First time using ASM.

[neisel]

I've been given about 15L of ASM & am going to try it on my next batch. Had a read here & it seems the current thinking on best practice is evolving all the time.

I have started under dosing when using KOH & NaOH, usually 15L of methanol with 750 grms of catalyst REGARDLESS of the batch size (which is approx 155-160L) & then finishing it off with S2 adjusted to dropout. Recently S1 has been done cold, heating to about 55-60 for S2. Oddly, I have found I get v. nearly the same S1 conversion as when I was using 20L & 1000 grams of KOH (at around 70 degrees for both stages) & save 5L & 250g.

So, the 1st question is, how much ASM do I need to add to 15L of methanol for S1 to proceed pretty much as outlined in para 2, sentence 1?

Can I do this batch cold as I've started to do with KOH or do I need to heat the WVO up?

If yes, for both stages? To what temp?

Thanks in advance. Any additional guidance welcome.

[dgs]

Hi neisel, As ASM gives rise to solid glycerol it is not a good idea doing your reactions cold if using ASM only. Why not use a 50/50 mix of ASM/KOH it works nearly as well as ASM only and gives rise to liquid glycerol no matter how much you starve the process of methanol.

You can then do both stages at ambient temp.

Re your post, as the reaction works exponentially you will always get the effect you describe if you underdose. If you use a certain amount of chemicals and get (say) 80% conversion, then do a comparison with 50% of the chemicals you will achieve more than 40% conversion as shown by a dropout test.

[neisel]

dgs,

I thought I read somewhere on here that it was better to do S2 at at least 55 degrees to avoid FFAs, or something along those lines. Have you been doing the full conversion (S1 & S2) cold?

Following your 50/50 plan I would still use 15L of methanol, 375g of KOH & how much ASM?

[dgs]

Hi neisel, 375gms KOH is equivalent to 810 mls ASM (allowing for KOH being 90% pure) give it a try and still use your 15 litres of methanol.

For ease of working it out you can just double the amount of KOH as mls ASM, it is close enough.

You are correct about the S2 at temperature, however over the last few months I have been doing a bit of work on this.

I was 'sick to death' of water washing aggressively and still getting the emulsified layer between the water and bio, this was with a clear 10/90 pass. This layer is due to unreacted monoglycerides. Question is, to get them all converted would this be a more temperature or chemical related thing.

I've found out it is more to do with chemical addition. I now try to get the dropout after S1 to between 0.2 and 0.5mls and then double up on the chemicals reqd for S2.Easier said than done sometimes, if i have a S1 pass I still do a small S2. If the dropout is greater than 0.6 or so I do an intermediate stage to get it to 0.3. Since doing this I have reduced the S2 temperature to ambient and have had no evidence of mono's. As the temperature falls towards autumn it will be interesting to see just how low I can do S2 at whilst still being mono free.

[neisel]

My 1st ASM batch is drying as I type, all converted to 100% BD.

AFAI can see it is the same as using KOH / NaOH, except for the fact A LOT more water washing is required for a 50/50 pass. I can see no advantages in using ASM, quite the contrary in fact.

Late Wednesday night S1 & S2 were completed & 4 water washes done. I went to bed anticipating maybe having to do 1, possibly 2 more on Thurs a.m. & then onto the drying. At 11p.m. Thursday I did my last of what, ANOTHER 7 or 8 w/washes at 11p.m. Stopped counting after a while but I spent the whole of Thurs doing bloody w/w after w/w.

No idea why. The WVO was treated twice with glys, 1st time with once used, second time with 'virgin'glys & left for at least 24 hours each time before adding any chems. On S1 of 155-160L (cold) I used 15L of Methanol with 375g KOH & 900mm of ASM. I got an 85% pass. S2 was @55 degrees, 4L + 140g of Sodium giving me a nice crystal clear 10/90 pass. 7% prewash looked the same as it does with pure KOH on S1, 1st proper w/w did not show an abnormal layer of soap. I don't think I overdosed so am stumped as to why I had to wash & wash & wash. I assume it's soap I'm trying to clear, is there something else produced w/ ASM that's a bastard to wash out?

What did I do wrong?

[RichardP]

Having used ASM for a few years and water washing never really had any problems. I bubble it with a 4/5lpm air pump, probably 4 washes over a couple of days & always comes clear easily. What's your washing method?

