47853Re: Vacuum Distillation Column
- Apr 6, 2011Hi,
Comments inserted bellow.
> The vacuum pump pulls down to 40 torr, that's what I meant "near" vacuum... why does that scare you?Just checking. In my world you either pull a vacuum , or not. The term "near vacuum" got me worried that you had very little idea as to what you were attempting to do. Sorry.
>I read somewhere that at pressures of 70 torr or less the water/alcohol azeotrope does not exist.That sounds familiar. Once the vacuum is removed though it will absorb moisture from the air again I believe. 40 torr is only about 1.5 psi if a remember correct, so not too bad to deal with.
>If I set the temperature no higher than the boiling point of alcohol at 40 torr could I not get pure alcohol off?Nope, still need reflux to achieve the separation. As noted by another poster, the whole "temperature setting" concept is a fools errand.
> I am looking to scale up the design to about 50 liter capacity. I was planning on using SS scrubbers in the column if I can, but I am unsure of the size of the column and reflux ratio (if needed?).Sound like an ok plan. I can't tell you what R/R to run (I could implement vacuum distillation in my software/model and see how it turns out). The key with the vacuum will be requiring less power input.
>I also read somewhere that it is better to have a wider column when distilling under a vacuum for some reason.I've not herd this before. This is usually base on the moler flow rate expected in the column (among other things ;)
>Any ideas on the height of the column (didn't understand "by as high as particle")?Sorry, my bad typing (after few too many glasses ;) I meant to say "as high/tall as practical".
>I'm trying to avoid getting another engineering degree if possibile :)Yes, one is more than enough! I garner the help of two of my mates when things get too serious (one is a chemical engineer, the other and refrigeration engineer (among other things, two much education all together!)
Hope this help a little. I try too be of more use asap.
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