Heat Transmission by Condensing Pure and Mixed Substances on Horizontal Tubes C. G. KIRKBRIDE, Standard Oil Company (Indiana), Whiting, Ind.
H
EAT t r a n s f e r by con-
Data are reported on heat transmission by t r a n s m i s s i o n , but its use for densing vapors in the purposes is quite corncondensing pure and mixed hydrocarbons on t i e o i l i n d u s t r y can, in plicated unless further simplificaoutside of a horizontal tube. Vapors are congeneral, be divided into three tions are made. It is valid only densed f r o m both the saturated and superheated important cases-namely, the where the mass velocity of the condensation of h y d r o c a r b o n states ( 1 ) while free of noncondensable gases, vapor-gas stream is above the v a p o r s (1) w h i l e free of nontransitional velocity (6) which is (2) in the presence of noncondensable gases, and c o n d e n s a b l e g a s , ( 2 ) in the 500 pounds per square foot (3) simultaneously with sfeam. ,%lethods f o r presence of n o n c o n d e n s a b l e per hour (2450 kg. per square predicting heat transfer coeflcienis f o r these three gas, and (3) s i m u l t a n e o u s l y meter per hour). cases are presented. with s t e a m . E a c h of t h e s e No reliable information apcases is very common; neverData are also presented on heat transmission pears to be available in the literat h e l e s s , sufficient information ture on heat transfer data from t o j u i d s f l o w i n g inside of tubes, both in turbulent that could be used in a design condensing mixed vapors such as and modiJied viscous motion. _ _ is not available in the literapetroleum fractions or on simulture. taneous condensation of two imIn’ 1916 Nusselt (26) derived the theoretical equation, miscible liquids. Accordingly, the work reported in this paper was undertaken in an attempt to obtain sufficient data to h = 0.725 permit design calculations for condensing hydrocarbon mix(to - t J 4 tures, saturated or superheated, pure or mixed with nonconfor the coefficient of heat transfer, h , when a vapor of one densable gases or steam. Information of secondary importance component is condensing on the outside of a horizontal tube of was obtained for liquids in forced convection through tubes. diameter, D. It was assumed that the thermal conductivity, APPARATUS k , the density, p, and the viscosity, p, could be evaluated a t The apparatus (Figure 1) consisted primarily of three the arithmetic mean of the tube wall temperature, t t , and the condensate film surface temperature, t,; g is the acceleration parts: a small pipe still to vaporize the hydrocarbons, a due t o gravity. A11 variables must be expressed in consistent single-tube horizontal condenser to condense a portion of the vapors, and a small box condenser containing three separate units. Kusselt’s paper was not abstracted in English, so hfonrad coils for condensing and cooling the three different streams and Badger (22) have presented it briefly. They applied leaving the test condenser. Equation 1 t o the work of McAdams and Frost ( 1 9 ) , Morris The hydrocarbon t o be vaporized and condensed was kept in Othmer (26), Clement and Garland ( 5 ) , storage tanks A from which it was pumped by a small gear pump and Whitman (H), and Webster (28). Good correlation was observed. More to the pipe still. Here it was vaporized and passed to vapor recently Lawrence and Sherwood (18) applied Kusselt’s equa- separator A . The vapors entered tangentially at a high velocity, any unvaporized liquid being thrown to the wall and draining tion t o steam. Apparently it predicted values within the from the bottom by gravity. Data were not taken while liquid experimental error. Fas draining from the bottom. The vapor left the top of the The case of vapors condensing in the presence of non- separator and entered the annular space of the single-tube concondensable gases has been studied theoretically and experi- denser. A portion of the vapors was condensed, and both condensate mentally by Colburn and Hougen (6). Based upon the and uncondensed vapors entered vapor separator B. The theory of diffusion, they developed the equation, uncondensed vapor was removed from the top and condensed in a small coil in the box condenser from which it passed to drip 0.5 f V , M , tank B. The condensate in vapor separator B drained out of the K= bottom and passed through a cooling coil in the box condenser (2) to drip tank A . The cooling medium was pumped from storage tanks B through the single-tube condenser to the third coil in where K represents the net amount of condensable diffusing t o the box condenser and finally back to the storage tanks. When and nitrogen were used, they were admitted between the the condenser surface per unit area of condensing surface per steam still and vapor separator A . unit of time per unit of partial pressure difference from the The condenser consisted of one steel tube having an internal condensate film surface t o the main vapor-gas stream. The diameter of 0.937 inch (2.380 cm.) and an outside diameter of mass velocity of the vapor-gas mixture, Vm, the mean partial 1.313 inches (3.335 cm.). The tube length exposed to condensva ors was 98 inches (248.9 cm.) and was enclosed in a 2.5pressure of the noncondensable in the gas film, Pgt,the diffu- ing inch 6.35-cm.) standard pipe, the condenser tube extending sion constant, d, the viscosity of the vapor-gas mixture, k , through packing glands at the ends of the shell. The exposed and the density of the mixture, p, must be expressed in the portion of the condenser tube had four thermocouples brazed on units in which it is desirable to obtain K since the equation is the surface. Two of them were located one inch (2.5 cm.) from ends of the exposed tube length, and the other two, 24 inches dimensionally homogeneous. The friction factor, f ,and the the (61 cm.) from each of these. Small grooves were filed in the exmolecular weights of the vapor, M., and vapor-gas mixture, posed surface, and the couples, made of No. 20 iron-constantan wire, were held in these grooves and brazed over, the excess brass M,, are dimensionless. Equation 2 is a n important contribution to theoretical heat being filed flush with the tube surface. The condenser tube was continuous from the inlet of the calming section to the stirrer * The value presented b y Colburn and Hougen is 5.3 b u t this was shown which mixed the cooling medium upon leaving the condenser. t o be.erroneous by Lawrence and Hogan, IND.ENQ.CHEM., 24,1318 (1932). The calming section was 5 feet (1.5 meters) long, and the exten-
(
1324
I N D U S T R I A L A N D E N G I K E E R I N G C H E JI I S T R Y
December, 1933
TABLEI. DATAON
-CONDENSATE
I
Kun
tt
tc
t.
to
out
in
VAPORS CONDENSING
FREEOF
(Consistent English units) - ,
To still hcaled. hobs, Gal./min.
IMPURITIES
COOLINQ
MEDIUM
hcalcd. 1. hobsid.
