Nitrogen Drying / Purging Services for Pipeline and Process Applications
The unique properties of liquid and gaseous nitrogen offer a wide range of capabilities to both onshore and offshore oil, gas and petrochemical industries. Used predominantly during plant maintenance shutdown and startup operations, nitrogen purging and subsequent nitrogen/helium leak testing form a critical path to the success of any project.
Nitrogen purging means to inert the atmosphere of hydrocarbon vessels and lines.In other words to limit the oxygen contents so that it cannot react with the hydrocarbons and make some explosive mixtures. Nitrogen Purging in Gas Well: (Oil & Gas Industry Terms, Well Activation )Generally for gas well activation air compressors are used. Air compressor puts in oxygen into the Hydrocarbon system in the well, this results in explosive mixture (as hydrocarbon & oxygen can explode by a single spark). To reduce oxygen content in the well, Nitrogen is circulated at high pressure @ 80-100 Kg/cm2 from annulus (casing) and returns of gases are taken out from tubing of the well. The Nitrogen purging job brings down chances of explosion / explosive mixtures.
Applications for Nitrogen
• Nitrogen purging – displacement/ pressure cycle
• Nitrogen foam inerting
• Helium leak testing
• Nitrogen foam cementing
• Nitrogen pigging
• Nitrogen drying
• Nitrogen cooling
• Nitrogen pressure testing
• Nitrogen high-velocity flushing
• Nitrogen gas lifting
• Nitrogen pipe freezing
• Nitrogen mothballing
Nitrogen purging is an industry standard technique for the replacement of a hazardous or undesirable atmosphere with an inert dry atmosphere. The two most common methods of purging are displacement and dilution. The geometry of the process system determines which method is used. For simple systems, displacement purging is usually more effective in terms of time and cost but, for more complex systems, dilution purging is used.
Using nitrogen offers a number of advantages for drying operations. Cryogenic nitrogen contains only trace quantities of moisture, making it very effective in drying operations (nitrogen gas dew point is between -80°F and -90°F [-62°C and -67°C]). Nitrogen provides an inert atmosphere for long-term preservation once the drying process is completed. This environment reduces oxidation and no purge is required after drying is complete. Nitrogen also provides time savings since it can be used to rapidly pressurize a system.
Nitrogen purging illustration
nitrogen purge procedure