This entire Methanol Recovery issue and practice has me completely stumped. I am really not referring to the actual principle of doing it as much as I am referring to the act of it.

Murphy, put up an example of 55 gallons of glycerin, and how much Methanol was anticipated to be recovered if he distilled the entire 55 gallons. The range was somewhere between 14-18 gallons, my personal guess was somewhere around 17, but that is also not the issue.

I am basically torn between the issue of to recover or not recover the Methanol to begin with. Since we produce about 350 to 700 gallons a week of glycerin, it is really more of a challenge. The question that keeps coming back, is recovering the Methanol even worth the exercise, because, there is no way unless I had the mother of all stills, is it ever going to pencil.

We built a still out of a beer keg to try this out, and basically learn the process, so that we could build a larger set up to go down this path. After running our still for almost 8 hours on 15 gallons of glycerin, we got like 4.5 gallons of methanol. This is where the rub comes in. 8 hours of trouble to recover $9 worth of methanol. When we started this, we had no idea what to expect, but now that we do, we are scratching our head going why bother. Yea, yea, I know it make good fundamental sense to do it, and yea, one is recycling and all that stuff, but seriously, 8 hours of trouble for a $9 savings. Sometimes one can do it while doing other things, and it is not as bad, but a lot of the time, we have to pay someone to do this kind of stuff, and the math just does not work. And we are not including any monies for electric, or repaying the cost to construct the still, or a ROI.

Now we really want to do Methanol recovery, but I need some wisdom on how to do it where as the thing can at least come close to paying for itself.

If we were to construct a larger still, how do we make it automated whereas someone does not have to sit and babysit the damn thing. On our BD set up, everything runs via PID/SSR's and it is pretty idiot proof, turn on, come back couple hours later, transfer, etc. I do not think we actually work more than 1 hour total to make 350 gallons of fuel. I think doing something in say a 60 to 100 gallon size would work for us, since we normally put our glycerin into 55 gallon drums for disposal.

This is just such a gut wrenching issue, it would be awesome to recover the Methanol, but we just do not want to spend $50 to recover $10 worth of Methanol. Now I know that Graham being the mad scientist that he is, probably can help us out on this issue, and some of you others, please feel free to toss some idea's in the ring. Gigem, it only took one look at that contraption that you built, and know that an Aggie built that thing. I could go on an on about Aggie jokes, but one look at that still of yours says it all.

So please pass along some of your input, advise, and wisdom on this issue for us.

Thanks

I do it like this...unattended.
Methyl Honey

Hi SpeedRacer

A few things to check, to get good, fast methanol output..

1. Did you have your beer keg REALLY well insulated? All over, including the tube to the condenser. An un-insulated pot makes for SLOW distilling.

2. Did you circulate the glycerol? Really helps to get efficient heat transfer from the element to the glycerol. If you don't circulate, you can get bubbles of methanol vapour forming an unwelcome heat insulator all around the element, and if there's any starchy material in there it will stick more easily to a really hot element, compared to an element cooled by a free flow of glycerol.

3. Did you keep pumping heat into the barrel? How hot did the glycerol get?

It's sweet when it gets going well, I really encourage you to persevere - you'll be glad you did, I'm sure.

Graham,

I am sure there are about 100 things we could do differently on our keg still, we just kind of threw it together to use as a test, nothing permanent. But even if we cut out time from 8 hours down to 4 hours, is it still even worth the hassle?

The main issue I am struggling with is how to construct a idiot proof, self running, 50 to 100 gallon still set up. Or the bigger question, is it even worth the expense or hassle. I'm down with trying to build it if it can be automated with PID's so that once you turn it on, it will turn itself off at certain temp. But is that even a practicable? I have not toyed with circulating, or adding air or other such items that I have been reading.

I think I might on a serious note, turn that keg still into a whiskey still, which after all, one can not place a value on quality whiskey.

SpeedRacer,
Of all the equipment you may build and/or use in the process of making BD, the still is the easiest to automate.

First break it down into the basic parts:
A large tank with insulation.
A heat source.
A fractioning/reflux column (optional but recommended)
A PID with thermocouple.
A condenser
An air supply and/or a pump.

On the pump, I've done quite a bit of methanol recovery and I stand firm in my belief that you don't need a pump to circulate if you just use a little air injection.

If you want to look at it from an automated standpoint:

You would need a PID with a thermocouple at the "head" of the still and the PID would have to have an "alarm" feature so you could set it to shut everything down when the final temp is reached. Some PIDs do this as a regular part of their function.

