My tests are done for methanol recovery.

I remember Tillys results a long time ago where it confirmed that the bulk of the methanol is in the glycerine layer. The rest of the methanol becomes methyl ester. Otherwise methanol would be a catalyst which we know it is not.

My kettle contained 2.25liters of glycerol. I made a self contained condenser unit. It contains ice cubes and water as I believe in being a water conservationist.

After each round I put the condenser back outside to cool it.

In the end I collected 855ml of methanol. I did a burn test and it was pure or pure enough.

When I dumped the glycerine out of the kettle I had 1.35 liters. This turned out to be the same amount I started with -2.25liters.

My recovery is 38%

In Canadian money, my methanol cost per liter at 20% to make biodiesel is 30cents. My recovery reduces that cost to 18.6 cents. The electricity to recover 1 liter of methanol is 13 cents.

Total methanol cost per liter is now 21.2 cents per liter.

If sold at 50 cents per liter, 28.8 cents is left to cover wages, other electricity costs, pickup and distribution costs.

Anyone else recovering?

You could lower your costs by another 13 cents by using the glycerine to heat glycerine to recover the meth.What do you do with your waste Glycerine Doug.

So far, we have tried the glycerine log, works well.

Recently a company called Topia Energy from Ottawa Canada, is a biodiesel outfit. They gave a sales pitch to a city council in Ontario where they pitched the spinoff of glycerine from making biodiesel.

Now correct me if I am wrong. The glycerine is virtually useless from biodiesel production. You cannot use it in protein bars etc. This is what this company said, yeah, protein bars.

I know glycerine can be made a number of ways.

It can be made from synthesis from propylene.

It can be made from fermentation from sugars.

It can be made from fats- hydrolisis, saponification and alcoholisis(biodiesel)

So I have 1.35 liters of nice gooy molasses type glycerine, now what. I have just started to see if it can be purified. However, I don't know how so burning it or candle making seems premo.

What about soap making, the problem is the color, it needs to be clear, I added sulphuric acid and it does not clear, at least this feedstock does not clear.

HELP

in all of its dark brown glory! Best de-greaser I have ever put my hands on, or greasy equipment.

This is my still:
http://www.rpi.edu/~morriw/mixer.htm

Pretty simple setup and there is a blurb under the pic.

If i were to use your setup with the following changes, would it work? Install a vacume pump between the "pot" and condersor, remove heat just use room temp. Also, since i am a mechanic by trade, would a auto ac condensor with fan insted of water work for methanol? I think i have the process down and am thinking that i can use alot of "throw away" items around my shop for bd production and meth recovery. Things like used "freon" tanks for mixing lye and methanol, same tanks for methanol recovery. I'm new to this and the search function just left me with more questions. TIA
Jason Gnatowsky

Good emails, good questions.

Wally, excellent picture of your still, looks like you are getting 40-50% recovery, right on!

jgnat1488, it all depends on your creativity and how much money and skill one has. I was designing mine for 3rd world type applications.

I have since burned some glycerin and the tests show very little black smoke. However, burn too fast without added air and I get black smoke.

I have a couple of freon cannisters from the previous tenant that lived here. I think they are full and frankly I don't know how I would rig those up, but hey, sometimes the best inventions are the ones that are unconventional.

Yes, the glycerin works well as a degreaser. HOwever I would like to find some way to clear the dark color.

Obvious safety point:
If using the byproduct as soap you really must remove the methanol. It's flammable and toxic.

I believe that technically there is no reason why the glycerol can't be used for any other food purpose. The distillation process involves high temperatures under vacuum and a number of evap/condensation stages. Whatever it's source, the product should be pure

However in the EU since the advent of BSE there are rules about what can be used in animal and human feedstocks. I'm fairly sure that all food waste products however processed are not allowable. This makes good sense for almost every other food product, but I wonder if glycerol got caught in the crossfire.


There is an issue about using vacuum to distill the methanol. Certainly lower pressures will drop the boil temperature, but as ever it's not that simple...

1 Methanol has a high heat of evaporation. You still have to add heat.
2 You have to condense the vapours. If you are boiling at close to ambient then you'll need a fridge to condense the vapours. Heat must be extracted to collapse the vapour.

The cost of raising the liquid temperature is small compared to the energy neede to actually boil the liquid.


