What a great idea!
I don't know if this is a good idea but I will use it in my next processor. I will heat up the air to 70C and pump it to BD. Doing this with a condenser I should be able to get the scum and methanol out.

...sound like a good idea?

This is interesting. Especially for people considering using Magnesol.

You could perform this technique to drop the soap concentration and get rid of / recover the methanol. Then do a soap titration, then add magnesol.

[QUOTE]Originally posted by GrahamLaming:

HI Grahanlaming

-------
Caddytd: You made a good point about the pre-wash - I think you're right that the water introduced by the prewash could impair soap separation.

I'll do a new batch next weekend and will skip the prewash, so there will be no water at all in the BD or wash tank.

I'm also going to try KOH instead of NaOH, because I want to have a good long settling period (24 hours) in the processor to drain off as much glyc as possible.
However, I've never used KOH before, so I don't know if the soap will coagulate like it does with NaOH - just have to find out.
-------
]

Haven't heard from you on this since May. What was the result without the pre-wash. It would seem that the test should only be done by changing one thing at a time. Keep using the NaOH without the pre-wash, then after you find out what happens using that method switch to using the KOH.

Roger

Hi Roger,

I still haven't bought any KOH, so haven't tried that yet.

However, I did try without the prewash and I believe the soap is given up more easily now.
Now the weather is nice and warm, I'm not so paranoid about the glycerol hardening in my tank.

The film of soap on the surface seemed firmer without the prewash.

My gut feel is that NaOH will allow you to harvest the soap easier.

I also tried spraying the hot bd into the open mouth of a 200 micron bag filter. This yielded plenty of soap, so much so that I blocked the bag filter within minutes. This seems to offer more rapid cleanup, but you need a good supply of filters to allow the process to continue. You can then wash and dry them afterwards. Or, use really big bags - pillow case?

The Methanol fumes pose a problem, though, when spraying - they would ideally be distilled for re-use. [ edit 20 june 2006 GL]

I'm working on a set of photos and diagrams to better explain the whole process, because I feel it is offering worthwhile time and water savings. Hope to have them ready this weekend.

This message has been edited. Last edited by: GrahamLaming,

Graham,

i'm wandering

since the purpose of the prewash is to limit soap formation(so to speak) you would have more soap to remove by bubbling if you did not do a prewash correct? if there were more soap then it would "appear" to free up easier because there IS more soap present?

it would be awesome if someone could

do a soap test before bubbling and after bubbling a batch with prewash

do a soap test before bubbling and after bubbling a batch with out the prewash

both with KOH or both with NaOH

i don't know how much work it would be (or what is even involved in a soap test) but i am speaking as a newbie to bio with a science background.

thanks
Higgins

Hi Higgins

The pre-wash helps the glycerol and soap to drop out of the BD quicker, and helps to keep the glycerol liquid for longer.

I don't think it limits soap formation, as it comes right at the end of the process, after soap has been formed.

But your suggestion is a good one - a proper methodical comparison. Any takers?

quote:

Originally posted by GrahamLaming:

But your suggestion is a good one - a proper methodical comparison. Any takers?

Why is everyone looking at you Graham ?

Hi Folks,

I have used my proposed soap removal method on an 80 litre batch and have managed to reduce
water usage to nil. I am delighted with the result and the speed of processing.

I collected the used oil on Sunday 11 June at 10:30 am.


The finished biodiesel was ready on 13 June at 08:00.

I've put in 2 full days at work, away from the BD in that time.




I did not wash the biodiesel with water.
I did not use magnesol.

The sample in the pic has had a vigorous shake-em up test and has sat in the sun all day today. I cannot detect a hint of clouding of the water. It is crystal clear. The viscosity appears identical to my conventionally washed biodiesel.

I shall write up the full process properly over the next couple of days in the hope that someone else will give this a try and verify that the procedure is practical and effective.

In a nutshell though, here's what I did...


1. Standard process 5g NaOH + Titration, 22% MeOH

50C process for 2 hours.

2. NO prewash - no water used at all.

3. Settled for 1 hour and drained off glycerol residue.

+++++++++++++++++++++++
NB!!! VERY heavy methanol vapour at this stage. Do NOT attempt unless you have a fresh air feed to breath. I use a breathing tube. I'm planning to seal the tank, force feed with air and install a venting chimney to take the fumes up and away.
+++++++++++++++++++++++

4. USE BREATHING APPARATUS ! Transferred to dry 'wash' tank and started pump circulating at 60 litres/minute.

Initially sprayed into the tank with a flat nozzle, to create a fan of biodiesel, which broke up as it passed thru the air. The liquid temperature dropped from 45 degrees to 25 degrees within 2 hours.

Soap scum began to form on the surface after a few hours' spraying.

