I have a condenser built in the same fashion as the Plumber's Delight. I should state at the outset that I didn't crimp the inside tube during construction as I didn't have my ViseGrips that day in the tool box. (I have far too many tools to have in any one box in the back of my truck).

I have been trying to do methanol recovery on glycerin that has been piling up over the past few months and to get it ready for soap manufacture.

I have been heating the glycerin to the appropriate temperature of about 170F and will get a steady stream with the glycerin flowing through the venturi and the coolant water is flowing at a good rate of about 5 gallons per minute through the condenser.

After about only 5 minutes, the condenser output dwindles down to a couple drips every 15 seconds or so.

Upon consultation with others who do methanol recovery, they said I should be getting at least 10 gallons of methanol out of 45 gallons of glycerin.

What gives? Have I missed something here? I hope I don't have to build another condenser, I'll have to cut things apart and re solder.

This message has been edited. Last edited by: Spencnaz,

quote:

What gives? Have I missed something here? I hope I don't have to build another condenser, I'll have to cut things apart and re solder.

I don't believe the crimps will make any difference in the condenser. All you need to do there is lower the temp of the saturated vapor to return it to liquid. The crimps should be in the column to make the vapor twist and turn to purify itself.

My condenser is modeled after the one at moonshine-still with a reflux column packed with raschig rings. The cooling water is circulated thru the reflux column and provides some cooling and condensation of the vapors on the way up the column. I keep the top of the column at 150 to 155F, but the glycerin temps reach 210 to 230F.

I use at least 20% methanol in my process (BioPro) more if I have exceptionally high T oils and need to give it a little extra "push". My latest recovery batch was 9.8 gallons of 98% purity from 42 gallons of glyc. I did quit a little early because it was Friday night and I had enough of that week, so I would have recovered 10.5 to 11 if I let it go to the end.

Methanol recovery is a lot like the home brew process. We all build something different, so you need to find your "Sweet spot" to make the system respond favorably. I suspect you are not getting the glycerine warm enough or are loosing too much heat on the way to the condenser. You may want to try insulating the tubing between the boiler and the condenser, but keep in mind that too high an input temp in the condenser will result in lower methanol purity.

Norman

Thanks for the input, Norm. I have been heating the glycerin to at least 170F. I don't have a temperature probe in the fluid stream but have to take measurements based on the outer temperature of the pipework. At the venturi I was reading about 160F on the external surface of the venturi.

As stated earlier the venturi is plumbed so as to suck the methanol vapors through the condenser. I do have minimal insulation on the piping leading to the condenser, will pick some up from the hardware store possibly Monday.

Temperature at the top of the column was showing a surface reading of about 120F, this is with copper tubing which has a very good thermal conductivity so it's obvious to me now that more insulation is required.

About how long does it take you to recover the amounts you're seeing? Is it an all day process?

while I don't use a plumbers delight condener..you find it use to know the I don't start getting methanol out until the 'pot' temps are around 180F..they'll stay there for hours on end..when I stop recoverying the 'pot' temps are 205F. higher is possible with the right refluxing setup..but I know the seal in pump will not take much past 210F. someday I'll replace these with vition high temp seals then I run up to 240F during recovery.

the condensor is only part of a good setup..a reflux column is the other part..good control at the top of the column is a must! if you want high purity methanol out..if you just want the methanol out..no column..no temp control at the top..just make sure you condensor can handle all the heat you can apply. ie your condensor must be cool to the touch at the bottom at all times.

-dkenny

The solution seems to come from two areas for this situation.

1. Patience, I need to be more patient to get the glycerin up to temperature (provided I can reach the levels required with the current single 4500 watt low density element).

2. Insulation: the input plumbing for vapor to the condenser needs to be insulated. All associated bends leading to the vertical condenser, likewise need to be insulated.

quote:

Temperature at the top of the column was showing a surface reading of about 120F, this is with copper tubing which has a very good thermal conductivity so it's obvious to me now that more insulation is required.

About how long does it take you to recover the amounts you're seeing? Is it an all day process?

When mine is up to speed (temp) I will have 220 F in the bottom of the boiler, 175 to 180 at the bottom of the reflux column and 150 to 155 at the top. I turn my heaters on with a timer at about 2 AM and the glyc is up 150 or so by the time I get to work at 7AM. I the turn on the additional belt heater and let it heat. I just got the temp controller on Friday that I intend to add to the top of the reflux column to try to automate the cycling of the silicone belt heater.

120 F is not enough to keep the methanol in vapor phase, it is condensing and running back into the still. Insulation alone may not be enough, you may need to add an additional heater element. I started out with two thinking it would speed the process up enough to finish it in one day, then added the silicone belt for an easier way to regulate the heat once I got it to temp. It is completed in about 12 to 14 hours. I am considering using 240 volt heating power rather than the 4500 W 240 V elements powered by 120 volt that i am using now. That change alone should get the recovery time down to 8 hours or so.

