r/ChemicalEngineering • u/davidsmithsalda • Mar 01 '25

Design Self Nitrogen Generation onsite vs. Purchased Liquid Nitrogen

Work in a small manufacturing facility in the New England area where the cost of energy and regulation is only matched by California. at the moment we are purchasing one truck load of liquid nitrogen a week from Messer, they own the tank and the evaporator and we don't have to deal with the operation of the unit. I am wondering if anyone has experience running a PSA container-size unit for onsite N2 generation. How often do you guys change the media, compressor parts, babysitting, and troubleshooting the unit? can you guys please spill the beans? we use N2 for tank blanketing, and purging process equipment and piping.

Thank you very much for the responses I have received so far. Real altruism!

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u/HugePersonality1269 Mar 06 '25

PSA nitrogen generators are relatively maintenance free. Replace the filters several times a year and calibrate the O2 sensor. Every year or two replace the O2 sensor.

First you need to know how many CFM of nitrogen you flow.

Then factor as the major cost, being energy consumption of your air compressor and or adding an air compressor. Factor in the life expectancy and maintenance of the air compressor. If you have experience with air compressors you will realize that 5 year operating costs for the air compressor supporting the PSA will easily exceed the acquisition costs of the PSA.

At the 5 to 10 year range the PSA will need a PM where the pneumatic solenoids are rebuilt or changed.

I have worked with a couple of Parker PSA units and everything I have stated has been true.

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u/davidsmithsalda Mar 08 '25

Excellent comment, thank you very much for sharing your experience.