I plan to use a PID installed in the brain box to control system temperature rather than just for the condenser.

I have been monitoring temperature in the condenser input via an infra red thermometer. The venturi it definitely working as heat can be detected moving in higher increments to cond. input from the TP valve at the top of the tank.

I ran through most of the GL process last evening up to the point of the 5% prewash, I got tired during the glycerin dropout, I'm going to check on the process and attempt a methanol recovery from the biodiesel phase prior to fuel drywashing and storage.

Hi Spenc,

Remember that that accuracy of your IR thermometer is dependant on the emisivity of the material that you are measuring. The measurements of of a copper pipe as opposed to an Iron pipe can be quite different. To insure a more accurate reading make several wraps of black electrical tape around the pipe and measure your temp there. The tape has an emisivity of close to 1 and will give more consistant readings.

The pot temp will float as a function of the percent methanol in the mix, the closer you get to no methanol the higher the temp will be. I use a grundfos pump with a rating of 240f and control the head temp of the condenser to 155f. By the time I am done with a 50 gallon batch of glycerin the pot temp is up to 260f and that is where I call it quits. I get about 97% purity as measured with a Tralles scale hydrometer. Any reflux we do here is purely incidental as we do not usually control the take off rate. The purity we achieve is mostly done thru temp control. A PID is the way to go controlling the head temp as tightly as possible.

Tony

Hey thanks for that tape trick! I'll put that stuff on next I head out the processor tomorrow afternoon.

Update.

I put on the electrical tape as suggested and am seeing an condenser input temperature of 165-170F with just heat (heating element direct connected to 240V power) and no circulation generated by the venturi.

I was drying oil last night in prep for another batch of fuel and there was a very steady stream of liquid coming from the condenser output for the entire 2 to 3 hours that I was running heat. I figure that I got about 3 gallons of a clear liquid (perhaps methanol and water, I put some glycerin in the oil as a pretreating measure), I'll have to test this liquid with a hydrometer later.

But, in short the condenser is working wonderfully after the heating element has the thermostat bypassed. A PID control is the next step for more precise control.

If you haven't crimped the inner pipe then that will not help either, the vapour hits the crimps and thus the colder side of the jacket and this helps it condense, if it's not crimped the vapour almost has free flow through and keep the processor and head space well insulated.

Most folks in the UK with GL style processor and plumbers delight seem to recover between 3 - 6 Litres per hour depending on their setup, I started something recently by posting that I averaged 5L per hour and since then everyone is trying to improve their meth recovery as lots were strugglin to get 3L per hour, and now 1 or 2 are getting 6L per hour

I get methanol starting to drip from the bottom of my condensor @ 40°C(104°F) and by 65°C(150°C) it's flowing well, I try to keep the vapour temp between 65 - 70°C(150 -158°F) for 97 - 98% purity (measured with tralles scale hydrometer) but I do sometimes go up to 75°C(167°F)

The inside tube is not crimped, but the output from the condenser is rather strong. A good steady stream of liquid was obtained.

I have a modified pipe cleaner to insert into the condenser to create more turbulent flow through the unit without impeding too much the vapor flow.

Good success with methanol recovery. I had about 40 gallons of raw biodiesel to heat. I had the heat up around 90C and a very steady stream of alcohol was coming out the condenser output. Input temp (condenser) was measured at around 65C.

I had to shut the element off as it was approaching the boiling point of water and didn't want to risk the biodiesel.

I recovered about 2 gallons of methanol, I have yet to determine purity.

Finished up distilling methanol off of about 40 gallons of glycerin. Looks like I recovered about 10-12 gallons of methanol. I had a small water leak out of the condenser into the methanol container, but methanol purity is at 90%.

With 90% you can use it again but only mixed like 25% with new methanol, or use a lot higher percentage of methanol.

Yeah I came to that conclusion as well. I'm going to fix the water leak in the condenser and install a tube to drain the methanol away from the condenser instead of the catch bottle just being right below the output.