1325
h 2 ti
fa
hobsvd.
k
Ir
C
0
1.00
Lb./hr,
X A T E R IA'SIDE O F T U B E AND B E N Z E N E VAPOR O U T S I D E
1 4 7 10 13 16 19 22 25 28, 31 34 37 41 46
120 136 111 132 119 120 126 118 124 125 134 130 113 122 125
178 178 178 178 178 178 178 178 178 178 178 178 178 178 178
178 178 178 178 178 178 194 178 178 184 247 180 178 248 200
50 59 68 77 86 95 104 113 122 131 140 149 159 169 179
212 170 158 181 169 160 163 171 157 163 178 149 174 175 160
234 234 234 234 234 234 234 234 234 234 234 234 234 234 234
257 237 235 249 235 234 235 240 235 243 243 235 234 235 236
1.25 2.04 1.19 1.92 1.21 1.08 1.65 1.06 2.14 2.02 1.73 1.73 0.96 2.50 1.77
284 312 276 305 283 287 316 293 292 303 338 304 290 315 325
253 369 249 310 242 253 353 262 308 314 356 270 244 381 332
1.12 0.85 1.11 0.98 1.17 1.13 0.90 1.12 0.95 0.96 0 95 1.13 1.19 0.82 0.98
91.0 85.5 69.0 82.0 84.0 81.2 73.5 75.5 79.2 78.5 79.0 81.2 72.0 71.0 81.0
98.5 102.0 77.3 98.0 91.5 89.0 83.2 84.0 88.0 87.3 98.0 97.0 80.5 82.3 90.5
5480 2640 5610 2500 5330 5280 5310 5190 5290 5290 2300 2300 5230 5290 5200
855 700 895 625 950 860 755 850 830 775 645 605 890 1030 950
2.60 2.46 2.74 2.50 2.54 2.58 2.67 2.63 2.60 2.60 2.54 2.52 2.69 2.69 2.58
45,100 24,100 40,200 22,200 45,400 43,900 40,700 40,700 43,000 43,000 20,000 20,200 38,700 39,200 34,100
19 1 156 205 139 212 192 172 189 185 172 144 135 204 237 2 12
1.00 1.00 1.00 1.00 1.00 1.00 1.00 1,OO 1.00 1.00 1.00 1.00 1.00
41,100 43.500 46:600 40,000 40,000 41,200 51,500 44,100 46,500 46,500 43,700 36,300 44,500 59,800 49.400
9,300 59,500 62,000 49,500 46,700 56,800 66,600 61,700 51,600 60,000 60,800 52,800 59,600 63,400 60,000
105 255 365 291 269 296 395 314 258 337 279 271 281 317 336
0.42 0.41 0.41 0.41 0.40 0.41 0.42 0.41 0.41 0.41 0.41 0.40 0.41 0.41 0.41
22,200 40,600 41,600 47,200 52,800 43,200 45,800 45,100 43,500 45,800 46,200 41,400 46,700 47,100 43,000
.... .. .. .. .. .. .. .. ..
60 60 50 78 81 55 51 58 73 97
0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45 0.45
19,800 19,600 17,200 22,700 23,600 18,300 16,500 18,700 21,600 24,800
.. .. .. .. .. .. .. .. .. ..
66 81 123 129 130 123 116 108 129 90
0.45 0.45 0.45 0.48 0.49 0.49 0.47 0.48 0.48 0.48
29,800 33,000 42,700 39,800 39,700 36,700 40,800 37,300 42,800 31,100
1.00
BENZENE INSIIIE O F T C B E A N D CLEANERS' N A P E T H A V A P O R OGTSIDEl
495 369 312 460 377 394 320 42 1 286 480 417 342 283 258 255
1.23 1.15 0.77
1:58 0.79 1.44 0.96
..
1:OB 0.96
.. .. ..
358 253 234 279 254 248 238 262 228 262 270 234 240 241 223
361 227 196 318 290 208 230 256 202 230 295 174 278 285 207
0.99 1.11 1.19 0.88 0.88 1.19 1.03 1.02 1.13 1.14 0.91 1.35 0.86 0.88 1.08
66.7 77.5 75.0 80.5 52.0 72.6 88.6 83.7 60.5 77.5 80.0 58.8 75.0 85.3 81.0
2.50 2.60 2.56 2.63 2.63 2.67 2.54 2.56 2.69 2.60 2.58 2.61 2.60 2.56 2.58
151.5 99.5 97.5 113.0 83.7 96.2 112.0 108.2 84.0 102.5 105.0 81.2 100.2 110.7 104.6
E S G I N E A R E D OIL I X S I D E OF TCBE AND O L E U M S P I R I T S V A P O R O U T S I D E
IZL __ 183 184 187 188 189 193 194 195 197 198
279 279 286 274 273 272 285 283 274 265
303 303 303 303 303 303 303 303 303 303
353 357 368 342 343 340 366 372 330 329
472 483 520 412 440 383 542 544 347 343
0.58 0.58 0.60 0.94 0.94 2.12 0.62 0.62 1.25 1.35
200 202 204 207 209 212 215 218 22 1 223
328 324 325 329 329 323 322 329 325 326
384 384 384 384 384 384 384 384 384 384
429 433 430 43 1 430 429 433 432 432 432
433 557 448 562 523 455 575 686 654 655
1.50 1.04 1.08 1.02 1.02 1.02 1.40 0.96 0.96 0.98
300 306 340 274 280 260 340 333 263 242
296 292 362 280 281 212 337 334 265 233
1.01 1.05 0.94 0.98 1.01 1.23 1.01 1.00 0.99 1.04
87.2 87.5 96.0 99.0 97.5 78.0 96.5 95.5 99.0 112.0
57 57 47 73 76 52 48 55 69 90
108.5 108.7 103.6 125.0 124.5 99.0 115.5 117.0 116.5 123.5
ENGIA-E A R E D 011, I N S I D E O F T U B E A N D P E R F E C T I O N O I L V A P O R O U T S I D E
1.07 1.13 0.79 0.88 0.85 0.95 0.96 1.02 0.92 1.25
75.5 96.0 108.5 130.0 132.5 131.5 100.0 113.0 108.0 127.5
sion to the stirrer ~ 7 : ~18 s inches (45.7 em.) long. The total tube length was accordingly 176 inches (447 cm.) The inlet temperature of the cooling medium w3s taken as it entered the calming section. As it left the test secticln, the motordriven stirrer mixed it thoroughly, and the outlet, temperature was taken. Observations made during blank runs indicated that temperature rises due to stirring could not be detected with the instruments used throughout the investigation. The vapor tem eratures Fere taken at the entrance, the center, and the exit of t l e condenser shell, with No. 20 iron-constantan couples, and the pressure on the condenser was determined by a manometer connected at the cent.er of the shell. The nitrogen and steam entering the condenser were measured by an accurately calibrated 0.03125-inch (7.94-mm.) diameter orifice. The condenser tube was removed a t regular intervals and cleaned with wire brushes, but no difference in data was detectable between the clean and dirty conditions. New thermocouples were installed each time, however, and checked. All thermocouple readings were made Kith a Leeds and Northrup semiprecision type potentiometer which read accurately to 0.1" F.