I then sprayed into a 200 micron bag filter.

Household fan blowing into the tank to dilute vapor concentration inside tank and help with evaporation and removal of methanol.

Aquarium bubbler at bottom of tank.

Here is the tank, a "poor man's cone-bottom".



This is a normal 45 gal drum with 2 bricks at the back to tilt it forward. A siphon tube enters the tank near the top, and drops down to the lowest 'corner' (?) I like this design as it has no leak potential and is at ground level, needing no stand. The cheap bit appeals to me too.

5. Scooped off soap scum every couple of hours.

Bag filter remained free flowing until approx 8 hours into the process, when I suspect the methanol level had reduced to a point where the soaps became saturated within the bulk liquid and were released in solid strand form.

6. Replaced 200 micron bag filter after further 10 hours, as it began to overflow.

7. The fresh 200u bag seemed to remain free flowing, so I exchanged it for a 10 micron bag filter.

Here you see the 10 micron fresh filter on the left, the clogged 200 micron filter on the right. (The clogged filters washed clean in warm water, look like new again.)




There is some residual soap/glycerol scum on the side of the tank, but none apparent in the biodiesel, as shown by the wash test. I believe the loss of methanol thru evaporation has rendered soap and glycerol insoluble in the biodiesel. Or, better put, has rendered the methanol-free biodiesel a poor solvent of soap and glycerol.

I shook samples with water from time to time to check on soap/methanol/glycerol removal progress, which seemed steady and reached a final result which surprised and delighted me.

The weather has been warm, with low humidity. Air temp 28C at start, 31C yesterday.

No added heat used in the cleaning process.

I could give this a go, I guess. I'm pretty happy with what I have now but in the interests of the community and all that...

Graham,

You have posted two similar, but radically different procedures. The first procedure you originally posted on 6 May 2006 called for a 5% water prewash. The second procedure was posted on 13 June 2006.

I think both procedures will produce good, high quality biodiesel and this seams to be your experience. However, your yield from the first procedure is probably considerably better than the yield from the second.

The 5% prewash of the first procedure will wash out a significant amount of the catalyst. The catalyst will settle with the glycerol and be removed from the reactor.

You do not use the prewash in the second procedure. So, a higher percentage of the original catalyst is left in the biodiesel.

By recirculating the biodiesel you are driving off the methanol. The catalyst that was dissolved in the methanol is now free to do whatever the fundamental chemistry of the reaction dictates. In this case the sodium hydroxide forms soap from the biodiesel and any unreacted oil.

In effect you are making soap out of the available catalyst. Your filtering/recirculating arrangement insures that you capture the soap.

If a loss of yield is not important, then you truly do have an effective way of creating good biodiesel. Think about it. There is no methanol in your finished product, there is no soap in your finished product, there is no catalyst in your finished product, and you do not have to dry your biodiesel.

I don't know the basic chemistry of soap production, but it may be that the catalyst might have an affinity for unreacted mono- and di-glycerides over methyl esters. If this is the case, then your final biodiesel also is free of these pesky little buggers that clog filters. Based on the photo and your description of the water shake test, you may have also gotten rid of unreacted glycerides.

If my theory and analysis is correct, then you have come up with a wonderfully effective and simple process that home brewers can easily duplicate. As long as reduction in yield is acceptable, your process should work well.

Hi Producer,

Thanks for your comments.

I opted for the zero water approach to speed cleansing. I can expel methanol far quicker and with less energy than I can expel water. Water is just another retainer of that soap & glycerol I want rid of.

And there's a psychological "Oh Yes!" kick to getting bright clear, soap-free fuel without the addition of a drop of water.

I saved all the recovered soap and weighed the filters and I recon I made 200g soap in an 80 litre batch. Difficult to be precise, because I couldn't remove all the BD from the soap or filter fabric.

I'm happy to sacrifice that oil which went into the soap for the ease and speed of processing and completeness of conversion.

I've gone to a 5 micron bag filter now and the BD is just falling right thru it.

My car was 1/8 full, it's now brim-full with this batch, so I guess if there are going to be any problems, I'll know about them soon enough!

But I am confident there will be no problems, the fuel is the cleanest I've ever made and I'm
entirely happy to put it in the car.

so producer which you think is better pre wash or no prewash? chemically speaking

you suggest that the catalyst helps remove any unreacted FFA which will help make higher quality (astm) fuel

but i guess if you do not have alot of unreacted FFA then the prewash will be better becuase it helps remove alot more soaps by settling in the gylcerine

Thanks for the work Graham i'm planning on trying this on the next batch.

i don't know if i can stop washing though with great confidence

Higgins

Higgins,

All things considered the 5% prewash will produce less soap, have a higher yield, and probably have no more water to contend with (after glycerol settling) than the "non-prewash" approach.

