Distillation Column Packing

1. Raschig Rings

●For random packing in a column having a diameter approximately ten times larger than that of a Raschig ring, a required quantity of rings is calculated by :
n=Quantity of rings in 1 m3

D=Diameter of Raschig ring

C=0.77 (Constant for random packing)
For packing Raschig rings, Lessing rings and other annular products in order, the constant C=1.0.

■ Materials
Stainless steel, iron, aluminum, copper

Pressure mmHg20304050607090


■ Characteristics
(Metallic Raschig Rings)
[1] High mechanical strength
[2] Light weight
[3] Uniformly layered with less probability of breakage
[4] High corrosion resistance
[5] Easy handling
[6] Applicable to columns of relatively large diameters
Diameter mm×Height mm×Wall Thickness mmMesh(pcs/m3)
5φ×5H×0.4t7,200,000 pcs
10φ×10H×0.3t770,000 pcs
12φ×12H×0.3t446,000 pcs
15φ×15H×0.5t230,000 pcs
20φ×20H×0.6t110,000 pcs
25φ×25H×0.5t50,000 pcs
35φ×35H0.5t17,000 pcs
40φ×40H×0.5t12,000 pcs
50φ×50H×2.0t6,160 pcs

2. Pall Rings


● A Pall ring has the same diameter and height, but is different from a Raschig ring in that several portions of the side wall are cut and bent inward so that a gas and a liquid can more efficiently come into contact with each other, achieving a lower pressure loss and a lower HETP than those of a Raschig ring. Pall rings are available in diameters of 12 mm (1/2 inch) or more.

Diameter mm×Height mm×Wall Thickness mmQty/m3Surface AreaVoid RatioDensity
12.7φ × 12.7H × 0.4t410,000430m2/m391.9%640kg/m3
15.8φ × 15.8H × 0.4t230,000370m2/m392.9%560kg/m3
25.4φ × 25.4H × 0.6t51,000210m2/m393.9%480kg/m3
38.1φ × 38.1H × 0.8t15,200140m2/m394.6%430kg/m3
50.8φ × 50.8H × 0.8t6,500110m2/m395.8%330kg/m3

3. McMahon Packing


■ Characteristics
[1] Applicable to columns of relatively large diameters
[2] High void ratio and low pressure drop
[3] High throughput capacity
[4] Easy packing
[5] Low cost
[6] Applicable both to laboratory and industrial uses

SizeMeshSurface AreaVoid RatioDensityHETP


4. Dixon Packing


■ Characteristics
[1] Very low HETP
[2] Low pressure drop
[3] Specifically advantageous for vacuum distillation
[4] Easily replaceable

● A flat section of thin wire mesh is formed into a cylindrical shape with one end curved in an in ward S shape to intersect the inner space, so that Dixon packing is also known as S-shaped partition packing.
By preflooding several times, a higher efficiency is achieved

SizeMeshSurface AreaVoid RatioDensityHETP