CONDENSING VAPORSFREEOF KONCONDE:SSABLE GAS I n Nusselt's mathematical discussion of condensing vapors (25), he presented in particular the special case of the condensation of saturated vapor. The Nusselt theory can be applied approximately t o the condensation of pure superheated vapors if it is assumed that the surface of the condensate film is a t the saturation temperature corresponding t o the existing pressure. Thus, if pure steam enters at one
88.5 110.5 145.0 171.5 173.0 169.0 144.0 153.5 154.5 140.0
5100 5070 2600 2000 2000 2000 1970 1920 1920 5190
62 77 115 119 120 113 108 101 120 84
0.000210 0.000212 0.000405 0.000494 0.000471 0.000471 0.000506 0.000508 0.000508 0.000188
atmosphere and any degree of superheat, the condensate film surface will be essentially 212' F. (100' C.). BosnjakoviE (4) has attempted to prove that this is not true. H e chose a n example of steam at 325" C. and one atmosphere and, using a n equation that he derived, calculated the condensing temperature to be 93.3" C. The derived equation is seemingly quite correct but appears to be applied incorrectly. I n presenting a relation between molecules entering and leaving a liquid surface, for instance, he made his computations as if the liquid surface were being bombarded by molecules a t the same temperature as in the main vapor body. This assumption is quite unjustified. The molecules entering the liquid surface Tyould probably have an infinitesimal amount of superheat but certainly not 225' C. If the wall had been a t 94' C., for example, according to his calculations no condensation could have occurred. It appears that the conditions chosen could not exist. Consequently, for all engineering calculations the temperature of the condensate surface may be assumed equal to saturation temperature corresponding to the given pressure. I n the condensation of superheated vapors, both latent heat and superheat are conducted through the condensate layer. Hence in applying Equation 1, X is equal to T s where T is the latent heat of condensation and s is the sensible heat of the vapor above the condensing temperature. It is rather common for superheated vapor entering a condenser to leave
+
1326
IKDUSTRIAL AND EKGIXEERING
CHEMISTRY
PPARATUS
EETWEEN
HEAVILY X 6 Y
Vol 25, No. 12
LAGGED
VLN
FIGURE1. DIIGRAM OF A P P A R ~ T U S
in a superheated state and yet have condensation occur. In this case s must be the total superheat removed from both condensate and vapors per unit weight of condensate. The heat transfer coefficient is then easily predicted by Equation 1. The value of At, is equal to the difference between the saturation temperature and the tube surface temperature. The heat density, H , which is the amount of heat given up to a unit area in unit time can noTv be computed from Equation 3: H
= hat,
(3)
Equation 1 applies only to a single tube, but, in practice, banks of tubes are more common and for this case it has been found that the equation,
(4) gives good results. This was proposed by hferkel (20) and gives the average heat transfer coefficient for n horizontal tubes in a vertical plane.
200
The average tube temperature was computed from Equation 5: (5)
The values of t4 and t 5 in general were essentially the same. The amount of heat transferred was computed from the rate of flow of the cooling medium, the temperature rise, and the specific heat. The condensing temperatures of the four condensates at one atmosphere are 178°F. (81.1"C.) for benzene, 234" F. (122.2" C.) for Cleaners' Kaphtha, 303" F. (150.6"C.) for Oleum Spirits, and 384" F. (195.6" C.) for kerosene (Figure 5 ) . A constant temperature of condensation is theoretically justified provided the condensate nhich forms on the tube from inlet to outlet is identical in composition. This condition was approached very closely by maintaining a sufficiently high vapor velocity. I n other words, the composition and vapor pressure-temperature relationship of the vapors entering and leaving the condenser were essentially the same. It mas observed that the lightest fraction-namely, Cleaners' Naphtha-produced the widest deviation. A typical set of A. S. T. 11. distillations for Cleaners' Xaphtha are as follows:
130
INI- 10 20 30 40 50 60 70 SO 90 % % % % % % % % % bfAx*
80
.y$qz:
TIAL
Feed,
O
F.
c.
40
Condeneate,
30
Vapor out,
' F.
