Amine Contactor Demister for Gas Sweetening Units

Amine contactor demisters reduce amine carryover, but carryover may come from more than the pad. Foaming, contamination, high vapor velocity and poor upstream distribution can all overload the mist eliminator.

First decide whether this is a separation or solvent problem

An amine unit can lose solvent through entrained droplets, vaporization, leaks, filter changes and other operating losses. A high make-up rate alone does not identify the demister. Look for liquid in downstream equipment, carryover sampling, pressure-drop changes and a relationship with gas rate or foaming events.

Foam is especially important because it changes the liquid presented to the pad and can occupy disengagement space. Hydrocarbon contamination, suspended solids, corrosion products, heat-stable salts and unsuitable additives can contribute to unstable operation. The process team should diagnose and control the solvent condition; a denser pad cannot correct contaminated amine.

Engineering review points

Use actual operating conditions for sizing. Elevated pressure changes gas density, so the allowable velocity should be checked with a conservative K factor instead of assuming a default value.

If salt, iron sulfide or hydrocarbon contamination is present, a dense mesh can plug quickly. In that case, vane internals, wash provisions or process cleanup may be more important than a higher-efficiency mesh.

Review the current minimum, normal and maximum gas cases at operating pressure and temperature, plus any debottleneck target. Check liquid circulation, foaming history, inlet separator performance, top tray or packing condition, disengagement height, outlet location and expected liquid load. A calculated average velocity does not reveal local overload from a damaged distributor.

Media selection by failure mechanism

• Clean, stable service: knitted stainless mesh is a common first candidate where the required droplet range and hydraulic margin support it.
• Fine amine mist after other causes are excluded: a documented composite or co-knit construction may be reviewed, with separate checks for pressure drop, drainage and fouling.
• High liquid load or solids: a vane or more open construction may be more robust, subject to droplet-size requirements and available height.
• Repeated plugging: analyze deposits and solvent condition before reproducing the old density.

Do not claim a collection percentage without a droplet-size and inlet-loading basis. If those data are unavailable, define a build-to-specification purchase and monitor operating results instead of inventing a performance guarantee.

Materials and documents

SS316L is a common starting material, but amine degradation products, chlorides and sour service conditions should be reviewed. If sour gas requirements apply, the buyer should align material and documentation with project specifications.

The material set includes mesh, grids, tie wires, hold-downs and any attachment parts. For H2S-containing production and natural-gas treatment, follow the project’s identified sour-service specification and environmental limits for metallic materials. A cracking-resistance requirement does not by itself establish resistance to amine corrosion, chlorides or deposits.

Specify in the RFQ the material or batch traceability record you need for metal wire and grids, especially when the demister is installed in a critical gas treating unit, so it is priced into the quotation and frozen in the PI; each shipment then carries those records as delivery evidence. EN 10204 Type 3.1 or Type 3.2 documentation, additional testing and third-party inspection are optional upgrades — request them before material procurement, production or inspection booking so traceability, cost and schedule are confirmed upfront.

RFQ checklist

Send gas flow, pressure, temperature, amine type, CO2/H2S service, foaming history, upstream trays or packing, vessel ID, manway size and old demister photos. For troubleshooting, include pressure drop trend and carryover symptoms.

Add amine concentration and circulation rate, known contaminants and solids, recent solvent-analysis trend, minimum and maximum operating cases, outlet geometry, support-ring dimensions, section layout and any planned capacity increase. Mark data as measured, design or estimated. For a replacement, photograph the pad before cleaning and map deposits, wall gaps, displaced sections and corrosion by component.

What the buyer should freeze

The PI should identify the purchase route, operating basis used for selection, material grades, mesh or vane construction, finished dimensions, section map, grid and wall-seal details, installation orientation, inspection points, material or batch records, photos and packing. Any performance route additionally needs inlet droplet and liquid loading assumptions, allowable pressure drop, carryover criterion and acceptance method.

Use the glycol contactor guide for a parallel solvent-loss diagnostic and the fouling guide when salts or iron sulfide are present.

Authoritative basis and limits

Sulzer’s gas/liquid separation guide identifies gas sweetening as an application for higher-performance mesh and treats liquid holdup, drainage and inlet distribution as design inputs. This supports a service-specific review, but proprietary performance remains construction- and duty-specific. Sour-service material controls must come from the project’s current controlled specification, not from a supplier’s generic compliance label.