2 replies to this topic

[vijji]

Hi,
We apply liquid nitrogen to batch reactor having limpet coil to cool to -60 Deg.C, LIN line size is 1'' and reactor limpet coil inlet line size 2''. what will be outlet of LIN line size??

[Art Montemayor]

Vijji:

Are you dealing with a conceptual cooling jacket or an actual, jacketed reactor that you are using liquid nitrogen (LIN) within the half-pipe (limpet) coil? Applying saturated, cryogenic LIN (-196 ^oC) inside a cooling jacket and subjecting it to instantaneous vaporization is a potentially hazardous operation unless carefully designed and instrumented. Critical issues are:

• How do you intend to control the reactants to only -60 ^oC? You have a 136 ^oC temperature difference between the reactants and the LIN.
• The rate of vaporization will be very rapid and will generate a lot of vaporized N₂ almost instantaneously. The produced vapor flow rate will be very high.
• The large temperature differences between the reactor shell and the welded half-pipe (limpet) will develop large, localized stress points in the coil and its welded joint as the cryogenic temperatures try to shrink the coil relative to the reactor shell.

Please give all the detailed, background information and supply a sketch of the operation, advising if the proposal is conceptual or existing.

[Art Montemayor]

Vijji:

I picked up the following information from a report issued on this thread:

“We apply LIN at 1.5 Kg/cm² line pressure, in limpet coil of reactor jacket at 25 Deg.C mass and time will be approx. 2 hrs to get -60 Deg.C. Reactor MOC is SS-316 and designed for cryo applications.”

I presume that this is a response from you to my questions in the prior posting. If so, please acknowledge that this is true and do not use the “Report” function as a response to a post. The Report function is for members to report objectionable postings or content to the Forums administration.

The reason I questioned your original post is because you wrote it as if the procedure was one being done by you at present. However, your query asks for help in determining the size of the gaseous nitrogen outlet nozzle and line from the limpet coil. My point here is: if you are already using liquid nitrogen to cool your reactor through use of the limpet coil, then you surely are already venting the resulting gaseous nitrogen through an existing nozzle and vent line. So you have no need to ask for the correct vent connection sizes. Am I not correct???

Of course, the above is correct only if the existing nozzle and vent line sizes are giving you the result you need. You may be having problems with the existing nozzle and vent line size. If so, it would not surprise me.

Please respond if you have need for our Forum to help you. But respond to this thread in a post, not to the reporting function.