C. F. C.
124 51 220 104 202 94
229 109 234 112 216 102
236 113 241 116 223 106
242 117 246 119 229 109
246 119 250 121 233 112
256 124 258 126 241 116
264 129 267 131 249 121
275 135 278 137 258 126
290 143 292 144 274 134
308 153 308 153 292 144
340 171 340 171 323 162
20
From pipe still distillation curves for the condensate and "vapor out," it is apparent that the two were not in equilibrium. The vapor a t the surface of the condensate film, of 1 / ! 1 I I I O I I I I l l l l l 6 I I I I 1111l I I I I i 1 1 1 1 course, was in equilibrium with the condensate on the tube IO00 2000 40W S E O 10033 20W3 40WO but it appears that much of the feed entering did not come in contact with the tube and no fractional part of it was conFLOWCURVE,VALIDFOR FIGURE2. TURBULENT densed. This point is confirmed by tests in which vapors D V / p > 2300 entered and left the condenser in a superheated state. There The study of vapors condensing free of impurities was made must have been a film of saturated vapor next to the conby condensing benzene, Cleaners' Kaphtha (58" A. P. I ), densate film which was in equilibrium with the condensate Oleum Spirits (47.9" A. P. I.), and kerosene (42.4' A. P. I.). on the tube, but the superheated vapor outside of this satuThere were 48 runs made with benzene, 131 with Cleaners' rated vapor film could not have been in equilibrium with the Xaphtha, 16 with Oleum Spirits, and 25 with kerosene. Fifty condensate. It has been customary in the past t o assume equilibrium of these runs were chosen a t random and are presented in Table I. The observed heat transfer coefficients were com- between the vapor and condensate leaving partial condensers pared with Equation 1, the maximum deviation between used in connection with fractionating equipment. It seems, the observed and predicted heat transfer coefficients in all of however, that a design may be in considerable error by making such an assumption. the 220 runs being 35 per cent and the average 13 per cent. ID
I N D U S T R I A L A N D E N G I N E E R I K G C H E RI I S T R Y
December, 1933
SIMULTAKEOUS CONDENSATION OF IMMISCIBLE LIQUIDS I n designing petroleum refining equipment, the case of simultaneous condensation of steam and hydrocarbons is important. The literature offers no means of predicting coefficients of heat transfer for this case; a method is therefore outlined herein. There is a possibility that drop-forming condensation occurs which complicates the problem, but the method presented below agrees fairly well with the data. It was assumed that Equation 1 could be used to compute the heat transfer coefficient for each component as if it were condensing alone. The average coefficient wa3 then computed from the equation:
which is a weighted average of the coefficient for steam, ha, and the other component, h,, as computed from Equation 1. The coefficients are weighted according to the amount of heat received per unit time from the steam, Q,, and the other component Q.. Advantage is also taken of the fact that, upon condensation of two or more components, there is only one temperature at which condensation can occur for each condensing pressure. I n order to obtain the condensing temperature for two components which are immiscible in the liquid state, it is necessary to know the vapor pressure-temperature relationships for each and the total pressure a t which condensation is to take place. The condensing temperature is that temperature a t which the sum of the partial pressures of each component is equal to the total pressure. It should be pointed out that quite a large partial pressure gradient is possible between the vapor mixture and the condensate film surface. For example, in the case of run 1 in Table I1 the partial pressure of steam a t the condensate film surface is over seven times that in the vapor mixtures. The steam was acting similarly to a noncondensable gas and a t the same time condensing. The experimental results appear in Table 11. There were thirteen runs made with benzene and three with Cleaners' Naphtha. A maximum deviation of 22 per cent and an average of 10 per cent were observed. The data were computed in the same way as those in Table I except, in the case of the condensing temperature which was obtained as described above. The agreement between predicted and observed coefficients is quite remarkable considering the possibility of dropforming condensation. This type of condensation is undoubtedly a function of the surface tension and the mass rate of condensation per unit area. This can be observed by condensing a light hydrocarbon such as gasoline on a glass tube and comparing it with the condensation of steam and also aniline. Gasoline nill form a condenfate film a t the lonest T.4BLE
11. DATAON
condensation rates because of its low steam and aniline nill form in drops surface tension. Nevertheless, upon densation rates of steam and of aniline
.
ti
P, In. Hg
tc
--
'9w
5001
2wo
io000 DV
20000
50000
F
FIGURE3. AGREEMENT OF DATAWITH DITTUSBOELTER EQUATION condense as a film on the tube. To obtain drop-forming condensation, it is necessary to have a highly polished surface which seldom exists in industrial practice. CONDENSING VAPORSIN PRESENCE OF NONCONDENSABLE GAS The problem of condensing vapors in the presence of noncondensable gas must be attacked from a rather different point of view from that for condensing vapors free of noncondensable gases. Consider a horizontal tube working under conditions where noncondensables are affecting the rate of condensation. Upon the tube surface there will be a film of condensate, and upon the condensate film surface there will be a film of noncondensable gas. The condensing vapors must diffuse through this gas film before they can condense. The important factor, then, is the rate of diffusion of the condensable vapor through the gas film. If the mass transfer rate can be computed, it is relatively simple to express it as a heat density. Using this theory, Colburn and Hougen (6) derived Equation 2 which can be used t o compute the mass transfer coefficient. Once the value of I< is determined, the value of H can be computed from the dimensionless equation, where AP
=
H = KXAP (7) partial pressure difference of the condensable across the gas film
This neglects the sensible heat of the noncondensable gas which gives slightly more conservative results. The sensible heat of the gas should be included when important.
S I A l K L T A S E O U s cOXDEXS.4TIOiV OF IhlMISCIBLE
(Consistent English units except where noted) CONDEHSATE-VAPOR STEAMq10 ha ho c. ' ohoalcd. Lb.1 in calcd. calcd. CIS h c d o d . hobsvd. hobsvd. hr. tl
k
%
surface tension, but owing to their high increasing the conthey can be made to
50
Run
1327
LIQ~IDS
COOLING MEDIUM
%
Q
hobsrd.
h@ k
43,600 45,500 41,700 45,000 45,000 60,600 53,800 53,800 48,200 42,500 42,500 42,500
1150 1200 1100 1125 1135 1780 1580 1680 1420 1420 1520 1420
256 267 245 251 253 397 352 375 316 316 339 316
1.87 1.87 1.86 1.87 1.87 1.94 1.82 1.82 1.82 1.80 1.80 1.80
42,500 42,500 43,200 45,900 45,900 45,900
415 373 398
364 327 344
1.94 1.93 1.93
54,000 56,800 56,800
t2
CP
o
(x>
a7 '
P
WATER INBIDE OF T U B E AND MIXTURE O F BTEAM AND B E N Z E H E V A P O R OCTSIDE
1 2 3 4 5 6 7 8 9 10 11 12
119 119 120 120 118 120 125 124 124 122 121 122
29.5 29.5 31.0 31.0 31.0 30.5 31.5 31.5 31.5 31.5 31.5 31.5
156 156 158 158 158 157 159 159 159 159 159 159
4.6 31.2 15.7 15.7 15.7 68.0 72.6 21.0 21.0 12.0 12.0 12.0
13 14 15
139 146 146
31.0 30.8 30.8
185 184 184
7.0
167 167 256 280 290 200 210 267 295 347 360 367
1600 1600 1610 I610 1610 1600 1610 1680 1690 1690 1690 1690
320 320 337 340 340 330 340 347 350 355 355 355
25.60 24.10 12.95 12.95 12.95 7.10 5.35 5.35 5.35 8.75 8.75 8.76
372 428 427 430 430 488 540 558 560 493 493 493
421 439 392 423 402 584 565 550 493 410 400 410
0.88 0.97 1.09 1.02 1.07 0.84 0.96 1.01 1.14 1.20 1.22 1.20
4900 4900 4690 4690 4690 4850 4680 4680 4680 4830 4830 4830
84.4 83.0 85.7 83.4 84.0 75.0 88.0 88.0 89.0 91.7 91.7 91.7
93.3 92.3 94.6 93.0 93.6 87.5 99.5 99.5 99.3 100.5 100.5 100.5
42,400 42,400 41,000 40,500 40,500 38,400
BENZENE INSIDE OF TUBE AND MIXTURE OF STEAM AND CLEANERS' NAPHTHA VAPOR OUTBIDE
7.5 7.5
342 351 351
1600 1680 1680
280 295 295
13.70 8.60 8.60
280 295 295
309 357 376
0.91 0.83 0.78
4400 4470 4470
68.9 74.2 74.2
91.0 95.0 96.0
39,800 38,100 40,000
I N D U S T 1% I A L AS D E S G I K E E R I N G C H E 31 I S T R Y
1328
T’ol. 25, Xo. 12
TABLE111. DATAo s COXDESSATION OF VAPORSIN PRESENCE OF NONCOSDENSABLE Gas
Run
ti
P, I n . HQ
te
(Consistent English units except where otherwise noted) CONDENSATE-VAPOR-GAS .,-Liquid Hcalcd. tu to gz NZ to out still in out in Vm Honlcd. Hobsvd. Hobsvd. ti tz Gal./min. yo 70 B. t . u . / s q . f t . / h r .