It's easier and certainly less technically complex to add heat to boil the methanol, then ambient temperature will be adequate to condense the vapours.

Excess energy is one thing a biodiesel plant is not short of.

Vacuum does make sense for dewatering oil. We dont want to be heating all that oil just to get a few percents of water out. Around 80% vacuum is ideal. The water will boil off fast at 50C (reaction temp) and while still under vacuum, will condense at 30C.

A better idea might be to spray the oil into an evacuated vessel (spray dryer). The water will flash out of the spray and cannot froth up the oil into the condenser.

If there are no leaks in the system there is no need to suck any vapours through the vac pump.

I am collaborating with a BD maker to see if it can work when fueled by the glycerin byproduct of BD maufacture. I use it to dewater wvo and am in the (longer than expected) process of safety and performance "tweaking".

I think that with such a heater the glycerin byproduct could provide process heat for BD manufacture, dewatering, and methanol recovery.

Sicne I rarely check the BD side of this forum (I use prefiltered wvo as fuel) if anyone is interested in this research please contact me directly at danalinscott@yahoo.com for updates.

I have discovered that refrigerator compressors are very useful for a lot of things other than what they were designed for. And being free they fit my budget nicely. I wonder if one can be used to set up a simple methanol recovery vacuum still?

Correct me if I am wrong...but wouldn't the recovered methanol have to be nearly annhydrous to be reused in BD production?

Dana Linscott

There is a common misconception that methanol recovery demands a compressor/vac pump to suck the hot vapours out of the recovery pot.

This is not necessary and without a flame proof compressor potentially dangerous.

If vacuum is used, the hot pot, condenser and cold pot should all be under vacuum. Hot vapour will naturally find its way into the condenser to fill the space left by the cold condensing vapour.

I believe that for methanol recovery a
vacuum system is not much help. The stuff will boil a lower temperature, but it will also condense at a colder temperature. You could easily find the condenser needing a chiller to do the job at a half decent flow rate. A chiller is far more hassle to set up than a simple heater.

That said, for water extraction from oil a
vacuum spray dryer makes sense. You dont want to go heating 98 litres of oil just to boil off 1 or 2 litres of water.

As Tilly said elsewhere, a plain pot still is fine for extracting methanol from oily/fatty byproduct. There's no problem with water contamination as there's none there to upset things .

Methanol can be extracted from unwashed biodiesel but the small methanol content probably makes it uneconomic. Same applies to extracting methanol from wash water with the added problem that a simple pot still wont do the job properly (moisture contamination).

DAVE UK

Thanks for the explanation.
Did you see the how to add an image post?

RAVeman

Dave UK,

I do not (completely) agree with what you said about needing a chiller.
If you use a compressor for methanol recovery, it can very easily been done... if you can get hold of the right equipment.

To do it by vacuum, you need a compressor which you can feed the vapours through.
So you suck vacuum on the glycerine side, through the compressor, and on the recovery side you just put a pot which can substain pressure.
No condensor needed (pot and compressor act as condensor)
On the vacuum side, lower boiling point because of lower pressure. On the high pressure side, higher boiling point because of pressure. It's that easy.... only, the pump has to be methanol resistant.

To be on the save side, also a pressure security valve on the pressure (recovery) pot needed.

Have done some tests on it, works well, but my pump is not methanol resistant.

Regards,
Filip

Interesting viewpoints.

Although I can't agree to the hazard issue that has been brought up.

I used a closed system and I regulate the temperature to 70C or around there. For methanol to burn you need an ignition source. Using a burner element running on electricity will not ignite the fumes and there has to be enough concentrated fumes to catch fire. Propane left on in room will not ignite until the room is saturated with 19-21% propane to the rest of the air, then switch on the tv and boom. Most people pass out from the gas before boom time. With methanol recovery, vacuum or regular atmosphere is just fine. Just make your system as safe as possible and recover that valuable alcohol.

to recover methanol for a long time.
I want to quickly point out that I am not knowledgeable about the dangers of using a refrigerator compressor for this procedure and supplying the above information in no way implies that I think it is a safe thing to do.

Tilly SBC/IBA

It's all about energy. And why make it more complex and possibly more dangerous than necessary.

