How to choose small tower diameter structured packing?

The selection of small column diameter structured packing should take into account the factors such as diameter ratio matching, structural characteristics, material adaptation and economy, etc. The specific strategies are as follows:

First, diameter ratio matching principle

Relationship between column diameter and packing size

Small tower diameter (such as D<300mm) should strictly follow the lower limit of D/d≥8 diameter ratio to avoid uneven liquid distribution or wall flow phenomenon. For example:

If the diameter of the tower is 200mm, the outer diameter of the packing should be ≥25mm (200/8≈25);

For easy plugging fillers such as step rings, the diameter ratio should be increased to D/d≥15.

Packing size selection

Small tower diameter preferred small size packing: such as DN25 or DN38 structured packing, can meet the diameter ratio requirements, but also reduce pressure drop.

Specific surface area balance: When a small tower diameter requires a higher mass transfer efficiency, a structured filler with a specific surface area of 250~350 m²/m³ can be selected (such as metal orifice corrugations), but the pressure drop needs to be balanced.

Second, structural characteristics adaptation

Blockage resistance is preferred

Corrugated packing (such as wire mesh corrugated) : pressure reduction (≤50 Pa/m), high separation efficiency, suitable for corrosive media.

Pulse packing: the flow channel alternately shrinks and expands, the blockage resistance is strong, and it is suitable for media containing suspended matter or easy polymerization.

Avoid large size grid packing: easy to lead to uneven liquid distribution, aggravate wall flow.

Hydrodynamic optimization

Low f number fillers (such as Henerwo Chemical mesh ripple f=20~30 1/m) : low pressure drop, high efficiency, suitable for vacuum distillation or heat sensitive material system.

High F-number fillers (such as grid f=80~100 1/m) : high flux, blocking resistance, but high pressure drop, suitable for high-load scenarios.

Third, material selection points

Corrosion resistance

Plastic fillers (PP, PVDF) : acid and alkali (pH 1~14), organic solvents, suitable for weakly corrosive media (such as wastewater treatment).

Metal filler (316L, titanium alloy) : resistance to high temperature and pressure and strong corrosion (such as hydrofluoric acid), but the cost is higher.

Ceramic packing: high temperature (>1000℃), but brittle, only recommended extreme conditions.

Temperature and pressure resistance

Small tower diameter equipment is susceptible to local overheating, it is necessary to ensure that the filler material temperature resistance (such as PP≤100℃, metal ≥300℃).

In high pressure scenarios (> 0.6MPa), metal or composite materials are preferred.

Fourth, economic considerations

Initial investment and operating costs

Plastic fillers: low unit price (about 1/2 to 1/3 of bulk fillers), but poor temperature resistance, need to be replaced frequently.

Metal filler: high cost (about 3 to 5 times of plastic), but long life (more than 5 years), suitable for long-term stable operation.

Pulse packing: low comprehensive cost, suitable for large processing capacity and frequent opening and stopping scenes.

Full life cycle assessment

Combined with mass transfer efficiency, pressure drop, maintenance frequency and other parameters, through small test verification (such as mass transfer coefficient, pressure drop curve) to determine the optimal scheme.

5. Recommended typical scenarios

Scenario Recommended Filler Type Key Parameter Reference source

Exhaust gas washing (weakly acidic) PP pulse packing specific surface area of 250~350 m²/m³, D/d≥8

Vacuum distillation (heat sensitive substance) metal wire mesh corrugated packing f=20~30 1/m, pressure drop ≤50 Pa/m

High pressure gas purification (such as desulfurization) metal orifice corrugated packing pressure ≥ 1.6MPa, opening rate of 8%~10%

Food Industry (Cleanliness requirements) PTFE structured fillers comply with FDA certification and are optimized for surface wettability

Sum up

The selection of regular packing of small tower should be based on the premise of diameter ratio matching. The corrugated or pulse packing with strong plugging resistance and low pressure should be preferred, and the comprehensive decision should be made according to the characteristics of medium and economy. In practical application, it is recommended to verify the performance through experiments, and optimize the design by referring to the manufacturer's technical parameter table.