New Member

[lozzzzzz]

Good thinking, I like that plan.  I'll give it a try. 

Could you elaborate on "no need to drain glyc"?  Do you mean after the second stage and before the 3rd? Or no need after second stage at all? 

[kamaangir]

He means for the 3rd stage, there won't be much glyc after 2nd stage.

[Dickjotec]

Correct also don't drain glyc if just adding meth to see if the reaction goes further. Drain before second stage.
Do, of course drain glyc before transferring to settling tank.

[lozzzzzz]

Well i'm back at the folks house and have taken a sample for the 50/50 test. This is it after 10 minutes:

 

I think this means tjere is no soap as th water is clear? Right?

It doesn't seem to have the creamy boundary though, i can't remember what that meant.

If i'm right about the lack of soap does that mean the oil mist have been nice and dry to start?

[Dickjotec]

A job to see how clear the water is, it should be crystal clear if there is no, or little, soap. Let it sit overnight to get a proper reading. If yo have a laser you can shine that through it and the beam should not disperse.
It is not an indication of dry oil particularly, rather that the soap created by processing has fallen out. In order for the soap in the bio to settle out all the methnol must be removed ( the meth keeps the soap in suspension) this is the reason for bubbling.
Take a number of tests over the comming days to compare the settling. Once you have seen the process through on this first batch there is no need to do it each time, just test befor you move it to the storage tank to make sure it is soap free.
The lack of an intermediate layer shows good conversion, no mono or di glycerides.
Btw I assume you took the sample from the bottom tap on the tank?

[lozzzzzz]

I understand, well there shoukd be very lottle meth left its still bubbling now, some 30 hours its jad so far.  i took it from the top tap. I thought they would give the same result as the bubbler is moving the liquid about a bit. I'll take it from tue bottom next time.

Thanks for the informative reply

[Tony]

The water test is something so vague you have to learn how to feel it.  Depends on many things not least of all water softness and glass cleanliness.  Sometimes blobs stick to the sides and make it look murky when it isn't.

The titrated soap test is the definitive answer, and NigelB here used to and may still well supply kits for this purpose.  I've got one and use it for confirmation on batches which are ambiguous with the water 50:50 test.

I use quite a violent vane pump for transferring my settled bio around and what stands out more than anything is the behaviour of the bio after this aggressive pumping, which introduces a lot of air bubbles into the bio.  If it's soap-free the bubbles quickly disperse, but if there is some soap left they take longer to go, and in bad cases form a layer of bubbles on top that don't quickly disperse.  So I tend to gauge soapyness on that now more than anything else.

[willbuild]

do you still have a thin white layer in between the bio and the water?
did you do any water washes in the processor after demething?
I do one acid wash then 2 or 3 water washes all at 55 60c then heat to dry bio. It then gets 12 hrs bubble 24 hrs later i get Crystal clear 50/50 test with no white layer.
My last 3 batches have been high acidity values 18 g,p,l.

[lozzzzzz]

Thanks Tony, all helpful info.

I've heard about water washing but I didn't do any this time.  There is no white layer. 

I used so little Meth, that I didn't even de-meth, just gave it a serious bubbling (60L/m bubbler) for 48 hours.  I intend to de-meth when I try and make fuel for a PD engine soon. 

[willbuild]

I've been running a polo gti 04 plate for 7000 miles on b100. only problem was needed to change fuel filter after about 5000 miles, was stuttering when turbo kicked in. filter had bits in it that were from inside of pipes (thin tube shaped brown film)

[lozzzzzz]

I did another batch on Saturday.  I did 150L this time. 

First I filled up with 160L, heated, left over night and drained 5L off. 

This left 150L !!!!!    I lost some last time too? but I've figured it out.  No matter how quickly I pour it in the pump pulls in air too so I'm getting about 5L of bubbles in the oil once it's up to 160L.  No matter, now I know. 

So I mixed up 15.5L of Meth with 775g of NaOH (did this friday night shorlty after loading the machine, so I still thought I would be working with 155L). 

Dosed and mixed for 15 mins (mixed for longer on the second stage). 

45/5 test gave 2.5ml so 50% veg still.  There was no 135L left after draining the glyc. 

Based on this volume I added 6.5L and 325g NaOH and mixed for half and hour. 

At this point, in the interest of learning a bit about it, I added 5L more meth, to see how much further that would push it. 

45/5 test gave 0.65ml so 13% veg oil before adding the 5L of meth and 0.125ml or 2.5% veg oil after adding the excess Methanol. 

You could argue either way here and say the extra Meth pushed it a little further over to bio or it was the extra mixing time (another half hour). 

Anyway...   based on all the above info I concluded that I needed a further 17.5g of NaOH to get B100.  Mixed with another 1L of meth it went in for another half hour and B100 was the result.  No fall out at all after the final 45/5 test.  Result!!!!!!   

Then into the settling tank for 48 hours of bubbling. 

The first water test resulted in this: 


Perhaps a bit of water still in the oil then!!!???   I have a little go at condensing the water out first next time, in the interest of slowing the built up in the bottom of the settling tank. 

[Dickjotec]

How long after processing was this sample taken, how long has that been settling for and where in the tank did it come from?

[lozzzzzz]

Dick,

It was straight after it went in, less than 10 mins.  It was from the bottom tap.  And that is after 24 hours of sitting in the rack. 

I've taken another sample now, and after sitting in the rack for a while it seems the proportions are similar, but the white layer now looks like a sponge with clear water in the gaps

[RichardP]

Your method sounds a bit odd to me, especially the amounts of methanol and NaOH you are using in various stages.

From my point of view:
- Heating and settling your oil will not dry it properly, and wet oil is the main cause of failed or crap batches. Dry it, then dry it some more! You have the means to do it on that processor so use it.
- You are using too little methanol and too much NaOH in the first stage, look at using 14% meth and 4g/l NaOH - use the right amounts and don't fanny about bunging in bits and pieces here and there to see what happens. Get a good baseline where you get consistently good results and then start tweeking or you won't know what has made a difference.
- You are not reacting long enough 10-15 mins isn't enough, you can run it for an hour and take samples at various intervals to check when the reaction stalls then cut the time back if you want.
- As you have used way too much NaOH, you will have produced a fair bit of soap, hence your low yield. 1100g of catalyst for 150L of oil is KoH territory, 700g of NaOH should have been enough.
- The 50/50 test photo proves my points above - a ton of soap in there has caused that emulsion in it.

Get the basics right and the rest is easy.

[Dickjotec]

Lozzzz Have a look at the spongy  sample tomorro and I think you will see that it looks a lot better.

Richard, I start with 750g on a 160 batch and add more for the second atage. When we were single stage alow titrating oil, say 2, would have had over 1000g to convert. His pump is seriously powerful, hence the short processing times. I do agree on the wet oil though.