Author Topic: 50 gal. Reaction/ Distillation Vessel Construction  (Read 7207 times)

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El_Zorro

  • Guest
Yeah, a ceramic pipe wouldn't be an absolute ...
« Reply #40 on: June 06, 2002, 05:16:00 AM »
Yeah, a ceramic pipe wouldn't be an absolute necessity.  I'm sure that two SS pipes with a vacuum jacket between them would surely suffice.

Do not go gentle into that good night.  Rage, Rage, against the dying of the light.  --Dylan Thomas

obia

  • Guest
quite how you get 30 psi vacuum (pressure ...
« Reply #41 on: June 07, 2002, 12:41:00 AM »
quite how you get 30 psi vacuum (pressure differential that occurs for example when outside is 2 bar and inside is 0 bar)but say that you did then the top flat is going to be under a lot of pressure, look at industrial reactors they don't use flat tops for anything more than 1-5 psi differential otherwise the top becomes extremely heavy we're talking 15mm thickness or even more for a 1m dia at 5psi the load on the top is something like 2 1/2 tonnes.
a better still on a smaller scale can be created from a keg, the biggest kegs around here are 90 litres plus.
kegs are guaranteed to withstand 40-60psi internal therefore a differential of up to 25-45 psi is reasonable.

alchemy_bee

  • Guest
On Vacuum Source
« Reply #42 on: June 07, 2002, 12:42:00 AM »
Alright, moving on, i think ill bring this up now, what kinda of vacuum source would be needed to vacuumate something this big to a degree where product oils could be distilled effectivly?

obia

  • Guest
steam ejectors are used industrially, i think ...
« Reply #43 on: June 07, 2002, 12:50:00 AM »
steam ejectors are used industrially, i think these use hp steam in a venturi to pull a vacuum theyre good for 5 psi vac and anything up to thousands of litres a minute i guess a search on the patent site should throw up some designs. a normal vaccuum pump would be a complete waste of time its capacity would be overwhelmed by volatiles and leaks

alchemy_bee

  • Guest
Vacuum source
« Reply #44 on: June 07, 2002, 02:58:00 AM »
I did some searching online and also Lugh provided some good direction to sources of steam driven aspirator setups. I think that somthing that eleborate would be over kill for a setup this small (or large) considering that industrial steam powered aspirators can be 20 feet long or more.

http://www.gea-jetpumps.de/produkt/vakuumsysteme/vakuum_allg.jpg

Also, as it was pointed out before in this thread, a steam source would run thousands of dollars on top of cost of the aspirator equipment,

Could a heavy duty direct drive vacuum pump be used for a setup like this?



Check out that last mofo, god damn the fucker weighs more than me!

alchemy_bee

  • Guest
ominous revelation
« Reply #45 on: June 07, 2002, 08:17:00 AM »
obia: You absolutly correct. I tried to calculate the stress that would be placed on the vessel under vacuum. Considering dimensions of the vessel to be that of a standard 55 drum, 24"x 34" the total surface area would be about 3467 cubic inchs. Given standard pressure at 15 psi, across the whole vessel that would mean a total of:

52,005 lbs of force if a perfect vacuum was obtained
50,664 lbs @ 20mm/Hg (safrole boils at 120)
48,652 lbs @ 50mm/Hg (safrole boils at 140)
45,971 lbs @ 90mm/Hg (safrole boils at 160)

Osmium

  • Guest
As I stated in another thread on the newbee board ...
« Reply #46 on: June 07, 2002, 11:12:00 AM »
As I stated in another thread on the newbee board lately you will experience big headaches when vacuum distilling oils with 6L flasks. I can barely imagine the amount of bumping you will experience in a 200L barrel. You need some extremely good stirring and capillaries to introduce small gas bubbles into your hot mixture to achieve a somewhat consistent boiling. This also means you need a big ass vacuum pump due to the intentional leaks you have to introduce.

There is a reason why the industry tries to avoid normal distillation of high boiling stuff like the plague. They prefer crystallisation for purification whenever it's possible.

Besides, it makes no sense to process such big amounts. A continuously running conventionally sized glass-made still can produce several liters of distilled precursor or product every day. And they don't need much attention.

You are not the first bee dreaming of becoming the local Escobar of the Ecstasy trade. Everyone lives through such dreams of grandeur at the beginning of their career. Don't do it.

