Plastic Tower Packing
A brief introduction to plastic tower packing.
Plastic Tower Packing
Plastic random packing is a core internal component in mass transfer and reaction processes in chemical engineering, environmental protection, and other fields, primarily manufactured through injection molding. It achieves a balance of lightweight design and corrosion resistance through the use of polymer materials (such as PP, PVDF, PTFE, etc.), and optimizes fluid distribution through structural innovation.
Structural Characteristics
Pall Ring: Rectangular windows on the wall with inwardly curved blades break liquid film flow, promote gas-liquid radial mixing, and reduce wall flow.
Step Ring: Height about half the diameter, with a conical flange at one end. The asymmetrical structure reduces ordered stacking, and the flange enhances local turbulence—a classic low-pressure drop design.
Conjugate Ring: A spherical or polyhedral structure formed by conjugately connected curved pieces, creating an open 3D network for multi-channel cross-flow and mixing.
Heilex Ring: Internal "cross" or "star" ribs are added inside the ring. The ribs break up large liquid droplets and reinforce overall structural strength.
Flower Ring: Multiple centrally symmetrical ribs/branches arranged radially. Large gaps between branches form tortuous yet unobstructed flow paths with strong clogging resistance.
Polyhedral Sphere: Usually a hollow sphere with surface windows or polygonal faces. The isotropic spherical structure ensures uniform packing, but liquid distribution is more random.
Core Characteristics and Performance Comparison
Packing | Type | Packing | Type | Packing | Type |
Pall Ring | Good radial mixing of gas and liquid, strong versatility | High | High | Medium | Medium |
Step Ring | Uniform pores, extremely low resistance | High | Very High | Low | Good |
Conjugate Ring | Thorough three-dimensional mixing, high mass transfer efficiency | Very High | Medium | Medium to High | Medium |
Heilex Ring | Internal ribs divide the liquid, enhancing turbulence and strength | Relatively High | High | Medium | Good |
Flower Ring | Smooth flow channels, extremely high void ratio | Medium | Extremely High | Extremely Low | Excellent |
Multifaceted Sphere | Isotropic, uniform and random packing | Medium | High | Low | Good |
Typical Application Areas
Environmental Engineering
Waste gas scrubbing / acid mist purification: Commonly use flower rings, polyhedral spheres, and step rings. Their low pressure drop, high throughput, and good clogging resistance make them suitable for dusty or scaling flue gases.
Wastewater aeration / biological treatment: Commonly use Heilex rings, conjugate rings, and Pall rings. They provide a high specific surface area for microbial biofilm and ensure efficient oxygen mass transfer.
VOCs absorption / removal: Commonly use Pall rings and step rings, balancing efficiency and processing capacity.
Chemical & Petrochemical Industries
Gas drying, decarbonization, desulfurization: Commonly use Pall rings and step rings for large-scale absorption processes.
Atmospheric / pressurized distillation: For thermoplastic media (e.g., certain organic separations), conjugate rings and Pall rings can be selected.
Extraction, resin regeneration: Commonly use polyhedral spheres and flower rings, utilizing their low flow resistance characteristics.
Special Scenarios
Highly corrosive environments (e.g., HF): Must use PVDF or PTFE Pall rings or step rings.
High-viscosity or foaming systems: Use high void fraction packings such as flower rings and polyhedral spheres to prevent flooding.
Selection Guide
Confirm primary process constraints
Pressure drop limits: For vacuum or energy-sensitive systems, prefer step rings and flower rings.
Anti-clogging needs: For media with particles, crystallization, or polymer formation, prefer flower rings, polyhedral spheres, or large-sized Heilex rings.
Corrosive environment: Determine chemical compatibility and select PP, PVDF, or PTFE material first, then choose a suitable structure.
Evaluate separation efficiency requirements
High-purity or high theoretical plates: Prefer conjugate rings and Pall rings.
Moderate efficiency needs (absorption, washing, rough separation): Can use Heilex rings, step rings, and polyhedral spheres.
Calculate processing throughput
For very high gas-liquid loads, the high throughput advantage of flower rings and step rings can reduce tower diameter and lower equipment investment.
Comprehensive trade-offs & safety verification
Temperature: PP ≤ 100°C, PVDF ≤ 140°C, PTFE up to 260°C. Ensure material softening point exceeds operating temperature.
Strength: In tall towers or harsh conditions, Heilex rings and conjugate rings offer better compression/deformation resistance due to internal support or mesh structures.
Summary
Plastic packing selection is a three-dimensional matching of process requirements, media characteristics, and packing structure-material performance. Pall rings and step rings are the default choices due to their excellent overall performance; conjugate rings and Heilex rings are suitable for scenarios requiring enhanced mass transfer or certain mechanical strength; flower rings and multi-faceted balls are specialized solutions for solving clogging and pressure drop problems. For more information, please contact us via email at annayu@169chem.net or WhatsApp at +8618909016373.