Harrison C. Carlson was born in Newton, Masr., in 7913. H e studied chemical engineering a t the Massachusetts Institute of Technology, receiving the degrees of bachelor of science in 7934 and master of science in 7935. Since 7935 he has been employed a t the Experimental Station of E. /. du Pont d e Nemours & Company, Inc., a t Wilmington, D e l . A f t e r a year as semiworks operator in the Ammonia Department, he d i d research in fluid flow, heat transfer, vapor-liquid equilibria, and distillation in the Chemical Engineering and Metallurgical Laboratory o f the Engineering Department. Recently most of his work has been in design of absorption and distillation equipment. W i t h A. P. Colburn he wrote a paper on the vapor-liquid equilibria of nonideal solutions which appeared in the M a y , 1942, issue of Industrial and Engineering Chemistry, pages 581 to 589. H e is a member of the American Chemical Society and Sigma X i , and is a licensed engineer.
D Harrison HE advances in this field are reviewed here from October, 1943, t o November, 1945. Arnold ( 2 ) derived an equation for the unsteady-state evaporation of a liquid from a plane surface into a n infinite volume of inert gas free from convection. The derivation assumes t h a t the inert gas docs not diffuse into the liquid and that the partial pressure of the evaporating liquid a t the interface is constant with time. The development is based on the Maxwell-Stefan differential equation, so that it is applicable t o large and small concentrations of the diffusing gas where the previously used integration of the Fick law was true only for low concentrations. Arnold used the equation to calculate the diffusion constants of liquids at the bottom of a vertical tube filled with air, from measurements of the rate of air displacement from the top. Sheiwood and Gilliland measured the rates of evaporation of liquids wetting the wall of a vertical tube with a countercurrent air stream. With the air in viscous flow, they found that the experimental data were fitted by a theory for a constant air velocity across the tube rather than the parabolic distribution expected in viscous flow. Boelter ( 5 )adapted a n equation previously derived for heat transfer to this case of diffusion. H e indicated that evaporation of the high-molecular-weight organic liquid increased the density near the wall and induced a convection current which increased the velocity near the wall and decreased i t near the center. This deformed the parabolic velocity distribution t o one nearly uniform across the tube. Consideration of free convection in correlating absorption in packed towers might be equally fruitful. Tiller and Tour (33) gave a clear exposition of the elemcnts of the calculus of finite differences and showed the applicability of difference equations t o chemical engineering. Equations for the absorption in a n isothermal plate column are derived with the material balance expressed in mole ratios, and the equilibrium curve with either the mole ratio in the liquid proportional to that in the gas or the mole fraction in the liquid proportional to t h a t in the gas. The calculus of finite differences offers the means of finding the solutions to difference equations which are too involved t o be solved by inspection. N a t t a and Mattei ( 2 1 ) discussed the calculation of the numbcr of theoretical plates and the amount of solvent and reflux necessary t o separate a binary gaseous mixture completely by a process known in this country as extractive distillation. They treated the case of a nonvolatile solvent in a n isothermal column, with
T
14