Norman

I'm using 240V power to the heating element with the thermostat bypassed. I of course watch it like a hawk when this is on.

A friend of mine uses a water heater system like mine with a single 240V heating element and has been having wonderful success with his system. The condenser he uses is air cooled via a squirrel cage type fan.

I only gave the glycerin a couple hours to heat thinking that it would be at the proper temperature for methanol recovery through the condenser, I can see that I was wrong. It will take more time to get to the appropriate vapor point. Probably 4 hours by my estimation. No problem, it will give me more time to keep the area in order and filter raw biodiesel through the sawdust columns.

I believe I get about 30ml per minute out of my plumbers delight...when the methanol starts to condense. Last time, it took about three hours to recover 9L methanol out of a combined batch of bio and glyc...the batch was still hot from the reaction and methanol started flowing out of the condenser almost immediately.

After a while of less than stellar results, I insulated all piping...the exterior of the condenser and the "column" part which lead to the condenser as well. This considerably increased the rate of recovery... It was probably less than half the current rate before.

Also, I have an inverted water heater tank as my processor. The bottom end (which is now on top) had no insulation under the sheetmetal cap. I pulled the cap off and applied that spray on insulation. This also helped big time.

quote:

venturi is plumbed so as to suck the methanol vapors through the condenser

Not sure if I missed a reply on this one but controlling the air flow rate is a key just like good isolation. I recall reading some of Gram's first experiments where he stopped and started the air flow throughout the process. When first attempting with vacuum I noticed that it was easy to over do it and pull methanol vapors past the condenser and catch tank. Trying some different tunings on your air flow from nothing to full open till you find that sweet spot is the trick. This speed tends to vary as you get further into the process time and boiling slows.

I also found that stopping and starting the air flow every few minutes actually produced good results, but was way to hands and unrealistic for such a long process without some automation.

-Ken

Ken,

I've been coming to a similar conclusion regarding the suction rate of venturi. I'm going to add several layers of insulation to all the plumbing of the reactor. After re reading Graham's instructions regarding his design, I can see that this is a critical design feature that I'm missing at this time.

We've done I think... 20+ recoveries on glycerin in our modified appleseed reactor (Steel piping, reflux column and more insulation than a house). On a 40-45 gallon batch we will get back at least 12 gallons of 95%+ purity. Before we had in addition to the plumbers delight another condenser to make sure we cool down the vapor sufficiently, now we use a modified window AC unit and it makes our lives much simpler by reducing water waste and keeping the cooling water around 50 F.

The plumber's delight needs to be crimped, it causes turbulence in the pipe that prevents "channeling" where you have hot vapor flying down the center that avoids getting cooled. The reflux helps quite a bit in the purity realm but also keeps the temperatures in check. It takes us on average 9 hours to do a full recovery on the glycerin (260F).

Spencnaz I'm guessing you are using GL eco-system? I have no idea if what I just said will be of any use for you, but maybe?

Ok I made another attempt a glycerin recovery today. I put several layers of insulation of polystyrene on all pipe work.

The highest temperature measured was 155F on the venturi surface. The condenser input was showing a surface temp of 133F. Coolant temperature was measured at 68F.

I see a couple new problems to overcome.

1. I'm not getting enough heat output from the existing heating element. Replacement with a 6500W element will probably have be done.

2. The GL system uses the venturi to draw a draft through the condenser, vapors that are "channeled" are controlled and drawn into to the venturi for more reprocessing.

I had preheated the glycerin for about 5 hours prior to starting venturi and condenser operation. After waiting for another 3 hours, the output was a drop about every second. Far too slow if you ask me.

quote:

Originally posted by Spencnaz:

1. I'm not getting enough heat output from the existing heating element. Replacement with a 6500W element will probably have be done.

What exactly is your goal here?

If you are going to use 6500W of heating power, I doubt that the amount of meth you recover will be economical from an operating cost POV, let alone a time and setup cost factor.

IF you are trying to recover the meth for "environmental" reasons, I doubt the amount of meth you recover is going to be ahead of the emissions etc caused by the electricity you use.

If your doing it just for fun, hopefully it works out for you.

This thing has a 220 element, it is controlled by a PID, the reflux column is full of marbles, it is set to keep the column at 155 degrees, it will start there and at the end of a run the pot will be around 210 degrees, it usually takes 12 hours to remove 10-12 gallons out of 40 gallons of glycerine, when the meth starts running it's like a solid stream coming out of the 1/4" condenser tube.
Once it comes up to temp the element is only on for maybe 50% of the time, so in 12 hours I recover around 20 bux worth of meth and the electricity cost is around 5-6 bux, quite worth while I'd say.

quote:

Originally posted by DCS:
What exactly is your goal here?

