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Best way to separate water from methanol???
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I am interested in separating the water out of my recovered methanol – I use a Plumbers Delight in a GL Ecoprocessor. Other than using expensive molecular sieves, I guess some kind of distillation setup would work – but the idea of heating up methanol to boiling sounds kind of scary to me . Any ideas out there?

cheers

richard
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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The idea behind the Plumbers delight is basic distilation. To keep the water out of the methanol being recoverd all you need is good temp control of the vapors. If your useing the plumbers delight you are already bringing the the methanol/water mixture to its boiling point so I can see nothing 'extra' to be scared of.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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i have a whole bunch of recovered methanol with water in it...what i was thinking of is re-distilling it. In order to do that with my current setup it would seem to me that i would be having methanol in direct contact with my heating element ...that is the part that scares me. So i was wondering if there are safer ways of doing this.
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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rdrake

Yes in that situation where trying to distill the methanol from the water useing your processor and a direct contact heating element could be risky. If the element was to become exposed to air from the decreaseing volume in the tank you would have a tank explosion. So there is a few ways around it.

1. Build a still that use's indiect heating i.e. heated water thru a heat exchanger.

2. At the end of the processing add 3 or four gallons of the methanol/water mix into the processor and redistill that way.

3. Use current processor with direct heating but add about 15 to 20 gallons of water to the mix so when the methanol is finally driven off you still have plenty of water to keep elements covered.

My suggestion would be build a seperate still with good temp controls and do all your methanol recovery in it. You could use your present processor if you had the decent controls and a column on it and not have the outflow of vapors come right off to the Plumbers Delight.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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or, you could add it in to glycerine that is yet to be distilled.
 
Registered: May 13, 2008Reply With QuoteReport This Post
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hooknline

Yup, I had actually thought of that one when I started makeing the list but it flew out the empty hole it was contained in before I got to it.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post



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Big Grin
sometimes the easiest answer is the one most overlooked or forgotten
 
Registered: May 13, 2008Reply With QuoteReport This Post
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You really need to get a hydrometer, you can go to the local wine or beer making supply store and get an alcohol tralles, you need to know how pure your distillate is, but, with a simple plumbers delight with no reflux capabilities I would guess you are 65 to 75% pure.
To have any chance of getting above 80% you would need to control your temp at the head of the still to 150-155 degrees.
 
Location: West Michigan | Registered: April 26, 2006Reply With QuoteReport This Post
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lots of great ideas...many thanks. I do use a hydrometer to measure my purity (which is how i know there is water in the methanol). I think i should be able to modify the plumbers delight to control the temp at the head end...its been a hit and miss affair up to now.

It seems that the most pure methanol comes off at the start of the distillation process - so i intend to take of samples every 5 degrees in temp, measure them for purity, and notice when the purity starts to drop.

I could also dump the contaminated methanol into the next batch of glycerine, and recover it when i do my glycerin methanol recovery.

cheers

richard
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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Fabricator,

I run esentially the same set up. With a sensor in the column head (just a 2' 3/4" pipe, no packing) and PID control I can get to 96% when distilling from glycerin. This is with a 4' PD condensor. This way I can use my processor for making fuel and distilling from glycerin as well. With a reflux column I would have to be able to bypass it when distilling from the fuel as I really need to get everything out of the fuel at that point. All of my distillation is done with the venturi pulling through the condenser.

Tony


2002 Ford Excursion 7.3l
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You're not finished when you lose,
You're finished when you quit.
 
Location: Tampa, Fl | Registered: April 27, 2007Reply With QuoteReport This Post
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How about an aquastat versus a PID for controlling the head temp? With a PID it looks like one also requires a specialized switching relay and sensor. I like the simplicity of an aquastat, as i have one wired into control the heating element (via a high current relay). However would it be accurate enough to give the desired amount of control for distillation?
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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if the aquastat can hold the temperature within a couple of degrees it'll work. otherwise get a PID..

I normally run my head temp at 152. higher the purity suffers. if you must have high purity you'll need a reflux column. I normally get 99% out. next time I have to try testing the purity as the process ends. I've always checked in the middle.

forgot to add..could use an inline heater..

