Effect of water on the solubility and mass transfer coefficients of CO and H 2 in a Fischer-Tropsch liquid

Abstract

The effects of water on the solubilities (C*) and mass transfer coefficients (k La) for CO and H 2, in a medium fraction (C 11 – C 22 of Fischer-Tropsch (FT) liquid were examined at elevated temperatures (423 – 498 K) and pressures (1 – 4 MPa, and at different stirring speeds. A new procedure, which utilizes only pressure-temperature data for FT liquid-water mixtures to estimate the equilibrium solubility of water in FT fraction is presented. The equilibrium solubility values of water in FT liquid increased with temperature and were higher than those reported in the literature for higher paraffins. The solubilities of CO and H 2 in FT liquid saturated with water increased with both pressure and temperature, and Henry's law behavior was adequate to express the experimental values. The C* values for H 2 appeared to be more sensitive to the presence of water than those for CO. k La values for H 2 at 700, 1000 and 1200 rpm decreased with the presence of water in FT liquid. For CO, however, k La values obtained at 1000 and 1200 rpm were higher in FT liquid saturated with water than those obtained in FT liquid containing no water. k La values for both CO and H 2 increased considerably with the specific power input and slightly with pressure and temperature.