INDUSTRIAL AND ENGINEERING CHEMISTRY
544
TABLE 11. Boil-Up, M1./ Hour
21002200
COMPARISON O F
.
R 50/1
30/1 30/1 24/1 20/1 20/1 10/1 10/1 10/1 10/1 11/1 5/1 5/1 5/1
2950
10/1 10/1 10/1
1390
h(yr
-
y ) against time back t o t =
p‘ Mln. 25.5 15.5 5.2 4.2
10.5 3.5 8.25 4.58 3.67 2.75 1.835 4.5 3.0 1.0 5.50 1.835 5.50
0.623 0.621 0.621 0.608 0.588 0.591 0.527 0.524 0,527 0.521 0.541 0.464 0.463 0.463 0.512 0.506 0.510
to gave
R4-1
CALCULATED AND MEASURED VALUES OF
Mole Fraction of n-Heptane Meajured C+d. Y Y
0.618 0.586 0.592 0.609 0.567 0.573 0.513 0.510 0.521 0.511 0.539 0.460 0,453 0.456 0.499 0.500
0.526
a calculated
value for y ~ . This permitted calculation of T using Equation 2. Rewriting i t in logarithmic form for y = yl and t = tl and solving for ra In
ra =
- Yf - Y/ Yl
Y2
tl
(16)
The ratio ra/a yielded the value for r. The values of T and p for each run were calculated from Equations 8 and 9. Values for for each run were calculated from Equation 7. Efficiencies were read from the plots in Figure 2. The efficiencies in all cases were close t o loo%, inasmuch as all values of T were less than 0.3. High efficiencies were measured in all the experimental runs, and these are confirmed by the plot of calculated efficiencies in Figure 2. The conditions for the runs varied over the entire conventional operating range, and within this range 7 always remained small. A comparison of the calculated and measured ‘values of ?/ and values for measured efficiency and constants r, a, T , and p are given in Table 11.
AND
Vol. 43, No. 2
EFFICIENCY
Measured Efficiency,
%
112. -1 0.0076 0.0115 0.0096 0.0100 0,0115
94.0 98.9 98.9 98.3 94.9 96.0 92.5 90.5 92.5 90.0 98.5 96.5 92.8 92.0 88.0 85.0 85.0
0.0110 0.0136 0.0124 0.0118 0.0123 0.0106 0.0153 0.0136 0.0110 0.0098 0.0099 0.0087
1‘
17.7 17.1 15.5 12.9 14.1 13.2 13.8 14.3 13.1 13.5
11 .o
14.3 16.3 18.9 13.1 14.0 17.2
P
7
0.74 0.64 0.66 0.65 0.59 0.60 0.42 0.41 0.43 0.43 0.51 0.26 0.24 0.27 0.43 0.43 0.37
0.26 0.27 0.07 0.06
0.20 0.06
0.24 0.12 0.09 0.06
0.04 0.22 0.14 0.04 0.13 0.04
0.12
LITERATURE CITED
(I) Beatty, H. A., and Calingaert, G . , IND.ENG.CHEM.,26, 504 (1934). (2) Berg, C., and James, I. J., Chem. Elag. Progress, 44,307 (l948), (3) Carter and Johnson, U. S~Patent 2,251,185(July 29, 1941). (4) Cohen, K.,J . Chem. Phys., 8,588 (1940). (5) Collins, F. C.,and Lantz, V., IND.Exa. CHEM,,ANAL.ED.. 18, 673 (1946). ( 6 ) Coulson, E. A., J . SOC.Chem.Ind.. 64. 101 (1945). (7) Q’Brien, M.S. thesis. Pennsvlvania State Collese. 1948. (8) Oldroyd, D.M., and Goldbiatt, L. A., IND. E&: CHEM.,- 4 ~ 4 ~ ED..18.761 (1946). (9) PodbieIniak,i$. J., Ibid., 13, 639 (1941). (10) Swietoslawski, W., “Ebulliometric Measurements,” pp. 24-7, 33-5, New York, Reinhold Publishing Corp., 1945. RECEIVED July 3, 1950
Air Humidification Coefficients in Spray Towers-Correction L
The editors regret the substitution of an incorrect cut of Figure 1 in the paper “Air Humidification Coefficients in Spray Towers” ENCI. CHEM,42,2521 (1950)l. by Bonilla, Mottes, and Wolf [IND. The correct figure is shown here.
ACKh’OW LEDGiMENT
This work was performed under the Gulf Research & Development Co.’s multiple fellowship a t Mellon Institute. The authors thank D. J. Griffiths for his assistance in the experimental work. NOMENCLATURE
a = growth constant for approach to equilibrium a t total reflux E = reflux efficiency, Equation 11 EO = minimum reflux efficiency, Equation 14 r = ratio of decay constant to growth constant R = reflux ratio t to
= time
= = y = y1 = tl
y2
=
yo =
= YT = y/ = p = T TO
= =
period of one complete cycle duration of zero reflux in a cycle instantaneous overhead vapor composition, mole fraction overhead vapor composition a t start of zero reflux operation overhead vapor composition a t start of total reflux operation overhead vapor composition with continuous reflux operation mean overhead vapor composition with intermittent reflux overhead vapor composition a t total reflux equilibrium feed composition a dimensionless variable, Equations 9 and 10 dimensionless variable, Equation 8 maximum value for r to obtain reflux efficiency of at least EO,Equation 14
*
3
4
6
8 1 0
90
30
A P, Lb./Sq. Inch Figure 1. N o d e Water Capacity
0 A
Experimental Rated by manufacturer
40
.