-dkenny


'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died..Frown 8.23.11 bus driven to scrap yard Frown )
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everything run B100 when its warm enough Smile
 
Location: RTP, North Carolina | Registered: December 15, 2004Reply With QuoteReport This Post



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so i have now installed a thermometer at the still head, and i have set my aquastat to keep the temperature at the head between 65- 68C. I decided that regular veg oil would be my "medium" to which i added my contaminated methanol - I had one batch of methanol that is 60% pure, and one batch that is 90% pure - a total of 40 litres in all.

The aquastat seems to work quite well at keeping the head temp within range. I have got about 10 litres out so far (its still running)..and its 90% pure.

i remember reading somewhere Tilly doing an experiment with a simple pot still where he re-distilled 5 times with increasing purity of methanol...once the flow ceases, should i re-distill it???..
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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rdrake

It sounds like your going to need to. If you dont you will have to mix that methanol at about 10:1 ratio to fresh. Be sure that on next run you drain out the oil in the still now and put fresh dry oil in or you will be back in the same spot you were. Also to get higher purity the temp at the head needs to come down a degree or two. You say your keeping the temp at the head within 3C which i think is pretty good for an aquastat. If you had a PID installed you could keep the temps within 1F which would raise the purity rate considerably.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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what i plan to do - this is still (!!!) a work in progress - is to let the temp rise to 90C to drive off the excess water, which is what i do usually to dry my oil anyway.then i will add my 90% purity methanol to the dried oil, which will already be heated, and re-distill.

i did look at a PID setup...however, i initially held the head temp at exactly 65C manually (switching my heater off and on) and tested the purity coming off, which was only 90%...so i am not sure whether the PID would make any difference...maybe my eco-processor setup needs to be modified???
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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The purity of your Methanol is strictly controled by the temp of the vapors leaveing your column. According to methanex the Average Temp you had if you have methanol of 90% is 66.3C http://www.methanex.com/produc...nts/TISH_english.pdf . If you had of had Temp of 65.4C (just .9C lower) your purity would have been 95%, and just 1.8C lower than your original temp would have givein you 100% pure. To get 100% is very hard because anything above that your purity starts to drop, and anything below that and the methanol already condenses and falls back down the column. The reason for going with an Pid over a Auqastat is the PID can hold the temp within a smaller range than an Aquastat.

Also you say you held the temp at 65C manually according to your guage. According to 'theroretical' charts your guage is a slight amount off or you had a slight pressure in the system. Either of those can account for the discrepency between your guage reading and your purity.

If you are getting Methanol purity of 90% no you dont need to modify your setup except to bring the head temp down a tad and maybe get a tigher control of the head temp.


Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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after i extracted my first 15 litres of 90% pure, i fitted another container, and collected the next 15 litres or so at about 80% pure, removed that container, and the last amount was around 40% pure. All this was within the range of 65-68C. would there be a pressure difference as liquid was condensed to explain this variation? I am using a GL system with a venturi, which i believe keeps the whole system at atmospheric.
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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another thought. I did try an experiment once before taking samples every 10C from 50C - 90C. each time the distillate was 90% purity...which would seem to contradict the temp changing the purity.
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post



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rd

On that GL system, is the ventui sucking air? If so that could be throwing the entire 'distillation' out of whack. Your not letting the heat vapors rise naturally but forceing them up. That could explain the discrepecies between what you are getting and distillatilation principles. The GL process was developed to remove methanol from the Bio not necessarily to produce high purity condesate.

Trc


If you can't dazzel them with brilliance, then baffel them with bullchit.
 
Location: north of houston, south of dallas, east of austin | Registered: August 31, 2006Reply With QuoteReport This Post
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hi

yes, i am recycling the vapours through the venturi...i could close that off and see what "natural distillation" does.There are lots of folks using the GL system who get good quality methanol, but my guess is that there isn't water in the product they are distilling.

On another note, i am going to try a small batch of 3A zeolite..there seems to be a few folks who have used that successfully to separate the water in methanol
 
Location: BC, Canada | Registered: August 18, 2005Reply With QuoteReport This Post
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