i am in the progress of building the GL eco

i actually gave up the idea of not using a venturi...i bought one...made with PE.

I did more reading about venturi...it is actually doing air mix with the oil INSIDE of the venturi..then blow it out to the tank.... So it's hard not to use a venturi in Gl's eco

And about pumps....most of the pump out there will stop working if there is air...=(

Hopefully the problem is due to the oil being cold, maybe when it is heated up it will draw again...

A pump that can draw air + oil...is really expansive

The pump size mention in the Gl's Eco system is too huge, move the whole tank in less than 2 minutes.....if someone got a 100 gallon tank, it's gonna need a pretty big pump which is expansive...

Do we really need that much power of pump? Btw anyone tried to use one of those land use fountain pump? Those are made of plastic, not sure if they can stand the temperature of 75 degree C?

Hi Pirocop

There are a couple of reasons you will need a pump which is able to pump the tank contents in 2 minutes or less.

Don't be tempted to use a smaller pump - you'll end up disappointed and if you are determined to make the system work, you'll end up buying a pump which can move the tank's contents in 2 minutes or less!

If you have a 100 gallon tank, use a pump which can shift 50 gallons or more per minute.

The reasons are ...

1. Agitation. If you use a smaller pump, your mixture will not be well agitated and you will probably experience poor reaction quality. (Unless you run the reaction longer than suggested)

2. Speed of distillation. If you use a smaller pump, you will probably become really bored waiting for the distillation to complete.

Go for the right sized pump and you'll more likely be pleased with the results you get, and your results will be good batch after batch after batch.

Also, the venturi can be as near to the vent as you like, it won't suck air in from the vent - take another look at the ecosystem page where it explains why this is so. Seems strange at first, but true! I've put that bit of the page at the end of this post for you.

Hope that helps,

All the best,

Graham

How about the watt of the heater? What size do i need?

I saw the GL eco's website saying 1kw per 30 liter

so for 400 liter tank...i have to buy a 12kw heater? that's pretty big..and waste alot of eletricity.

please advice

Hi

You may think this is odd, but 12kW of heating should actually waste less electricity than 3kW in your 400 litre tank.

Think of it like this ...

Let's use a really small heater, say 100 watts.
You will switch on your 100 watt heater and wait for the 400 litres to reach 60 Degrees C.

How long do you think you will have to wait? If your insulation is REALLY good, you will have to wait 10 times longer than if you use a 1kW heater.

During that 10 times longer period, you will loose heat due to insulation losses and this loss is waste.

In fact, with a 100 watt heater, you may be waiting forever, because your temperature may never reach its target, so most of your heating energy will be wasted.

Low power does not necessarily mean low waste.

If you use a 12kW heater as I suggest, you will reach your processing temperature quickly, you can then start the reaction and switch of the heater.

You will need the same amount of ENERGY to raise a perfect 400 litres of oil to 60C whether you use 100 Watts or 12kW, but the journey there will be quicker and more efficient if you use 12kW.

So 12kW does not necessarily mean more wasted electricity.

Hope that helps,

regards

Graham

Graham

Thanks for all the information you have provided here and on your website.

I have just finished my 5th 30 gallon batch and have been using bio-diesel in my Dodge Ram 250 for 800 miles.

I am using an Apple Turnover design with a 50 gallon water heater. Prior to building my processor I had never sweated copper pipe but managed to build my venturi and plumbers delight condenser. Both work beautifully. Each batch passed the 3/27 test for complete reaction and pHLip test after settling time.

I am going to work on incorporating a 2 stage reaction process with glycerin pretreatment before stage 1 and water pre-wash after stage 2 in an effort to reduce methanol and lye requirements. I'll let you know how that works out.

Again thanks for a beautifully designed system and all the help you have provided.

Charles

Thanks to Graham's generosity in providing his knowledge freely, I have built a processor along the lines of 1-day ecoprocessor.

It's performing very nicely, but I was wondering if it's possible to vary the process slightly. I'm willing to do some experimentation if this hasn't been done, but decided to ask first in the off chance that it's been tried or someone has an answer.

What I am considering is whether it's possible to process the oil with methoxide, do the 5% prewash, and then distill the methanol and dry the biodiesel before allowing the glycerine to settle? By my way of thinking, if I've processed for long enough the reaction should be complete before this point, and therefore it won't matter when I remove the methanol and water.