[neisel]

For the 1st two washes I suck in about 15L slowly through the venturi & when all the water is in, run the pump at full blast for at least 30 mins.

After 2 washes I've found the possibility of making an emulsion is all but zero so I just open the lid, dump 15L in & turn on the pump for the same amount of time.

[RichardP]

How long do you let it settle before dropping the water? I did pump wash years ago and found after a wash it needed a couple of hours for the bio/water to split properly. May be worth trying bubble washing it, see what that does.
None of this though explains why the ASM/Koh gave rise to needing so much washing than your usual method. Could be just one of those pain the arse batches than come along.

[dgs]

Hi neisel, like Richard I don't know why your batch was so hard to wash, but what I do know is that it would be due to one of two things; 1 soap and 2 monoglycerides. one a result of under conversion ( even with a clear 10/90 ) and one from too much catalyst.

Your chemical addition for S2 is in balance but your S1 is 'unusual' Only 10% methanol and very low amounts of mixed catalyst but you still achieved an 85% conversion. Was the oil partly converted after your glyc wash?

One thing for certain is it will not be anything to do with the ASM.

It's good to test for soap after your wet glyc on your 7% prewash has settled, then you would know what you are dealing with.

[neisel]

Richard,

It rests for between 75 & 90 mins min between each water wash, which has always been enough using KOH or NaOH.

dgs,

I recently started to underdose so I could make an additional 5-7 litres per batch, no other reason. Quite by chance I discovered that by using 15L & 750g of KOH I was getting surprisingly similar conversion rates as I was when using 20L & 1000g of KOH. No idea if the oil was partly converted by glyc washing, I don't test it.  I double glyc wash in the belief/hope that it dries the oil. I'd be quite surprised if there is a sig conversion, since I'm re-introducing glyc which was made by the 15L/750g 1st stage. I would have expected just about all the chems to have been used up already, since it's significantly underdosing.

Anyway, can someone tell me, what is/are the supposed advantage(s) of using ASM over pot or sodium? I can't see any &, even if I had had to w/w this troublesome batch 4 or 5 times as normal, it appears to be the same process, the same # of stages & the same amount of work & time as the old fashioned way.

[dgs]

ASM is anhydrous and even 'consumes' any water in the methanol. In theory you will produce 104 litres of bio from 100 litres of oil with a perfect water free process.

When using KOH or NaOH 320gms of water are produced for every 1000gms used, in addition the reason for KOH being only 90% pure is that the other 10% is water, then we also have water in the methanol. This is the reason our 'yield' is in the region of 96% or so.(usually)

With methoxide that is dryer much less soap is produced, so less volume of glycerol is made and more volume of bio is left.

I am not a chemist, but understand a little. The methoxide producing reaction is quite complicated, it isn't just a case of dissolving the catalyst in methanol. If countrypaul sees this he will explain properly.

[neisel]

dgs,

I'm going to make a batch tomorrow using 100% ASM for S1. S1 will be 15L of methanol + xL of ASM.

Using 'A real world example' figures from the bottom of http://www.biopowered.co.uk/wiki/Processing_with_anhydrous_sodium_methylate I calculate x to be 2.5L. Does that sound about right to you.

[dgs]

Hi Neisel, yes the wiki is correct. However I always calculate every batch from scratch. It seems simpler to calculate your total amount of NaOH using your usual base amount then just divide the result by 0.3 to get mls of ASM to use.

Good luck, let us know your results.

[neisel]

Hope I'm not tempting fate by posting this too earlier but ASM has been a MUCH happier experience this time (so far).

15L methanol + 2.5L ASM in S1, which was about 150L of twice glyc washed (1 x once used, 1 x virgin glyc) WVO.

85% conversion.

130g NaOH + 3L methanol for S2. Clear pass.

1 x 7% pre-wash & 3 (1 x 12 & 2 x 15L) water washes & I have a very, very nearly clear 50/50 pass. I'd say it would do as is but being an idiot I have decided to do a final w/w for that crystal clear look.

I'll check again back in again later this afty.

I reckon underdosing on S1 saves me about 5 or 6L of methanol per batch. I don't know what % of ASM is methanol but discounting the ASM content I calculate I'm only using a total of 12% methanol, which I think is pretty low.

[neisel]

Sigh....

Has anybody else ever experienced a 50/50 test getting cloudier after being v. nearly perfect?