Biopowered - vegetable oil and biodiesel forum
Biodiesel => Chemistry and process => Topic started by: willbuild on August 01, 2013, 10:01:51 PM
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built my own gl processor over the past few months. first batch 75 litres only hiccup was my digital scales was incorrect so only used half of the Noah i should of used, so added the extra Noah to 5 litres of methanol and re processed.
passed the 27/3 test, a little bit cloudy but after 3 days in settling tank had a clear diesel which i have now used without any probs.
made a second batch 2 days ago, this time have used potassium flake. it is also cloudy, after two days seems to have cleared a little but am worried that last batch seemed clearer. should i worry or should i just wait?
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Well done for getting this far without asking for help.
To check if the bio is ready you need to do a 50/50 soap test, read this it will explain all
http://www.biopowered.co.uk/wiki/Soap_tests
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I've only done one batch, and it's as cloudy as a winters day. Blocking filters like a good 'un, but seems to keep the van moving.
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just done the 50/50 test water is't crystal clear but def not milky.
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will leave to settle 24 hours more then repeat test. thanks
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still is cloudy. used 7gr pot flake base rate and 7gr per litre on used cooking oil, would i be correct in thinking that i have soap in the bio because I've used to much pot flake.
I think for next batch will do a 2 stage reaction.
should i leave to settle or will i need to filter?
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I reckon that you've still got methanol in it. How are you demething?
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yes, final stage. heated to 90c left it there for 30 Min's and kept condenser running for another hour.
was getting a drop every 5sec when i stopped, collected 2.5 to 3 litres on a batch of 65 litres using 14 litres of methanol
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No one's said it so far ... how rude! ... welcome to the wiki and forum.
There's a chart on this page that gives you recoverable methanol figures ... http://www.biopowered.co.uk/wiki/Whole_batch_demeth
You should have been able to easily recover around 4-5 ltrs from that batch. Have you tried doing a 7% water pre-wash? http://www.biopowered.co.uk/wiki/Water_prewash
If you have a slow demeth, as many of us do, that will help remove the remnants of the methanol as will bubbling in the settling tank while the bio cools.
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Thank you Julian.
Did a 5%pre wash after the reaction then left to settle.
looking at the chart i should have about 6ltr of recop methanol not 3.
dont do bubble (its new to me) will look into it.
so do put back into gl and demeth, leave or filter????
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It's difficult and probably not economical to distill every last drop of methanol especially if your pump, venturi, condenser set up isn't up to scratch (as mine isn't).
If you can afford the time the bio will eventually clear in the settling tank. Take a sample and leave it on the side. You should notice a slowly increasing depth of clear bio appearing at the top.
Returning it to the processor and continuing to distill should work but isn't very economical. After well over 100 batches I'm currently dealing with a batch that won't clear (probably due to an incomplete reaction), so don't worry, it happens to the best of us ... it's all part of the fun of making bio!
Bubbling in the settling tank is quite a valuable and cheap facility to set up. Don't think we have a dedicated page on the wiki, but it's touched upon here ... http://www.biopowered.co.uk/wiki/Drying_wet_biodiesel and the set up is shown here under bubble washing ... http://www.biopowered.co.uk/wiki/Water_washing
I use a small aquarium pump bought off off ebay for 8 quid and a cintered pneumatic silencer similar to this ...
(http://media2.rsdelivers.cataloguesolutions.com/MediumProductImages/C454736-01.jpg)
Make sure the bio won't eat the material. Brass versions are available and will be bio proof. Be a little wary of bubbling when ambient humidity is high, you may be adding water instead of removing it!
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OK, am going to digest the info and sit out by the shed with a mug of tea and see what way i go.
But i fear that i might go the distill again method as 1st batch has nearly all gone (last 10 litres in the tank) it will also be educational seeing what happens. Thank you for your help will post results
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As Julian has outlined, you need to remove the residual methanol content. Sticking it back into the processor would be pretty uneconomical. Generally, you'll struggle to remove all the methanol using a venturi and condenser.
I spray dry mine - it's circulated in the settling tank through a spray bar overnight. It's clear by the morning.
Although bubbling also works well.
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As Julian has outlined, you need to remove the residual methanol content. Sticking it back into the processor would be pretty uneconomical. Generally, you'll struggle to remove all the methanol using a venturi and condenser.
I spray dry mine - it's circulated in the settling tank through a spray bar overnight. It's clear by the morning.
Although bubbling also works well.
I fear you may have confused the issue as he's not water washing.
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He said he was doing a 7% pre-wash.
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Some people find bio made with KOH (potassium)can take a lot longer for the soap to settle, over a week at times.
I suffered just this when I started, then changed to NaOH (sodium) and had clear 50/50 tests in two days (or less) of settling.
The secret to fast settling times is a compleat reaction, if the 27/3 doesn't go instantly clear as opposed to cloudy then clearing over time then you haven't got a compleat reaction.
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He said he was doing a 7% pre-wash.
Are yes, sorry about that.
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have dug out a central heating pump, cleaned it up and will make a spray bar tomorrow. not sure if to go for a strait bar in copper or build a circular one using polypipe.
have put back into prossesor will heat it to 60 c then put into settling tank then do the dry wash.
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ran a dry wash for 5 hours today, it looks a lot clearer. will leave overnite to settle.
my 27/3 tests have stayed clear with zero fall out
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