A gas plant (natural gas processing plant) is a midstream facility that turns raw wellhead gas into two salable products: pipeline-quality methane that meets transmission specs, and natural gas liquids (NGLs) such as ethane, propane, and butane recovered from the stream. It sits between the gathering system and the transmission pipeline.
Gas Plant in one line: A gas plant is a midstream facility that removes water, acid gases, and heavier hydrocarbon liquids from raw natural gas, producing pipeline-quality methane and separately marketable natural gas liquids.
Raw gas from a gathering system is "wet" and often "sour": it carries water vapor, hydrogen sulfide and carbon dioxide (acid gases), and heavier hydrocarbons. Left in, these cause problems - water forms hydrates and corrodes lines, acid gases are toxic and corrosive, and heavier hydrocarbons drop out as liquids in the pipeline. A gas plant conditions the stream so the residue gas meets pipeline specifications for heating value, water content, and contaminants.
Processing generally proceeds through several stages: inlet separation to remove free liquids and solids, acid-gas removal (commonly amine treating) to strip H2S and CO2, dehydration (glycol or molecular sieve) to remove water, and NGL recovery - often cryogenic, using turboexpanders to chill the gas so ethane and heavier components condense out. The recovered NGL mix is then fractionated, on site or downstream, into individual products.
A gas plant is effectively a small chemical plant with towers, heat exchangers, compressors, pumps, and cryogenic equipment operating at extremes of pressure and temperature. Product quality, energy efficiency, and safety all depend on holding hundreds of loops - column temperatures and pressures, amine circulation, glycol regeneration, expander performance - within tight bands, so plants run on a DCS or PLC control system with extensive instrumentation.
Custody or allocation measurement lives at both the inlet (raw gas received) and the outlet (residue gas and NGLs delivered), using AGA-compliant meters and flow computers. Beyond the plant's own control system, operators frequently want plant KPIs, inlet volumes, recovery rates, and equipment health rolled up alongside their field gathering and compression data. A cloud SCADA platform can subscribe to plant data over OPC UA, Modbus, or MQTT to provide that unified midstream view and remote monitoring.
Residue gas is the lean, mostly-methane product that meets pipeline specification and goes into the transmission system after processing. NGLs (natural gas liquids) are the heavier hydrocarbons - ethane, propane, butanes, and natural gasoline - recovered from the stream and sold separately, often after fractionation into individual purity products.
Water vapor in gas causes two problems: at high pressure and low temperature it forms solid hydrates that plug lines and equipment, and combined with acid gases it accelerates internal corrosion. Dehydration with glycol or molecular sieve drops the water content below the pipeline spec so the gas can be transported safely.
The plant itself runs on a DCS or PLC. For an operator managing field and plant together, a cloud SCADA platform can pull plant KPIs, inlet and outlet volumes, and equipment status over OPC UA, Modbus, or MQTT, so gathering, compression, and plant data appear in one live view rather than in separate silos.
This page references the protocol specifications published by the organizations below. Editions, product capabilities, and documentation change over time - confirm current requirements and specifications directly with the source.
Last reviewed: July 27, 2026. Merobix is not affiliated with, endorsed by, or sponsored by these organizations; their names are used only to identify the standards and products discussed.
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