quote:

the sample which heated to 180F is still cloudy in spite of passing all the tests.

What specific tests did you do? Have you tried freezing a sample then letting it slowly thaw to room temperature while observing if any stratification occurs?

Hey john,
you must not have read the first post regarding the micro....I may have to try and sneak a jar into the freezer in the garage. She does not go in there much. I will let you know.

The vapor test or the hot pan test can be easily done on a simple 'hot plate', it's a quick and easy way to determine if moisture is present.

Mike if we have gone from cloudy to not as bright as usual then I would say its better..

I still stand by that you need to wash a little more.. I know its a pain but what do you have to lose? I do not think its a moisture issue because its sounds like you dried it..

It may not be dry enough for some of the perceptions here but dry enough to know the cloudy is from something else.
If you really dont want to rewash it then I would just use it.. Thats just my opinion of what I would do in my own truck. I wouldnt do it everytime but one tank wont kill my truck..

Here is what I know.

It is not water. the bio has been heated and bubbled long enough.

It is not soap. When I wash, I wash to the point where wonder if I am washing the good stuff out of the fuel. shake test is excellent, titration could not be better. Nothing drops out when settled.

I had a similar batch I think I just had a little emulsification I continued to dry for about 24 hours and it eventually went amber crystal clear I would do the pan test or heat it to 230 and see if you have any bubbles

well if you have done everything else and refuse to rewash I dont know what to tell you. the only reasons for cloudy would be moisture or soap.. under reacted csan be clear..I have passed the soap test and still had soap and vice versa.. have a whole thread on it.. those test are just a guide and def not 100% accurate.. I have thought I was clear of soap and in fact not.. I also used to wash 5 hours and thought I was more than good and didnt want to hear it any other way.. well I ate my words and now I continual wash for 8-10 hours to over do it and then polish with resin..
rewashing is simple and easy but at this point if you do not want to then I would only suggest to use it

good luck and i hope you get it clear

I just lost a 35 gallon batch. I use the 80/20 method, usually with good result. I then wash with about 1/3 water, bubble wash for 4 hours, wash with another 1/3 water then bubble overnight, and wash with the last 1/3.
The last 10 batches or so, I have also done the 5% prewash.
Do the 80/20/
After the 20%, I drain all but about .5 to 1 gallon of glycerine, add 5% water for about 20 min.
I would up with tapioca pudding, would not pump, barely drained.
The initial titration was 3.5.
Any ideas?
thanks
duramax driver

yes.. you have to have the glycerin still in the processor before adding the water.. what you made was an emulsion.. the water attaches to the glycerin and that is what prevents an emulsion..
when you do an 80/20 sometimes you even need to add at least 2 gallons of glycerin back in the processor before adding the 5% water.. your calculations should be 5% of what is in the processor before you add water.. so if you have a total 48 gallons of Bio and glycerin you would put in 5% of that..
I have twice added the water on the second stage without adding glycerin back in and probably only had about 1 gallon of glycerin.. if you do that be darn sure its passed the 3/27 and watch it for 10 -15 min.. its a scary feeling when you watch it change colors but it separates overnight...

HTH

Just to be pedantic,
The 5% Water wash at the end of the reaction is about 5- 6% of the volume of oil reacted. Tests performed by members of this forum have shown that anywhere between 5% to 20% is fine.
Idaho originally recommended 15%

If you want to read the threads that pertain to the original testing look
Here and
Here

OK!
better 35 gallons in the mulch pile than in the tank.
I just started trying the pre-wash. Worked well for a few.
Appreciate the quick (and sounds accurate) reply.
duramax driver

quote:

Originally posted by pril:
Just to be pedantic,
The 5% Water wash at the end of the reaction is about 5- 6% of the volume of oil reacted. Tests performed by members of this forum have shown that anywhere between 5% to 20% is fine.
Idaho originally recommended 15%

If you want to read the threads that pertain to the original testing look
Here and
Here

Sorry but its not just of the reacted oil.. its the total volume including the glycerin and methoxide.. When you go to add the water you calculate 5% of the total thats in your processor at that time of all its contents.. You do it before you turn off the processor and there is no know way to tell what the reaction is at that point without settling plus it the glycerin the water attaches to.
I believe at the time of those articels 4 and 6 years ago then maybe but at this time it is total volume.

Biogirlz, Have you read the links to the original development of this procedure that I have provided in my above post? I have provided you with a link to the original development of this procedure. It is clear that the 5%- 6% was based on the volume of oil reacted only. If you can show me tests that support your contention that it is based on oil+ methanol I would be happy to see it.
Right now I will stick with the original test results which I have linked to above.

quote:

Originally posted by biogirlz:
Sorry but its not just of the reacted oil.. its the total volume including the glycerin and methoxide..

I'm sorry pril that is not correct.. I'm positive of that..

I dont want others on here following that after we have had sooo many threads about it the correct way.

Lisa

FYI -the percentage of water is irrelevant here. it has been tryed with 5-20% there is no incraeaed effect by increasing the amount of water above 5%. If you want to use more , go ahead, but the more water you use the greater the chance an emulsion will occur. You really have to be careful if your prewashing after the second base stage.
-if your bubble drying, the amient RH plays a big factor in how dry the bio will get. one one hand your trying to dry the oil, on the other you are injecting moisture from the air. If your oil is cloudy, and all the tests pass, do WHW, you will be surprised how wet it can be!! Tom

yes Tom agreed. I was just telling him the rule of thumb here is to do 5% of the total volumne and not just of the reacted oil..since a prewash is done before you ever turn off the processor it would be hard to tell otherwise anyways... every thread on this forum will tell you that if you search it..
since I do 80/20 base/base now I dont do the prewash anymore but anymore water than the 5% I was using would have been scary..

