Page 335 - Applied Process Design For Chemical And Petrochemical Plants Volume II

324 Applied Process Design for Chemical and Petrochemical Plants

Table 9-36A Calculate required column area and diameter using the
Mechanical Characteristics of Common Standard Packing maximum superficial vapor velocity, u,,l, and the actual
Styles (ACS Wire Mesh) vapor load.
.........
~ Convert the mass vapor load, G, (lb/hr) to the actual
ACS Number Strand Density, Pct vapor volumetric flo147, V, in ft3/sec. Divide by umax to
Packing of Diam., lb/ft3 Void Sp. Surf., obtain the minimum cross-sectional column area, A, ft2.
Style Strands In. (stainless) Vol. Ft2/Ft3
_. ....... ..... Correct this area by dividing the fraction of capacity at
X-100, S100* 12 0.0043 27.5 94.5 585 which the designer intends for the column to operate. A
X-200," S200 8 0.0043 20.1 96.0 426 value of 0.7 is recommended, unless some other consider-
*For Series X, standard style is X-200 (8 strands) ation suggests a different percentage.
For Series S, standard style is $100 (12 strands)
By permission of ACS Industries, Separations Technology Group, Bul. E A = V/u,, = column area, ft2
129 (1992). Final Column inside net area = AF = A/0.70 capacity factor

Calculate the column net inside diameter from the area
Table 9-36B values. Round to the nearest practical commercial column
Experimental HETP Values from Various Sources for diameter such as 12 in., 15 in., 18 in., 24 in., 30 in., 36 in.,
Packings Equivalent to Stainless Steel X-200 and in increments of 6 in. Then recalculate the actual
resulting vapor velocity.
Diam., Absolute HEW,
System In. mmHg In. or, A, = A/0.7, ft2 required (9 - 64A)
~ __
Methylcyclohexane & toluene 1.25 760 1.25-2.00 Column diameter = d-,
1.25 200 1.75-2.30 ft (9 - 64B)
Methylcyclohexane & toluene 6 200-760 2-3
18 200-760 4-6 Commercial size columns using Series X or Series S
Improved liquid distribution-. 18 200-760 3.5 packing will operate at full efficiency with liquid loads as
Methylcyclohexane & heptane 3 760 1.25-2 low as 5 gal/hr/ft2 column area, and sometimes less liquid
rate. They can operate satisfactorily exceeding liquid rates
Ethylene dichloride & benzene 12 760 479 of 2,650 gal/hr/ft2. See Figure 9-49.
Orthodichlorobenzene 1.23 50 1.23
& orthodiethylbenzene 1.23 10 1.63 HETP for ACS Series X-200 Structured Packing:
Phenol & orthocresol 4 7-25 2.M
(no distributor used) 4 85-100 2-3.5 1. If plant or pilot plant data are available, use it.
4 760 2-3.5 2. Table 9-36B presents references for packings equiva-
n-Hexanol & aniline 1.25 50-300 2.3-2.73 lent to the X-200 for the systems and conditions
Nitrobenzene & aniline 1.23 5 3.54 noted. See Figure 9-50.
n-Decanol & methyl naphthalene 4 3 5
(no distributor used)
10
n-Decanol & methyl naphthalene 4 3 4 5.0
Methanol & water 1.25 760 9 c I I I I I I I I I I I i I l I i I I II
I
....
By permission of ACS Industries, Separations Technology Group, Bul. B- 3 1.0
129 (1992). $ 0.5
(I
0
E 0.1
Table 9-36C E .05
Rough HEW Correction Factor for Diameter 1 I I I I I I I I 1 1 1 1
- ....... .~ .01
..
10 20 50 100
Column Diameter HETP Proportional to:
___ Operating load as percentage of maximum flood load
Below 2 in. 1.0
2 to 6 in. 1.5 Figure 9-49. Estimated pressure drop referenced to percentage of
6 to 18 in. 2.0 maximum flood load for structured wovedknitted wire mesh X-1 00
Over 18 in. 2.3 to 3.0 and S-1 00. Referenced to liquid of 60 Ib/fl?. To correct other liquids,
-. ..... .. ~ multiply AP from figure by ratio of actual liquid density to 60. Used by
By permission of ACS Industries, Separations Technology Group, Bul. E permission of ACS Industries, Inc., Separation Technology Division,
129 (1992). Bull. B-129 (1 992).