My theory is that all remaining catalyst will convert product to soap. The soap making process continues until all catalyst is consumed. So less catalyst means less soap.

Graham and I both hate the thought of adding water to the biodiesel. But, the water added in the 5% prewash should all settle with the glycerol. If that is truly the case, then the 5% prewash is far superior to the non-prewash approach.

The basic chemical equation is:

FFA + Catalyst = Soap + Water

As you can see a by-product of soap formation is water. And, since the rate limiting factor in the relationship is catalyst, then more catalyst means more water.

Therefore, my opinion is that 5% prewash, followed by proper settling, will actually result in less water, which ultimately must be removed from the final product. Most of the "chemically produced water" will probably evaporate with the methanol.

Please take the above for what it is worth. A little chemistry and a whole lot of personal conjecture.

quote:

Originally posted by producer:

Please take the above for what it is worth. A little chemistry and a whole lot of personal conjecture.

LOL!

Hell, producer - thats what makes these forums so interesting and so much fun!!

Higgins, one additional point of clarification. I did not mean to suggest the following:

quote:

Originally posted by Higgins:

you suggest that the catalyst helps remove any unreacted FFA which will help make higher quality (astm) fuel

Higgins

There are no FFA in the biodiesel AFTER the transesterification reaction. Any FFA in the raw WVO immediately consumes the catalyst to form soap. This happens at the very beginning of the reaction. After the FFA have been converted, then the remaining catalyst works with the methanol and WVO to produce methyl esters.

This is why it is so critically important to run an accurate titration to determine the FFA present in the WVO. The only catalyst available for the transesterification reaction is the catalyst left behind AFTER the FFA converts to soap. If too little catalyst is added based on titration, then there will not be enough catalyst for transesterifcation.

I suspect most problems associated with poor washing performance are based on either: 1) not enough catalyst to accomodate FFA conversion to soap; and/or 2) methanol evaporation during the reaction.

quote:

Graham and I both hate the thought of adding water to the biodiesel. But, the water added in the 5% prewash should all settle with the glycerol.

That's an interesting point. I've been doing the prewash for quite some time now and as others have noticed, my settled product with 5% prewash is slightly cloudy when it goes into the wash. I had assumed that the "cloudy" nature was due to the presence of water in the bio...a sort of "pre-orange juice" haze type of thing.

I agree that the majority of the water drops out in the glycerine layer, but even if a bit remains in the bio, I'm imagining that the recirculation / fan setup will dry that water out rather quickly.

I'd like to try this, but I'm a little hesitant right now due to my semi-enclosed production space. If I'm going to be evaporating methanol, I'd like some sort of hood vent setup.

I was contemplating installing a bathroom fan or a friend suggested a boat bilge fan (170cfm for a 4 inch fan!) attached to the outside with a drier vent hose kit. Perhaps it's time to look into that more closely...

Hello Producer

I think you may have spotted the reason that the 5% wash gives a slightly higher yield.
Neutral did some tests which showed this was the case.
Neutral also did some tests that demonstrated that the excess NaOH in the biodiesel is consumed making soap from the biodiesel which leaves virtually no NaOH/KOH remaining in the unwashed biodiesel.

I do have doubts about your suggestion that mono and di glycerides are responsible for clogging filters.
If that were the case I would have been changing filters every day.

Tilly,

Are you sure you have mono and di glycerides in your fuel?

My comment was based on direct second hand reports. (Can't get much more accurate than that). A local commercial purchaser of large quantities of biodiesel reported excessive filter plugging. They sent samples off for GC analysis. The results showed elevated levels of mono-glycerides. Hence my comment.

Tilly, Nuetral, Girl Mark, Diff, other elder jedi of biodiesl whom i humbly apoligize for not mentioning

what are your comments on this process of removing soaps/methanol/ffa?

would washing/mag. still be necessary?

comments from the jedi biodiesel enthusist?

PS; Just as after thought. I'm not trying to knock your test or experiences Gram. I just am just trying to get more converstation about this going. I don't know where you stand in your biodiesel learning curve but mine is still straight up

Wooooow...This "breakthrough" comes at the absolute perfect time for me! I've been reading hardcore through the archives on waterless washing for the past week, and I'm picking up my 55gal barrel of methanol tonight to get my first big batch going. Now, with a few tweaks, I can incorporate this washing method and be soooo happy!

I haven't seen this being tried with KOH yet; did I miss it? Since my oil is typically 6-9ml NaOH oil, it always gels when it cools and takes HUGE amounts of water to wash (1 gallon water per liter BD), so I was switching to KOH, maybe now I shouldn't (although my KOH just came it last night, but I'm sure there is somebody here who would buy it if I decided to sell it).

YEEHAW!