Page 317 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Mechanical Separations 285

u., = Terminal settling velocity as calculated from Greek Symbols
Stokes Law, ft/sec
v = \'i = Terminal settling velocity, in./min £ = Void fraction of wire mesh, dimensionless
Va = Average velocity of gas, ft/sec T) = Fraction of dispersoid in swept volume collect-
vag = Terminal settling velocity of hydrocarbon ed on target
droplets in aqueous phase in bottom of vessel, 8 = Factor for establishing type of flow for
in./min decanters, Reference [32]
vc = Velocity down flow channel for continuous µ = Viscosity of surrounding fluid, cp, except
where it is lb/ (ft-sec)
phase, ft/sec µc = Viscosity of continuous phase, lb/ (ft) (sec)
"ct = Terminal settling velocity of a droplet, ft/ sec
µH = Viscosity of heavy phase, lb/ (ft) (sec)
vhc = Terminal settling velocity of aqueous droplets u, = Viscosity of fluid, cp
in hydrocarbon phase in top of vessel, in./min µL = Viscosity of light phase, lb/ft sec
v, = Terminal settling velocity of particle under µ = Fluid viscosity, (lb mass) I (ft) (sec) = cen-
action of gravity, ft/sec tipoise/1488
v,., = Terminal settling velocity of particle as calcu- urn = Milli-micron = 0.001 millimeter
lated from Stokes Law, ft/sec 1t = 3.1416
V = Velocity of gas or vapor entering, ft/min p = Pd = Fluid density, or density of fluid in droplet, lb
V (separator)= Separator vapor velocity evaluated for the gas mass/cu ft
or vapor at flowing conditions, ft/sec Pc = Density of fluid continuous phase, lb/en ft
3
V' = Vapor velocity entering unit, lbs, per minute Pr= Density of fluid, lb/ft or kg/m 3
per square foot of inlet pipe cross section PL = Liquid density, lb/ cu ft
Pct= Density of fluid continuous phase, lb/cu ft
Va = Maximum allowable vapor velocity across inlet PL = Density of light phase fluid, lb/ cu ft
face of mesh calculated by relation, fl/sec Pp = Density of particle, lb/cu ft
Vaci= Actual operating superficial gas velocity, ft/sec Ps = p, = True density of particle, lb mass/cu fl
or ft/min, for wire mesh pad o, = Vapor density, lb/ cu ft
Vn = Design vapor velocity (or selected design
value), ft/sec References
Ve = Cyclone inlet velocity, average, based on area
1-\' ft/sec 1. Alden, J. L., Design of Industrial Exhaust Systems, 2nd Ed.
V max = Calculated maximum allowable superficial gas Industrial Press, 1940, New York, N. Y.
velocity, ft/sec, or ft/min wire mesh pad 2. Bulletin, Sales Book Sheet, DC-271, American Air Filter Co.,
V, = Superficial gas velocity, ft/sec 1953, Louisville, Ky.
V,a = Separator vapor velocity evaluated for air-water 3. Bulletin MF.r9-58, Metex Mist Eliminators, Metal Textile
system, ft/sec Corp., 1958, Roselle, N.J.
V,e, = Active volume of settler occupied by one of the 4. Carpenter, C. L., D. Ch. E. Dissertation, Polytechnic Institute
phases, cu ft of Brooklyn, 1951.
\'i = Settling velocity for single spherical particle, 5. Carpenter, C. L. and D. F. Othmer, "Entrainment Removal By
ft/s or m/s a Wire Mesh Separator," A .. I.Ch.E.Joumal, Vol. 1, 1955, p. 549.
Vts = Settling velocity for hindered uniform spheri- 6. Chilton, T. H. and A. P. Colburn, "Heat Transfer and Pres-
cal particle, ft/s or m/s sure Drop in Empty Baffled and Packed Tubes," Part II,
Wi= Width of rectangular cone inlet duct, ft "Pressure Drop in Packed Tubes," Trans. Am. Inst. Chem.
Engrs. 26, 178, 1931.
zh = Heavy phase outlet dimensions of decanter 7. "Cyclone Dust Collectors," Engineering Report, American
measured from horizontal bottom, shown on Petroleum Institute, Division of Refining, 50 \.Vest 50th St.,
Figure 4.-12 New York, N.Y.
z, = Interface of decanter liquids measured from 8. Engineering Manual, Centrifix Corporation, Cleveland, Ohio.
bottom, Figure 4-12 9. Friedlander, S. K., L. Silverman, P. Drinker, and M. ,v. First,
zi = Light phase cutlet measured from bottom of Handbook on Air Cleaning Particulate Renuroal, United States
decanter, Figure 4.-12 Atomic Energy Commission, 1952, Washington, D. C.
10. Kane, John M., Operation, Application and Effectiveness of Dust
Collection Equipment, Heating and Ventilating, August 1952.
Subscripts 11. Kane, John M., "Guideposts Tell How To Select Dust Col-
lecting Equipment," Plant Engineering, November 1954.
L, or I = Light phase 12. Montrose, C. F., "Entrainment Separation," Chem. Eng., Oct.
1953.
H, or h = Heavy phase 13. Perry, John H., Ed. Chemical Engineer's Handbook. 3rd Ed.,
C, or c = Continuous phase "Dust and Mist Collection" by C. E. Lapple, 1950, McGraw-
D, or cl = Dispersed phase Hill Book Co., lnc.
1 = Liquid 14. Pollak, A. and L. T. Work, "The Separation of Liquid from
v = vapor or gas Vapor, Using Cyclones," Amer. Soc. Mech. Engrs. 64, 1942, p. 31.