Cyclonic separation · vessel internals · gas processing

Heavies to the wall, gas up the core.

A vortex cluster is a set of vertical tubes inside a vessel. Gas enters each tube on a tangent, spins, and the G-force throws liquid and solids to the wall while the clean gas leaves up the centre. No moving parts. This page explains it — and what an inspector looks for once one is in service.

How it works ↓Ask a question
gas + liquid in (tangential) orifice plates gas out (low-pressure core) liquids + solids drain G-force pins liquidto the tube wall

What it is

An internal, not a vessel. It goes inside a separator — new or existing — and does the separating.

Internal

A cluster of vortex tubes

Several vertical tubes mounted in a vessel, each with a large tangential entry and internal baffling. The vessel gives the volume; the tubes do the work.

Physics

Cyclonic separation

Spinning the stream inside a tube creates G-force. Liquids and solids are the heavies — they go to the wall and slide down. Gas is the light — it leaves up the low-pressure core in the middle.

Three-phase

Oil, water, gas

Because the separation is by density, liquids of different densities separate from each other too, not just from the gas.

vs. vortex tube

Why a cluster

A single vortex tube can flood when a big slug of liquid arrives. A cluster spreads a slug or a surge across many tubes and keeps separating, which also shrinks residence time and vessel size against a conventional design.

How it works, step by step

Follow one parcel of gas through a tube.

Tangential entry

The stream enters the side of the tube on a tangent, so it is already spinning as it arrives. No nozzle, no impeller — the geometry does it.

G-force at the wall

The spin compresses the liquid against the tube wall and squeezes the gas out of it. Solids go with the liquid.

Gas up the core

A low-pressure "tornado core" forms on the tube axis. Clean gas climbs it and leaves through the top of the tube.

Liquids out the base

Liquids and solids exit the bottom of the tube into the vessel sump. Internal orifice plates stop liquid climbing back into the tubes.

Where it's used

Anywhere gas carries liquid or solids it should not — as a retrofit into an existing vessel or built into a new one.

  • Inlet and compressor scrubbers
  • Production and test separators; free-water knockouts; emulsion treaters
  • Slug catchers and pipeline inlets
  • Steam separators; flare knockouts and vents
  • Gas plants, amine and dehydration units, fuel-gas skids
What operators like

No moving parts, low pressure drop, wide turndown

The designers of the cluster internal publish roughly 1 psi of pressure drop, turndown up to 10:1, and removal of solids and free liquids into the micron range. Those are the maker's figures, not ours — see the source below. What every operator notices first is the one that never changes: nothing inside rotates, so nothing inside wears out.

Source for the design description and figures: Taylor Forge Engineered Systems' technical library — Vortex Cluster Separation in Gas Processing.

Inspecting one

The vessel is still a pressure vessel. The internal adds a few things to look at.

API 510

The vessel, as always

Shell and heads, nozzles, welds, supports, thickness against t-min, corrosion rate and remaining life — the internal changes none of that. The U-1 still governs the design basis.

Erosion

Tangential inlets

The inlet is where velocity and solids meet the wall. Look for erosion at the entry and along the first turn; measure it, do not eyeball it.

Attachments

Tube supports and welds

Support rings, tube-to-plate welds and hold-downs carry vibration and thermal cycling. Cracks start at the toes; MT or PT them at the internal.

Plates & drains

Orifice plates and sumps

Fouled plates and blocked drains show up first as carryover downstream. Check them clean, check the drain nozzles for corrosion under the liquid line.

Signs

What performance tells you

Rising pressure drop, liquid carryover, or solids downstream mean the tubes are fouled, eroded or flooded — reasons to open the vessel, not to wait for the interval.

Record

Put the internal on the record

Drawing, material, weld map and inspection points for the internal belong on the vessel's own record, so the next inspector knows what is inside before the manway comes off.

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