Simultaneous Absorption of Hydrogen Sulfide and Carbon Dioxide into di‐isopropanolamine Solution

Abstract

AbstractThe simultaneous absorption of hydrogen sulfide and carbon dioxide into di‐isopropanolamine (DIPA) solution was investigated in a 183 cm long, 2.72 cm OD wetted‐wall column at atmospheric pressure. The influence of liquid flow rate, gas flow rate, temperature and liquid concentration on the absorption rate, overall gas‐phase mass transfer coefficient and selectivity factor were studied at a constant gas feed ratio. The results show that the absorption rate of CO2 increases rapidly with increasing liquid flow rate (the Reynolds number of the turbulent liquid film ranges from 2600 to 4350) but increases moderately with increasing gas flow rate (G = 18‐91 L/min), indicating that it is liquid‐phase mass transfer controlled. In contrast, the absorption rate of H2S increases very slowly with increasing liquid flow rate but increases rapidly with increasing gas flow rate, indicating that it is gas‐phase mass transfer controlled. The absorption rate of CO2 also increases with increasing temperature (26‐80°C) but H2S absorption rate decreases with increasing temperature. When the concentration of DIPA solution increases from 0.2 to 2.6 mol/L, the absorption rate of both CO2 and H2S increases but with a larger rate of increase for CO2 For selective H2S removal, it is preferable to operate at low liquid and high gas flow rates, low temperatures and low DIPA concentrations.