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EXPERIMENTAL STUDIESThe continuous phase was distilled water and the dispersed phase was kerosene. Both phases were mutually saturated and continuously recirculated. Figure 1 is a scale drawing of the spray column. The column design was based on the design recommended by Blanding and Elgin (3 ) .The column proper was a glass pipe, 15 cm.-I.D. and 160 cm. long. The distance between the inlets of the kerosene and the water was 195 cm. The settlers and the conical entry section were made of aluminum, with parallel Perspex windows along their lengths at the front and back. The diameter of the settlers was 35 cm. The piping system and the feed tanks were made of aluminum. The valves were made of chrome-plated brass to minimize corrosion in the system. The kerosene distribution plate was 8.5 cm. in diameter with 130 nozzles arranged in concentric circles 5 mm. apart. The nozzles were stainless steel tubings, 1.5 mm. I.D. and 4 cm. long. ous data in t B e literature on holdup, drop size, and floodvary along the column for a wide range o P operating and drop con-size of the previous work o r Lapidus and Elgin ( 8 ) , is pre--was: k r the disperse B phase Vd = 0.475 to 3.8 cm./ All measurements were carried out at room temperature. The flow rates were measured by calibrated rotameters. The flow rate of each phase was measured at both inlet and outlet of each phase from the column. Control valves at the outlet of each phase were used to maintain constant flow rates and to change or maintain the position of the kerosene-water interface at the top of the column. The accuracy of the flow rate measurements was f 0.5% at high flow rates and & 2% at low flow rates. The range of flow rates in this work was 5 to 40 liters/min. of kerosene and 0 to 50 literdmin. of water.Local holdups in the column proper were measured by a photoelectric system. A light source and a photocell were positioned next to the column, opposite each other. The glass column was covered by dark paper, except for narrow slits, 1 cm. high and 2 cm. wide, for the photocell and light at each location. Measurements were made at four locations ( S = 30, 70, 120, 150 cm.).The light source was an ordinary 150-w. light bulb. The photocell was a Weston Photonic model 856. The output of the photocell was amplified and then reduced by a resistor to the l-mv. range of the recorder used in this work, The accuracy of the voltage reading was -t 0.01 mv. The intensity of the light source at each location was adjusted to the same reading of the recorder, with the column full of water, by controlling the distance of the light source from the column.The kerosene contained a low, constant concentration of a blue dye, insoluble in water, in order to increase the contrast between kerosene and water. by twelve sets of flow rates, for which the local holdup d i g not vary along the column and was equal to the mean holdup. The range of holdups for the calibration points was 6 to 70%.The total fraction of light absorbed in the column is due to a combination of light scattering and lig...

a spray column Temperature profiles of dispersed kerosene and water were measured in I heat exchanger,. 15 cm. in diameter and 160 cm. long. Dispersed packing of drops and narrow temperoture ranges were used. The flow rates used were 0 to 50 liters/min. of water ond 5 to 40 liters/min. of kerosene. The physical picture that emerges from the temperature profiles is that heat is transferred from fully mixed drops to fully mixed wakes while the wakes are formed, by shedding and renewal of elements of wakes in most of the column and by complete mixing of all streams ot the water inlet a t the top of the column. Mathematical equations were developed from the physical model. The volume of the wakes and the rate of shedding of wake elements were estimated from the temperoture profiles and were used to calculate the temperoture profiles for this and for other studies. The agreement of the calculated profiles with the experimental data is very good.A spray column heat exchanger system is composed of two spray columns. In one column heat is transferred bv direct contact from hot water to a countercurrent flow of cold oil. In the other column the heated oil transfers heat to cold water. This type of heat exchanger has been suggested for use in desalination schemes (23, 3 2 ) . The favorable features of a spray column heat exchanger are simplicity, low cost, high heat throughput, and no scale deposition on heat transfer surfaces. An attempt to scale up a spray column heat exchanger from a laboratory sized column failed ( 3 0 ) .In most studies of heat transfer in single spray columns ( 1 to 3, 7 , 9, 12, 15, 26, 27, 30, 32) only inlet and outlet temperatures of the two streams were measured. Plug flow and ideal countercurrent heat transfer were assumed, and log mean temperature differences were used to calculate volume heat transfer coefficients or values of HTU. This large amount of data cannot be correlated to give the quantitative effects of the many parameters involved.The temperature profiIes of the continuous phase were the temperature profiles of both phases in this work. About 200 temperature profiles were measured. The temperature profiles showed, consistently, the following features (Figures 8 to 12) : At the bottom of the column the drops temperature changed rapidly while the continuous phase temperature remained constant. At face value this appears to violate the conservation of energy. This is the key evidence for the role of the wakes of drops in the mechanism of heat transfer. In this region both drop and wake experience a rapid temperature change, while the continuous phase temperature remains constant. A short region with no temperature change of both phases (at low holdups only) folIowed. Higher up the column the temperature of the two phases changed continuously, with a small temperature difference between them. At the top of the column a sharp temperature jump of the continuous phase at its inlet took place and all streams leaving that region were at the same temperature. These observations confirm earlie...

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