Vertical Gas Separator

How it works

Gas carrying a heavy liquid load enters the low side inlet, below the disengaging region. As the gas rises the turbulence subsides, particles coalesce into larger ones and disengage by gravity. All but the finest liquid particles are removed here.

The Anderson pocket type vane bundle is the final stage. The mixture is forced to change direction several times. The low density gas negotiates the tortuous path; the high density liquid cannot, and impinges on the vane wall. Droplets coalesce, absorb others striking the vane, convert to sheet flow and travel to the pockets — where they are isolated from the gas stream.

Pocket drainage runs by gravity into the collection hopper under the bundle and down the drain line into the sump, its outlet sealed by liquid so gas cannot short-circuit up the pipe. Clean gas leaves through the outlet, and separated liquid leaves the sump through the bottom drain and out through the base to the flanged connection.

Why the Anderson pocket type vane

• Shielded pocket. Uninterrupted liquid collection and drainage. The draining liquid is protected from re-entrainment, so the vane handles an increased volume.

• Lower pressure drop. Increased capacity compared to hook-type vanes.

• More laminar flow. Lower turbulence, from an advanced flow profile design.

• Smaller bundle. Anderson bundles are smaller than hook-type vanes in similar applications, giving a smaller, more efficient and more economical design.

Separation performance

Efficiency falls as droplet size decreases. To separate below the vane threshold the bundle must be preceded by a coalescer — either a special hookless vane bundle or the stainless wire mesh pad on the vane face — which grows incoming droplets to a size the vanes can remove.

• 0–110% of design flow. 100% removal of liquid particles 8.0 micron and larger.

• At design flow. 100% removal of liquid particles 5 micron and larger.

• With an inlet coalescer. 100% removal of liquid particles 3 micron and larger.

Inside the vessel

The unit modeled here is a 36″ diameter ASME Code vessel, 96″ tangent to tangent, with 2:1 elliptical heads. The connections and internals shown are the ones that carry the separation duty.

• Low side inlet. 16″ 150# RF, entering below the disengaging region.

• Pocket type vane bundle. 24 zig-zag plates, 6 passes — shielded pockets, drain gutters, spacer combs and tie rods.

• Vane drain line. Carries pocket drainage from under the bundle down to the sump, liquid sealed.

• Outlet connection. 16″ 150# RF, high side or top.

• Bottom drain. 3″ 150# RF drain, swept elbow out through the base to a flanged end.

• Vent connection. 2″ 150# RF blind-flanged connection on the top head.

• Ring base support. Rolled skirt on an anchored base ring.

Typical service

Chemical and petrochemical plants, refineries and natural gas pipelines — any application with an expected heavy incoming liquid load where the liquid to gas weight ratio is in excess of 5% by weight.

• Compressor suction. Protecting the suction side of compressors from slugs and entrained liquid.

• Steam lines. Removal of condensate and lube oil.

• Gas transmission and distribution. Bulk liquid removal, and product recovery.

• Ahead of desiccant beds. Removal of liquids to improve desiccant life.

• Glycol service. Removal and recovery of glycol downstream of glycol contactors.

Sizing

AVGS separators are custom engineered to the duty, not selected from a size list. Vessel diameter, vane bundle face area, internal elevations and level settings follow from flow rate, operating pressure, gas and liquid densities and inlet loading. Supply those with the connection schedule and required code stamp; the arrangement shown — AVGS 16-36-150, model, line size, vessel diameter and design pressure — is a representative build of that arrangement.