COOLIXG MEDIUM c11
Q
Lb./hr.
0’37
hobwd.(%)
DV
hD
7 7
WATER I X Q I D E OF T U B E Ah-D M I X T C R E OF NITROGEN A N D B E N Z E N E VAPOR OUTSIDE
1 121 4 101 6 105 8 97 11 84 99 14 96 18 22 117 24 109 27 121
29.9 29.9 29.9 29.8 29.9 29.9 29.9 29.9 31.0 30.5
158 120 138 134 99 140 121 146 156 156
176 175 170 178 150 179 177 163 168 174
29 31 33 35 37 40 42 46 49 52
31.0 30.7 30.0 30.0 30.3 30.3 30.5 30.4 30.5 30.7
184 185 170 175 188 169 186 159 185 179
326 226 219 223 235 214 230 216 226 218
1.29 0.88 0.81 0.74 0.74 0.88 0.89 1.58 1.69 1.50
3.4 10.0 4.2 6.5 7.1 3.7 8.5 3.5 2.8 1.8
17.5 22.3 16.8 23.0 33.4 12.4 15.5 29.3 16.0 12.5
245 203 183 215 180 208 230 203 205 184
11,900 6,200 8,100 4,720 4,000 6,340 5,550 12,000 15,100 12,200
12,300 7,900 11,200 1?,900 ,,200 13,800 10,500 9,900 15,500 13,400
13,100 8,000 8,600 13,500 7,200 13,300 9,100 10,100 15,700 10,900
0.94 73.5 0.99 74.5 1.30 71.5 0.95 58.7 1.00 6 7 . 7 1.04 63.5 1 . 1 5 70.7 0.98 70.7 0.99 70.3 1.23 79.5
8 6 . 6 2810 8 2 . 5 2810 8 1 . 7 2360 7 0 . 5 3210 7 3 . 5 3480 7 0 . 8 5130 7 6 . 2 4610 8 3 . 5 2220 7 8 . 9 5120 9 2 . 9 2280
36,800 22,500 24,100 37,900 20,200 37,400 25,400 28,400 44,000 30,500
BENZENE I N S I D E OF T U B E A N D M I X T U R E O F SITROGEN AND CLEANERS’ KAPHTIIA VAPOR OUTSIDE
156 149 142 144 154 144 154 137 147 150
1.08 0.89 0.85 0.64 0.65 0.79 0.68 0.90 0.76 0.85
9.0 8.0 9.5 10.0 8.0 9.0 10.0 17.8 9.8 9.6
31.0 24.0 33.0 24.0 23.0 28.0 22.0 33.0 21.6 18.8
365 330 297 370 424 248 441 415 443 342
8,300 8,300 7,160 6,550 6,550 7,010 6,230 4,820 6,120 4,570
10,200 11,200 9,100 11,300 10,900 8,600 11,400 9,000 11,800 10,000
343 375 305 344 339 333 342 376 360 403
13,700 11,800 11,800 11,300 12,300 10,000 11,400 9,100 12,600 12,400
1.91 1.89 1.95 1.91 1.90 1.89 1.87 1.89 1.91 1.89
60,500 64.100 53;SOO 60,000 62,000 62,500 61,600 61,200 57,600 64,500
301 329 267 301 297 292 300 330 315 354
B E N Z E N E I N S I D E OF T U B E A N D M I X T U R E OF STEAM A N D CLEAKERS‘ N A P H T H A V A P O R O G T S I D E
I!zO in 56
148
31.0
188
225
0.89
Ha0 out
%
%
7.1
21.9
361
8,020
11,800
14,200
0.83
68.9
91.0
4400
39,800 350
1 . 9 4 54,000
E N G I N E A R E D OIL I N S I D E OF T U B E A N D M I X T U R E OF N I T R O Q E N A N D OLEUM S P I R I T S VAPOR O U T S I D E
57 58 60 61 63 64 67 68 70 71
246 246 247 246 219 222 206 239 255 255
30.5 30.5 30.3 30.3 30.0 30.0 30.0 30.1 30.1 30.1
259 269 258 257 227 230 210 255 270 270
313 310 315 315 288 289 274 312 343 345
73 74 75 76 77 78 79 80 81
283 299 295 270 260 260 270 291 296
30.5 30.5 30.5 30.3 30.3 30.3 30.3 30.3 30.3
320 338 335 300 288 288 317 328 332
356 398 392 365 356 359 394 405 409
0.62 0.62 0.62 1.19 1.19 1.19 1.19 1.41 1.55 1.55
%
%
17.0 5.2 17.5 17.5 34.0 34.0 32.0 18.4 11.6 11.6
33.1 10.1 36.0 36.0 42.0 42.0 42.0 32.5 27.6 27.6
377 377 380 383 325 329 342 439 499 495
4,600 4,600 4,200 4,200 3,000 3,100 2,200 5,600 5,400 5,300
4,400 4,800 4,400 4,800 3,700 3,200 2,700 5,000 6,400 6,900
1.05 0.96 0.95 0.88 0.81 0.97 0.82 1.12 0.84 0.77
81.5 76.0 83.0 77.0 85.0 79.5 86.5 80.5 91.0 86.5 91.5 87.5 99.0 88.5 71.2 65.0 97.0 71.2 72.5 100.0
5100 5100 5100 5100 5060 5060 1610 5080 1560 1560
307
kL -hDk DZVO 37 42 38 43 40 35 34 41 54 58
E N Q I N E A R E D OIL I N S I D E O F T U B E A N D M I X T U R E OF N I T R O Q E N A N D PERFECTION OIL V A P O R O U T S I D E
1.15 1.15 1.15 0.84 0.84 0.84 1.10 1.10 1.10
9.0 8.0 8.0 20.1 20.1 20.1 10.3 10.3 10.3
38.7 33.4 33.4 33.7 33.7 33.7 42.3 42.3 42.3
405 430 425 404 400 403 497 522 542
8,250 9,350 9,280 6,330 6,260 6,260 8,680 8,640 8,640
8,300 8,900 8,700 7,200 6,900 6,900 10,400 9,400 9,200
8,200 9,400 9,000 6,400 6,800 6,400 10,600 10,200 11,200
Equation 2 contains several unknowns which can be obtained only approximately in most cases. The friction factor can be computed from the equation (consistent units),
where the vapors are flowing parallel to the tubes. However, if the vapors are flowing perpendicularly over the condenser tubes as is frequently the case for reflux coils in bubble towers, the equation (consistent units) bDV, --0.24 f = 0.085 (7) which was developed by Monrad ( W I ) , is proposed. The value of b is 15, 1.7, 2.0, and 2.2 for n = 5, 10, 20, and 30 rows of tubes, respectively. The value of PQfis the most difficult variable to evaluate. It is defined by the equation:
