Storage Tank Polymerization Relief Case

[TiCl4]

I have a PHA recommendation regarding vent sizing for bulk monomer storage tanks, specifically to ensure the storage tanks have adequate over-pressure protection (there is no design basis documentation existing for the current weighted manway protection).

I have used the services of 3rd party testing facilities (specifically Fauske) in the past for specific scenarios for obtain vent sizing for the developed two-phase foamy flow for our reactors. I have done a good deal of research so far into bulk monomer relief, but there is a dearth of hard data. The material storage and handling guides from the manufacturers of the monomers are no help in this case. In the absence of available data, I will have to pursue the same route. However, I figured I'd ask a few questions on here to see if anyone knows of available information or has any advice. My questions are as follows:

[ul]
[li]Does anyone know of available runaway data for any monomers? I have asked our suppliers and gotten nowhere fast, nor have I found any data via search engines.[/li]

[li]For bulk monomer runaway polymerization, is the relieving flow expected to be two-phase, or just vapor phase?[/li]

[li]For those of you familiar with this type of sizing, are there any runaway scenarios that are able to be relieved (i.e. for styrene, butyl acrylate, ethyl acrylate, vinyl acetate, etc)? Some monomers (e.g. acrylic acid and methacrylic acid) develop such a quick rate of reaction that the necessary vent diameter exceeds the vessel diameter. In those cases, frangible roof designs are used to eliminate the possibility of violent vessel rupture.[/li]

[li]If info is not available, I will pursue the 3rd party sizing. Any suggestions/advice as I pursue this route?[/li]
[/ul]

 

[pierreick]

Hi ,
You may check for " EBAM safe handling and storage of acrylic monomers " using your favorite search engine. Same for Styrene monomer BLEVE>
Good luck
Pierre

 

[TiCl4]

Pierre,

Thanks. I have already read EBAM's storage and handling guide, as well as individual storage and handling guides for specific monomers from various manufacturers. EBAM simply mentions calorimetric studies that might need to be performed, but I have not seen any mention of runaway kinetics.

It seems that I will likely need to engage 3rd party services for testing a bulk runaway reaction.

 

[Latexman]

In my 41 years of experience, I’ve never known companies to share their runaway kinetics. Everyone has them, hopefully. We have ours, or we have a quantitative analysis showing we have mitigated it to an acceptable risk.

Good Luck,
Latexman
Pats' Pub's Proprietor

 

[TiCl4]

Everyone has them, hopefully.

Everyone but us, it seems, Latexman. Hence the PHA recommendation. Thanks for the input. This forum has an excellent knowledge base in its members, so I figured I wouldn't try to reinvent the wheel if I didn't have to. Alas.

 

[Latexman]

No, there are others, many others.

Good Luck,
Latexman
Pats' Pub's Proprietor

 

[don1980]

By default, polymerization reactions are expected to be 2-phase. That's because the heat is generated internally and throughout the x-sec of the vessel ("volumetric boiling" rather than "wall boiling"). Volumetric boiling results in a much greater "liquid swell", and a much lower opportunity for gas-liquid disengagement, thus leading to 2-phase fluid entering the relief device.

In my experience, rupture disks are used for these reactive scenarios involving runaway polymerization of reactive monomers. These disks are very large - I recall a vessel with a 36" disk - but they're usually smaller than the vessel diameter. If the vessel is an API tank, then I think a weak-seam roof is the best design option for this reactive scenario.