Engineered Nitrogen Systems
Nitrogen gas is used for a variety of applications, with many related to safety. Nitrogen is used to inert potentially explosive environments in tanks and piping systems.
Fuel, oxygen, and a source of ignition are the three components necessary to support combustion. In petroleum transport or storage, the formation of hydrocarbon vapor is difficult to control and the sources of ignition are difficult to eliminate, so lowering the oxygen content to a safe level with nitrogen is a practical solution in creating a fire-safe environment.
Employing a PRISM Membrane system ensures that an abundant supply of nitrogen is always available to meet the demands of each specific application.
PRISM® Membrane systems are designed for nitrogen flow rates in the 25-12,000 Nm3/h (~880-440,000 SCFH) range. The nitrogen purity is typically 95-97% with capability to produce up to 99.9%.
Membrane productivity increases with rising pressure so a small system at high pressure can do the job of a larger system at lower pressure. Typical feed pressures range between 7 and 13 BARG, but it is possible to operate PRISM Membrane systems from 5.5 to 20 BARG. This allows engineers to optimize systems to maximize compressor efficiencies, balancing the power and space requirements in each application.
- Purging of flare systems and atmospheric vents
- Back-up purging of flare system
- Seal gas on export gas compressors
- Purging of pig launchers and receivers
- Leak testing, gas-freeing and oxygen-freeing
- Regeneration of glycol in dehydration systems
- Heave compensation systems
- Oxygen stripping from injection water
- H2S stripping from produced oil/water
- Drying confined areas
- Instrument air/gas
- Down-hole nitrogen services
- gas lift
- coiled tubing
- well work-over
- Inert purging and blanketing of:
- low flash point chemical storage tanks
- methanol storage tanks
- diesel day tanks
- seal oil tanks
- lube oil tanks
- heating medium tanks
- injection water tanks
- slop oil tanks
PRISM Nitrogen Systems
Each of the PRISM Membrane systems incorporates proprietary membrane gas separation technology, recognized as one of the most efficient and effective nitrogen generation methods available. Over three decades of experience building membrane-based systems has proven their durability.
A worldwide service network is available for shipboard units, ensuring that systems are running at optimum efficiency. Factory-trained, qualified technicians are available to get things running smoothly, minimizing costly down time.
How Membranes Work
PRISM Membrane separators are used to generate the nitrogen in these systems. Each separator consists of a bundle of hollow fibers in a cylindrical shell. Compressed air is fed to the inlet of the separator and flows inside the hollow fibers towards the opposite end. Molecules migrate through the walls of the fibers according to their permeability: Oxygen, carbon dioxide and water vapor permeate through the membrane walls more quickly producing a dry nitrogen stream at the outlet. The secondary oxygen-rich stream is vented through a port in the shell wall.
Each gas has a characteristic permeation rate which is a function of its ability to dissolve and diffuse through a membrane. This characteristic allows “fast” gases, such as oxygen, to be separated from “slow” gases like nitrogen. The driving force of the separation process is the differential partial pressure which is created between the compressed feed air side and the low pressure side of the membranes.
Air contains nitrogen (78%), oxygen (21% ), plus other gases, like argon, helium, and water vapor (1%). PRISM Membrane systems use this unlimited supply of raw material to produce nitrogen for a number of industrial applications.