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--></style></head><body lang="EN-US" link="#0563C1" vlink="#954F72"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Hi Tom,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">We installed a 3000 cfh generator in our facility several years back. The installation coincided with the opening of a new facility that was expected to have increased N2 requirements over our old facility. After running the generator for several years, I can say without a doubt it has been worth the effort and cost. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Our facility currently runs 3 feeds of N2. We run 99.999% boil-off from our LN2 tank as “utility N2” for chamber vents, turbo purges, gas cabinet venturis and pneumatics, and several other applications. We also run the LN2 boil-off through purifiers for our “process N2.” The generator was installed to run 99.9% “purge N2” for wet deck head casing purges, some pump purges, and other “waste gas” applications. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">The generator was sized for 3000 cfh at just over 100psi, and we nominally run at 2000 – 24000 cfh on a regular basis (wet decks alone require over 1000 cfh continuous flow). Even though it was spec’d at 99.9%, we often produce close to 99.99% N2. At this rate of usage, we saw an ROI of under 2yrs. At a higher rate of usage, we would have even shorter ROI, but we wanted to ensure there was some margin for added capacity. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Our system requires up to 210cfm of compressed air at 110psi. It uses pressure swing absorption (PSA) through a carbon molecular sieve (CMS), and the output of the generator goes to a 1000 gal receiver tank before being pushed out to labs. The generator portion of the system is very robust and has low maintenance cost, but the air compressors can require a significant amount of maintenance. Fortunately, ours are maintained by the University facilities group. However, I have one word of caution. Make sure to discuss the cycle times for the PSA process with the air compressor vendors to ensure their compressors can handle the application. In the PSA process, the N2 generation takes place in one of two towers containing a CMS. After the CMS in one tower becomes saturated, the air is diverted to the other tower, and a blow-down is executed to regenerate the first tower. The process is not too dissimilar from a twin-tower dessicant dryer, with the exception that cycle times are much shorter in the PSA process. Our generator cycles every 60sec, which cause the variable drives on the air compressors to constantly ramp up and down, adding more wear and tear than expected. With that in mind, you may want to consider a large buffer tank in between the air compressors and generator. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Lastly, we also set up our system for at least some level of redundancy. The air compressor system is mostly redundant, but there can be single points of failure, such as a power outage. In such a failure, we have a cross-over valve that allows the generated N2 lines to be supplied by our LN2 tank. We don’t want to run this way for very long, but it gives us enough time to receive notifications and conserve N2 usage until the compressors and generator come back online. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Hope this helps. I’m happy to elaborate further if needed.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Best Regards,</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><br>Matt</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">--</span></p><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Matthew T. Moneck, Ph.D</span></b></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Executive Director, Claire & John Bertucci Nanotechnology Laboratory</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Electrical & Computer Engineering | Carnegie Mellon University</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">5000 Forbes Avenue, Pittsburgh, PA 15213-3890</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Phone: 412-268-5430</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><a href="http://www.ece.cmu.edu/">ece.cmu.edu</a> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><a href="http://www.nanofab.ece.cmu.edu/">nanofab.ece.cmu.edu</a> </span></p></div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><div><div style="border:none;border-top:solid #e1e1e1 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> labnetwork <<a href="mailto:labnetwork-bounces@mtl.mit.edu">labnetwork-bounces@mtl.mit.edu</a>> <b>On Behalf Of </b>Ferraguto, Thomas S<br><b>Sent:</b> Tuesday, July 26, 2022 8:12 AM<br><b>To:</b> Labnetwork (<a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a>) <<a href="mailto:labnetwork@mtl.mit.edu">labnetwork@mtl.mit.edu</a>><br><b>Cc:</b> <a href="mailto:thomas.ferraguto@baesystems.com">thomas.ferraguto@baesystems.com</a><br><b>Subject:</b> [labnetwork] Nitrogen Generation</span></p></div></div><p class="MsoNormal"> </p><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">Colleagues,</span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"> </span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">Has anyone taken the leap moved to Nitrogen Generation or at least supplemented with Nitrogen Generation (for 3 9's house Nitrogen)?</span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"> </span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">FYI... I'm no longer at UMass but there is nothing better for fast feed back than the Labnetwork!</span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"> </span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black">Tom</span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"> </span></p></div><div><p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:black"> </span></p></div></div></body></html>