ABSTRACT Application of methanol solvent for physical absorption of CO2 and H2S from CO2/H2S/CH4 mixture in gas–liquid hollow fiber membrane gas absorber (HFMGA) was investigated. A computational mass transfer (CMT) model for simulation of HFMGA in the case of simultaneous separation of CO2 and H2S was developed. The membrane gas absorber model explicitly calculates for the rates of mass transfer through the membrane and components concentration profiles. Due to the lack of experimental data in the literature, the model was validated using available individual components’ water absorption data. The numerical predictions were in good agreement with the experimental data. The effects of operating conditions such as liquid velocity, gas velocity, temperature and pressure were analyzed. It is shown that methanol solvent can successfully be used for CO2 and H2S removal in membrane gas absorber. Also it is found that the concentration distribution of CO2 and H2S in the gas phase along the fiber length obeys plug flow model whereas in the methanol absorbent deeply affected by the interface concentration, absorbent velocity and diffusivity. In addition, it is shown that application of membrane gas absorber using methanol absorbents for H2S removal and at higher flow rate is more efficient. Moreover, at operating pressures above 10 atm even at low absorbent rate, H2S concentration depletion is relatively complete while at 1 atm this value is about 30%. This means that removal efficiency decreases with an increase in temperature and it is more important especially for H2S.
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M. Mahdavian, H. Atashi, M. Zivdar and M. Mousavi, "Simulation of CO2 and H2S Removal Using Methanol in Hollow Fiber Membrane Gas Absorber (HFMGA)," Advances in Chemical Engineering and Science, Vol. 2 No. 1, 2012, pp. 50-61. doi: 10.4236/aces.2012.21007.
 R. Faiz and M. Al-Marzouqi, “Mathematical Modeling for the Simultaneous Absorption of CO2 and H2S Using MEA in Hollow Fiber Membrane Contactors,” Journal of Membrane Science, Vol. 342, No. 1-2, 2009, pp. 269-278.
 R. N. Maddox, “Gas Conditioning and Processing,” Campbell Petroleum Series, 3rd Edition, Vol. 4, 1982.
 L. Sumin, et al., “The Enhancement of CO2 Chemical Absorption by K2CO3 Aqueous Solution in the Presence of Activated Carbon Particles,” Chinese Journal of Chemical Engineering, Vol. 15, No. 6, 2007, pp. 842-846.
 A. Mandowara and P. K. Bhattacharya, “Membrane Contactor as Degasser Operated under Vacuum for Ammonia Removal from Water: A Numerical Simulation of Mass Transfer under Laminar Flow Conditions,” Computers and Chemical Engineering, Vol. 33, No. 6, 2009. pp. 1123-1131. doi:10.1016/j.compchemeng.2008.12.005
 A. Gabelman and S. T. Hwang, “Hollow Fiber Membrane Contactors,” Journal of Membrane Science, Vol. 159, No. 1-2, 1999, pp. 61-106.
 V. Y. Dindore, D. W. F. Brilman and G. F. Versteeg, “Modelling of Cross-Flow Membrane Contactors: Mass Transfer with Chemical Reactions,” Journal of Membrane Science, Vol. 225, No. 1-2, 2005, pp. 275-289.
 H. Jeon, et al., “Absorption of Sulfur Dioxide by Porous Hydrophobic Membrane Contactor,” Desalination, Vol. 234, No. 1-3, 2008, pp. 252-260.
 K. A. Hoff, et al., “Modeling and Experimental Study of Carbon Dioxide Absorption in Aqueous Alkanolamine Solutions Using a Membrane Contactor,” Industrial & Engineering Chemistry Research, Vol. 43, No. 16, 2004, pp. 4908-4921. doi:10.1021/ie034325a
 A. Kohl and R. Nielsen, “Gas Purification,” 5th Edition, Gulf Publishing Company, Houston, 1997.
 G. Hochgesand, “Rectisol and Purisol,” European and Japanese Chemical Industrials Symposium, 1970, Vol. 62, No. 7, pp. 37-43.
 J. A. Delgado, et al., “Simulation of CO2 Absorption into Aqueous DEA Using a Hollow Fiber Membrane Contactor: Evaluation of Contactor Performance,” Chemical Engineering Journal, Vol. 62, 2009, pp. 396-405.
 R. Wang, D. F. Li and D. T. Liang, “Modeling of CO2 Capture by Three Typical Amine Solutions in Hollow Fiber Membrane Contactors,” Chemical Engineering and Processing, Vol. 43, No. 7, 2004, pp. 849-856.
