There are numerous applications that require high pressure nitrogen. Some of those applications are laser cutting; auto claves; aircraft tire filling; pressure testing of valves or tubing/ coils; gas assist – plastic injection molding; storing large volumes of nitrogen. Many companies are currently using high pressure cylinders/ dewars for these applications. There are numerous disadvantages of using high pressure cylinders/ dewars such as cost; handling charges; running out during operation; and safety. The biggest problem is not being able to use all of the gas from the cylinder/ dewar. If you require 1000 psig and are using 2200 psig cylinders you are sending back almost half of the unused nitrogen. A way to eliminate this problem is to generate high pressure nitrogen in house. There are typically two ways to boost the nitrogen pressure from a nitrogen generator. Below are two main methods to generate high pressure nitrogen with a brief overview of each. ON SITE NITROGEN INDUSTRIAL APPLICATIONS
Air-operated nitrogen boosters:
Air operated nitrogen boosters consist of a large and small area reciprocating air driven piston directly coupled by a connecting rod. The gas piston operates in a high-pressure gas barrel section. High-pressure inlet and outlet check valves are contained in each gas barrel end cap. When air is supplied to the air drive inlet, the air drive section that includes a cycling spool and pilot valves provide a continuous reciprocating action. To prevent air contamination from entering the gas stream, dynamic seals are used. Cooling is provided through an intercooler on the interstage line and by routing the cold exhausted drive air through an individual jacket that surrounds the gas barrel.
1. 100% oil-free
2. air operated – no electricity used
3. ideal for hazardous areas since no electricity is required
Reciprocating nitrogen boosters:
There are both oil free and oil lubricated units available. The application will dictate which system is best suited for that application.
Reciprocating compressors use pistons driven by a crankshaft. They are multi-staged, and are normally driven by an electric motor. The discharge pressure of a nitrogen generator varies but normally operates between 75 psig and 150 psig. The nitrogen is fed into the intake side of the booster compressor. At this point the nitrogen will go through the various stages of compression until it reaches the required operating pressure of the application. If the booster compressor is oil lubricated design the nitrogen will then enter a filtration system to eliminate any oil carryover. If any trace amounts of oil cannot be tolerated in the process an oil-free compressor should be utilized. From there the nitrogen will be stored in high pressure DOT cylinders and regulated down to the necessary point of use pressure.