I'm not fat just horizontally disproportionate.

alchemy_bee

  • Guest
;-)
« Reply #47 on: June 08, 2002, 01:14:00 AM »
What would be the largest you could go for the setup described and still have it be pracatically fuctional?


There is a reason why the industry tries to avoid normal distillation of high boiling stuff like the plague. They prefer crystallisation for purification whenever it's possible.


What are industrial methods for purifacation of high boiling oils (that cant be crystalized)?

Besides, it makes no sense to process such big amounts. A continuously running conventionally sized glass-made still can produce several liters of distilled precursor or product every day.

You are not the first bee dreaming of becoming the local Escobar of the Ecstasy trade. Everyone lives through such dreams of grandeur at the beginning of their career.

Not dreaming, just doing my part in the war.

Osmium thanks for the post. No one is trying to kid anyone here, this thread is strickly for informational purposess only.

Osmium

  • Guest
> What would be the largest you could go for ...
« Reply #48 on: June 08, 2002, 01:44:00 AM »
> What would be the largest you could go for the setup
> described and still have it be pracatically fuctional?

I don't know, that can't be easily answered. Depends on many factors. Vacuum requirements, vacuum pump size, mode of stirring, if and how you introduce air through capillaries (to avoid bumping) etc.
Work your way up slowly, do not start big!

> What are industrial methods for purifacation of high
> boiling oils (that cant be crystalized)?

They do distill them, but everybody is glad when distillation can be avoided. If they have to distill high boiling stuff then they have all the necessary equipment and experience (which we do not have).


I'm not fat just horizontally disproportionate.

alchemy_bee

  • Guest
What application range would thoes pumps pictured ...
« Reply #49 on: June 08, 2002, 02:15:00 AM »
What application range would thoes pumps pictured above be practicall for? They are the best/biggest motorized vacuum solution i can find.

obia

  • Guest
heavy duty pumps
« Reply #50 on: June 08, 2002, 07:14:00 PM »
it really depend on what your distilling and there are load of mechanical variables too.
 essential oils in my experience are a real pain with oil pumps the low BP terpenes contaminate the oil very quickly leading to a very poor vacuum, the pump has to be heavily air ballasted and the pump/oil has to run hot in order to wash the contaminants out of the oil.
I would however guess that being able to evacuate two or three time the swept volume in a minute would be ample provided the volatiles could be got rid of and the vacuum connections and lines are short. The leak through a capilliary several capilliaries is small, in fact the finer the stram of bubbles from a capillary the better. Alternatively vigerous stirring during vacuum distillation is very effective at preventing superheating and bumping 

A quick looka those pumps.. they look much like backing pumps which work in conjunction with other pumps and cold traps. I've seen similar in large labs providing a ring vacuum, but theyre always used with traps. 

if you look around there are surplus reciprocating vacuum pumps around these don't create a very hard vacuum but they handle volatiles well and are a lot cheaper than a vane type pump.

El_Zorro

  • Guest
Had a thought
« Reply #51 on: June 08, 2002, 09:39:00 PM »
With regard to the coolong/heating coils, would you have two sets of coils, or one?  If you only had one set, then you would probably have to have some sort of switching manifold for when you wanted to go from hot to cold.  If you had to go from hot to cold quickly, it would present some serious problems.  First off, you were talking about using high-pressure steam for the heating coils.  The only kind of cooling agent I can think of would be fluid, so that would mean you would have to bleed the line EVERY time you changed.  And if you had to go from really hot to really cold quickly, not only would you go through the bitch-ass line bleeding, switch over to what you need, then when you got ready and started up, the rapid temp change could cause some pretty bad warping.  And if you had two sets of coils, it would cut out the hassle of bleeding the line every time, but it could still cause warping.

Do not go gentle into that good night.  Rage, Rage, against the dying of the light.  --Dylan Thomas

tmf

  • Guest
if you dont have a copy
« Reply #52 on: June 09, 2002, 04:58:00 AM »
if you dont have a copy of Perrys Chemical Engineers' Handbook in's in youre college library (mine's next to my Merck Index).

Nothing but data regarding very big rxns/scaleups - more geard towards the continuous processes (like oil refining) vs the 'batch' processes (like drugs) - but good hard data everywhere.