= partial pressure of noncondeneable a t conwhere PCjs,P,,, densate film surface and in main gas-vapor stream, respectively
The value of Pcf8can be computed if the total pressure on the condenser and the partial pressure of the condensate film at its surface are known. The partial pressure of the condensate film surface can be computed by applying Xusselt’s Equation 1 or the modified Equation 4,
1.01 0.95 0.97 1.13 1.01 1.08 0.98 0.90 0.82
49.0 72.5 75.0 80.0 80.0 81.0 91.5 93.0 93.5
59.5 84.0 86.0 88.0 88.5 89.0 118.5 119.0 122
5050 5100 5100 4990 4990 4990 2390 2390 2390
51 62 61 51 57 54 92 80
87
0.000215 0.0002 1 0.00021 0.00021 0.000217 0.000450 0.000217 0.000450 0.000450
53 65 64 54 60 57 97 84 92
(4) hAt, = H = 0.725Atc
Equation 11 permits the calculation of the temperature drop across the condensate film. The tube temperature plus the temperature drop across the condensate film is the condensing temperature. By use of a vapor pressure-temperature curve, the vapor pressure a t the condensate film surface can be calculated immediately. The difference between this value and the total pressure is the pressure of the noncondensable a t the condensate film surface. The final variable to evaluate in Equation 2 is [1
+ 5.9 v 7 ([$I
PV
- lj]
In all the tests conducted in this investigation, it was observed that the value was very close to 0.75. Arnold (1) proposed the equation
+ I(T5/2 j 4-
0.0324
a=
(V,l/a
+
%‘/3)2
sq. ft./hr. or 10.8 sq. m./hr. (12)
as a means of predicting the diffusion constant, d , for two gaseous components having molecular weights of M v and M,, and molal volumes of vr and v,, cc. in the liquid state a t
December, 1933
INDUSTRIAL AND ENGINEEKIKG CHEMISTRY
their respective boiling points (T = O C. absolute). The Sutherland constant, C, can be computed from the equation: C = 1.47 F ~ T T BB ~ ~ (13) where TBr, Tgg = boiling points of respective components, in C. abs. O
The variable, F , is a function of the molal volume ratio of the two diffusing substances in the liquid state a t their boiling points :
3 or 0. V"
tJg
F
1 2 3 4 5 6 8 10 1.00 0,980 0.953 0.920 0.894 0.875 0.838 0.805
The method for predicting heat densities just described is a trial and error method. This is due to the fact that At, is a function of H . 200
1329
which gave the initial mass velocity. The amount of condensate caught in drip tank B was measured, and that plus the noncondensable and the amount of condensable leaving the vent as vapor gave the exit mass velocity. The temperature of the noncondensable leaving the vents from drip tanks A and B was taken, and this permitted the coniputation of the amount of condensable leaving with the noncondensable gas. The viscosities of the vapor-gas mixtures were taken equal to weighted averages of the viscosities of the components. The weights assigned were proportional to the percentage of the respective components. This gives results which are close enough since the viscosity enters only as the fourth root. Tmenty-seven runs were made with benzene, twenty-six with Cleaners' Kaphtha, sixteen u i t h Oleum Spirits, and nine with kerosene. The data from forty runs are presented in Table 111. Over the total seventy-eight runs made, a maximum deviation of 34 per cent and a n average of 12 per cent were observed. CONVECTION HEATTRANSMISSION
AD%
C
FIGURE 4. DATASHOWING EFFECTOF FREE CONVECTION
If the outline below is followed in a design, computations will be greatly simplified: Compute the duty on the exchanger. Fix the tube length. Assume heat density. Compute number of tubes based on assumed H . Find average value of n. Compute average temperature of fluid inside tubes. Compute inside coefficient. Calculate temperature drop from fluid t o tube wall, At = H / h (ET must be corrected to inside area). Compute Atc from Equation 11. Compute condensate film surface temperature by adding values obtained in steps 8 and 9 to that obtained in step 6. (If At through the tube wall is riot negligible, it must also be added.) Evaluate partial pressure of noncondensable at film surface from step 10 and the vapor pressure temperature relationship. Comtmte A P and Pot. sume it to equal 0.75. Compute K from Equation 2. Calculate H from Equation 7 . If value found in step 15 does not agree with that assumed in steD 3. assume a value verv close t o that obtained in 15 and repear, procedure.