C. Carlson the solubilities of the gases smd1 and without mutual influence. If the operating line is drawn with the composition on a solventfree basis, it will be curved if the solubilities differ. Xatta and Mattei obtained a straight operating line by expressing the compositions in solubility equivalents. If the solubilities follow the solubility equivalent Henry's law, yy = rnlzl and y: = m2x2, yPmJ. in the gas of mole fraction yl would be ylml/(ylm~ Katta and Mattei pointed out the advantage of a packed column over a plate column for this type of separation employing high ratios of liquid to gas. For the separation of gaseous hydrocarbons with a n unspecified solvent, the height of a theoretical plate in a column packed with l/2- or 1-inch Raschig rings was 4 feet at gas velocities of 0.5 to 1.0 ft./sec. Tour and Lerman (34) derived a theoretical equation for the spreading of a liquid in a packed tower, distributed from a n area source rather than the point source used in their previous paper. Data on the flow of water through packed columns without any countercurrent gas flow were used to evaluate constants characteristic of the packings. Observation of packed columns by Bain and Hougen (3) and Schoenborn and Dougherty (37) revealed that the gas flow played a n important part in distributing the liquid in a fashion which has yet to be analyzed mathematically. Goff and Gratch (9) presented tables of the humidity, specific volume, enthalpy, and entropy of dry and saturated air and of liquid water or ice in equilibrium for a total pressure of 1 atmosphere and in the temperature range - 160' to +200 O F. Deviations from the perfect gas law were taken into account in the calculation of these reliable and useful tables. The article gave critical review of the available data on the thermodynamic properties of air and water and their mixtures. I n measuring humidity under conditions where the wet-bulb temperature was below the freezing point of water, Wile (37) suggested using a thermometer graduated to 0.1 ' F. and previously coated with a film of ice rather than using a wick wet with liquid water. Wile reviewed the adiabatic saturation and diffusional theories of the wet-bulb hygrometer to arrive at a recommended air velocity of 5 ft./sec. t o make radiation to the thermometer negligible. The problem of selecting a refrigerated coil to cool and dchumidify air was treated from different approaches by Siegel (50) and Boehmer ( 4 ) . Siegel assumed a complicated function of the dry-bulb and dew-point temperatures of the inlet and outlet
INDUSTRIAL AND ENGINEERING CHEMISTRY
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air to calculate an average surface temperature. For no dehumidification, the surface temperature becomes the dew point. The method depends on obtaining three tests on a coil dehumidifying air to calculate the heat transfer coefficients on the air and refrigerant sides. Boehmer (4) worked from the equivalent bypass theory, which assumes that part of the air is unchanged in temperature and humidity by the coil and the other fraction is cooled to the refrigerant temperature. Boehmer pointed out the effects of installing too large or two small coils on th’e humidity and temperature of the refrigerated space, but did not compare the predicted conditions with those observed, as did Siegel. Both of these approaches are empirical and limited to the case of dehumidifying air at atmospheric pressure. A more fundamental approach to the problem was given by Colburn and Drew (6). LIMITINGGAS VELOCITIES IN COLUMNS.Knowledge of the effect of the physical properties of fluids on flooding velocities of tower packings has and Schoenborn and ured the flooding vel hydrogen, and carbon dioxide. The liquid rates in th column were varied from 250 to 21,000 lb./(hr.)(sq. ft.) Schoenborn and Dougherty measured the flooding velocity and pressure drop in the flooding range with air flowing countercurrent to water or one of two oils, having viscosities up to 38 centipoises when the tower was packed with l/h-, I/%-, or I-inch Raschig rings or ‘/$-inch Berl saddles. The liquid rate in the 8-inch tower was varied from 400 to 20,00Olb./(hr.)(sq. ft.). They found that the gas velocity at flooding was inversely proportional to the liquid viscosity raised to a power between 0.33 for Ija-inch rings and 0.15 for 1-inch rings. Bain and Hougen checked the conclusion of previous investigators, using smaller towers, that the gas density raised to the 0.5 power is the proper correction on the gas velocity, Both investigations found that the oils channeled in the packing even though given an initially uniform distribution. From the abstract of an article by Zhavoronkov (89)’ of which the original does not seem to be available in this country, it is impossible to tell whether new data on pressure drop and fiooding velocity have ,been measured. Schutt (98) reported difficulty from foaming of an absorption oil, whi+ decreased the gas-handling capacity to one-fourth of that of a nonfoaming medium. The absorption oil was a pyrolysis product, which circulated in a closed cycle and foamed worse as the oil became more aromatic. Tests indicated that the plate efficiency decreased as the gas velocity increased. Observation of the foaming in a glass apparatus showed that the pyrolysis absorption oil foamed worse than a paraffinic oil. RATESOF ABSORPTION.Cooper, Fernstrom, and Miller (7) measured the rate of absorption of oxygen in aqueous sodium sulfite solutions in tanks between 6 and 96 inches in diameter with vaned-disk or flat-paddle agitators. Absorption coefficients were measured for a range of gas velocities, liquid depths, and power inputs up to 3000 ft.-lb./(min.)(gu. ft.). The absorption coefficient was found to increase with the power input raised to the 0.95 power and with the superficial gas velocity raised to the 0.67 power. The increase of the absorption coefficient based on the unaerated volume of the liquid with the gas velocity is probably related to the increase in volume of the aerated solution, which Foust, Mack, and Rushton (8) found to increme with the 0.53 power of the gas velocity. The absorption coefficients and power requirements may be compared with those for a packed tower for oxygen transfer to water without chemical reaction. The highest coefficient measured by Cooper, Fernstrom, and Miller (7) with the driving force expressed in mole fraction of oxygen in the liquid was 5260 lb. mole/(hr.)(cu. ft.)(Az) with a power input of 330 ft.-lb./min. to a vaned disk in a 0.5-inch jar. Molstad, McKinney, and Abbey January, 1946
(80) reported a coefficient of 380 lb. mole/(hr.) (cu. ft.) ( A x ) for oxygen stripping with a liquor rate of 11,000 lb./(hr.) (sq. ft.) on a grid tile. With the vaned-disk absorber, the power required was 330 ft.-lb./min. for agitation and 150 ft.-lb./min. to force the gas through. In a packed tower to absorb oxygen at the same rate, the power would be about 1500 ft.-lb./min. for pumping the liquid and a negligible amount for gas resistance. The agitated tank has a slight advantage in size and power over the packed tower, but it is limited to gas velocities below 0.2 ft./sec., which is approximately the rate of rise of gas bubbles in a liquid. Groes and Simmons (10)measured the rates of absorption of benzene, trichloroethylene, and chloroform from air by kerosene in a 12-inch tower packed with 1-inch Berl saddles. Over-all heights of gas-film transfer units of 2.5 to 5 feet were obtained at gas rates between 15 and 70 lb./(hr.)(sq. ft.), which are too low to be of commercial interest. Molstad, McKinney, and Abbey ($0) reported a large amount orption of ammonia from air by water and on gen from water by air with a 15-inch square 1-inch rings, 1-inch saddles, 3-inch spiral d grids, or sevBra1 styles and artile. For the absorption of amfrom 100 to 11001b./(hr.)(sq. ft.) at a constant liquor rate of 3000 lb./(hr.)(sq. ft.), and the water rate was varied from 1800 to 18,000 lb./(hr.)(sq. ft.) at a constant gas rate of 500 lb./(hr.)(sq. ft.). With these high ratios of liquid to gas, more than 85% of the resistance was in the gas film. The height of a transfer unit for ammonia absorption was in the range 0.8 to 3.0 feet on the over-all gas film basis. The absorption coefficient for ammonia was found to vary with the gas rate raised to a power varying from 0.4 to 0.9, with the higher exponents for the smaller pacltings. Molstad et al. used the pressure drop per transfer unit as a guide to show that the large packings with low pressure drops result in lower column and power costs than the small packings. Scheibel and Othmer ($6‘) measured rates of absorption and desorption in water of acetone, methyl ethyl ketone, methyl isobutyl ketone, and methyl n-amyl ketone borne by air. The tower was 4 inches in diameter and packed with 0.3-inch glass Raschig rings for a total height of 74 inches, but divided for sampling in the middle. The authors attempted to separate the over-all Coefficientsinto gas and liquid film coefficients, and proposed a general equation for the over-all coefficients for any s y ~ tern on 0.3- and 1-inch rings. The correlation is unusual, since they conclude that the separate film coefficients are proportional to the first power of the diffusion coefficient times the 0.8 power of the flow rate. Having the diffusivity enter to the first power is characteristic of laminar flow, and the 0.8 power if the flow rate is usually found for turbulent flow. Previous experiments on evaporating liquids in packed towers indicated that the diffusivity entered to the 0.17 power, The height of an over-sll transfer unit on the liquid film basis for the absorption of acetone was between 3 and 6 feet. Walthall, Miller, and Striplin (36) studied the absorptlon of SUIfur dioxide and oxygen in water containing 0.03% Mn++ to produce 30% sulfuric acid. When the gases were bubbled through a porous plate in the solution, the addition of 1% aluminum sulfate improved the gas dispersion and rate of absorption. Iron salts, grease, and carbon dioxide inhibited the catalytic effect of lfn++, but the addition of 0.0001% Alkanol €3 overcame the grease difficulty. As the porous plate plugged d t h dust, the sulfur dioxide was absorbed in an 18-inch tower packed with 15 feet of 1-inch glass rings, and oxidized in an external tank by air and ozone bubbled through a porou8 carbon plate. Several absorption COefficients for sulfur dioxide in the packed tower are presented graphically. Lichtenstein (18) reviewed the theory and performance of mechanical-draft water cooling towers from the designer’s (Continued on page 33) viewpoint. The case of calculation
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
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Chaddock, R. E., and Saunders, M. T., Trans. Am. Inst. Chem. Engrs., 40, 203 (1944). Chilton. T. H..Drew, T. B.. and Jebens, R. H., IND.ENQ. CHEM.,36, 510 (1944). Clapsaddle, L. J., and Graham, G. B., Can. Patent 415,892 (1943).
Connell, L. J. C., G. E . C. Journal, 13, 10 (1944). Csarniecki, W., German Patent 717,497 (1942). Danforth, J. D., U. S. Patent 2,333,845 (1943). Davis, E. S., Trans. Am. Soc. Mech. Engrs., 65, 755 (1943). DeLorenzo, B., and Anderson, E. D., Ibid., 67, 697 (1945). Donlan, T. R., U. S. Patent 2,324,770 (1943). Dusinberre, G. M . , Trans. Am. SOC.Mech. Engrs., 67, 703 (1945).
.
Emmons, H. W., Ibid., 65, 607 (1943). Fiene, M. E., U. 8. Patent 2,348,000 (1944). Fischer, R. C., IND.ENG.CHEM.,36, 939 (1944). Gardner, K. A , Trans. Am. SOC.Mech. Engrs., 67, 31 (1945). Zbid., 67, 621 (1945). Glinke, K., German Patent 735,741 (1943). Gunter, A. Y., and Shaw, W. A,, Trans. A m . SOC.Mech. Engrs., 67, 643 (1945).
Hasleton, R., and Baker, E. M., Trans. Am. Znst. Chem. Engrs., 40, 1 (1944).
Henning, A., and Gebauer, E., Kunststofe, 33, No. 6, 161 (1943). Houlton, H. G., IND.ENQ.CHEM.,36, 622 (1944). Jameson, S. L., Trans. Am. SOC.Mech. Engrs., 67, 633 (1945). Katz, D. L., Beatty, K. O., and Foust, A. S., Ibid., 67, 665 (1945).
Kayan, C. F., Ibid., 67, 713 (1945). Krats, A. P., Konzo, S., and Engdahl, R. B., Univ. Illinois Eng. Expt. Sta,, Bull. 351, 1-58 (1944). Larson, R. F., IND.ENG.CHEM.,37, 1004, 1010 (1945). Lel’chuk, Y . L., J . Royal Aeronaut. SOC.,‘48, Suppl. 149-51 (Marc$, 1944). Lemmon, A. W., Colburn, A. P o , and Nottage, H. B., Trans. Am. SOC.Mech. Engrs., 67, 601 (1945). Lippman, A., Chem. & Met. Eng., 52, 112 (1945). London, A. L., and Brewster, J. L., Trans. A m . SOC.Mech. Engrs., 66, 75 (1944). McAdams, W. H., Drexel, R. E., and Goldey, R. H., Zbid., 67, 613 (1945).
Mackey, C. O., and Wright, L. T., Heating P i p h g Air Condiditioning, 16, 546 (1944). McKinney, D. S., McGovern, J. J., Young, C. W., and Collins, L. F.. Ibid.. 17, 97 (1945). McMillen, E. L.,’ and‘ Larson, R. E., Trans. Am. Inst. Chem. Engrs., 40, 177 (1944). Martinelli, R. C., Boelter, L. M. K., Weinberg, E. B., and Yakahi, S., Trans. A m . SOC.Mech. Engrs., 65, 789 (1943). Merkel, F., “Die Grundlagen der Warmeubertragung”. (51) More, J. L., Quail, F. J.. and Bain. J. W.. IND.ENG: CHEM.. 37, 912 (1945).
Mumford, A. R., and Powell, E. M., Trans. A m . Soc. Mech. Engrs., 67, 693 (1945). Othmer, D. F., and Berman, S., IND.ENG. CHEM.,35, 1068 (1943).
Otten, P. S., Chem. Industries, 54, 50 (1944). Ibid., 54, 210 (1944). Parsons, P. W., and Gaffney, B. J., Trans. Am. Znst. Chem. Engrs., 40, 655 (1944). Paschkis, V., “Industrial Electric Furnaces”, New York, Interscience Publishers, 1945. Paschkis, V., Refrig. Eng., 47, 469 (1944). Paschkis, V., and Heisler, M. P., Trans. A m . Soc. Mech. Engrs.,
.
66, 653 (1944).
Patton, T. C., IND.ENQ.CHEM.,36, 990 (1944). Peck, R. E., and Bromley, L. A., Ibid., 36, 312 (1944). Reavell, J. A., U. S. Patent 2,357,286 (1944). Rickerman, J. H., Trans. Am. SOC.Mech. Engrs., 67, 531 (1945). Rosenbaum, A. G., Elec. World, 121, 72 (1944). Ryant, C. J., IND. ENG.CHEM.,35, 1187 (1943). Schryber, E. A., Trans. A m . SOC.Mech. Engrs., 67, 683 (1945). Schumann, E., Wdrme, 66, 169 (1943). Schware, M. W., Chem. & Met. Eng., 51, No. 5, 120 (1944). Stoever, H. J., Zbid., 51, No. 5, 98 (1944). Stout, L. E., Caplan, K. J., and Baird, W. G . , Trans. A m . Znst. ” Chem. Engrs., 41, 283 (1945). Strom, 9. G.. U. S. Patent 2,360,739 (1944). Tate, G . E., and Cartinhour, J., Trans. A m . SOC.Mech. Engrs., 67, 687 (1945).
Ten Broeck, Howard, IND. ENG.CHEM.,36, 64 (1944). Tiller, F. M., Chem. Products, 8, 35 (1945). Tsukhanova, 0. A., and Shapatina, E. A., Bull. amd. sci., U.R.S.S., 1943, No.’7, 62-72. January, 1946
ABSORPTION AND HUMIDIFICATION CONTINUED FROM PAQE
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by the enthalpy driving-force method is brought out. Lichtenstein pointed out t h a t taking the logarithmic mean driving force rather than the integrated value may result i n towers 20% too small, and he used a table of the integral for all possible design conditions. From some data on a slat-packed tower, he showed t h a t the transfer coefficient divided by the liquor rate is a function of the liquor-to-gas ratio which is nearly independent of the absolute gas and liquid rates. Hutchison and Spivey (16) presented data on natural- and forced-draft water cooling towers packed with triangular bars having a n open arrangement with a surface of only 2 sq. ft./cu. ft. and with a slat packing which is not fully described. T h e data were calculated as a heat transfer coefficient using the difference in temperature between the exit water and the wet bulb of the inlet air as the driving force, b u t sufficient d a t a are recorded so t h a t they could be recalculated on a n enthalpy driving force basis. EVAPORATION OF LIQUIDS. The evaporation of a liquid from a‘ plane surface into a tangential gas stream has received considerable experimental and theoretical treatment. When the evaporating surface is a plane suspended in the air stream, the air velocity is uniform at the upstream edge of the plate, but as the stream passes along the plate, i t is retarded at the surface and thus sets up a velocity gradient perpendicular t o the plate and a net outward flow of air from the plate. Pasquill (23)measured the rates of evaporation of bromobenzene from a strip near t h e leading edge of one 50 cm. downstream, and found the rate 40% higher downstream. The theory of eraporation into a gas stream in turbulent flow was amplified by Sutton ( S I ) . T h e theory neglects the laminar layer and assumes the velocity is a power function of the distance from the evaporating surface. To obtain the fully developed turbulent flow required t o check Sutton’s theory, Pasquill set the evaporating surface in the wall of the wind tunnel. Evaporation rates of bromobenzene, water, aniline, methyl salicylate, and furfural were measured from square, rectangular, and circular strips. B y substituting t h e diffusion constant for the kinematic viscosity in Sutton’s theory, the experimental results of Pasquill and Wade (35) could be predicted within 20%. Wade (36)had measured the rates of evaporation of water, acetone, benzene, toluene, ethyl acetate, trichloroethylene, and carbon tetrachloride from a n 8.9-cm. square pan with natural convection or in a tangential air stream up t o velocities of 10 ft./sec. An attempt to correlate the natural convection data on a dimensionless basis, as Sharpley and Boelter (19) and Hickox (11) did for water, would be interesting. The partial pressures were as high as 0.5 atmosphere, suggesting that the driving force should be the natural logarithm of the partial pressures of air on both sides of the film. COMMERCIAL ABSORPTION PROCESSES. Articles on this subject have value in indicating what methods are used for removing impurities from synthesis gases, although sufficient data are not recorded t o permit calculation of absorption coefficients. Hull (I4 described the drying of natural gas at 1000 lb./sq. in. with diethylene glycol in a bubble-cap column. Russell (166) also reported on the drying of natural gas with diethylene glycol. Howat (IS)reviewed the data in the literature on the mte of absorption of carbon dioxide in alkali carbonate-bicarbonate mixtures, ethanolamines, sodium hydroxide, and i n potassium carbonate solutions containing ammonia. Woolam and Jackson (38) outlined the development of a process t o convert the sulfur
INDUSTRIAL AND ENGINEERING CHEMISTRY
33
dioxide in the tail gases of a sulfuric acid plant to sulfur and arnmonium sulfate, by absorbing i t in a n ammonia solution and heating the mixture of ammonium salts. Thau (88) and Ilowat (18) reviewed the numerous processes for removing hydrogen sulfide from industrial gases. Descriptions of plants removing hydrogen sulfide with a sodium carbonate solution, ethanolamine, and the Thylox process were given by McFnddin (IQ), by Phillips (64),and anonymously ( 1 ) . Larlre (17') has given operating data on the absorption of naphthalene in oil from coke oven gas, and reviewed the types of absorbeis used for a very low ratio of oil t o gas. Oppelt and Munz (2%) reported laboratory experiments on the increase in viscosity and asphalt content of absorption oil caused by bubbling oxygen and hydrogen sulfide through the oil a t temperatures encountered in absorption and stripping. Kirkbride and Bcrtetti (16) measured equilibrium constants for methane, ethane, propane, butane, and pentane in paraffinic, naphthenic, and aromatic bbsorption oils a t about 85 F. and at pressures from 125 to 3000 lb./sq. in. The three types of oils were compared for removing pentane from a natural gas with regard t o oil circulation, methane absorption, and loss of oil in the outlet gas. CONCLUSION. The published papers on absorption and humidification represent only a small fraction of the advances in the field, Many of the data on the design and performance of absorption equipment in industry are never published. It is unfortunate that secrecy, inability to conduct tests on plant units, and the failure of management to understand how little is really understood about diffusional processes have limited the published material. LITERATURE CITED
Anonymous, Ind. Heating, 11, 410-14 (1944). Arnold, J. H., Trans. Am. Inst. Chem. Engra., 40, 361-78 (1944).
Bain, W. A., Jr., and Hougen, 0. A,, Ibid., 40, 29-49, 389407 (1944).
Boehmer, A. P., Refrig. Eng., 50, 329-37 (1945). Boelter, L. M. K., Trans. Am. Inst. Chem. Engrs., 39, 557-64 (1943).
Colburn, A. P., and Drew, T. B., Ibid., 33, 197-215 (1937). Cooper, C. M., Fernstrom, G. A , , and Miller, S. A., IND.EXG. CHEM.,36, 504-9 (1944). Foust, H. C., Mack, D. E., and Rushton, J. H., Ibid., 36, 517-22 (1944). Goff, J. A., and Gratch, S., Heating Piping Air Conditioning, 17, 334-48 (1945), Gross, W. F., and Simmons, C. W., Trans. Am. Inst. Chem. Engrs., 40, 1 2 1 4 1 (1944). Hickox, G. H., Proc. Am. SOC.Civil Engrs., 70, 1297-1327 (1944). Howat, D. D., Chem. Age (London), 49, 75-8,99-105 (1943). Ibid.,50, 243-9, 265-9, 285-8 (1944). Hull. R. H.. Petroleum Refiner. 24. 353-6 (1945). Hutchison, W. K.. and Spivey, E., SOC.Chem. Ind., Chem. Eng. Group Proc., 24, 14-29 (1942). Kirkbride, C. G., and Bertetti, J. W., IND.ENQ.CHEM.,35, 1242-9 (1943). Larke, R. H., Gas World, Coking Sect., 118, 17-20 (1943). Lichtenstein, J., Trans. Am. SOC. Mech. Engrs., 65, 779-87 (1943). McFaddin, D. E., Petroleum Reliner, 23, 347-9 (1944). Molstad, M. C., McKinney, J. F., and Abbey, R. G., Trans. Am. Inst. Chem. Engrs., 39, 605-62 (1943). Natta, G., and Mattei, G. F., Chem. Tech., 46, 201-4 (1943). Oppelt, W., and Munz, W., Oel u. Kohle, 39, 95-7 (1943). Pasguill, F., Proc. Roy. SOC.(London), A182,75-95 (1943). Phillips, H. L., Natl. Petroleum News, 36, R16-18 (1944). Russell, G. F., Petroleum R~finer,24, 139-42 (1945). Scheibel, E. G., and Othmer, D. F,, Trans. Am. Inst. Chem. E ~ Q ~40, s . ,611-53 (1944). Schoenborn, E. M., and Dougherty, W. J., Ibid., 40, 51-77, 389-92,402-7 (1944). Schutt, H. C., Petroleum Refinsr, 24, 249-53 (1945). Sharpley, B. F., and Boelter, L. M. K., IND. ENQ.CHEM.,30, 1125-31 (1938). Siegel, L. G., Heating Piping Air Conditioning, 17, 90-6, 104 (1945). Sutton, W. G. L., Proc. Roy. SOC.(London), A182,48-75 (1943). Thau, E. A,, OeZ u. Kohle, 40,208-20 (1944).
Tiller, F. A l . , arid Tour, It. S., Tram. Am. I n s t . Chem. Engrs , 40, 317-32 (1944).
Tour, R. S., and Lerman, F., Ibid., 40, 79-103 (1944). Wade, S. H., SOC.Chem. Ind., Chem. Eng. Group Proc., 24, 1-13 (1942).
Walthall, J. H., Miller, P., and Striplin, M. M., Jr., Trans. A m Inst. Chem. E ~ Q T S41, . , 53-140 (1945).
Wile, D. D., Refrig. Eng., 48, 291-301 (1944). Woolam, C. 9., and Jackson, A., Chem. Trade J., 116, 325-0 343-4 (1945).
Zhavoronkov. N. M.,Khimicheshaua Prom., 1944, No. 1 , 4-14, No 2, 12-19; Chem. Abs., 38, 3514, 4839 (1944).
FLUID DYNAMICS C O N T I F U E D F R O V PAQE
?
small ones, some control systems employed a condensate valve only; this expedient put full steam pressure on the reboiler and forced the single valve t o dissipate all of the pressure difference between the steam and condensate systems except t h a t lost through pressure drop in condensate lines. Operating experience forced modification of many such oversimplified installations where the phenomenon of the critical pressure ratio discussed in the previous paragraph tvas encountered. The flow problems where very low pressure drops for vaporliquid mixtures are controlling are typified by the design of onccthrough or natural-circulating-type vertical reboilers, employed in connection with high-pressure fractionation of normallv gaseous liquids. Such operations are carried out under pressure and temperature conditions approaching the critical, in which case the difference between vapor and liquid density becomes very small. Since the vertical position provides increased drivinq force over the horizontal in inducing circulation, it is preferred. Reliable data on the characteristics of such systems are not always available, and the allowable margin of error may bc exceeded unless a detailed analysis is made. BIBLIOGRAPHY
(1) (2) (3) (4) (5)
Allen, Petroleum Refiner, 23, 93-8 (July, 1944). Anonymous, Ibid., 24, 128 (May, 1945). Anonymous, Proc. Am. Petroleum Inst., 111, 20 (1939). Anonymous, Natl. Patroleurn News, 33, R403-6 (1941). Bain and Hougen, Trans. Am. Inst. Chem. Engrs., 40, 29-49
(1944). ( 5 8 ) Benjamin and Miller, Trans. Am. SOC.M e c h . Engrs., 1942, 657-69. (6) Binder, Product Eng., 15, 466-7 (1944). (7) Boelter and Kepner, IND.ENG.CHEM.,31, 426-34 (1939). (8) Chenicek, Natl. Petyoleum News, 36, R678-82 (1944). (9) Evering, Fragen, and Weems, 021 Gas J . , 43, 77 (Oct. 28, 1944). (10) Fowler and Brown, Trans. Am. Inst. Chem. Engrs., 39, 491 (1943). (11) Frey, Chem. & M e t . Eng., 50, 126-8 (Nov., 1943). (12) Gerhold, Iverson, Nebeck, and Kewman, Trans. Am. Inst. Chem. Engrs., 39, 793 (1943). (13) Gradishar, Faith, and Hedrick, Ibid., 39, 201-22 (1943). (14) Hankins, Engineering, 157, 158-60, 177-80 (1944). (15) Lobo, Friend, Skaperdas et al., IND.ENG.CHEM.,34, 821-3 (1942). (16) Murphree, Brown, Fischer, Gohr, and Sweeney,I b i d . , 35,768-73 (1943). (17) Murphree, Brown, Gohr, Jahnig, Martin, and Tyson. Trans. Am. Inst. Chem. Engrs., 41, 19-33 (1945). (18) Murphree, Fischer, Gohr, Sweeney, and Brown, Proc. Am. Petroleum Inst., 111, 24 (1943). (19) Newton, Dunbam, and Simpson, Trans. Am. Inst. Chem. Engrs., 41, 215-32 (1945). (20) Shoenborn and Dougherty, Ibid., 40, 51-77 (1944). (21) Simpson, Oil Gas J . , 44, 88-90 (May 12, 1945). (22) Simpson, Evans, Hornberg, and Payne, Proc. Am. Petroleum Inst., 111, 23 (1942). (23) Simpson, Evans, Hornberg, and Payne, Ibid., 111,24 (1943). (24) Watson, IND. ENG.CHEX.,35, 3 9 8 4 0 0 (1943).
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Vol. 38, No. 1
