HE absorption of gases inliquids h a s i 11 t e r e s t e d T m a n y i n v e s t i g a t o r s .C o n s i d e r a b l e work has been done on the resistance to gas flow (27), the distribution of the liquid over the packed surface (S), the form of the packing material, and the mechanism of transfer ( 2 , 7 , 9, 10, 13, 15, 16, 21, 25, $4, 25, 27). S o study has been reported in the literature on the earliest type of absorption apparatus, the spray tower (12, 17). It has been the purpose of this investigation to obtain data on the absorptionOver-all transfer coefficients f o r the absorption of ammonici and sulfur dioxide into a water spray, and the absorption of benzene vapor from air into art, oil spray, were determined for a n inner "wall-free" section of a spray type absorption tower.The effects of variable jluid jlows at three tower heights were investigated. Empirical equations indicating the correlation of these variables are developed and the results compared, when possible, with previous accepted data. The use of these equations for practical spray tower design is pointed out with special consideration of their limitations.of typical gases in Ypray towers and to discover, if possible, a correlation for the more important variables.
PHYBIC.4L COKCEPTS O F hfATERIAL TRAKSFERThe following mathematical equation for expressing the mechanism of material transfer from a gas to a liquid has been developed by Lewis (24) :where P = gas concn. C = liquid concn. S = interfacial surface dW/de = weight of material transferred per unit of time Subscripts g, i, L refer, respectively, to conditions at the outside of the gas film, a t the interface, and at the inside of the liquid film.Equation 1 in the integrated form is:where W / e = weight of material absorbed, lb./min. a = interfacial area, sq. ft./cu. ft. of tower vol. (an indeterminate quantity and usually expressed with K g as Koa) Koa = material absorbed, 1b.l min./cu. ft. of tower vol. /mm. of partial pressure driving force V = vol. of the tower, cu. ft. ( AP)av. = logarithmic mean partial pressure ( d r i v i n g force) difference in the s o l u t e gas a n d t h e l i q u i d between the top and bottom of the tower The evaluation of these over-all coefficients under various conditions has been determined hy a number of investigators. Seedless to state, the data are far from complete even with the most common gases. Hasl a m , H e r s h e y , and Keen (9) give data for the absorption of sulfur dioxide in a wetted wall tower. These authors have analyzed the data and found that the over-all gas film resistance, 1/K, is proportional to 1/G0.8, where G is the mass velocity of the gas. The correlated data of several workers (24) in this field indicate that for a packed column the over-all t r a n s f e r resistance is p r o p o r t i o n a l to I where L / A represents pounds of effluent per ~V ' W G O .~ square foot per minute.Kowalke and others ( I S ) , working on the absorption of ammonia in various types of towers, took the over-all coefficient and set it equal...
