Ceramic-supported Teflon AF2400 hollow fiber membrane contactors for dissolved gas-in-oil extraction has gained importance in online dissolved gas analysis (DGA) monitoring. An improved understanding of the mass transfer characteristics is certainly justified to enhance process efficiency and long-term stability. This work presents an investigation of the effects of operating parameters on gas transport in dissolved gas-in-oil extraction for seven key penetrants (i.e., H2, CO, CO2, CH4, C2H6, C2H4, and C2H2) encountered in DGA. During extraction, the permeate fluxes decreased exponentially with on-stream time due to membrane wetting. After stabilization, the overall mass transfer was controlled by gas transport in both the liquid phase and the membrane. Through Wilson plot analysis, it is found that gas transport in the liquid phase is the rate-limiting step. This could be attributed to extremely low gas-in-oil diffusivity and solubility. Furthermore, owing to membrane wetting, gas transport in the membrane is dominated by gas-in-oil solubility. Increasing temperature can enhance the overall mass transfer. However, gas transport performance through the membrane deteriorates with increasing temperature, attributed to the fact that the degree of membrane wetting increases with an increase in temperature. As a result, the rate-limiting step is sensitive to temperature, and the risk of oil leak increases with increasing temperature. Therefore, temperature plays a key role in determining both process efficiency and long-term stability of dissolved gas-in-oil extraction.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering