Distillation, absorption and stripping columns sit at the centre of refineries, gas plants and petrochemical units. Whether the job is a new column or replacing internals during a turnaround, the internals have to be supplied to the column’s process design, fit through its manways and arrive before the shutdown starts. This guide explains the main types of internals and what to include in an enquiry.
Packing or trays?
The choice between packing and trays, and the specific type, is made by the process designer from the column’s hydraulics, pressure drop, fouling tendency and turndown. The supplier’s job is to manufacture exactly what the design calls for. If your column has a licensor or engineering contractor, their internals data sheet is the starting point.
Random packing
Random packing consists of individual elements dumped or loaded into the column, such as Pall rings, saddles, Raschig rings and ladder rings, in metal, plastic or ceramic. It is often used where fouling or corrosion means the packing will be replaced periodically. See our plastic ladder ring packing and plastic saddle rings.
Structured packing
Structured packing is made of corrugated sheets or wire mesh arranged in an ordered pattern. It offers low pressure drop and is widely used in vacuum service and where capacity matters. See our metal wire mesh structured packing.
Trays
Sieve trays, valve trays and bubble cap trays are supplied to the tray layout drawings: number of passes, active area, downcomer arrangement and the opening pattern.
The internals that make packing work
- Liquid distributors spread liquid evenly across the top of each bed — for example orifice riser distributors, weir-type distributors and pipe distributors.
- Collectors and redistributors gather liquid between beds and spread it again.
- Support grids carry the packing while letting gas and liquid pass — see our packing support gratings.
- Mist eliminators remove entrained droplets from the gas — see our wire mesh demisters.
Uneven distribution is one of the most common reasons a packed bed underperforms, so distributors deserve the same attention as the packing itself.
What to put in an enquiry
- Column inside diameter, bed heights or tray count, and the internals data sheet or drawings.
- Packing type, size and material, and the volume or number of elements per bed.
- Material for each component, for example stainless steel grades or plastics suited to the process temperature and chemistry.
- Manway size, so that every part is sectioned to pass through it.
- The turnaround date or installation schedule, so that delivery is planned backwards from it.
How we work
YuxingCorp coordinates supply from manufacturers we have visited and qualified, together with supplier coordination and shipping and freight logistics coordination. Each shipment comes with a complete export document pack — commercial invoice, packing list, certificate of origin and bill of lading. Import customs clearance, duties, taxes and local registration are the buyer’s responsibility. Our standard payment terms are T/T: 30% deposit and 70% before shipment.
Related reading
- All tower packing and column internals we supply
- Finned tubes and U-bend tubes for heat exchangers
- Pipe fittings and flanges: what to specify
- Line pipe and OCTG: what to specify
Send us your column data
Send the internals data sheet or drawings, materials, quantities, destination and your turnaround date. We respond within one business day.