You guys are way beyond me. Just a question though. You mentioned a glycerin prewash increases soap content. I just did a pre wash on my last batch. So you aren't a fan of that? I had read that it helped so tried it. It emulsified after 2 washes I'm having trouble understanding how you can bubble after the reaction with no emulsion. What kind of bubble do you use?
1997 Dodge Ram 2500
It increases the soap content of the Glycerine layer by neutralizing some/ all of the FFA's in the WVO being procesed
I have nothing against the prewash, from what I have read there are benefits to be had from using it.
I do not personally use the glycerine prewash because it takes too much time for the possible small benefit.
I now just do a single stage reaction and am finished. My WVO typically titrates around 1.
I use an aquarium bubbler with just several open hoses into the biodiesel.
A very simple rule...
If you get an emulsion during your wash cycle, its because you have a poor quality reaction.. IE: Lots of left over unreacted oil.
If you have properly made fuel, you can be extremely aggressive washing. If you have to bubble wash, its because the fuel quality is low and you have unreacted oils that shouldn't be there.
Soap can play a part in making emulsions but its usually poor fuel.
The proper thing to do is to make sure you have removed all water before reacting and to use an acid stage if your oil titrates high. Everything else is a poor substitute.
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So, I could do a soap test after reacting to see if I should react again?
How do I de-meth? Just let it sit? I'd much rather let it sit a week rather than do all this water wash.
1997 Dodge Ram 2500
a soap test will tell you only how much soap you have left.
The conversion test 3/27 or 10/90 will tell you if you need to re-react.
If you remove the methanol and let the batch settle for long enough the quality of the biodiesel will be as good as a water washed product.
As I don't recover any methanol I just bubble off the methanol at about 50degs with a compressor which will get rid of most of it.
I then bubble with an aquarium bubbler for another 12 hours.
If the batch is allowed to then just rest for a while you can then do your soap test. By all means then filter through some woodchips if you want the soap to get down to zero.
Dgs- OK, right. The 3/27 will tell me about my reaction, not the soap test. I must have done something wrong on my last batch since the 3/27 didn't have any drop out. I thought I had a really good batch. Maybe I didn't shake enough. After two static washes the bubbler emulsified the batch.
OK, so your 'de-mething' is simply airing it out... Maybe I should do a 2nd reaction just to be safe and see about bubbling. I recall reading a formula somewhere for the 2nd reaction, i.e. how much methanol and KOH to add. I know it was less than the first round. Do you know it off the top of your head? I can look around for it.
In my system, I have a 10 micron biodiesel filter before going to my finish barrel. From there I use a portable pump with a 2 micron filter for vehicle fuel. Finally, I am driving an old 12 valve dodge so I've heard they can handle less than perfect bio. but I do want to make sure I'm below ASTM soap standards.
Seriously, thanks for all the info. I went back to the batch yesterday and the shake test still showed some cloudy water. I heated and added more water and will let this one sit for a few days.
1997 Dodge Ram 2500
If you had no dropout in the 3/27 test there is no need to reprocess the biodiesel.
Reprocessing high conversion biodiesel will only produce more soap.
What do you mean by a static wash? If you mean you pump water under your biodiesel and let it sit, there is no meaningful washing going on.
2 spray washes would be much better at clearing the soap from your biodiesel.
Soft water is much more likely to give you an emulsion than hard water.
I have never seen a shake-em-up test give perfectly clear resultsThis message has been edited. Last edited by: Tilly,
Tilly, by static wash he means the bio is just stood on water, as you say there is no meaningful washing taking place. It just gives the dropping soap/glycerol something to fall into instead of welling up in the bottom pipe.
Re your comment about the shake-em-up, are you referring to the biodiesel or water layer.
azjed, as you say the de-mething is as you put it 'airing out' As Tilly says, don't do a further reaction if your 3/27 is clear.
That is what it used to mean.
Unfortunatly, Biotom started using static wash to mean Spraying water over the biodiesel uses a shower head or similar spray devise with no adjitation of the biodiesel such as bubbling
So now static wash can mean two very different procedures on this forum and you must ask to be sure which procedure someone is talking about.
I use the bottom of the storage container to "catch the dropout". There is no point in getting water anywhere near the reaction.
OK, yeah, let me clarify since I'm only using language I've picked up and wondered how the heck a static wash did anything in the first place. So, what I am doing is after removing the glycerin layer out the bottom is heating up the bio and heating up 5% water and pouring it in the top by hand very gently.
I had done this originally using a heated misting system I built but then I got an emulsion. I was also bubbling at the time so I freaked out and thought maybe the mister was too much. Now I'm realizing that probably the bubbler was the cause.
I can go back to the heated mister and do a couple washes. Maybe just running the bubbler for a shorter periods of time? 10 minutes, let sit overnight-run another 10 with the same batch of water. Not sure.
