressure using membrane contactors was described.
• The model predictions were in a good agreement with the experimental behaviour.
• The influence of diffusion and solubility coefficients on H2S absorption was negligible.
• Pseudo-wetting phenomenon was confirmed to be critical at high pressure operations.

In this article, the removal of H2S from natural gas at high pressure using hollow fibre membrane contactors and water as the absorbent solvent was described and validated by a 2D comprehensive mathematical model. The modelling predictions were in a good agreement with the experimental data at low pressure of 1 bar under non-wetting conditions. However, the experimental behaviour at high pressure in the range of 10–50 bar was always lower than the modelling predictions. And thus, a sensitivity analysis was carried out to study the influence of gas, liquid, membrane diffusion and solubility coefficients of H2S at high pressure upon the modelling behaviour compared with the experimental trend. The modelling results confirmed that these parameters were still insensitive as the model predictions changed slightly with altering these coefficients. Conversely, membrane wetting was confirmed to be an important factor even for small ratios, i.e. pseudo-wetting (1–3%). The model was able to predict the absorption of H2S at higher pressures under 3% pseudo-wetting. Although the type of membranes used in this study was highly hydrophobic (ePTFE) and thus membrane wetting was not expected, pseudo-wetting phenomenon was confirmed to be an important factor at high pressure.

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