that is as high as I can get my appleseed to go just running it with oil, no reaction, I assume reacted would bump it up 5 -10 degrees.

if I make a condensor will I remove enough methanol to make it worth the effort?

I have only done one 20 gallon batch so far (base base method) and passed 3/27 with no drop out even after a week. I just finished washing and drying and would like to get away from so many washes if I can

Since no one else more knowledgable has responded, I don't think you will get significant recovery at that temperature.

thanks for the reply UFO. I kinda figured that but the way I look at it, it dont hurt to ask!

no..

you'll need a pot temp around 180 and higher..

if you bypass the thermostat it'll go higher..
if you bypass you must watch the temps!!!

-dkenny

I've been looking for a way to bypass the thermostat. How do you do it? I would like to wire in a higher temp thermostat instead. Maby from an oven. Possible?

I use a PID and thremocouple.

-dkenny

O.K. I'll bite....what's a PID? Electricity and I...uh.. don't get along very well. And where can I get a PID and how hard to wire in?

a PID is a fancy electronic thermostat.

I got mine on ebay.

the companys manual should give you idea on how to wire it.

-dkenny

I am sure there are waterheater tstats out there that go higer than 180, I just need to look for one.

thanks for the replies

There is an EXTENSIVE thread on using PIDs to control temperature during recovery here in the methanol recovery section. Do a couple of searches.

You really only need a column head temperature around 150 to get nice pure methanol. You will need higher than that to drive all of it out.

-Jim

Mike,

Assuming that you have your water heater hooked to 110V, I have an alternate solution which is much simpler. I would like to employ a PID someday but not yet. That type of equipment is simply outside of my experience base.

For my GL-Eco / Appleseed setup, I have very functional heat control for methanol recovery. I feel very safe about using it and I purchased everything at Lowes.

I use 3 110V spring wound timers from Lowes. I think they cost $14each or less. I use one 12-hr timer for my pump (with a switch and indicator light), I use one 12-hr timer for the acquarium pump hooked to the condenser (with a switch and indicator light). I use one 60-minute timer for the heating element (with a heavy-duty switch). I run 110V to the timer, then to the switch, then to a modified water heater thermostat, then to the heating element. The modified water heater thermostat (also from Lowes) has had the plastic dial taken off the temp adjustment screw, turned counterclockwise 30degrees and put back on the set screw. Now I can set the high limit higher than 140. The model is made by thermodisc and its a 59T. Lowes sells it under a branded name but it looks like this:



Now its true that this type of thermostat is no where near as sophisiticated as a PID, Thermocouple, SSR, digital timer combo. But my temp control is really based on time of heat applied. I can't apply more than 60 minutes of heat and the thermostat is set to click off at around 185 F so I feel fairly confident that I'm not going to have a run-away heating element on my hands.

Methanol has a flash point of 11deg C doesn't it? And I've found that if you just leave the lid off the bio container all the methanol will have flashed off at 25 deg C ambient and reasonably dry days after about a week, even without circulating it at all. Gentle circulation and a small fan blowing over the open topped container will usually do it in just a few days. All the soap and other crap (residual catalyst, glycerin etc.) will drop out over the ensuing few days. So as long as there is a temp diff between the oil temp and the condensor water feed temp, why is it necessary to heat the crap out of it?

As long as the oil is above methanol's flash point (11deg C) and the condensor temp is kept below that the meth can be recovered can't it? And at considerably higher purity than if you are heating it up a lot, in which case you are going to be recovering a lot of water too?

We just need the meth to evaporate out of the bio don't we, not BOIL out of it?

I know it takes longer this way, but you don't consume nearly as much energy and you don't beat the **** out of the bio. Maybe I'm missing something, but the less you heat the bio before it is actually combusted in your engine the better.

Cheers.

Stuart,

We are not dealing with pure methanol here to start with. We are driving the methanol out of either the bio-d layer or the glycerin layer.

As the methanol concentration lessens in the material it is being extracted from, the higher temp the material needs to be heated to drive it out.

That said, It would take a very long time for the methanol to "find its way out" at room temp 11-20*C.

There does seem to be a "sweet spot" of temp that has been reported to work best for quickest recovery and least water entrapment.

That is why I am building a reflux still. I use just a plumber's delight on the processor and that seems to work well but, I want to have the residual methanol as low as possible in my glycerin because I am making soap and fire logs from it.

quote:

Originally posted by RNCarl:
Stuart,

We are not dealing with pure methanol here to start with. We are driving the methanol out of either the bio-d layer or the glycerin layer.

As the methanol concentration lessens in the material it is being extracted from, the higher temp the material needs to be heated to drive it out.

That said, It would take a very long time for the methanol to "find its way out" at room temp 11-20*C.

There does seem to be a "sweet spot" of temp that has been reported to work best for quickest recovery and least water entrapment.