The attraction is complete distillation in one process, less energy use and slightly faster processing.

There's far greater minds than mine at work on the subject of biodiesel production, so it's highly probable that there's a fundamental misunderstanding in my thinking that prevents my idea being feasbile - if so apologies for the simple question.

Any info appreciated.

Cheers,
Ben

help, our venturi doesn't work... attached is a picture to help describe. the pipe coming up is a 3/4 inch coming off of the 1/2 hp pump. it makes a 90 degree bend going into the venturi. the venturi has a reducer that goes down to about 3/8 inch. (3/4 to 1/2 adapter with copper solder in to further reduce. the end of the nozzle extends just about to the end of the air inlet on the tee, so the oil shouldn't be able to turn back and go out the air inlet, but it does. The 3/4 inch pipe coming out of the tee is about 7 inches long. we then have a 45 degree bend, going into another 8 inch straight piece, then a 90 degree elbow going into the tank. When we tested the setup with water, it did have a slight vacuum, but with oil, oil actually drips out the air intake in a steady stream. what is wrong with our engineering?

thanks,
Trent

venturi.jpg (30 KB, 67 downloads)

can you post a sketch of how the venturi is built?

Hope this helps

venturi_drawing0001.jpg (7 KB, 74 downloads)

I am wondering if there is back-pressure from somewhere, causing the venturi to blow instead of suck? maybe if we put the venturi just before the tank?

Three things come to mind.

1) the end of the nozzle needs to be even with the centerline of the opening in the side of the tee for best performance

2) I've always had better performance when the venturi was mounted in the vertical position.

3) you may need to go smaller with your nozzle. It depends on your pump. do you have a pressure gauge that you can install between the pump and the venturi? The higher your pressure the better the performance. If the nozzle is too large, you won't get any pressure increase. If it's too small you will restrict flow and hurt the mixing stage.

The end of the nozzle is past the centerline, but before the edge. Maybe can dremel about an 8th inch off. As far as vertical, never heard that before, might give it a try. We do have the plans using the educator and the 1/4 inch compression fitting. might try that. Another forum suggested that the 90 elbow is causing too much back pressure. Maybe need to have the venturi going straight into the tank, or only use a 45 after it.
Will look at things again tomorrow. thanks again.

Rushmore: I suspect the velocity of the oil is less than the velocity you had with water when you tested the venturi. Since you mention that you had a "slight vacuum" with water, I would try using a smaller nozzle to get the velocity back up where you need it. Oil will have greater friction losses in the pipes than water, which might be the biggest difference. Otherwise, I think it should work OK. My experience is limited, so I could be wrong, but that's the general pattern I've seen in my limited experiments - smaller nozzles make greater vacuum, up to a point. After that point, they restrict the oil flow too much, and the suction declines. With my blue clear water pump, pumping room temperature oil, the peak vaccuum was with an orifice roughly equivalent to a 1/8 inch hole, but adequate vacuum was obtained with larger orifices.

Cheers,
JohnO

Spent most of the day re-plumbing the venturi. I made the copper one go straight into the water heater. Didn’t make a difference as far as vacuum, but at least it didn’t blow. Anyway then made the version with the ¾ inch black iron pipe as an educator. Still no vacuum. Pictures are attached. any ideas? Oil temp was about 40 degrees. All pipe is 3/4 inch. There are 3 90 degree elbows and a 45 coming off of the pump, which is 1/2 hp.

venturi_4.jpg (4 KB, 47 downloads)

here's another pic, couldn't do 2 at once.

venturi_2.jpg (4 KB, 42 downloads)

I'm not sure I have enough details there to be helpful. Can you explain how the two venturi are made with a little more detail? nozzle sizes?

I'd suggest mounting a 45 deg elbow on the tank, pointing down, the venturi to the elbow, then do whatever you need to get back to the pump in steel.

there was a picture of an educator assembly on this forum using a pipe like the one that is sold by b100 supply, a 3/4 by 1/2 by 3/4 tee, and a compression fitting threaded in the educator pipe. the opening in the fitting looks to be a little less than a 1/4 inch, and is screwed in the the educator pipe. thinking of just getting a mazzei venturi from b100 or ebay.
A 45 going up into the tank, to keep the venturi full? wouldn't oil run out the 1/2 inch air intake? thanks again

venturi pics. might help

looking_into_venturi.JPG (22 KB, 47 downloads)