Methanol testing, recovered methanol, purity, and process?

[nigelb]

text speak....it's just for knobs. That's why I cant do it. everything has to be grammatically correct. Some have the gift....some dont..........I know you read them

[Jamesrl]

I'm just not down with the kidz

You're far too tall to be doing with anyone young or old.

[nigelb]

yp ur prbbly rite

[julesandtash]

LOL..... PMSL M8

[thewormman]

1 x Stevenson Reeves Spirit Hydrometer / Alkohometer 0-100% (alchometer) = £4.29
1 x Glass Trial Jar (glass trial jar) = £5.75
------------------------------------------------------
Sub-Total: £10.04
Shipping: £2.00
Total: £12.04

 http://www.balliihoo.co.uk


The trial jar is cheaper than getting one off ebay, however, its base is small, so its not that stable.
If that's a problem for you, there's one on ebay that i was otherwise going to buy - i can look up the item number for you later.

Got it through today thanks

My reclaimed seems to be 99% could that be right? Did the test at 20C 

[Julian]

Sounds a little too good to me ... are you using ASM?

[thewormman]

Sounds a little too good to me ... are you using ASM?

Yes ASM when I did the demeth my PID wasnt working properly i discovered  so I used the temp gauge on the front of the processor, didnt want to push the temp up any more than necessary so only took it to just under 80C.

Reasoned that Methanol boils at 64.7C so as my processor is well insulated, temp at the head would still be high. I could hear it vaporizing in the head and it was running out the condenser so I thought that was high enough. Maybe not being near boiling point of water helped?

[Julian]

With ASM may be it's possible, but the likely hood is that your virgin methanol was only 99% in the first place, so to have recovered methanol with the same purity is unlikely.  I've only once checked methanol purity since I started using ASM and that only because I suspected the process I was using introduced water and indeed it did ... it was off scale on my hydrometer!

The acid test will be if it processes OK in the next batch ... my guess is that it will.

You reasoning regarding water and methanol separation is logical, but I'm afraid it doesn't work as easily as that.  Water and methanol are miscible and as such are very difficult to separate.  Several of us tried at length to do it with a GL, but regardless of how carefully you control the temperature the methanol will never be pure enough to reuse.  It is possible but you need several stages of reflux and to be honest just isn't economical at the scale we work at.

Best bet is to dry the oil very well, use ASM sparingly and then recover the methanol before doing any water washing.

[Jamesrl]

Got it through today thanks

My reclaimed seems to be 99% could that be right? Did the test at 20C 

Sounds about right Dave, been getting those sort of readings since I started using asm.

I did 10 batches in a row continually using all the reclaimed topped up with virgin and the 11th reclaim measured 98%.

As for the temperature, the higher you go the more methanol can be distilled out of the bio, purity doesn't seem to change.

[nigelb]

Now that is interesting gents. With ASM being a "dry" catalyst it could be worth dipping my toes into recovering again.

[julianf]

With ASM may be it's possible, but the likely hood is that your virgin methanol was only 99% in the first place, so to have recovered methanol with the same purity is unlikely.  I've only once checked methanol purity since I started using ASM and that only because I suspected the process I was using introduced water and indeed it did ... it was off scale on my hydrometer!

The acid test will be if it processes OK in the next batch ... my guess is that it will.

You reasoning regarding water and methanol separation is logical, but I'm afraid it doesn't work as easily as that.  Water and methanol are miscible and as such are very difficult to separate.  Several of us tried at length to do it with a GL, but regardless of how carefully you control the temperature the methanol will never be pure enough to reuse.  It is possible but you need several stages of reflux and to be honest just isn't economical at the scale we work at.

Best bet is to dry the oil very well, use ASM sparingly and then recover the methanol before doing any water washing.

If i had the time / energy required (and, more importantly, did not want to spend it doing somthing else!) i would try a colum, as high as possible, filled with marbles from the toy shop.

If / when i ever get sorted, id like to build a still running from solar.  Id just dump all the glyc etc in it, and leave it.  Come back to get the methanol, which, for me, is the most expensive part of the process.

A 54mm copper pipe may do.  Possibly even soil and vent?

[julianf]

I forget what percentage you can get up to with ethanol from standard distillation alone, but its certainly not 100%.
I seem to recall that its then dried with benzene or something?


Wikipedia to the rescue -

(this is for ethanol)

Distillation

Ethylene hydration or brewing produces an ethanol–water mixture. For most industrial and fuel uses, the ethanol must be purified. Fractional distillation can concentrate ethanol to 95.6% by volume (89.5 mole%). This mixture is an azeotrope with a boiling point of 78.1 °C, and cannot be further purified by distillation. Addition of an entraining agent, such as benzene, cyclohexane, or heptane, allows a new ternary azeotrope comprising the ethanol, water, and the entraining agent to be formed. This lower-boiling ternary azeotrope is removed preferentially, leading to water-free ethanol.[39]
Vapor-liquid equilibrium of the mixture of Ethanol and Water (incl. azeotrope), composition given in molefractions

At pressures less than atmospheric pressure, the composition of the ethanol-water azeotrope shifts to more ethanol-rich mixtures, and at pressures less than 70 torr (9.333 kPa), there is no azeotrope, and it is possible to distill absolute ethanol from an ethanol-water mixture. While vacuum distillation of ethanol is not presently economical, pressure-swing distillation is a topic of current research. In this technique, a reduced-pressure distillation first yields an ethanol-water mixture of more than 95.6% ethanol. Then, fractional distillation of this mixture at atmospheric pressure distills off the 95.6% azeotrope, leaving anhydrous ethanol at the bottoms.

[thewormman]

Sounds about right Dave, been getting those sort of readings since I started using asm.

I did 10 batches in a row continually using all the reclaimed topped up with virgin and the 11th reclaim measured 98%.

As for the temperature, the higher you go the more methanol can be distilled out of the bio, purity doesn't seem to change.

Thanks Jim I am not going mad then 

With ASM may be it's possible, but the likely hood is that your virgin methanol was only 99% in the first place, so to have recovered methanol with the same purity is unlikely.

Picture speaks a thousand words, what do you read it as?
I know there is a little Bio in there but Tony said this is normal I think

Best bet is to dry the oil very well, use ASM sparingly and then recover the methanol before doing any water washing.

Thanks for the advice that is exactly what I am doing, nice to have it confirmed 

[Julian]

I've never seen that with any methanol I've recovered.

Are you sure it's bio?  Bio is miscible with methanol.  Will it mix?

Bio has an sg of between 8.6 - 9 and methanol 7.91, so significant quantities could adversely effect the reading.

I can't remember further back in the post, but is the hydrometer reading up to 100% alcohol (it's not clear from the photo), if so they are not the most accurate indicators, but should be adequate for our use.  Personally I wouldn't hang my hat on the reading being very accurate, but it should be a good indication that the methanol is OK to re-use.

[Julian]

I must get round to finishing this page, but if you look here ... http://www.biopowered.co.uk/wiki/Testing_methanol_purity  you can see the difference between an alcohol hydrometer and a laboratory version.

The scale on my lab. hydrometer probably represents around 3-4% over it's full length (that's just a guess but you get the idea).