The LNG industry grows fast year after year, and so does the application of PIPENET in various LNG projects.

Our new application bulletin shows the use of PIPENET Transient module in performing surge analysis of the firewater system on the FLNG development in Africa. The FLNG facility is a turret moored double-hull floating vessel. Gas receiving, processing, liquefaction, and offloading facilities are mounted together with LNG and condensate storage there.

The document shows some of the capabilities of PIPENET Transient module for performing surge analysis of the firewater system on the FLNG. It also shows how PIPENET Transient module could be used in finding a method of bringing the pressure surge down to an acceptable level.

The firewater system on this FLNG has a number of high points for the purpose of supplying hydrants. The scenario under consideration is the deluge system start up. It is assumed that the hydrants at the high points may be treated as dead ends. This makes the system susceptible to cavity formation. When cavities collapse the result could be very high pressure surges.

Two cases are considered and a method of eliminating the high pressure surge is pinpointed.

Case 1: Basic system without the installation of surge alleviation devices.

Case 2: Installation of vacuum breakers.

One standard method of reducing pressure surges in firewater systems is the installation of vacuum breaker/air released valve. In this case 17 vacuum breakers are assumed to be installed.

The simulation results showed that cavitation is likely unless surge alleviation devices are installed. Cavitation is likely at the high points of the system. The potential pressure surge is around 152.3 barg. By installing 17 vacuum breakers at the high points cavitation is eliminated and the pressure surge comes down to 19.3 barg.

Check for all the details and results in application bulletin Surge Analysis of the Firewater System on an FLNG.