4 replies to this topic

[process-man]

Hi Everybody
As per attached schematic drawing, I need to design a Styrene storage tank of least inventory of 145 m³ to store styrene monomer at max ambient temp of 35 ^oC. What I have designed is a 145 m3 (H=6.4 m & D=5.4m) vertical fixed roof tank made from carbon steel with design press of 10 mbarg; the tank is equipped with :
-vacuum breaker
-PSV
-Circulation system
I was extremely wondering if anybody could advice me the followings:
1-Is the design press OK?
2-What I have considered is a bared tank, Is it needed to be insulated?
3 -In order to observe safety issues , and maybe eliminate any polymer generation (of course styrene will contain more than 15 ppm TBC), do I need double or triple smaller tank , instead??
4-is Carbon steel ok for SM?
5-Do I need to inject air to the tank to keep O2 concentration in 10-15 ppm thus accelerating TBC performance and inhibiting the polymer formation? If so any advice??
6-What about any requirement of double hull tank for better cooling?

Attached Files

•  Styrene storage.xlsx   28KB   148 downloads

[breizh]

A lot of information are available on internet , take a look at the link.
You should give us more information on the application of styrene monomers . When I was producing synthetic latexes the storage tank (100 m3) was in Stainless steel to avoid coloration of the final product .As long you are using chilled water to cool the product , yes you need insulation . Of course TBC is key , just enough not too much depending on the application . What you have to worry about is the polymerization underneath the ceiling of the tank , known sometime as pop corn .

For your capacity take account the frequency of replenishment of SM for TBC control .

Again use the link .

Breizh

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http://www.google.co...iw=1118&bih=636

[process-man]

dear Breizh
SM is to be consumed in XSBR reactor as a monomer (emulsion polymerization).

Edited by process-man, 30 June 2012 - 06:02 AM.

[latexman]

1-seems low to me. Have you sized the PSV yet?
2-yes.
3-I don't understand.
4-for applications where appearance is not so important, say carpet backing, CS may be ok. Unless your competitors have a SS tank and they will use color against you with the customer. I.e. "look how dirty their product looks". These emotional issues sometimes prevail and the customer will use it to reduce your price. For applications where appearance is important, say paper coating, CS may not be okay. For applications that are used directly or indirectly in the regulated food and drug industries, SS is a must, IMO.
5-no.
6-it's less expensive to insulate.
What Code is the tank to be built to?
What are the local conditions, i.e. climate?
Turn-over times are critical for styrene. You will need a strong administrative policy.

[Dazzler]

Hi process man,

• Air injection subsurface might be needed, and should be provided, but in practice will be hard to prove is needed. Keep it low flow in comparision to any N2 inerting flow to the vapour space.
• Allow for occasional draining of a liquid phase from the bottom.
• TBC and water phase might mean CS is not appropriate. I think we had CS with a painted lining.
• Design and construct the vent lines to be readily dismantled and cleaned due to polymerisation regularly. Vent line and vacuum breaker
• SM with TBC has a shelf life, so low temp storage and regular turnover (sales) is needed.
• Tank as a minimum insulated. Double hull etc might be excessive, depending on ambient temperature. Although insulation might not have a great effect on temp and storage life, if can be important for minimising venting rates each daytime.
• If TBC is reasonably low then can probably be used directly is SBR reactors without pre-treatment.

Dazzler