Also, if the vapor-gas rate varies widely, it will be necessary to divide the exchanger into several parts for design purposes. Unfortunately the computations are more complicated than are generally encountered in heat transmission, so by use of the outline presented above considerable time can be daved. A nomographic chart has been constructed, but it does not seem wise to present it at this time. I n order t o compute the results of the investigation, the value of f was calculated by Equation 8. The log mean average mass velocity, V,, was determined from a knowledge of the rates a t the inlet and exit. The noncondensable gas and the hydrocarbon entering the system were measured
The data obtained for condensing vapors included information regarding heat transfer coefficients for liquids flowing inside of tubes both in turbulent and modified viscous motion. Both water and benzene were used in the turbulent region. T o prevent corrosion, 0.75 gram of sodium dichromate per liter of water was used. Good correlation of the data was obtained by using the coordinates as suggested by Morris and Whitman (25). The results are in good agreement with the work of Lawrence and Sherwood (18) as shown in Figure 2. A good correlation was also obtained (Figure 3) using the equation for heating as proposed by Dittus and Boelter (8). . For low values of D Y / p it seems that the Lawrence-SherI\ , wood c u r v e g i v e s 40 ' + ' i I results somewhat too 30, BENZENE
-
I ,
10 Sherwood, Kiley, and 8 Mangsen (27') p u b 6 l i s h e d r e s u l t s ob4 3 tained on the same 2 apparatus. These data were considerably lower than those IO' of Lawrence and SherT wood at 10W values FIGURE5 . V.4POR PRESSURE-TEMPERATURE RELTIO ON SHIP of D V / p and were in good agreement with the work of Morris and Whitman. The curve drawn in Figure 2 is a combination of the Morris and Whitman curve for heating and the Lawrence and Sherwood curve. The data in the modified viscous region were taken with Engine A Red Oil (26.3' A. P. I.). It was not possible. ho\t ever, to obtain good correlation by methods presented in the literature. The data are represented in Figure 4 mith the curve presented by Kirkbride and McCabe (16). The coordinates hD/k and kL/D2T'c are those suggested by Nusselt (24) and Grober ( I S ) . An unsatisfactory correlation was also obtained from the coordinates (tz- t J / ( t t - t J and Wc/kL which were suggested by Graetz (12) and used by Drew, Hogan, and NcAdams (9). The Xusselt-Grober coordinates are preferred since they can be more efficiently applied to industrial design problems. Consistent units must be used in Figures 2 to 4. Thus, if the reader expresses D in inches, T' in pounds per squarp foot per secmd, p in centi-
INDUSTRIAL AND ENGINEERING CHEMISTRY
1330
Vol. 25, No. 12
PHYSICAL PROPERTIES OF SUBSTANCES TESTED CLEANERS'
NAPETEA Figure 5
220 234 241 246 250 258 267 278 292 308 340
OLEUM
SPIRITS Figure 5
PERFECTION OIL
Figure 5
(104) (112) (116) (119) (121) (126) (131) (137) (144) (153) (171) . .
.
107
136
168
0.65 0.52 0.48
1.20 0.85 0.76
2.23 1.48 1.30
....
.
(5)
=
0.66(17) 0.48 0.42
142.0 34.5 2!.IJ
o.'ooQio:14)
.,. ,..
....
....
...
78
(Values used were computed from the equa-
tion given below)
IL
EXGINE BENZENE REDOIL
.....
0.01225
4.I
...
L a t e n t heat referencea (7) Thermal conductivity: t o F.
86' F. (30' C.) 140' E'. (60' C.)
.....
..... , p . ~ o ~ , 6 011 + 0.0003 ( t ..... . . . . ,.
.
their assistance and suggestions. Also thanks are due Allan P. Colburn of E. I. d u Pont de Nemours & Company for his constructive criticism.
d
f 9 h
H
k
K L M n
P Q r S
t 1
= = = =
= = =
= = =
= = =
o'.oii~io(rs) 0.01977 0.0217
SOMEKCLATURE' heat capacity, B. t. u./' F./lb. Sutherland constant diameter, ft. diffusion constant, sq. ft./hr. friction factor in Fanning's equation, dimensionless acceleration due to gravity, ft./hr. film heat transfer coefficient, B. t. u./O F./sq. ft./hr. heat density, B. t. u./sq. ft./hr. thermal conductivity, B. t. u./ft./O F./hr. mass transfer rate, lb./sq. ft./(lb./sq. ft.)/hr. length of tube, ft. molecular weight, dimensionless number of tubes in vertical row, dimensionless pressure, lb./sq. ft. duty, B.t.u./hr. latent heat, B. t. u./lb. sensible heat o,f vapor, B. t. u./lb. temperature, F.
In consistent English units except
and #, as noted.
.....
..... .....
- 32)l (7)
(Same a8 oleum apiritr, etc.) 0.0887(17) ..... 0.0875
.....
.....
ACKNOWLEDGMENT The writer is indebted to C. C. Monrad, E. W. Thiele, and W. G. Whitman of the Standard Oil Company (Indiana) for
= = = =
0.'00953(24) 0,01683
.....
poises, k i n B. t. u. per foot per F. per hour, h in B. t. u. per square foot per F. per hour, L in feet, and c in B. t. u. per O F. per pound, it will be necessary t o multiply his values of bdlk, c p / k , D V I p , and kL/DZVc by 0.0833, 2.42, 124, and 0.04, respectively, in order to use these figures. Undoubtedly natural convection is much more important than has previously been assumed. At higher velocities where the effect of natural convection was less, the data are in agreement with the curve in Figure 4, but a t lower velocitiex the relative effect of natural convection was great and poor correlation resulted. The heat transfer rate for natural convection is probably a function of the Grashof and Prandtl groups (20) which are D3ppzAtg/p2 and c p / k , respectively. The author was not able t o find any published results for natural convection inside of horizontal tubes. Until this problem has been studied, it will be difficult to correlate data on modified viscous motion.
C D
..... 1,124 0.684 0.560 0.287
M
(6)
=
NITROQEN
s p . gr. a t T B and
Sp. heat: Liquid references Vapor references
C
WATER
Figure 5 ( 1 7 )
T V V
W
2
P
x I*
P
= temperature, O F. (abs.) = mass velocity, lb./sq. ft./hr. = molal volume of liquid a t boiling point, cc. = weight rate, lb./hr./tube = viscosity, centipoises = thermal expansion coefficient (volumetric), = r s, B. t. u./lb. = viscosity in consistent units, lb./ft. hr. = density, lb./cu. ft.
+
I/' F.
SUBSCRIPTS: B = boiling point C = condensate film surface calcd. = predicted = noncondensable at condensate film surface cjs = equivalent diameter computed from hydraulic rae dius = gas ij = gas film = gas-vapor mixture = liquid = mean m mgs = main gas stream obsvd. = observed 0 = other component S = steam T = total t = tube V = condensable vapor 1 = inlet cooling medium 2 = exit cooling medium 3, 4,5, 6 = tube temperatures from inlet to exit
?
LITERATURE C I T E D
(1) Arnold, IND.EKG.CHEW,22, 1091 (1930).
