Page 315 - APPLIED PROCESS DESIGN FOR CHEMICAL AND PETROCHEMICAL PLANTS, Volume 1, 3rd Edition

Mechanical Separations 285

ut, = Terminal settling velocity as calculated from Greek Spb~
Stokes Law, ft/sec
v = V, = Terminal settling velocity, in./min E = Void fraction of wire mesh, dimensionless
v, = Average velocity of gas, ft/sec = Fraction of dispersoid in swept volume collect-
vag = Terminal settling velocity of hydrocarbon ed on target
droplets in aqueous phase in bottom of vessel, 0 = Factor for establishing type of flow for
in./min decanters, Reference [32]
v, = Velocity down flow cha.nnel for continuous p = Viscosity of surrounding fluid, cpj except
where it is lb/ (ft-sec)
phase, ft/sec pc = Viscosity of continuous phase, Ib/(ft) (sec)
vd = Terminal setding velocity of a droplet, ft/sec pH = Viscosity of heavy phase, lb/(€t) (sec)
vhc = Terminal settling velocity of aqueous droplets & = Viscosity of fluid, cp
in hydrocarbon phase in top of vessel, in./min pL = Viscosity of light phase, Ib/ft sec
v, = Terminal settling velocity of particle under ~1 = Fluid viscosity, (lb mass) / (ft) (sec) = cen-
action of gravity, ft/sec tipoise/ 1488
vts = Terminal settling velocity of particle as calcu- pm = Milli-micron = 0.001 millimeter
lated from Stokes Law, ft/sec n: = 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, Ib/cu ft
pf = Density of fluid, lb/ft3 or kg/m3
V‘ = Vapor velocity entering unit, Ibs, per minute pL = Liquid density, Ib/cu ft
per square foot of inlet pipe cross section pd = Density of fluid continuous phase, lb/cu ft
Va = Maximum allowable vapor velocity across inlet pL = Density of light phase fluid, lb/cu ft
fa.ce Q€ mesh calculated by relation, ft/sec pp = Density of particle, Ib/cu ft
V,,, = Actual. operating superficial gas velocity, ft/sec ps = ps = True density of particle, lb mass/cu ft
or ft/min, for wire mesh pad py = Vapor density, h/cu ft
V, = Design vapor velocity (or selected design
value), ft/sec References
V, = Cyclone inlet velocity, average, based on area
4,‘ ft/ sec
V,, = Calculiated maximum allowable superficial gas 1. Alden, J. L., Design of Industrial Exhaust Systems, 2nd Ed.
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,, = Sepamtor vapor velocity evaluated for air-water 3. Bulletin ME-9-58, Metex Mist Eliminators, Metal Textile
system, ft/sec Corp., 1958, Roselle, N. J.
V,,, = Active volume of setder occupied by one of the 4. Carpenter, C. L., D. Ch. E. Dissertation, Polytechnic Institute
phases, cu ft of Brooklyn, 1951.
V, = 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.1.Ch.E. Journal, Vol. 1,1955, p. 549.
V,, = Settling velocity for hindered uniform spheri- 6. Chilton, T. H. and A. P. Colburn, “Heat Transfer and Pres-
sure Drop in Empty Baffled and Packed Tubes,” Part 11,
cal particle, ft/s or m/s “Pressure Drop in Packed Tubes,” Trans. Am. Inst. Chem.
Wi= Width ~frectangular cone inlet duct, ft 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 West 50th St.,
Figure 412 New York, N.Y.
zi = Interface of decanter liquids measured from 8. Engineering Manual, Centrifix Corporation, Cleveland, Ohio.
bottom, Figure 412 9. Friedlander, S. K., L. Silverman, P. Drinker, and M. W. First,
zi = Eight phase outlet measured from bottom of Handbook on Air Cleaning Particulate Bemoval, United States
decanter, Figure 412 Atomic Energy Commission, 1952, Washington, D. 6.
10. Kane, John M., Operation, Application and Effectiveness of Dust
Collection Equipment, Heating and Wentiluting August 1952.
11. Kane, John M., “Guideposts Tell How To Select Dust Col-
lecting Equipment,” Plant Engznem’ng, November 1954.
E, or 1 = Light phase 12. Montrose, C. F., “Entrainment Separation,” Chem. Eng., Oct.
H, or h = Heavy phase 1933.
C, or c = Continuous phase 13. Perry, John H., Ed. Chemical Engineer> Handbook, 3rd Ed.,
“Dust and Mist Collection” by C. E. &apple, 1950, McGraw-
D, or d = Dispersed phase Hill Book Co., Inc.
I = Liquid 14. Pollak, A. and L. T. Work, “The Separation of Liquid from
v = vapor or gas Vapor, Using Cyclones,” Amm Soc. Mech. Engrs. 64, 1942, p. 31.