Simulation of CO<sub>2</sub> and H<sub>2</sub>S Removal Using Methanol in Hollow Fiber Membrane Gas Absorber (HFMGA)

Abstract

Application of methanol solvent for physical absorption of CO<sub>2</sub> and H<sub>2</sub>S from CO<sub>2</sub>/H<sub>2</sub>S/CH<sub>4</sub> 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 CO<sub>2</sub> and H<sub>2</sub>S 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 CO<sub>2</sub> and H<sub>2</sub>S removal in membrane gas absorber. Also it is found that the concentration distribution of CO<sub>2</sub> and H<sub>2</sub>S 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 H<sub>2</sub>S removal and at higher flow rate is more efficient. Moreover, at operating pressures above 10 atm even at low absorbent rate, H<sub>2</sub>S 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 H<sub>2</sub>S

Desorption of CO2from low concentration monoethanolamine solutions using calcium chloride and ultrasound irradiation

“…This may come from the ionization of H 2 CO 3 in the near-neutral region, as shown by Eqs. (11) and (12). 37,38)…”

“…[3][4][5][6][7][8][9] The capture of CO 2 from exhaust gases from thermal power plants can be achieved using several methods, including the chemical absorption of CO 2 by an absorbent such as an amine, the physical absorption of CO 2 by an absorbent such as methanol at a high pressure and a low temperature, and the absorption of CO 2 by a membrane. [10][11][12][13][14] Many studies aimed at increasing the effectiveness with which CO 2 can be desorbed from the absorbents used in absorber units in coal-fired power plants. In particular, the properties of alkanolamines have been studied through laboratory experiments and model simulations because alkanolamines are often used as chemical absorbents.…”

Efficient separation scheme for binary mixture of CO2 and H2S using aromatic components

“…With fossil-fuel consumption accounting for more than 80% of energy use, CO2 concentration in the atmosphere is bound to increase [1] [2,3]. This increase in CO2 concentration is considered the main cause of climate change and the increase in global temperatures [4][5][6].…”