Just a thought/question regarding placement of the condensor.

Shouldn't the vacuum be pulled on the heating vessel - to help with vaporization of the methanol - and then vented to atmospheric pressure into the condensor - to help with condensation?

I know that methanol (like any liquid) will vaporize better under vacuum, and condense better under pressure (no vacuum). Seems like if the condensor is under vacuum it would reduce the amount of condensation that takes place...

 

I am planning to recover methanol from my glycerine and in need of plans or pictures of what you all are using. I read where fabman was working on a design but the post was sometime in 2005. As far as the condensor is concerned, would a finned condensor such as a large oil cooler with a fan blowing through it work or does the copper coil thru an outer jacket work better? I have a 40 gal water heater tank and a 2000 watt incoly element to heat but what type of thermostat do you use to control the heat to 180? Any help will be appreciated as I have 200 gals of glycerine to process.
Dave

 

A copper coil in a piece of pipe with cooling water will work just fine. I used a oven thermostat to control the temp. The design I've been working on works much faster, and is usable with the bio itself. I have had great results with it and several others that I've shown how to build it have also had good results. Tom built one of my new systems, but has had problems with his condenser. Hopefully we can get his running well. I cannot post the plans here yet as I'm working with a patent lawyer to see if I can get a patent on the process.

 

Hi guys sorry to be gone so long. I went to MD Anderson for follow up on my surgery last Oct and what I thought was going to be a 1 or 2 day deal turned into a week of poking, probing, being turned upside down, radiated, injected, and several other rather ignominious "tests".

The good news I am still here and have no signs of cancer at this time.
The bad news they are not certain they got it all so it is a wait and see game for now.

Re: the condensor problem

I don't understand the purpose of "pulling a vacuum" at any point in the process. Methanol is quite volitile and will vaporize easily under normal atmospheric conditions, the addition of heat accelerates the process exponentially. If you apply a vacuum in either the vaporization vessel or the condensor you will greatly reduce yield of condensate.
It is quite possibly the vacuum coupled with the open vent in the heating chamber that account for Tom Ds missing methanol.

I have set up many distillation systems over the years and never found it necessary to use a vacuum.

 

First, good to have you back again. Hopefully they can leave you alone for awhile.

If you're familiar with the GL Eco-Processor, they use a venturi with a valve to pull a vacuum. Next time I distill, I'll leave the valve closed and see if I get more Methanol.

 

Where is the vacuum applied?

 

there is a "tee" between the condenser and distillate tank where the vacuum is applied. The theory is that the vacuum helps pull vapor through the condenser. Last batch I ran I left the valve on the venturi closed. Once I opened the valve, it did seem to increase the drip rate. I also could see vapor being pulled up into the venturi...

 

OK
Pulling a vacuum thru the condensor will increase the flow rate thru the condensor. That may or may not be desirable, depending on the length of the condensor.
An increased flow rate will increased drip rate; however, if it results in an increase concentration of MeOH vapor at the distillate end you will lose total recovery volume because some of the residual MeOH will be vented thru the venturi.

 

OK here we go again. First and foremost, I am concerned about Phydeaux 88. I haven't seen any posts from him in quite a while. Hope he is well. Don, did you get in contact with him?
I tore my condensor apart the other day and can report more closely how it is built now that I am inside.
It is made with 16 ft of 3/8 copper tubing and 4 ft of 1/4 tubing.(total 20 ft) The tubing has a 2 3/8 outside diameter twist to it with a total of 30 twists. Each twists consumes 8" of copper. It WAS housed in a 3"x24" PVC tube with caps on either end. The water flowed in the bottom and out the top at 52 deg (this last time). I heated the BD and Glycerin to 170 deg (separately) and vented into the condensor. I DID get some liquid Methanol out the condensor line but VERY little. It seemed to flow out better when I heated verses running it through Don's chamber. Don't know if this will help but I now have a 4"x24" PVC pipe I will put the coil in if you all think I am headed in the right direction. I am doing something wrong and cant pinpoint it. Both BD and Glycerin are stored in sealed containers. I thought of building the plumbers delight but hate to throw this away if there is any hope. I am processing at 140 deg.
I'm looking forward to hearing from all.
Tom

 

Morning Tom. I am also worried about Phy...............I've sent him a PM and an email with no response. Sure hope everythings OK. Yes! Put your coil in the new tube. We need to get you up and running with a working condensor, and simple heating to get you started. Once we get a steady stream of Methanol we can work on using my system. I think this was part of the problem all along. I should have had you learn with a heated system first. My Bad..................Anyho......Get it built and running and We'll go from there. I'll be gone till tonight, I've got 1,500 gallons of Glycerol to move home today....................
Don.

 

What will I gain by putting the same coil in a larger pipe? If nothing, I will return it to the 3"x24" PVC pipe. I will try Phy's test and boil some water to see what output I will get. Do you have any suggestions for my new condensor? I made sure the coil is not touching the walls and the coils are not touching each other. My last batch, I cooled the water to 52 deg. I mix in open container at 140 deg. I don't think I am losing methanol from that do you?
Tom

 

By putting it in a larger tube it may condense better with more water around the vapor tube. I don't think your losing much from your open processor. When I was using heat to recover my Methanol I would start to see some about 150-160 deg, but it really started running at a fast rate when I got the temp above 180 or so.

 

Ok, I'll use a bigger tube. Do you think I should put a valve on the vapor line so I can slow down the flow of vapor?

 

You should never have ANY vapor coming out of the condenser line! I would put the condenser vertical if possible. Your output line should be as low as possible in the recovery container so vapor cannot escape, and air cannot be drawn back in.

 

The last time I had any luck, the condenser was vertical, and liquid was dripping out the line BUT vapor was also coming out. It was as if I was forcing the vapor too fast through the line and not giving the condenser a chance to process the vapor. The line leaving the condenser was above the liquid. Are you saying to submerge it?