Absorption of Gases in Spray Towers

Abstract

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...

The CO2 capture performance of a high-intensity vortex spray scrubber

“…8 show that the K g a is proportional to the −0.24 to −0.41 power of the tower height. A similar trend has been found in previous experimental studies [13,14,47]; however, the values of the exponent, ranging from −0.34 to −1.03, depend on the gas-liquid system and the operating conditions.…”

“…In the past, many experimental studies have been carried out to examine the mass transfer characteristics of spray towers for various gas-liquid systems, which include air-CO 2 /NaOH [6,7,9,10], air-CO 2 /H 2 O [7,10], air-CO 2 /Na 2 CO 3 /NaHCO 3 [11], air-SO 2 /NaOH [6,9,11,12], and air-NH 3 /H 2 O [13][14][15][16][17][18]. The mass transfer performance of a spray tower depends not only on the operating conditions, gas/liquid flow directions and the physical properties of the fluids, but also strongly on the solvent spray characteristics, such as the liquid distribution and the droplets size and its distribution, which are in turn influenced by the spray nozzle specifications [19].…”

Mass transfer and axial dispersion in a spray tower for gas‐liquid contacting

“…These values are comparable to the results obtained in this work for kGa, that ranged from 0.8 X to 1.7 X kmol/s m3 kPa. Hixson and Scott (1935). studied the absorption of sulphur dioxide in water at similar gas and liquid flow rates to the ones used in this work and they found slightly smaller k a values ranging from 2.8 X lo-' to 6.1 X kmol/s m3 kPa.…”

“…Data and equations for kGa in spray columns have also been reported in other studies (Hixson and Scott, 1935).…”

Mass transfer parameters in spray columns: 2. The system benzene-wash oil

“…Dit word bevestig deur ander navorsers. [10][11][12] 'n Breedvoerige uiteensetting vir 'n tipiese sisteem soos in die ondersoek word ook in Foust3 gegee.…”