Methanol still?

[julianf]

I have 2-off those 400ltr stainless 'why-waste' tanks.  I bought the pair back when Glenn was still in business, and the second has never really found a use.



I'm considering a still, to demeth glycerol.



The methanol is by far the most costly part of my process, and, whilst im running on minimal quantities even now, there are other advantages for me -


a) i make glyc logs, so id rather not have methanol vapours when im making them
b) the still may be good for liquifying the glyc again for glog production


I can produce near boiling point water, without financial cost, from burning glogs, so the heat would come from that.


As for the design -


Id like to double skin the bottom of the tank, but that may not happen.  If it does not, ill have to fit a coil inside the tank.

Questions -

Would i have to have a pump?  If i kept the tank at, say, 75c, for a number of days, would the methanol boil off itself, or would i need a pump / venturi combination?

Would a fractionating column do me any good?  (a 54mm pipe filled with glass marbles)  And, if so, would there be any sensible way to mount it anywhere other than above the reactor (which i doubt id have headroom for).

[therecklessengineer]

Would i have to have a pump?  If i kept the tank at, say, 75c, for a number of days, would the methanol boil off itself, or would i need a pump / venturi combination?

Would a fractionating column do me any good?  (a 54mm pipe filled with glass marbles)  And, if so, would there be any sensible way to mount it anywhere other than above the reactor (which i doubt id have headroom for).

I feel that it probably wouldn't. You'll need to introduce circulation.

We have a commercial version of what you're wanting to do here. It's designed for removing water from oil. It's essentially a heated chamber in which the fluid is pumped from the bottom to the top. It cascades over baffles on the way to the bottom of the chamber. A blower moves air over the baffles, through an evaporator part of a refrigeration circuit, through the blower and back to the chamber again.

It's essentially a commercial GL type plant, with a few ££ extras.

Unless you have water in your glyc, there would be no advantage to a fractionating column.

[Jamesrl]

To improve the purity of your reclaimed methanol just use a simple reflux column.

I'm sure that turning the hot glycerol over would certainly improve the rate of evaporation.

[Julian]

Rather than marbles, try broken bits of toughened glass, bigger surface area and cheaper. (Just walk round a car park with a plastic bag and an automatic centre punch.)  Whoops, did I just type that out loud?

[oakwoodtv]

now you tell me I have been buying marbles at the car boot for the last two years