I can see how it's easy to get hooked on this. I want to quit and just go straight veggie oil but I'm also stubborn and want to make this work. Plus, is it weird that the bio smells kind of good!?!
OK, thanks again guys. I'm going to take all these ideas into consideration on the next batch and keep washing this one but I'm really interested in eliminating the water washing in the next batch.
1997 Dodge Ram 2500
oK azjed, let us know how you go.
Tilly, it is certainly easier to obtain a very clear shake-em-up on water washed as opposed to settled.
If water washed until the last water is completely clear a shake-em-up only confirms what the water washing has shown.
the bio phase will remain cloudy for a while if the the test is vigorously shaken as we are saturating the bio with water. Once this is the case when excess water has dropped out of the bio it then depends on temperature if we have any suspended water or if it is clear.
To clarify, I have a test on the window sill. If the morning is sunny and the test above 20degs the bio is clear. If no sun and the test is cooler the bio is misty.
Back in the days when I water washed, I would mist water over the top of the biodiesel.
1 part water to 2 parts biodiesel- the wash tank was 2/3 full of biodiesel when I started mist washing.
I then allowed the water to settle for an hour or three.
I then drained the water.
I would do this twice.
I did not bubble air through the water at any time.
I would then bubble air through the biodiesel or if I had time just leave the biodiesel sit for a few days covered with a fly screen in the hot summer sun until the biodiesel was bright and clear and I could clearly see the bottom of the 200 litre drum through the biodiesel.
Azjed. Did you come right with the water wash?
If you are creating an emulsion with a gentle wash then I would be more than a little certain that you have allowed some of the glycerine layer into the wash cycle. As has been pointed out the glyc is somewhat concentrated as a soap base, so it doesn't take much to get things into a lather. Now if you couple that with an incomplete reaction an emulsion is almost guaranteed.
If you have settled the fuel properly and then allowed no glyc to get in the wash cycle you can wash fairly aggressively with no concerns for emulsions.
That is for water washing. Then you can go the route of dry media purification using either just resin or a combination of hard wood chips followed by resin towers and a small micron fuel filter for final polish. This requires you to properly settle and then demeth by heating the biodiesel only (sans glycerine) to drive off the residual methanol which will release the soaps which then fall out of solution by gravity. The dry media here only serves to speed up the process that time could do all on it's own if you are not in any kind of hurry. http://www.graham-laming.com/b...tate_diagram_new.htm is for Graham Laming's Eco System set up. He uses neither water or resins and gets great results.
I have used all three methods and prefer the dry media approach.
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I think that was the last batch if I recall. Seems like it turned out OK after lots of washing. I only do a soap test and then filter to 10 micron, settle, and filter though a 2 micron and into truck.
This current batch I had to reprocess and now am trying a small bubbler for 48 hrs. The bio is heating but I'm not sure how much as I'm not near the processor. Hopefully it gets to at least 100F.
1997 Dodge Ram 2500
Hi Azjed. Leagle eagle has vast experience here and gave good advice.
My own experience is limited 25 200 litre batches. AND of course my plant. I am still water washing while testing a vacuum processor. My latest procedure is this. I use a 30/270ml test for conversion
here in RSA a 500ml coke bottle has a ring moulded into the bottle at 270ml. take a syringe casing and glue it to the bottle top with a 6mm hole in the cap for the fallout to fall into the syringe. I have two a 10ml syringe and a 5ml syringe. Add 30 ml of your raw bio to the methanol and invert after shaking and check the fallout. There is a video on IMAKEBIODIESEL web site about this.
I do a 80/20 process as my processor tends to stall at about 80% conversion. I then wait 30min and drain off the glycerol do 30/270 test and reprocess using the formula 1ml fallout is 3.3% of batch. I only add back the calculated amount I have always got a 100% pass on second run. once passed drain of Glycerol after 30 min.
Then I add back 10litres water and a big handful of salt in the water and mix again straightaway I have an emulsion. Let it settle overnight. Drain off remaining glycerol and salty water. seeing colour change can be tricky so you need to mark the volume before you add the water.
After that I water wash with sprayers about 30 litres hot water. It will wash easily and soap comes out with the water. Once the PH of the wash water is within 1 or 2 of the water going in I stop washing. Usually 3 times anyway. Then heat with submersion element to 40deg C and bubble dry with silica jell before the air supply. I bubble till bio is clear, draining settled water often. Bubbling can take three days. Water is then less that 500ppm soap 50 or so ppm.
There are much better ways to dry than what I described even for water washing. I just was working on other stuff and never got around to that.
Maybe this will help.
And yes I have made emulsion with air stoned. Just heat and drain free water from the bottom of the cone otherwise one is circulating water also or you end up with a wet layer of bio on the bottom of the cone. Keep what you drained off let it settle or brake with salt and add the wet bio back into the next batch at the wash stage.
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