Using acetone for reacting and Washing.

[dgs]

I read through all 15 pages of the original thread last night.

http://biopowered.co.uk/forum/index.php/topic,860.0.html

It takes a bit of 'sorting through'. I think the original photo is very impressive. So for those of you that have been through all this 3 1/2 years ago I can't blame you if you don't want to read on.

After the acid wash tests I did (which did work very well but I was so disappointed that the washes left the bio a darker colour) I thought I would give the acetone wash a try

I did the wash on a full 205 litre process;

Bubbled for 15 hours, left to rest for 30 mins then checked the soap at the surface. It was 570ppm

It was left to stand for 24 hours then the soap checked at the surface again, 290ppm.

Transferred to the wash/drying tank. Heated to 30 degs, washed via the compressor with 10 litres of water (only) for 2 mins.
let it settle for 30 mins soap at surface was 350ppm. This is not suprising as the bio had been really churned up with the compressor and the 290ppm result was done at the bio surface after being stood 24 hours.

added another 10 litres of water with 40mls of acetone added. Washed for 10 mins, rested for 30 mins. Soap at the surface was 210ppm. This was a really strange wash, a lot of the water was left suspended in the bio, it was almost like an emulsion except the water (but not all of it) did split. It is almost as if the acetone acts as a co solvent between the water and the bio.

Added another 10 litres of water with another 40mls of acetone, washed for 20 mins then let it settle for 30 mins. Soap at surface 20ppm. This time the water had dropped out.

Another 20 min wash with water only, soap now 10ppm, but wash water not clear, so I had to do another wash (No5) I added 20mls of acetone for this one and the wash water was clear. Soap was <10ppm.

The test did not result in a lower number of washes, i always had to do 5 washes in the past. With acid I only had to do 4.

The soap did not reduce proportionally and did not reduce any quicker than the acid washes.

The acetone wash does not increase the colour of the bio (this is one of the lightest coloured batches I have ever made) I'm wondering if it even makes it slightly lighter in colour.

Just like the acid wash, the acetone wash does seem to supress the formation of the emulsified mono layer.

Success? well, partial I suppose. I prefer it to the acid wash because of the lighter coloured bio, but it certainly didn't reduce the amount of washes or get rid of soap any sooner.

[Head Womble]

Um, that's interesting, if I read right this was done after an acid wash which is something I didn't do.

Can I suggest trying it with just the acetone washing next time.

[dgs]

Sorry if it gave you that impression Mark, No it was only acetone used, no acid at all. I was mentioning the acid washes for comparison.

[Manfred]

Why did you do the first wash with no acetone added. It might have cut out one wash.

[dgs]

Really it was just a case of mixing it up, lowering the soap a little and then making sure a sample from the top was representative of the contents.

This is what I used to do when I was acid washing, to do just a water wash first to lower the soap so the ffa level would be lower when the acid hydrolysed the soap.

You could be correct though, but I will find out with future batches.

It is a very strange proceedure compared to just using water. I suspect the acetone acts as a co-solvent and the cloudyness in the wash water is partly due to some tied up bio as well as soap.

[dgs]

I thought I would use this thread for this, even though this is only 'sort of ' on topic. EDIT - Not now cos I've changed the thread title.

I've been reading through the various threads about reacting with acetone in the mix. I do believe there is an advantage to using acetone, although for someone (like me ) than doesn't do WBD it is probably not economical to use acetone as the cost outweighs the catalyst and other savings.

I have just used 250 mls of acetone during S1 of my present 190 litre batch. I didn't intend on this batch to take note of any measurements, times etc for comparison but really just wanted to observe if there were any differences.
In any case I now have my own way of processing (too complicated at times) so I can't really compare my findings to anyone elses.

I use a mix of KOH and ASM and for S1 I don't (at this time of year) use any heat at all, so I leave overnight and do S2 with heat the next day. I also only use 12% methanol for S1.

Anyway, to get to the point; I completed S1, with the 250mls of acetone at about 11.30 this morning and let the batch rest for 1 hour or so. A 10/90 showed 0.8mls dropout.

As the batch has cooled during the day (end temp is about 35degs due to methoxide temp and tam120)  I have been running off the glycerol. I have just come into the house from locking up the bio room and have noticed (considering methanol is still in the mix) how light coloured
the bio is. It is quite unbelieveable after S1, I have never seen this before, I can only conclude the acetone addition has made the glycerol drop more efficiently. I have read the wiki re using acetone and the reasoning given for a more efficient glycerol drop is the lower viscosity created by the acetone. in my case i cannot see this being the reason. 250mls in 190 litres isn't going to make that much difference. There is something else going on here.

I will add a smaller amount of acetone for S2 tomorrow and report back.

[Glycer-rides]

Interesting, Dave.
I will not be trying this yet as 250 ml of acetone would cost me over 50p!

[dgs]

Yes, as I say I don't think adding the acetone can ever be cost effective unless it can be recovered and the catalyst is just ASM.

From the previous thread some that used considerably more acetone in the mix reported reduced catalyst usage of up to 1/3.  So just using NaOH or KOH on an average 180 litre batch would mean a saving in catalyst of 50 to 60 pence or so and an extra spend of several £'s depending on acetone %. They also reported better conversion rates, however this can be achieved by using ASM.

The original thread also ends up mostly talking about HMPE's that seemed to appear. The thread was mid Winter time so wheather the HMPE's were to do with the time of year or the acetone is a guess.

Does anyone that still posts on here that was involved with the original Thread still use acetone either for reacting or washing?

Interesting exercise though, I'm impressed with the way the glyc drops.

[dgs]

I have now completed the next batch using acetone in the wash water.

The wash cycle was done again at 30degs.

Starting soap level was 290ppm, Each wash (except the last one) had 40 mls of acetone added.

First wash was again 2 mins, soap level was 210ppm.

Second wash was 10 mins, soap level was 106 ppm.

Third was was 20 mins, soap level was 47ppm

Fourth wash was 20 mins, soap level was 15ppm.

Fifth wash was 20 mins, soap level was <10ppm.

After the fifth wash the water was still not quite clear, even though the soap was virtually non existant.

I reported with the previous wash test that the water was clear after wash No5, now I'm not so sure. I have recently changed the bowl that I use to collect the water in, it is now a beige colour and I've just noticed it is difficult to see how cloudy the water is/isnt.

Conclusions;

The 250 mls of acetone that I added to S1 of this process certainly helped to settle the glycerol after mixing. I also would suspect that it helped with the reaction (although I was not recording any reaction parameters other than from the added chemicals the conversion was a little higher)

After this encouraging result I am certain the addition of acetone helps the reaction in several ways. As said unless the acetone/methanol could be recovered (depending on acetone addition) this could prove to be very uneconomical.

The 50mls of acetone added to S2 did not make any obvious difference.

As regards the addition for water washing, I did not find that there was any advantage, in fact I would go so far as to say I found it counter productive. Number of washes were not reduced and soap levels per wash were no better than just using water and certainly not as good as acid.

As the acetone acts as a co solvent between the water and bio this results in a small amount of bio being suspended in the water, giving a cloudy appearance even when virtually no soap is present. Also the acetone addition encourages more water to be suspended in the bio layer, if this is at the start of the wash it results in a higher soap level.