Abstract: The tube-grid jet is a novel, simple and efficient device for mass-transfer. fts construction is shown in Fig. 1. The main experimental equipment employed in this study consists of a tube-grid jet unit, an absorption section and a separation section. The diameter of the absorption section is 150mm. The ratio of height to diameter of the absorption section is 10.7, and thearea ratio of tube-grid slits to absorption section 0.113. The schematic diagram of the apparatus employed in this study is given in Figure 2. The fluid-dynamic experiments have been carried out with the air-water system and the mass-transfer experiments with the ammonia-air-water system. The conditions of the present work were- the gas velocity calculated over the whole cross-sectional area of the absorption section w=2-9m/s, the gas velocity at the slits of the tube-grid w0=17-76m/s, the liquid-gas ratio w=3-501/m3. Two flow patterns were observed in the fluid-dynamic experiments. The transition of the two flow patterns occurs at where m - liquid-gas ratio, 1/m3, Wo- gas velocity at the tube-grid slits, rn/s, u- viscosity of the gas, kg-s/m2, density of the gas, kg/m3, and de - equivalent diameter of the tube-grid slits, m.the pressure drop across the wet-drained tube-grid jet unit can be calculated from where La is the Lagrangian number Two operating regions for the different mass-transfer characteristics were also observed. Empiric regression equations for the number of overall gas transfer units NOG based on the tube-grid jet unit are N oo = 0. 027 W-W8 when zw<475 l/m2s, and when Mvw>475 l/m2s. It should be pointed out that the maximum deviation of all the experimental data from the above empiric correlations is ?0%. It is important to see that the pressure drop across the tube-grid unit is about 30% less than that across the cup- jet unit, and the gas mass-transfer coefficient per unit pressure drop Ky,/AP of the tube-grid jet unit is higher than that of the cup-jet unit. Besides, the construction of the tube-grid jet is simple and it is very easy to manufacture. Hence the tube-grid jet, in general, is superior to the cup- jet.