Selecting valves for cryogenic applications in liquefaction plants can be quite tricky. Application expertise, along with a high quality valve, is needed in order for the valve to operate effectively and efficiently in these demanding facilities. This article presents the latest in valve innovations for liquefaction plants. The valves used in liquefaction encounter natural gas made up of a mixture of several components.
The typical range of these components is:
- Nitrogen: 0 – 1%
- Methane: 80 – 99%
- Ethane: 1 – 17%
- Propane: 0 – 1.5%
- Butanes: 0 – 1.2%
- Pentanes+: <1%
Once liquefied, the gas is then properly treated and stored at atmospheric pressure of approximately -161°C and a density of 424.1 kg/m3 in a volume approximately 625 times smaller than when it was gaseous.
Within the liquefaction plant are isolation, check and control valve applications in a range of temperatures and pressures from ambient to -161°C and ASME class 150 through 900 (20 barG to 150 barG). These conditions and the specific nature of low temperature cryogenic fluids demand specific valve performance for plant reliability, protecting equipment and operational safety.
Three innovative valve designs that command a significant share of the global LNG market are:
- Triple offset rotary tight isolation valves
- Noise control and automation in control valves
- Single and dual flapper non-return (check) valves