 W. Rongwong, R. Jiraratananon and S. Atchariyawut, “Experimental Study on Membrane Wetting In Gas-Liquid Membrane Contacting Process for CO2 Absorption by Single and Mixed Absorbents,” Separation and Purification Technology, Vol. 69, 2009, pp. 118-125.
 D. Wang, W. K. Teo and K. Li, “Removal of H2S to Ultra-Low Concentrations Using an Asymmetric Hollow Fibre Membrane Module,” Separation and Purification Technology, Vol. 27, No. 1, 2002, pp. 33-40.
 P. Keshavarz, J. Fathhikalajahi and S. Ayatollahi, “Mathematical Modeling of the Simultaneous Absorption of Carbon Dioxide and Hydrogen Sulfide in a Hollow Fiber Membrane Contactor,” Separation and Purification Technology, Vol. 63, No. 1, 2008, pp. 145-155.
 S. Wang, K. Hawboldt and M. Abedinzadegan Abdi, “Novel Dual-Membrane Gas-Liquid Contactors: Modelling and Concept Analysis,” Industrial & Engineering Chemistry Research, Vol. 45, No. 23, 2006, pp. 7882-7891. doi:10.1021/ie051368d
 A. Mansourizadeh, A. F. Ismail and T. Matsuura, “Effect of Operating Conditions on the Physical and Chemical CO2 Absorption through the PVDF Hollow Fiber Membrane Contactor,” Journal of Membrane Science, Vol. 353, No. 1-2, 2010, pp. 192-200.
 R. Faiz, and M. Al-Marzouqi, “CO2 Removal from Natural Gas at High Pressure Using Membrane Contactors: Model Validation and Membrane Parametric Studies,” Journal of Membrane Science, Vol. 365, No. 1-2, 2010, pp. 232-241. doi:10.1016/j.memsci.2010.09.004
 J. Happel, “Viscous Flowrelative to Arrays of Cylinders,” AIChE Journal, Vol. 5, No. 2, 1959, pp. 174-177.
 M. Al-Marzouqi, et al., “Modeling of CO2 Absorption in Membrane Contactors,” Separation and Purification Technology, Vol. 59, No. 1, 2008, pp. 286-293.
 M. Mavroudi, S. P. Kaldis and G. P. Sakellaropoulos, “Reduction of CO2 Emissions by a Membrane Contacting Process,” Fuel, Vol. 82, No. 15-17, 2003, pp. 2153-2159.
 P. Keshavarz, J. Fathhikalajahi and S. Ayatollahi, “Ana- lysis of CO2 Separation and Simulation of a Partially Wet-Ted Hollow Fiber Membrane Contactor,” Journal of Hazardous Materials, Vol. 152, No. 3, 2008, pp. 1237-1247. doi:10.1016/j.jhazmat.2007.07.115
 G. F. Versteeg and W. P. M. Van Swaaij, “On the Kinetics between CO2 and Alkanolamines both in Aqueous and Non-Aqueous Solutions I. Primary Andsecondary Amines,” Chemical Engineering Science, Vol. 43, No. 3, 1988, pp. 573-585. doi:10.1016/0009-2509(88)87017-9
 J. J. Carroll and A. E. Mather, “The Solubility of Hydro-Gen Sulphide in Water from 0°C to 90°C and Pressure to 1 MPa,” Geochimica et Cosmochimica Acta, Vol. 53, No. 6, 1989, pp. 1163-1170.
 K. Lunsford and G. Mcintyre, “Decreasing Contactor Temperature Could Increase Performance,” GPA Annual Convention, Bryan Research and Engineering, Inc., Texas, 1999, pp. 121-127.
 E. L. Cussler, “Diffusion Mass Transfer in Fluid Systems,” Cambridge University, Cambridge, 1984.
 M. V. Diaz and A. Coca J., “Correlation for the Estimation of Gas-Liquid Diffusivity,” Chemical Engineering Communications, Vol. 52, No. 4-6, 1987, pp. 271-281.
 R. H. Perry, “Perry’s Chemical Engineers’ Handbook,” 7th Edition, McGraw-Hill, New York, 1997.
 B. E. Poling, J. M. Prausnitz and J. P. O’Connell, “The Properties of Gases and Liquids,” 5th Edition, McGraw-Hill, New York, 2004.
 R. Faiz and M. Al-Marzouqi, “H2S Absorption via CarBonate Solution in Membrane Contactors: Effect of Species,” Journal of Membrane Science, Vol. 350, No. 1-2, 2010, pp. 200-210. doi:10.1016/j.memsci.2009.12.028
 V. Y. Dindore, D. W. F. Brilman and G. F. Versteeg, “Hollow Fiber Membrane Contactor as a Gas-Liquid Model Contactor,” Chemical Engineering Science, Vol. 60, No. 2, 2005, pp. 467-479.