On single stage tho I do agree that starting with 5% of the total volumn and going up from there is just fine..

quote:

Originally posted by biogirlz:
yes Tom agreed. I was just telling him the rule of thumb here is to do 5% of the total volumne and not just of the reacted oil

Who's rule of thumb? Where is this rule of thumb located and what testing was performed to arrive at this rule?
In all the threads I provided links it is clear that all the chemists at Idaho and all the chemists on this forum and everyone else who was doing testing were all talking about 5% of the volume of the oil.

quote:

..since a prewash is done before you ever turn off the processor it would be hard to tell otherwise anyways...

Of course you know how much Oil you have put in the reactor.

quote:

every thread on this forum will tell you that if you search it..

I have searched and every thread I have read says to use 5% of the oil put in the reactor

quote:

since I do 80/20 base/base now I dont do the prewash anymore but anymore water than the 5% I was using would have been scary..

Yes, the 5% pre wash was developed for the single stage reaction.

Have you read any of the threads I have provided links to? It sure does not seem like it. The information is all there if you would care to read it.

I have been on here a while now and ALL of the threads that I have started and read say otherwise..
sorry.. I do not have interest in dated outside articles.. on this forum I promise you its total volumn..(oil +methoxide).. You cannot tell at all what is reacted. if you start with 40 gallons you have no way of knowing your reacted yield until it has settled and a prewash is done without turning off the processor.. there are 74 pages of %5 prewash you should read.

But like Tom says its really irrelevant... I liked using more like 10% on my single stage but its just a matter of preference. If you want to use less then that what you should do...

this is from CBT website
read the bold

http://www.biodieselcommunity.org/waterprewash/

Prewashing Biodiesel with 5% Water

by Chug from www.biofuel-uk.net/ and Maud Essen
Questions? Comments? Feedback? Click Here


Introduction

A 5% water prewash is a way to give your biodiesel a preliminary wash after the reaction is finished but BEFORE draining off the glycerol byproduct. Performing a 5% water prewash stops the transesterification reaction dead in its tracks by drawing much of the water-soluble methanol, lye, and glycerol out of the biodiesel and into the glycerol layer. This can help reduce soap, inhibit emulsion formation, and make further washing easier.

Why You May Want to Adopt the 5% Water Prewash

Washing has traditionally been thought of as the most challenging, time-consuming aspect of biodiesel homebrewing. For many people who use the 5% water prewash method, this is no longer the case. In fact, most people who have used the 5% water prewash method report that their biodiesel is much easier to wash afterwards. Not only can it take a much more vigorous wash than biodiesel that has not been given a 5% water prewash but also it usually requires much less washing. In fact, following a 5% prewash you may need only one or two additional washes instead of three!

Although this technique may help you save wash water overall, be aware that it will add water to your glycerol byproduct and therefore may make it harder to recover the methanol from it. If you don't recover methanol from your glycerol, carry on.

What You Need to Do

Start by running the biodiesel reaction in your processor as normal. Process as usual until your batch is finished. But BEFORE turning off your pump or mixer, add in your prewash and continue mixing. Here are the details for the two most common base reactions:

Single stage base reaction
Process as usual until your batch is finished but keep your pump or mixer running.
With your pump or mixer still running, add 5% water (that's 50ml per litre of water for every litre of liquid in the processor---oil plus methoxide.)
After you have added in the 5% water, continue pumping/mixing for an additional 15 to 20 minutes.


Two-stage 80/20 base reaction
Process as usual until your batch is finished but keep your pump or mixer running.
With your pump or mixer still running, re-introduce the glycerol you drew off at the end of Stage 1 back into your processor PLUS 5% water (that's 50ml per litre of water for every litre of liquid in the processor---oil plus methoxide.)
After you have added in the Stage 1 glycerol PLUS the 5% water, continue pumping/mixing for an additional 15 to 20 minutes.


When you are finished mixing the prewash, settle the entire batch as usual in your processor or after pumping into your settling tank or wash tank.

After your batch has settled, drain off the glycerol byproduct. Now that it has 5% water mixed in with it, your glycerol byproduct will be much thinner than usual and of course there will be more of it.

Using your usual technique, wash your biodiesel until the wash water is clear. With the 5% water prewash you may find that you can use a faster, more vigorous washing technique with less risk of causing an emulsion. You may also find you need to wash your biodiesel just once or twice instead of three times. This technique can save you a lot of time, water, aggravation!


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Collaborative Biodiesel Tutorial - Copyright 2005

Many people come to this forum because it has a reputation for providing the newest and bestest information available concerning biodiesel production from people who have lots and lots of experience in biodiesel research and production.
It is clear that you do not fit into either category.
I have provided several links to the exact type of information contained on this forum that people come here looking for.
I have asked you several times to provide a link to testing that has been performed and posted to this forum that support your statement.
The best you can do is provided a link to a website that has nothing to do with this forum and from what I can see at a quick glance has problems with the information it contains.

While we are posting links to websites that have no connection to this forum, I would like to direct you to an article titled The 5% Water Prewash for Biodiesel on another website which starts out:
"The concept is that you add water after the reaction is complete, but before settling has started. This helps the settling process, giving a faster more complete settling.Testing has shown a 30% to 50% reduction in soaps in the unwashed biodiesel. I have seen 95% settling in as little as 30 minutes. The disadvantage is that it introduces water into the processing tank.
The procedure came initially from the University of Iowa. Their process was further developed by a group effort on the internet to provide fine tuning that fit the homebrewing style. The highest yield came from adding 5% water by volume of the original amount of WVO. So for 100L veggie oil you would add 5L of water."

Now back to my original question. Can you provide a link to real tests posted to this website that supports your position?

Links should go to specific information - best to test after posting to make sure it works.

...don't feed the trolls, tril...