Page 372 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

340 Applied Process Design for Chemical and Petrochemical Plants

P = NP = Power number, dimensionless, Equation 5-19 Greek Symbols
O
P pew = Plate coil width, one plate, ft
Ll.p = Pressure drop, psi 8 = Blending time, min
Ll.P = Pressure drop for open pipe, psi u, = Viscosity of liquids at wall surface, lb/ (sec) (ft)
0
Li.P, = Static mixer pressure drop in turbulent flow, psi µ = Viscosity in body liquid, lb/ (sec) (ft)
Q = Flow rate or pumping capacity from impeller, cu µ' = Fluid viscosity, centipoise, cp
ft/sec, or L3/t p = Density, lb/ cu ft
(): = Flow rate or pumping capacity from impeller, CJ = Standard deviation (statistics), or interfacial tension
2
cu ft/min r = Torque on shaft, consistent units, FL or ML /t 2
0
Qc = Volume entrained into circular jet from propeller <1> =Np= P = Power number, dimensionless
mixer, cu ft/ sec <I>= Power number, P 0, or ratio of power number to
Qg- = Flow, gal/min Froude number, NFr, to exponential power, n
R = Scale-up ratio
rw= Resistance of heat transfer barrier wall hr/ (sq ft) References
(°F)/BTU, = L//kw
Sg = Fluid specific gravity (not density), referenced to 1. Brown, R. W., M. A. Scott and C. Toyne, Trans. Inst. Chem.
water = l .0 Engrs., 25, 1947, 181.
s = Exponent of Schmidt group 2. Bulletin 74A, International Engineering, Inc., Dayton,
T = Tank diameter, ft, or L (consistent units), Figure 5-34 Ohio, 1954.
t = Residence or holding time, sec, or time of mixing 3. Chilton, T. H., T. B. Drew and R. H. Jebens, "Heat Transfer
U = Overall heat transfer coefficient, bulk mixing liquid Coefficients in Agitated Vessels," Ind. Eng. Chem., 36, 1944, 510.
0
to transfer fluid on opposite side of heat transfer 4. Cooper, C. M., G. A. Fernstrom and S. A. Miller, "Perfor-
wall (coil, plate,jacket), Btu/hr/sq ft/°F mance of Agitated Gas-Liquid Contactors," Ind. Eng. Chem.,
u = Velocity of mixed fluids through mixer, ft/sec 36, 1944, 504.
V = Volume, consistent units 5. Cummings, G. H. and A. S. West, "Heat Transfer Data For
W = Physical depth or height of turbine mixer, ft or in., Kettles With Jackets and Coils," Ind. Eng. Chem., 42, No.
consistent with other dimensions, Figure 5-34 11,2303, 1950.
or, W = Impeller blade width, ft 6. Dunlap, J. R. Jr., and J. I-I. Rushton, Heat-Transfer Coeffi-
cients in Liquid Mixing Using Vertical-Tube Baffles,
w = width of baffles in vertical tank, Figure 5-34. AI.Ch.E. Symposium Series No. 5, Vol. 49, l 953, l 37.
X = Distance from impeller source, not to exceed 100 7. Faust, I-I. C., D. E. March and J. H. Rushton, "Gas-Liquid
jet diameters, ft Contact by Mixers," Ind. Eng. Chem., 36, 1944, 517.
x = Mixing correlation exponent, or empirical constant 8. Fluid Agitation Handbook, Chemineer, Inc., Dayton, Ohio,
x = Arithmetic mean (statistics) 1956.
xi = Concentration of measurable variable 9. Folsom, R. G. and C. K. Ferguson, Trans. Arn. Soc. Mech.
Xm = Dimension of model Engr.,Jan. 1949, p. 73.
xp = Dimension of scale-up unit l 0. Johnson, A.I. and Chen:Jung Huang, "Mass Transfer Studies
xR = Ratio of dimensions on scale-up in an Agitated Vessel," A.I.Ch.E.Jour 2, 1956, P: 412.
Z = Overall liquid vertical height of mixing vessel, from 11. Lowenstein, J. G., "A Nomograph for Turbulence Mixers,
top liquid level to bottom (flat or dished or ellipti- Chem. Eng., April 7, 1958, P: 141.
cal), ft or in., consistent with other components of 12. Lyons, E. J. and N. H. Parker, "The Turbine As a Mixing
equations, see Figure 5-34 Tool," Chem. Eng. Prog., 50, 1954, 629.
z = Empirical constant 13. Oldshue, J. Y. and A. T. Gretton, "Helical Coil Heat Transfer
in Mixing Vessels," Chem. Eng. Prag. 50, 1954, 615.
14. Oldshue,J. Y., H. E. Hirschland and A. T. Gretton, "Blending
Subscripts of Low Viscosity Liquids With Side Entering Mixers," Chem.
Eng. Prag. 52, J 956, 481.
h = Heavy fluid 15. Quillen, C. S., "Mixing," Chem. Eng.,June 1954, 177.
l = Light fluid 16. Rushton, J. H., 'The Use of Pilot Plant Mixing Data," Chem.
r = Ratio of values of two conditions Eng. Prag. 47, No. 9, 1951, 485.
' = prime, to designate a different use of similar symbol 17. Rushton, J. H., "Mixers for Large Tank Blending," Pet. Ref
1 = Initial condition 33, 1954, 101.
2 = Second condition 18. Rushton, J. I-I., E. W. Cos ti ch and I-T. J. Everett, "Power Char-
f = Film acteristics of Mixing Impellers," Chem. Eng. Prag., Vol. 46, No.
8, 395 (Part 1) and Vol. 46, No. 9, 467 (Part 2), 1950.
i = Inside surface (heat transfer) 19. Rushton, J. H., R. S. Lichtmann and L. H. Mahoney, "Hear
o = Outside surface (heat transfer) Transfer to Vertical Tubes in a Mixing Vessel," Ind. Eng.
G = Gravity Chem. 40, 1948, 1082.
I = Inertia 20. Rushton, J. H. and J. Y. Oldshue, Mixing-Present Theory
R = Ratio and Practice," Chem. Eng. Prog., 49, No. 4, 1953, 161.
v = Viscosity 21. Rushton, J. I-I. and J. Y. Oldshue, "Mixing of Liquids," pre-
t = tube sented at A.I.Ch.E. meeting.June 1958, Philadelphia, Pa.