That is why I am building a reflux still. I use just a plumber's delight on the processor and that seems to work well but, I want to have the residual methanol as low as possible in my glycerin because I am making soap and fire logs from it.

But that's what I'm curious about. All the methanol will 'flash' off exposed bio or glycerin as long at is it held at above the flash point of methanol (11deg C). Even when the methanol concentration is only trace, it will still be evaporating off, as long as the concentration of methanol in the gas it is evaporating into is kept low. The concentration of methanol in this 'gas' will be low if it is just free dry air or air (or some other gas) in a closed loop condensing system where the condensor temp is kept below the flash point of methanol.

Of course the driving off the methanol will happen a lot faster if the bio (or glyc) is heated, but it seems to me that the reason people think they have to heat it at all is because they don't cool the condensor sufficiently. Just running the condensor coolant through an iced water bath would achieve this.

I must point out that at the moment I don't recover methanol. But I have been 'GL' drywashing bio by allowing all the methanol to just evaporate off my bio, for years (after which all the impurities simply drop out). If you circulate the bio and blow a fan over the surface -at AMBIENT temps, it only takes a few days to flash off ALL the methanol, and a few more for the fluffy soap layer(which had been slightly clouding the fresh bio) to accumulate at the bottom of crystal clear bio.

cheers

Stuart,

That is an interesting concept. I know partial pressures come into play here. I must admit, my Dalton's law physics is rather limited.

I have a batch of bio that I have been settling for over a week now and the barrel is quasi open. I cut a flap on one side that I hinged and there are no plugs in the bungs. there is still a scum on the top layer of the bio and it isn't "crystal clear" by any account. I guess I could try and blow a fan across it.

How humid is it where you are? I wonder if the whole partial pressure thing (of a gas) is related to moisture saturation in the air as well. It's winter there now yes?

As far as using iced water for the condenser bath to cool the vapor below 11*C that's interesting. I use tap water that's about 68*F so that's what 20*C? So I would have to keep my water column below 52*F is what you are saying?

I wish others would pipe in here because it does cost to use electric to heat the gly and bio so hot to recover. Not to mention it is more dangerous.

As far as just letting the methanol be released into the air. thats is another issue entirely.

I've no idea about the partial pressure exerted on methanol evaporation by humidity, but it's certainly interesting. If you blow a fan across the top of your fresh bio, make sure you ciculate it too. Even rising bubbles from an aquarium bubbler would do this as well as introducing an evaporative (methanol) interface throughout the bio mass.

But Flash point doesn't change the less methanol there is in your bio. As long as it is kept above 11deg C the methanol will continue to evaporate at the air/bio interface (which if you are circulating the bio will be changing constantly).

Also cooling your condensor coolant below the flash point of methanol would seem to be an obvious way of increasing the liquid methanol condensing into it. It costs to artificially cool the condensor (ie. refridgeration costs) but not nearly as much as heating the bio which has considerably more thermal mass than the gas rumming through the condensor. Particularly if you are chasing the BOIL point ot methanol in your bio rather than just the flash point simply because you neglected to keep the condensor coolant under the flash point. If the vapour going through the condensor isn't cooled below methanol's flash point a lot of the evaporated methanol driven off the bio by heating the %%%% out of it will simply make it through the condensor still in vapour form. It doesn't matter how efficiently the condensor transfers its coolant temp to the vapour if that coolant temp is above methanol's flash point.
If your Bio container is insulated it isn't difficult or expensive to raise its temp above methanol's flash point for a week.

It is winter here at the moment. We actually had 6deg C a few nights ago, which is about as 'cold' as it gets.

Cheers

I have not built anything for methanol recovery yet as I have been fine tuning my processor and dry washing. Do you think the following method is working?
I built a simple recirculating heater out of 1.25" pipe with a hot water element inside. I then circulate the biodiesel through it and out through a nozzle that has enough spray force to actually aerate the biodiesel in an open tank. I am reaching temps of 46.6C and I circulate for 6 hours or so. When I notice soap start forming, I feel like I am almost finished.

Thanks

Knotwild,

Sounds like what you are doing is working.

After I run a batch of BD, I heat it back up and then pump it into a 55 gallon drum. The next day I insert a cat pump, a fountain pump(the one used in small ponds) and splash the BD against the side of the drum with a fan blowing at an angle down toward the surface of the BD. After a few hours soap begins to form on the surface. I let it run for another day before letting it settle for about a week.

Then I proceed with the filtering/drywashing.

Thanks Eurocab.
I am not letting it settle as long as you are, only 24 hours or sometimes 48. I have noticed that dryer oil = less soap and that the biodiesel starts to clear up within 4 hours of de-mething. I use the seat of the pants method of estimating the amount of Magnesol I need by the amount of soap I have settle out. The fuel is looking really good after the magnesol, and when I let it settle longer, it is so clear I believe I could run it without dry washing.

Best wishes and thanks,Jim