(2) Bahlke and Kay, Ibid., 21, 942 (1929). (3) Ibid., 24, 291 (1932). (4)Bosnjakovi6, Forsch. Gebiete Ingenieurw., A3, 135 (1932). (5) . . Clement and Garland, Univ. Ill. Eng. Expt. Sta., Bull. 40 (1909). (6) Colburn and Hougen, Univ. Wie. Eng. Expt. Sta., Bull. 70 (1930). (7) Cragoe, Bur. Standards, Miscellaneous Pub. 97 (1929). (8) Dittus and Boelter, Univ. CaEif. Pub. Eng., 2, 443 (1930). (9 Drew, Hogan, and McAdams, IND.EXQ.CHEM.,23, 936 (1931). (lo{ FitsSimons and Bahlke, Am, Petroleum Inst. Proc. 10th Ann. M e e t i n g , 11, No. 1, Sect. 111, 70 (1930). (11) Fortsch and Whitman, IND.ENG.CHEM.,18, 795 (1926). (12) Graets, Ann. Physik, 18, 79 (1883); 25, 337 (1885). (13) Grober, "Die Grundgesetze der Wirmeleitung und des Warmeuberganges," pp. 179-87, Springer, 1921.
December. 1933
INDUSTRIAL AND EXGINEERING CHEMISTRY
(14) International Critical Tables, Vol. I11 and V, McGraw-Hill, 1927. (15) Kirkbride and hfoCabe, IKD.ESG. CHEM.,23, 625 (1931). (16) Kraussold, Forsch. Gebiefe I n o e n i e u r w . , d3, 21 (1932). (17) Landolt-Biirnstein, Phys. Chem. Tabellen, Springer, 1912. (18) Lawrence and Sherwood, ISD. ESG. CHEM.,23, 301 (1931). (19) RlcAdams and Frost, I h i d . , 14, 13 (1922). (20) hlerkel, "Die Grundlagen der ~ ~ ~ i r m e ~ ~ b e r t r a g l p. i n g140, ," Theodor Steinkoyff, Dresden and Leipzig, 1927. (21) hlonrad, IXD. ESG. CHEX, 24, 505 (1932). (22) Monrad and Badger, I b i d . , 22, 1103 (1930).
(23) (24) (25) (26) (27) (28)
1331
Morris and Whitman, Ibid., 20, 234 (1928). Kusselt, 2. Ver. deut. Ing., 54, 1154 (1910). I b i d . , 60, 541 (1916). Othmer, IKD.ESQ. CHEY.,21, 576 (1929). Sherwood, Kiley, and Mangsen, Ihid., 24, 273 (1932). Webster, Trans. I n s t . Engr. ShipSuilders, Scot., 57, 58 (1913).
REC&VEDM a y 13,1933. Presented before t h e Division of Petroleum Chemiatry at t h e 85th Meeting of t h e American Chemical Society, Warrhington, D. C., March 26 t o 31, 1933.
Studies in Distillation 11.
Liquid-Vapor Equilibria in t h e Systems Ethanol-Water, MethanolWat,er, and Acetic Acid-Water'
L. VALL LACE CORNELLAND RALPH.E.
fiIONTONNA,
University of Minnesota, h'hneapolis, Minn.
The nieihod of Rosanoff, Bacon, and White the i n d i c a t e d level in a suithas been used for the determination, at atmosable l i g h t oil, held a t a temmental study of the plate perature high enough t o efficiencies Of a pheric pressure, of the liquid-vapor equilibrium p r e v e n t condensation of the column for different binary mixtures, it was found that values Of systems ethanol-water, mefkanol- v a p o r s . The oil b a t h was considerably Over 100 per writ water, and acetic acid-water. This method is heated electrically, the temshown to be consistent and reliable. The equilibperature being controlled to were obtained for ethanol-water rium data obtained by it are when the most reliable equigraphi- *0.5 " c. b y t h e m e r c u r y bulb, M, through a relay. The librium data were used* The cally with all other data found in the literature. t e m p e r a t u r e w a s varied b y method of calculation was that raising or lowering the contact proposed hy McCabe and Thiele (12) and gave the plate requirements for theoretically perfect wire in the capillary tube, C. The heater, H , in the still, S, was of KO,24 nichrome wire operation; hence, it was indicated that the equilibrium data were not accurate. It was decided, therefore, to determine in the work on the alcohols, but for acetic acid-water it was the eauilibrium curve for ethanol-n-ater by a reLable method, necessary to change to KO.30 platinum wire. This heater was a small coil wound in the form and later also those for methanolof a spiral as indicated in Figure 1, .AY water and acetic acid-mater. and the l e n g t h s of wire were as uT0 AC. EXPCRIMEKTAL PROCEDURE f o l l o w s : KO.24 n i c h r o m e , 36 31L LEV inches (91.4 cm.); No. 30 platinum, There are a number of different _ _ - - - 11-- - -38 inches (96.5 cm.). Contact was methods for the determination of made with the mercury in the leadequilibriuni curves of binary liquid in tubes by means of loops of No. m i x t u r e s . d careful review of 24 platinum wire sealed through the literature indicated that the the glass. methods of Rosanoff and his coI n the work with the alcohols, the workers are r e l i a b l e . They are corks which were in contact with r e c o m m e n d e d by Y o u n g (23). hot vapors were covered with lead Rosanoff, Lamb, and Breithut (19) foil, but t h i s was r e m o v e d f o r a n d R o s a n o f f arid Easley (18) acetic acid-water. have developed an a c c u r a t e but The oil bath was heated to a temi n v o l v e d m e t h o d . Rosanoff, p e r a t u r e 2" to 5" C. above the Bacon, and White (17)have worked initial boiling point of the liquid out a less involved method based mixture to be tested. The apparaon an entirely different principle. tus was dried before each run by Young (22) states that these two drawing air through it for 10 to 15 methods have been found to give m i n u t e s . Then the temperature M results in good a g r e e m e n t , a n d inside the still was allowed to rise for this reason the simpler method to 4" to 5" C. below that of the oil of Rosanoff, Bacon, and White was bath, a n d a b o u t 130 ml. of the selected for this work. binary mixture were run into the A diagram of the apparatus is ALL DIMENSIONS inner boiling vessel, S, through A . shown in Figure 1. The still, of IN CENTIMETERS GLASS WORM The composition of this liquid had Pyrex g l a s s , w a s i m m e r s e d t o been determined previously. The CONDENSER * The first paper in this s e r i e s was addition of the liquid lowered the p u b l i e h e d by L. H. Shirk and R. E. FIGURE 1. APPARATUS FOR DETERMINATION OF Montonna, IND. ENQ.CHEM.,19, 907-11 COMPOSITION OF VAPORS FROM BOILING BINARY temperature shown by the still thermometer, and, as soon as this had (1927). SOLUTIONS
I
S THE course of an experi-
A
1
