Several questions were referred to me regarding cost. See below for examples. No, boil-off gas is not free (unlike grad students) But then everything associated with NMR is at the opposite end of the spectrum from "free". I am one of the lucky ones who has a large cryostat at our location that serves multiple purposes. However, keep in mind that LN2 can be delivered in 100 or 160 liter portable cryostats. These can be self pressurized to provide larger boil-off gas volume. The amount of flow you need can only be determined by you. In the case of portable LN2 containers the cost is your local cost of LN2. BUT, there is no compressor, **no electricity required to run the gas system**, no noise, no dryers, no mechanical maintenance, no contamination, no moisture and no filtration necessary and a reasonably chemically inert drive gas.
The cost of installing a permanent LN2 cryostat and having it kept full is probably prohibitive for any but the largest NMR facilities but you need to check with your supplier.
Michael J. Rokosz
Nuclear Magnetic Resonance Facility
Physical and Environmental Sciences Dept.
Ford Research Laboratory
p. 313-594-3451
f. 313-248-5981
mrokosz_at_ford.com
-----Original Message-----
> From: Dr. W. L. Jarrett [mailto:William.Jarrett_at_usm.edu]
> Sent: Monday, September 29, 2003 9:09 AM
> To: Rokosz, Michael (M.J.)
> Subject: RE: looking for a solution for dirty compresed air
Michael:
My only criticism is that gas boil-off, while being great, is not
free. Unless you have a facility that will absorb the costs of setting
up/filling a liquid N2 tank, it is often easier to convince administration
to by/upgrade your compressed air.
Bill
And from Ed Chainani
Hi,
Just a follow-up question if you don't mind: do you have any idea how much
this solution costs? This sounds like something worthwhile looking into.
Thanks.
Edward
At 09:53 AM 9/26/2003, you wrote:
>It seems like there have been several requests for this type of info
>lately. The solution I offer won't work for everyone but if it is feasible
>at your site it is far far superior to compressor pumped air. These days
>many research facilities have liquid nitrogen tanks. It is easy to
>dismiss their presence if you do not directly use the cryogenics.
>
>If you have a liquid nitrogen tank near your NMR facility you can use the
>boil off gasses as a very clean dry source of drive gas without the worry
>of ANY compressor and with only some straightforward piping and
>regulators. We have such an installation at the Ford Research Lab and it
>is a great way to go. The cryogens are used for various applications and
>the additional boil-off gasses are used as a source of clean nitrogen for
>emissions measurements (and to provide spin and lift air for out two NMR
>spectrometers (Bruker MSL300 and AC200). BOC Gasses installed and
>maintains our system. If this sound like it might work for you contact
>them for more info. I am sure there are other companies that supply LN2
>but they may not be qualified to install the gas plumbing. We have
>experience with BOC and are very satisfied with them.
>
>Michael J. Rokosz
>Nuclear Magnetic Resonance Facility
>Physical and Environmental Sciences Dept.
>Ford Research Laboratory
>p. 313-594-3451
>f. 313-248-5981
>mrokosz_at_ford.com
>
>
>-----Original Message-----
>From: Hongjun Pan [mailto:hpan_at_utk.edu]
>Sent: Wednesday, August 13, 2003 10:52 AM
>To: ammrl_at_chemnmr.colorado.edu
>Subject: looking for a solution for dirty compresed air
>
>
>Dear Friends:
> We are experiencing dirty oily building compressed air
>problem recently which seriously affects our NMR facility. The
>antique building compressor will not be replaced soon. Now I am
>looking for a solution for this problem. However, the only solution
>seems to install a suitable compressor for NMR facility in the NMR
>room. I need your input about your experience if you had a similar
>problem before:
> What measure you took to protect the NMR facility if you
>did not install the compressor?
> If you installed the compressor, who is the vendor and what
>model. Did you install a dryer? if you did, the vendor and model?
> What is the noise level of the compressor and dryer?
> Any related comment and suggestion are highly
>appreciated.
>Thank you for your help.
Dr. W. L. Jarrett
Assistant Research Professor
University of Southern Mississippi
School of Polymers and High-Performance Materials
Department of Polymer Science
Box 10076
Hattiesburg, MS 39406-0076
Phone: (601)266-4551
Fax: (601)266-5504
email: William.Jarrett_at_usm.edu
Received on Mon Sep 29 2003 - 17:38:07 MST