The effect of heat treatment on hollow fiber membrane contactor for CO2 stripping

Abstract

The scope of this study was to investigate the effect of the heat treatment process on the performance of the PEI hollow fiber membrane contactor for CO2 stripping process. The membranes were fabricated via a wet spinning technique into water as a non-solvent bath. Then, the membranes were heat treated by exposing them to various temperatures of 80,120 and 160 °C for the time intervals of 5, 15 and 30 min under a hot air atmosphere. The observations revealed that the most pronounced enhancement belonged to the membranes with the lowest heat treatment temperature preferentially at the shorter exposure times. It was shown that the absorbent velocity and temperature had substantial influence on the CO2 stripping flux, however the temperature exhibited a stronger influence. In fact the dual functionality of temperature on the system i.e. (i) thermodynamics (by decrease in CO2 solubility) and (ii) kinetics (by increase in CO2 diffusivity) led to the enhancement in CO2 stripping flux. Also, it was revealed that by increasing the heat treatment temperature, more tendency toward the pore wetting will be observed. There was a meaningful correlation between the wetting ratio and the CO2 stripping flux. Also experimentally it was revealed that, a marginal progress in the wetting ratio, surprisingly caused to a dramatic decline in the stripping flux.