Gas Processing Facilities

1. Inlet Gas — Raw gas from the gathering network
2. Inlet Separation — Raw well fluids arrive as a mixture of gas, hydrocarbon liquids, water and solids. The inlet separator is a large three-phase vessel that slows the stream down so gravity can make the first cut: condensate and produced water fall out and are drawn off, entrained solids settle, and a clean gas stream leaves the top toward compression. Stable separation here protects every unit downstream from liquid slugs and fouling.
3. Inlet Gas Compressor — Field pressure is rarely high enough for processing. The inlet compressors raise the feed gas to the plant’s operating pressure, with interstage coolers and scrubbers knocking out the liquids that condense as the gas is compressed and cooled. A steady discharge pressure gives the treating units a constant, predictable feed.
4. Mercury Removal Unit — Trace mercury occurs naturally in many gas fields, and even a few micrograms per cubic metre will attack the brazed-aluminium heat exchangers of the cryogenic unit, causing amalgam corrosion and embrittlement. The gas flows through fixed beds of sulphur-impregnated adsorbent, where mercury is captured as stable mercuric sulphide. Placing the unit early in the train protects every exchanger downstream.
5. Gas Sweetening — Sour components — hydrogen sulphide and carbon dioxide — make gas corrosive, toxic and unsaleable, and CO₂ would freeze solid at cryogenic temperatures. In the amine contactor the gas bubbles up through a counter-current of lean amine solution that absorbs the acid gases; the rich amine is regenerated with heat and recycled, while the sweetened gas moves on to dehydration.
6. Gas Dehydration — Any water vapour left in the sweetened gas would form ice and hydrates the moment temperatures drop in the cryogenic section, plugging exchangers and valves. The gas therefore passes through twin molecular-sieve adsorber beds — one drying while the other regenerates on a heated cycle — leaving the stream essentially bone-dry before it is chilled.
7. Cryogenic Unit — The heart of NGL recovery. Dry, sweet gas is chilled to roughly −90 °C through brazed-aluminium exchangers and a turbo-expander, which extracts work from the gas while flashing its temperature down. The heavier hydrocarbons condense and are separated in the demethaniser: lean gas leaves the top for export compression, while the liquid NGL stream leaves the bottom for the debutaniser.
8. Export Compressors — The lean residue gas leaving the cryogenic unit is at low pressure after expansion. The export compressors restore it to sales-pipeline pressure, with after-coolers bringing it back to specification temperature. A regulated slipstream is drawn off as fuel gas to run the plant’s own turbines and utilities, and the remainder is metered into the sales-gas pipeline.
9. Debutanizer — The NGL stream from the cryogenic unit is a mix of propane, butane and heavier gasoline-range liquids. The debutaniser is a distillation column that makes one clean cut: propane and butane vapours rise overhead, are condensed and become LPG, while the pentane-plus bottoms leave as a stabilised natural-gas liquid suitable for blending into crude oil.
10. LPG Storage — LPG is held as a liquid under its own vapour pressure in pressurised spheres. Storage buffers the difference between steady production and batch offtake, and each sphere carries relief, deluge and gas-detection systems. Product is loaded onto road tankers for delivery to market.
11. NGL Storage — Stabilised pentane-plus liquids are held in low-pressure storage before being pumped into the crude-oil export stream, where they add volume and value to the blend.

Products

• EXPORT GAS (To sales gas pipeline) — Lean, dry, sweet natural gas metered into the sales-gas pipeline.
• FUEL GAS (Powers plant & utilities) — A slipstream of treated gas that fuels the plant’s own turbines, heaters and utilities — the facility runs on the product it makes.
• LPG (To LPG road tankers) — Liquefied petroleum gas — a propane–butane mix — dispatched by road tanker.
• NGL (To blend with crude oil) — Stabilised natural-gas liquids blended into the crude-oil export stream.

Utilities

Support systems — not part of the gas flow

• Flares — Safely combust relief and depressurised gas during upsets and maintenance.
• Drain Systems — Closed and open drain headers collect hydrocarbon liquids for safe recovery.
• Fire & Gas — Detectors and shutdown logic that protect the plant on fire or gas release.
• Instrument Air — Clean, dry compressed air that powers valves and instrumentation.
• Fuel Gas — Conditioned gas distributed to turbines, engines and heaters.
• Fire Water — Ring main, pumps and hydrants delivering firefighting water on demand.