You would set the whole process with a "holding" circuit. You know, a relay that holds itself energized once started but the hold circuit is broken by the contacts activated by the PID.

You would need a simple solenoid for the air supply and the water supply for the condenser. You may also opt to have a recirculating system to cool the water for the condenser. This would be set to simply turn off when the holding circuit was broke.

You start the operation by turning on the whole operation and setting the hold circuit. It would continue (unattended) until the preset temp was reached and the whole system would shut down.

There should be 1 back up redundant "over temp" device.

It's really that simple.



-mcguyver

Mcguyver,
well said..
I have 2 pids on processor/methanol recovery wired just that way. I used simple relays in the 'holding' setup. the controller on the 'head' is the turn off controller. I just set this Pid to cool instead of heat.

now to add some air...and try using the pid to control the head temp instead of the pot temp.

back to the question.
if you're not counting the time the heating the oil, adding the methoxide, the settling of the glycerine in making BD why count the hands off time in methanol recovery. the PIDs control the process and leave.
as far amount returned..
the last batch I ran I got around 10 gallons out of 40. not great but a 2.30 a gallon..not bad. I might have spent 1hr total over 24hrs checking and watching. some was playing. I wanted to check the purity near early in the process instead just when it was done.

cost..I think i got both PIDs for $ 50 and another 20 for thermocouples. I think its worth the time to recover.

at 350 gallon/week-> this might yield 90 gallons of methanol/week. the yield depends on on how much you use to start with.

-dkenny

Hey dkenny,
When I mentioned using the "alarm" feature I was accidentally referencing some planning I've been doing in my head for a control panel I'm going to build for my still. The PID I plan to use only has 1 "set" temp that it will respond to. I was planning on using one PID to turn on the solenoids when the temp reached a certain preset value and then turn off the entire operation when it hit another value. I figured if I set the temp on the PID to roughly 160F that would turn on the water to the condenser and the air injection. Then I could set the "alarm temp" to de-energize the holding circuit when the head temp reached 200F or so. From what I've seen lately, I might even build in an "off delay" relay to allow the air and water to run for 4 or 5 minutes after the heating elements have been turned off.

I always have some ideas floating around in the old noggin It's just a matter of getting them into practical use.


-mcguyver

Mcguyver,
sounds interesting..I had to use the 'cool' feater in my PID for the same reason. it doesn't have an alarm(would require a 2nd output, but doesn't have).

-dkenny

Can you tell me what PID stands for and where I can get info on what they are and how they work?
Thanks
Lynn Walton

All right guys, thats what I'm talking about. Turn it on, let it run for say 12 hours +/- and have it shut off. I'm good with having to check once and a while.

With the PID's that we use on everything else we have, they are pretty sweet. You basically set to goto a certain temp, hold the temp for a set time, then ramp up to another temp, hold the temp for a set time, then ramp up again, and so on and so on, then shut off. I think they call it a ramp and soak option, but either way, we have had good luck with them, they are about $80 each.

The reason I ask, is because some of the articles I have read, people have said the juice quits flowing when the element turns off. So I was unsure how it would work with the ramp & soak option turning things off and on all the time. Just a thought. Adding air is pretty easy, we have air added to Grahams water less wash set up we built, so that part is easy to install.

So I guess the question now is, what is the best reflux column to build that works well and easy to construct. I am guessing 4" pipe would be the best?

Keep the idea's coming, thanks.

quote:

Can you tell me what PID stands for and where I can get info on what they are and how they work?

Hi Wwalton47834,
Welcome to the forum.
PID stands for:
P= proportional band
I= Integration time
D= Diffenciation time

All a PID is is a very elaborate thermostat controller. It turns the heat on and off just like the one on the wall at your house. The one at your house (assuming it is a bimetal)probably has a temperature swing of 8F during its operation where as a PID can be as little as a 1F swing in temp and it can account for overshoot and undershoot of your desired temp. It can also do complex operations such as the one SpeedRacer mentioned.
I really wouldn't concern myself with all the programming mumbo jumbo. Most of the PID's have an auto tune feature that works quite nice. You can read the manual and learn enough to tweak the PID, after the auto tune, to work just the way you want it to.

Example: If you want to process your BD at 140F you simply set the PID to 140F and it will keep the temp right there exactly at 140F.



SpeedRacer,
I don't think you can use the ramp feature on your PID, Just like you mentioned, as soon as it turns off the heat the methanol will also stop. Besides, that's more complicated than need be. You simply provide a heat source matched to you tank and volume of glycerin. This might take a time or two to get it right or you may get a stronger than needed heat source and use a variac to adjust it to the correct output. Either way you want a conservative but constant heat supply.