"Chemists make grams, Chemical engineers take what the chemists did and use it to make tonnes - of product and money - Hence 'Engineers are the pimps of science'" -

Where the FUCK is my medication!

alchemy_bee

  • Guest
Obia: it really depend on what your distilling ...
« Reply #53 on: June 09, 2002, 09:05:00 PM »
Obia:

it really depend on what your distilling and there are load of mechanical variables too.
essential oils in my experience are a real pain with oil pumps the low BP terpenes contaminate the oil very quickly leading to a very poor vacuum, the pump has to be heavily air ballasted and the pump/oil has to run hot in order to wash the contaminants out of the oil.


I think initial simple distillation up to reasonable temp and maintained there for some time will effectively remove water and low BP volatiles - as is basic lab process anyway to avoid undo bumping for vacuum distillations. Also in an old post of an archived thread

Post 107852 (missing)

(psyloxy: "Re: Info Request - Lost Archives", Methods Discourse)
Eleusis gives a method for the solvent extraction of terpenes followed with subsequent vacuum distillation. Also on the topic of terpenes, Masaki Sato, Motonobu Goto and Tsutomu Hirose,"Supercritical Fluid Extraction on Semibatch Mode for the Removal of Terpene in Citrus Oil" Ind. Eng. Chem. Res., 35, 6, 1906-1911, 1996

The leak through a capillary several capillaries is small, in fact the finer the stream of bubbles from a capillary the better. Alternatively vigorous stirring during vacuum distillation is very effective at preventing superheating and bumping


Is vigorous stirring the present industrial method of choice for bumping control? Are capillaries still used on an industrial scale and if so what is the mechanism that is used for the introduction of air and how is it regulated/monitored? As Rhodium stated in

Post 253541 (missing)

(Rhodium: "Re: Sassy distillation problem", Newbee Forum)
, "the outdated practice of using a fine capillary for the introduction of air".


A quick looka those pumps.. they look much like backing pumps which work in conjunction with other pumps and cold traps. I've seen similar in large labs providing a ring vacuum, but theyre always used with traps.


Can you describe these systems in greater detail? What is a cold trap and what is a ring vacuum?

El_Zorro: Steam heating is the more effective method, but for the purpose of this discussion lets consider oil heating for now as it is more practical. Additionally it probably would not be needed to go from heat to cooling rapidly enough to make use of a second run of coiling. The oil could be evacuated and cooling fluid circulated from an alternate source probably within 15 min.

TMF: Thanks for the reference! I'll have to check that out soon. One can order it online from BN.com for 119.95 or 295.00 on cd-rom! Any other suggestions for books to read that might be helpful?

El_Zorro

  • Guest
oil heating would definately cut down on the ...
« Reply #54 on: June 10, 2002, 12:07:00 AM »
oil heating would definately cut down on the labor, just try to avoid reactions that need drastic temp changes to happen rapidly.

Do not go gentle into that good night.  Rage, Rage, against the dying of the light.  --Dylan Thomas

alchemy_bee

  • Guest
It perhaps would be nearly impossible to design ...
« Reply #55 on: June 10, 2002, 08:58:00 AM »
It perhaps would be nearly impossible to design and build a vessel, 50 gal in capacity that which could be vacuumated to the point where product oils could be distilled efficiently for the simple reason that the structure could not be economically built to withstand the atmospheric forces, as sighted above. With an internal pressure of 1 psi, the force on the lid would be 6,328 lbs!

Therefor what design elements would have to be present to function under these conditions?

Its desired that the body material be thin enough so that the coils supply as direct a means of heat/cooling as possible. However it is also key that vacuum distillation be applicable to the design. I came up with these general ideas on solutions, again this isn't my area, and your input would be appreciated:

* Thicker steel - would allow for more stress on the body, while it would mean less efficiency of the coils primarily in the application of heating however flame heating may counter this loss of efficiency.

* Design elements such as stiffening bars as suggested could be used. The most practical placement for these bars I think would be on the inside. Lengths of heavy steel bar could be welded to the inside of the tank at regular intervals, and would allow for more support of the lid.

* Downsizing of the vessel most obviously should be done - while holding to the optimum material thicknesses and the dimensions given, a reduction of size to 20 gallons would mean 60% less stress.