Filtering feedstock

[Dickjotec]

Molecules like phospholipids and diglycerides, which have both polar and nonpolar components, can form worm like micelles in the presence of small amounts of water. These long micelles can become long enough to act like polymers, become entangled and form gels. I haven't found any reference that talks, in particular, about mono or diglycerides and these tubular micelles, but I don't see why these molecules would not be subject to the same behavior."


Interesting but from the article it seems that the phospholipids would be removed from processed oil and are more of a problem with raw oils. It could be that they have something to do with the HMP? That I am seeing with the acetone batches, though in the second batch HMP? Seems much less of an issue so far. (It has settled clear with good 50/50 in 3 days) certainly the micelles/ long chain polymer theory looks very attractive.
How could we check for them?
Dick

[nathanrobo]

certainly the micelles/ long chain polymer theory looks very attractive.
How could we check for them?
Dick

Open to ideas. 

Reason for posting on this topic was the idea that they can be eliminated at the feedstock stage??

If the can be eliminated at this stage you'd expect to be able to produce lots of batches without any evidence of HMP stuff

[nathanrobo]

Could this be another piece of the puzzle.

http://www.biodieselmagazine.com/articles/1179/bound-by-determination/

While von Wedel was in Berlin, he learned of Dr. Fischer's hypothesis, which suggests these sterols may aggregate into complexes with monoglycerides and diglycerides present in biodiesel, helping to form a precipitate that falls out of solution. "What it does is amplifies what used to be just a residual trace amount of a [monoglyceride and diglyceride], and they will suddenly form precipitates under certain conditions," von Wedel says.

[Dickjotec]

certainly the micelles/ long chain polymer theory looks very attractive.
How could we check for them?
Dick

Open to ideas. 

Reason for posting on this topic was the idea that they can be eliminated at the feedstock stage??

If the can be eliminated at this stage you'd expect to be able to produce lots of batches without any evidence of HMP stuff

I take your point absolutely re removing them but if we can't check for them we won't know when they have been removed?
From the articles it seems that removal is complex and simple filtering won't be enough?

[nathanrobo]

One article, suggested centrifuging (although I think this was with raw veg oil - i.e, not WVO).  I'm set up to do this so I'll give it a go.

Initially, I didn't expect this line of enquiry to go very far... now I'm not so sure!

[thewormman]

Any more on this?

[nathanrobo]

Any more on this?

Just got a large inverted rotor fuge and robust nylon drum strainers (600 / 400 / 150mu)  and collecting a tank from JRL next week, so news soon.

[nathanrobo]

Prepped 400 litres of bio ready for my first reaction (since last Nov).  I think the key to fine filtering the feedstock is to course filter - 600 mu, then heat run off any obvious water and then with more heat, pump via the gear pump through a 400 mu strainer until it's all been through once, then change to a 150 mu and continue pumping :



Goes through the 150 pretty easy at 70 deg.



After straining hot I fuged (first time fuging feedstock) and got this:








During filtration, I left the lid of the tank slightly up and ran the centrifuge for 2 hours, steam was pouring out to begin, but nothing I could see after an hour or so.

Next step is to see what sort of experience i get making a batch.  New machine is in place, just need to wire the 110 lpm pumps and connect the condenser 

[Rotary-Motion]

the 600 / 400 / 150 mu filters are they inline piped ones under pressure?

[nathanrobo]

No... they are nylon drum strainers.  On the vid it may be difficult to recognise what you are looking at... it's a drum strainer inside the top of one of James' conicals.  The oil is heated and running through my gear pump with the bypass of the fuge fully open - so all running back to tank via a tube which is sat on top of the strainer.

The gear pump can cope with the fine bits <600 mu and the heat means that the oil will flow nicely through the 400 & 150 strainers (I had these produced to my drwgs, coz the other drum strainers that I had used, which were plastic sides with a silk screen, tore too easily.

Anyway the set up works really well, and with all of the crud that gets taken out I figure that it's better than filter cartridges that need to be continually changed.

[nathanrobo]

First batch in over 6 months - probably a bit rusty on the finer points.

Anyway this was also the first batch in the SS 500L (380 lite batches) reactor, with mixed results.  First stage got 10% drop out, 2nd stage initially got a fraction of 3%, but then I had left the reactor running whilst I was doing the test, mixed up for 3% and decided to double check results, which then went down to a fraction of 1%, I then tried to make a judgement as to how much to let in.  Anyway, I guess I overdosed things and to make things worst, didn't neutralise well enough, so got a bit of bother washing.

Too early to decide whether the extra prep on the feedstock was worthwhile, although my gut feel is that it probably did.  Centrifuging the finished product resulted in only the very finest film on the bowl (looked like glyc), the fuel is definitely lighter in colour than normal (my wash / dry tank is on a trolley and doubles up as a polisher and dispenser, so pvc wire reinforced clear hose to the gear pump still has bio from my last batch from November last year, where as the suction hose to the tam is had the dried fuel from this batch, so I was able to make a clear comparison - could be to do with feedstock - although nothing has changed. It seemed to smell less during drying too (could be me).

Next batch cooking tonight, followed by a further batch before I hang my boots up for the summer It'll be interesting to see if there is any pattern.  Without going to the bother of side by side, filtered then non filtered batches, I'm looking for evidence of more uniformity with each batch, so very similar drop-out readings, similar washes (assuming that I can get things right). 

[nigelb]

I think you're over cooking this whole biodiesel thing Nathan. Far too complicated. I think you need to simplify things. That's my advice

[Rotary-Motion]

dont we all?

 

[nathanrobo]

Dewatering / filter the first half of my third batch in new machine.  Strained down to 150 micron and then fine filtered.  Here's what I've pulled out - (580 ish grams of bcbs)