If you are going to use 6500W of heating power, I doubt that the amount of meth you recover will be economical from an operating cost POV, let alone a time and setup cost factor.

My goal here, DCS, is to recover methanol that would otherwise be wasted in the glycerin, to have glycerin ready for soap production, and to further reduce operating costs.

Here in the US, electricity is relatively inexpensive. I have calculated the cost of electricity needed for methanol recovery.

Many many others (who actively make biodiesel), including other homebrewers in my local area are doing methanol recovery to great success using various methods.

All the equipment has been in place for months and a methanol extraction/recovery stage is a vital step for the GL process. Take a look at the instructions for Graham's GL 1-day system. for further information. Removal of methanol removes the requirement for water washing, and further driving the quality of the fuel to higher levels. I recommend that you acquaint yourself with the GL 1-day process.

Fabricator:

12 hours huh? I think that I'm reaching a temperature plateau and that is hampering methanol recovery rates. Some are relaying temperature of over 200 degrees inside their reactors. The nature of the design in my system does not allow for the provision of measuring tank temperature at the center.

quote:

Fabricator:

12 hours huh? I think that I'm reaching a temperature plateau and that is hampering methanol recovery rates. Some are relaying temperature of over 200 degrees inside their reactors. The nature of the design in my system does not allow for the provision of measuring tank temperature at the center.

Spence--

What are you using as a still? Is it insulated? I have a 50 gallon water heater that is going to be my "final" still after I get done playing and tweaking my system. Right now I am using a 55 gallon drum with a drain. Initial temp tests indicated that about 160 degrees was the best I could expect to maintain with no insulation. I added one layer of 1 inch insulation and could get it up to 185 pretty quickly, but it continued to climb slowly. I removed the insulation and put a layer of silver bubble insulation on and covered it with the one inch building roll and now I can get 220 in the still and maintain it. Insulating the top and bottom of the barrel is something that I overlooked initially, but it is also covered.

Norman

I must be doing something wrong. I use my old appleseed processor (50gal HWH)as a still. I have plumbed a plumber's delight condenser with a crimped inner tube to it. For a 43 gal batch of glycerol I reach fluid temps of 210°F and head temps between 156°F and 179°F. My coolig water is contained in a 20 gal plastic barrel. I use low-tox antifreeze in the cooling water. The cooling water does heat up during the process.

My best recovery to date (18 batches)was 4.5 gallons of 98% pure methanol.

I am thinking I need to plumb a radiator in the cooling water line to cool the coolant further. What do you all think?

quote:

Originally posted by bdubet:


My best recovery to date (18 batches)was 4.5 gallons of 98% pure methanol.

For 43 gallons, you should be getting triple that number. At what temp does your methanol come out?

quote:

Originally posted by bdubet:
My coolig water is contained in a 20 gal plastic barrel. I use low-tox antifreeze in the cooling water. The cooling water does heat up during the process.

My best recovery to date (18 batches)was 4.5 gallons of 98% pure methanol.

I am thinking I need to plumb a radiator in the cooling water line to cool the coolant further. What do you all think?

That is quite low if you are using 20% methanol in your process. If you are sliding by with 15% methanol, you may be getting it all. The 98% purity speaks well for your temperature control, although I think 179 F is high.

Is there a specific reason for the antifreeze? I make a couple big ice cubes out of gallon milk jugs and cool my recirculating water that way. One could also get a few of the big blue cooler blocks from Wally World, that wouldn't effect your antifreeze.

Norman

quote:

Originally posted by StorminNorman:
Spence--

What are you using as a still? Is it insulated? I have a 50 gallon water heater that is going to be my "final" still after I get done playing and tweaking my system. Right now I am using a 55 gallon drum with a drain. Initial temp tests indicated that about 160 degrees was the best I could expect to maintain with no insulation. I added one layer of 1 inch insulation and could get it up to 185 pretty quickly, but it continued to climb slowly. I removed the insulation and put a layer of silver bubble insulation on and covered it with the one inch building roll and now I can get 220 in the still and maintain it. Insulating the top and bottom of the barrel is something that I overlooked initially, but it is also covered.

Norman

Norm,

I am using my GL reactor. The main tank is an 80 gallon water heater with R12 insulation on the tank itself with the original steel/aluminum casing around that. I used a no contact thermometer on various points of the system from the venturi to coolant water temp, to temperatures at the top of the tank to see how much heat is being lost out the top of the tank.

The insulation all around the water heater tank is fiberglass. As mentioned in previous posts, I have added polystyrene insulation to all pipe work that is carrying heated fluids (either gaseous or liquid).

I've been giving the glycerin at least 4 hours to get hot, is this too short a time?