Pressure Letdown when Tapping Gas from Underground Storage

Axial flow valves used as throttle valves

At a glance

Device type: Axial flow valve
Valve size: NPS 4 to 48
Pressure rating: Class 150 to 1500 (up to Class 900 in NPS 28 and larger)
Permissible temperature range: up to 200 °C

Special features

  • Compact design
  • High flow capacity
  • Suitable for media containing solids

Natural gas is stored in underground facilities for later consumption. Normally, these storage facilities are filled during the summer – when prices are low – and the gas is then withdrawn during the heating season. The gas is stored under pressure, which means that the pressure needs to be relieved again before the gas can be released into the transport networks. To do so, the wellhead of the storage facility is fitted with throttle valves, which must possess a high hardness level as the stream of gas carries along liquids and solid particles.

Since 2016, Humbly Grove Energy has been using axial flow valves manufactured by SAMSON RINGO in its natural gas storage facility located in Humbly Grove, North Hampshire, UK. The valves in NPS 6 and Class 1500 reduce the pressure at the wellhead inlet and are equipped with tungsten carbide trims, which are particularly suitable for this application. The valves meet strictest seat leakage requirements (leakage class VI) to prevent any unnecessary loss of gas.

Humbly Grove Energy underlines that the SAMSON RINGO valves installed in the facility comply with the required specifications and standards and that they mastered all performance tests.