Tower Packing and Column Internals

Random packing

Random (dumped) packing is poured into the column and forms a bed with a high open volume. Larger pieces give more capacity and a lower pressure drop; smaller pieces give more surface area per cubic metre and better separation, at the cost of a higher pressure drop. Random packing also copes with moderate fouling better than structured packing, because its flow paths are larger and less regular.

• Metal rings and saddles — metal Pall rings, improved Pall rings, metal cascade mini rings, super mini rings, metal saddle rings, VSP rings, metal Raschig rings and double metal conjugate rings, for higher temperatures and services where plastics are not suitable.
• Plastic packing — plastic Pall rings, ladder rings, saddle rings, super saddle rings, Heilex rings, rosette rings, conjugate rings, Raschig rings, hollow spherical packing and polyhedral hollow balls: light and corrosion resistant for scrubbers, absorbers and cooling duties within the plastic’s temperature limit.
• Other media — graphite Raschig rings for strongly corrosive service, knit mesh packing, covering balls and hollow flotation balls, and ceramic multichannel bricks for catalyst carriers and heat media.

Structured packing

Structured packing is made of corrugated sheets stacked in blocks, so vapour and liquid follow regular inclined channels. It gives a low pressure drop per theoretical stage, which is why it is chosen for vacuum distillation and for revamps that need more stages in the same column height; its narrow channels make it less suited to fouling service. We supply metal orifice plate corrugated packing, metal wire mesh structured packing and mesh corrugated packing.

Column trays

Trays suit high liquid rates, columns that must be cleaned in place, and duties that need a wide operating range. Sieve trays are the simplest and cheapest but have the narrowest operating range; valve trays turn down further and resist fouling better than small-hole sieve trays; bubble cap trays keep liquid on the deck even at very low vapour rates, at a higher cost.

Liquid distributors and collectors

A packed bed only performs as well as its liquid distribution: uneven flow across large areas of the bed can cut packing efficiency sharply. We supply orifice-type distributors for smaller towers, weir-type distributors, pipe distributors and orifice/riser pan and plate distributors; between beds, liquid collectors gather the liquid for redistribution or draw-off.

Packing supports

The support plate carries the bed and must leave enough open area for vapour, or the column floods at the support before the packing reaches its capacity. Hump (gas-injection) supports and packing support grating grids are sized to the column diameter and bed weight.

Mist eliminators

Wire mesh demisters catch fine droplets, including droplets below 10 µm, in clean service at moderate gas velocity. Vane pack mist eliminators handle higher gas velocities, heavier liquid loads and fouling service with a lower pressure drop, and are most effective on droplets above about 10–40 µm.

What to send for a quotation

Send the column diameter and height (or a drawing), the service (distillation, absorption, stripping or scrubbing), the system and its operating temperature and pressure, vapour and liquid flow rates, the packing or tray type and material you use now, and the quantity — volume in m³ for random packing, number of trays or internals for each bed. If you are replacing existing internals, add photos and dimensions of the old ones. For a fuller checklist, see our guide Tower packing and column internals: what to specify.

Related

• Guide: tower packing and column internals — what to specify for new columns and revamps
• All products
• Contact us with your column data for a quotation