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I was wondering if someone could lead me to the right pid controller on ebay( or someplace reliable) for my methanol recovery peoject. I'm lost on which one is the right one,plus it needs to be connected to a(solid state relay) SSR and the thermocouple needs to be enclosed in a thermowell. My present setup has no temp control and the methanol is almost 10% water. At least I've been able to get something to work using just a 55 gal.drum ,heating element and copper coil in a 5 gallon pail of running cold water. I'm surprized how simple it works and with the heating element maxing out on 110 v. I get 5-6 gal. of methanol(and water) in one day from 30-35 gallon of glycerin. I can't use this stuff for future batches. Its going to take longer to the recovery once I get a pid in place but I'm hoping I can use the methanol for future brewing. I'm hoping I can pour the junk methanol back in a batch of glycerin to be recovered. Not all at once ,but spread over a couple of batches. At first the thought of vaporizing methanol scared me and I stood inside a building with the MR unit outside when I first plugged the element in, but everything worked OK . Another thing I learned is not to let the glycerin cool down too much when the methanol flow stops or it'll take forever to drain out.

This message has been edited. Last edited by: heatbeater,
 
Location: western new york | Registered: November 19, 2008Reply With QuoteReport This Post
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Are you adding water to your biodiesel/glycerin before recovering the alcohol?

There are a number of control systems that would work. But, for the most part all you should really need is a thermostat, and a high temperature shut-off.

Your problem though, is that for some reason your glycerin is very WET.

A PID won't dry out the wet glycerin.

The only choice would be fractional distillation or reflux distillation. But, that would significantly increase the time and cost of your methanol recovery.

Your best choice is to keep the glycerin DRY before recovery.
 
Location: Oregon | Registered: October 17, 2007Reply With QuoteReport This Post
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Are you adding water to your biodiesel/glycerin before recovering the alcohol

No, I didn't realize the water content is higher than normal. Where did that much water come from? I don't know. Is this a freak incident? Since I don't have any control on the element maybe this is normal. Some of this glycerin has sat around for a couple of years in sealed cubies and I dewater my wvo before reacting by heating and circulating until it passes the HPT.
My thinking with the PID was that it would maintain an accurate head temp,and not overshoot the setting which could allow more mositure in the methanol. If I can maintain a head temp of 160 F wouldn't that help?

This message has been edited. Last edited by: heatbeater,
 
Location: western new york | Registered: November 19, 2008Reply With QuoteReport This Post
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A good thermostat should be able to maintain the temperature at a set-point.

Distillation temps should hang out at near the BP of the first solvent until it is almost all gone, then it should bump up to the BP of the second solvent.

So, if methanol's boiling point is 148.4. Then your shut-down temp should be below 160.

I would think you could wire a shut-off relay directly into a thermostat.

The problem with alcohol distillation is that a lot of water will come off with the alcohol at a much lower boiling point (thus the reflux distillation). If you are making Vodka, then a little water and contaminants give it flavor. It is bad for biodiesel.

Some people have setup Allen Bradley PLC controllers for biodiesel processing. They are programmed with relatively simple "ladder logic", although the programming software is often purchased separately from the PLC. They come in stand-alone units as well as card-rack mounted units for added flexibility. Many different models are available.

I've just picked up a Parallax Basic Stamp Kit. They come in kits as well as individual components, and have both analog and digital inputs. One of the kits says that it has temperature sensor inputs. They have downloadable software, as well as a lot of manuals and sample projects to work with.

But I still think a basic thermostat and relay shutoff would be all you need.

How are you determining the water content?

Have you tested "pure methanol"?

The density of Methanol is 0.7913 g/cc
The density of Ethanol is 0.789 g/cc

I guess that is pretty close, but using Ethanol equipment might throw you off by a couple percent.

I am still puzzled at where you are getting so much water from.
 
Location: Oregon | Registered: October 17, 2007Reply With QuoteReport This Post
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Have you tested "pure methanol"?

Yes,it was about 2 months ago . I haven't spent alot of time with my homebrewing lately but I did check some methanol that I purchased and it was 99%. I also was curious on my hydrometer readings and temp conversions.
 
Location: western new york | Registered: November 19, 2008Reply With QuoteReport This Post
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fyi..

I have my PID set for 152F..when running its +-1F..

a good thermostat won't even be that close.

at 160F you get too much water in the methanol. I found at 155 I got too much water..remember this is methanol/water vapor..so the closer to pure methanols boiling point the better. the trade off is distillation time..

I'm running a 5 foot tall reflux column, loosely packed the stainless scrubbies(cheap).
I also inject air into the pot to speed recovery.

the methanol I get out is good enough for 27/3 testing so its pretty pure.

is the PID the only way to get this level of control?? I would say no, but that depends on your skill set..for me PIDs were a quick and easy way out..if I were to start over..no pids..parallax propeller..Xbee..my own program..that's how I would do it..
thinking remote monitoring from the comfort of your own couch vs walking out and checking??? when it 20F outside..

cost??hard to compare I got my PIDs on Ebay cheap..I might have spent $150 for all of them..I think the current count is 8...2 got fried from oops..2 a power surge..think lightening. most were around $25 each. I have watlow series 965, 985, and 935..

-dkenny


'84 bluebird school bus, DD8.2L turbo( 4/2011, the bus tranny has died..Frown 8.23.11 bus driven to scrap yard Frown )
2006 Jeep Liberty CRD Smile - the wife's
99 dodge 2500 5.9l 24v..-mine Smile
everything run B100 when its warm enough Smile
 
Location: RTP, North Carolina | Registered: December 15, 2004Reply With QuoteReport This Post



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