Abstract
Heat and mass transfer coefficients during ammonia gas absorption into a falling liquid film formed by ammonia water on a horizontal tube were obtained experimentally. The test absorber is comprised of a 200-mm i.d., 600-mm long stainless steel shell; a 17.3-mm o.d., 14.9-mm i.d. stainless steel test tube with a working length of 600-mm mounted along the axis of the shell; and a 12.7-mm o.d. pipe manifold for supplying the absorbent. The results clarified that absorption volume could be increased and heat and mass transfer coefficients could be enhanced by increasing the difference in concentration between the inlet absorbent solution and the ammonia gas. The heat transfer of the falling liquid film was affected by the driving force between the temperature of the liquid film and the temperature difference between the vapor and the inlet absorbent solution. The mass transfer was affected by the driving force between the concentration of the liquid film and the difference in concentration between the vapor and the inlet absorbent solution. A new correlation for heat transfer in a dimensionless form was proposed taking into consideration the driving force resulting from the difference between the temperature in the liquid film and the difference between the vapor and the inlet absorbent solution. Also, a new correlation for mass transfer in the vapor-liquid phase interface in a dimensionless form was proposed taking into consideration the driving force resulting from the difference between the concentration in the liquid film and the difference between the vapor and the inlet absorbent solution.