The PID I've been using is a TET 612 available on e-bay for around $35. One sellers name is coldfusion. The manuals are less than great but if you take a little time to re-read it or if you already have some experience with a PID you won’t have any trouble.

On the reflux, I made one that is kind of a combination of a fractioning column and a reflux. I've had pretty good luck with it. There are a lot of better designs out there, this is just a reasonably good design that is compact and cheap and easy t build. Here is a crude drawing.


The water that comes from the condenser then goes up to the top of the column and travels through the condenser at the top. The condenser at the top helps promote a good "reflux" flow to help in the "scrub" the vapors coming up the column. Like I said it is quite crude but it works.
Here is a picture of one on a 27 gallon still.

Note: I don't use a recirculating pump any more.

-mcguyver

BTW, a taller slender still seems to work better than a shorter wider one.
This is also somewhat true for the reflux column.

-mcguyver

Thanks for the info mcguyver. I'm all good building the still, have built several in my day for making moonshine & whiskey. I like to build the Charles803 Still, it a reflux basically, but high purity.

My issues are with the PID, if you do not provide enough heat, this process takes forever, that is my problem. Running a couple of elements (3800kw,4000kw,5500kw) at 220v will heat this up pretty fast, but if you stop the elements will the flow will stop? That is why you see a lot of people put dimmer switches on them to control the voltage manually, which is basically what you recommended, but that means more manpower time.

This is where I get stumped, if you set you PID to goto say 140 hold for 30 min, then goto 145 hold for 30 min, then goto 150 hold for 30 min, etc., that is the only way it will run by itself, unattended that I can see. At each set point the amount of available methanol will vaporize up the reflux. Other wise, you would have to come pretty regularly and adjust the power to the flow.

If I understand what you a saying, you are advising to use one smaller element, and let it take however long it takes to heat up, and just set the PID to shut everything off at say 190. That way you just turn on and walk away, knowing at 190 the power shuts off. It seems like you would have to do quite a few runs to figure out the correct element size. The second problem is that if you changed the amount of gallons in the tank, it would also change your element size? If one always did 50 gallons every time, it would be simple, but 50 gallons one time, 60 gallons the next, and 40 gallons the third would sure make things complicated. Unless my ramp, hold, ramp hold theory would work, then the gallon content never matters, the PID will automatically just keep rising the temp.

Just some thoughts, unfortunately, someone a lot smarter than me, probably needs to ponder this issue to arrive at an answer for running unattended.

Hey SpeedRacer,
My still is a 27 gallon air tank that I have turned on end. I have a 5500W element that I start on 220v. The pot gets to temp in about 20 minutes then I switch to 110v and let it go. I have tried letting the pot continue at 220v and it gets incredibly hot very quick. What I found is that the purity of the methanol dropped considerably. Everything got real hot and lots of water started boiling out before the methanol is recovered. Also, my condenser couldn't keep up with the demand and I have a fairly large condenser. It didn't take long for things to get out of control.

Another note: I can fill the still near full without the concern of the glycerin boiling over into the methanol. The reflux action keeps the glycerin foam washed down.

Also, I have a ball valve on the output of the reflux column to slow the flow of methanol a little to increase the purity.



I think that distillation is something done at a certain rate and pushing it too fast gives negative results.

I could imagine having a larger tank, just say 75 gallon, and having one element on at 4500 to 5500w and a second 5500w that was hooked to a variac of similar device to control the actual voltage and thus the heat output (the amount of insulation on the tank will have a bearing on this). It usually takes me about 6.5 hours to do a batch and I believe that if everything was properly sized it would take around the same amount of time to do a larger batch. I usually process 20 to 23 gallons at a time and the 5500w element on 110 v works great. It may not be a direct correlation but you could probably get a pretty good idea of what you need to do 60 gallon batches. It's not too tough to get the correct heat setting. You would get the pot to temp then leave one element on high and set the other down low. It wouldn't take long to see if you need a little more heat to get a good flow of methanol. Once this setting is established it should be good for the rest of the process. This setting could be marked on the dial for repeatability.

The methanol leaving the processor will regulate the temp of the pot. Once you run out of methanol the temp will raise and you will know it is time to shut it down.

I do know that if for some reason the heat is turned off the methanol stops flowing almost immediately.

The only way I could see the ramping method working is if you used air injection. This seems to keep the methanol flow going even if the heat is turned off.

If you have a drawing of the reflux you mentioned (Charles803) I’d love to take a look. I am always looking for better ways of doing things.


-mcguyver