[labnetwork] LN2 vs N2 generation on site

[Tribble, Thomas]

Richard,

We haven't switched to onsite generation for the fab, but we (Harvard) have looked at it.  The Harvard fab has a 9000 gallon LN2- 3δ storage that gets re-filled approximately once a week.  The storage facility occupies approximately 300 GSF, and there  is no more real estate available for this purpose.  Based upon a much smaller on-site generator recently completed, on-site generation to replace the fab storage facility would require more real estate than is available.  Part of the demand for space is the self-imposed requirement for N+1 redundancy.  This also affects the capital budget.

But if saving money is your focus, I suggest that your discussion should be focused on the purity of your gas requirements. Locally generated 1δ gas is inexpensive cheap to produce. Locally generated 3δ gas is moderately expensive to produce.  Locally generated 6δ gas is very expensive to produce.  From the refinery, 3δ gas is all that is produced and transported.  What we at Harvard use is 6δ gas (3δ gas run through a purifier).  An unofficial audit has shown that less than 10% of our usage actually demands 6δ purity.

Want to save money?  Figure out your demand by purity and segregate the flows (piping).  Provide your pump and gas cabinet purges with on-site generated 1δ gas.  Your facility will save.

Tom Tribble
From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Morrison, Richard H., Jr.
Sent: Tuesday, March 24, 2015 12:04 PM
To: labnetwork at mtl.mit.edu
Subject: [labnetwork] LN2 vs N2 generation on site

Hi everyone,

I am paying >$220K per year for LN2 to generate Nitrogen for my fab. Have any of you guys switched to onsite Nitrogen generator?

Looking for ideas on:
Cost of system
Maintenance cost of system
 Quality of the Nitrogen.
Operating cost per CuFt of Nitrogen

Rick


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