You can make a liquid boil at below its ambient temperature by lowering the pressure. But, you still have to input the energy necessary to make the liquid boil. Heat of evaporation demans considerably more energy than the sensible heat needed to warm the liquid up to boiling point.

In the case of methanol you'll find your heater is going full belt just to maintain the pot at boiling temperature.

An electric kettle is a good example. Boils water in a couple of minutes, but would have to run for 30 to 40 minutes to boil 1 litre dry.

If you boil that water in a vacuum it will boil at a lower temperature, so lets say it now boils at 50C and needs only 1 minute to get 1 litre to that point. It will still need 30 to 40 minutes to boil dry.

Methanol is no different that's why a splash of it on your skin feels so cold.

If your vacuum pump can pull to 150torr (0,19atm), the methanol will be boiling at 25 degrees celsius. So no need for a heater, the room your standing in will suplly the heat.
Only need some good transfer of room temp to glycerine (some heat-exchanger).

regards,
Filip

right in theory but to put that heat exchanger into practice could be quite a poem! Dave UK says it in his post: The amount of energy required to evaporate all that methanol is considerable. In practice, under vacuum, you would evaporate some methanol until you have used all stored heat in your vat. By then the vat would be so cold that you would be under the temperature needed for evaporation of methanol at that given (low)pressure. This is why propane cylinders in balloons are delivering liquid propane up to the burners coil, where it is preheated: The heat transfer from the athmosphere to the gas cylinder is not sufficient to boil the propane in the cylinder to deliver gazeous propane to the burners at this rate.

The two certainties of life: Death and Taxes

So for my 'theory', the problem lies in the compromise (or should I say problem) between contact-area for heat transfer, and having the same construction under vacuum.

So I agree, better go for heating till 65-70 degrees celsius, with conventional condensor.

So anyone having already a setup in which he uses the glycerine to head the glycerine.... you know what I mean.
I will look further into this one.
A shame this setup could become rather 'bulky'

Filip

I have tried both methods of recovering my methanol.
* Heat: is very energy hungry and more dangerous. I recover from both the biodiesel and methanol. Heating 200 litres of biodiesel and keeping it hot (about 90 C to get a reasonable flow rate) requires lots of energy. As the methanol is vaporised it takes away a lot of heat. Then you have to deal with vast amounts of very hot methanol vapour and it requires a lot of cooling to condense. Heating 40 litres of glycerine is even worse. As the methanol boils off it creates a bubbling foam on the surface which can get into your collection pipes and condenser. Pipes choked with hot glycerine while methanol vapours build up behind is a very scary thing.
* Vacuum: By comparison, this is nice, friendly and safe(er). I seperate the glycerine from the biodiesel as soon as possible to save heat. Then apply a vacuum to the chamber and the methanol will boil off and the vapours will be sucked out. On the other side of the vacuum pump the pressure is returned to normal and the vapours condense. No need to provide extra heat or cooling.
My system is not ideal as I use old fridge compressors. They draw the vacuum over the motor. These pumps only last a few months (@ 200 litres per week of biodiesel production) but they are free and until I can find a real vacuum pump at the right price I will have to continue using them.

Andrew.

Andrew:

Check your local autoshop equipment dealer. Line oilers and seperators are a common item for the bump shop operators (bodyshop). Standard compressor oil is injected on the vacumm side and then seperated and returned on the output side. Should work well with little or no contamination of the methenol.

The paint guys use them to assure clean air to spray with and still allow the rest of the shop to oil their tools.

Bill

I did say that heating large volumes of oil or ester to remove a small percentage of water or methanol is not economic. In that case a vacuum spray dryer would be the best option.

For dealing with the byproduct you do need a water bath type heater or better a hot water coil inside the byproduct pot. Don't heat directly with an electric element or naked flame.

Yes there is considerable energy involved - an unavoidable issue with methanol. The fact that a simple pot needed 90C to get a good boil off rate proves this.

Regarding safety, methanol vapour is nasty at any temperature so make sure the pipes are strong, you have a good safety valve blow-off system and a condenser that can extract the heat.

Above all avoid any leaks. Air sucked into a condenser under vacuum is as bad as vapour leaking out of an atmospheric pressure system.

With no leaks the vapours will displace the air - no oxygen to make an explosive mixture.

[This message was edited by Dave UK on 13 March 2003 at 05:14 AM.]