In both gas and liquid applications, pressure reduction regulation is required.
In a gas distribution system, a network of transmission pipelines transports natural gas from the producing fields to consumers. Gas transmission pipelines normally operate at high pressures. As customers do not usually require gas delivered at such high pressures, it is necessary to control the pressure and flow rate.
Gas pressure and flow rates are controlled at pressure reduction stations located along the pipeline system. The gas pressure may start in the pipeline above 1,000 psig and end up at a plant or at a residence at a pressure as low as 15 inches of water column. Pressure regulating/reducing skids are packaged stations utilized by gas pipelines.
The pressure-reduction system controls the supply pressure to gas users at a regulated value. Each system consists of at least two pressure-reduction trains—one operating and the other on standby.
Each train will normally comprise two regulator valves in series.
Regulator valves should be sized for the maximum anticipated volumes at the minimum anticipated inlet pressure during periods of maximum demand.
For stations serving multiple residential customers or other non-interruptible services, sufficient regulator capacity must be provided so that the failure of one regulator valve run does not reduce facility capacity below the required demand. Regulator valves in custody transfer stations are typically designed to fail in the open position.
Basic Equipment Detail for Gas Regulating and Metering Station. The Regulating and Metering Station consists of an inlet pipeline with filter separator, pressure regulator, relief valve
- Insulating joint
- Inlet emergency shut down valve
- Knock out drum scrubbers and filter separators.
- Gas heaters or heat exchanger
- Valves and valves actuators
- Slam shut valve
- Relief valves
- Pressure regulators
- Silencers
- Meters
- Liquid separator.
- Pressure Gauge
- Temperature Gauge
- Chart recorder
- Differential pressure transmitter
- Density and specific gravity transducer
- Gas Chromatograph
- Flow Computer
- Electronic Volume Corrector
- Supervisory Control and Data Acquisition (SCADA) System
- Condensate tank
- Weld-neck Flanges, Blind Flanges, Metallic and Asbestos Gaskets, Tees, Elbows, End caps, Reducers, Saddle/weld-o-lets, Needle valves, Screwed gate and ball valves, Socket welded fittings (Flange, Tee, Elbow, Reducer etc.), Screwed Fittings, SS tubes, Compression Coupling and Stud Blots (As per requirements).
