Hi all,

As I am thinking of buying a new VW 1.9PD, this test would be much less nerve wracking than just pouring it in.

After a year of knocking out very consistant batches, I thought I had it down. Now I think there may be room for some fine tuning.

I use the "Biodiesel Matic" programme from the Collaborative website, and have always punched in 90% in the KOH purity box.

From this thread, a couple have said that this is not neccessary if you use the same KOH in your titration solution (which I do).

Is this the case?

Some seem to swear by 20% meth, others 22%.

Opinions?

I have always used the 5% prewash, which now seems in doubt???

If using the prewash, maybe the test should be carried out after drying the bio?

Tilley/Mark, if you're out there, you gave me some sound pointers when I was a newby (thank you).

Could you clear these few up for me, so I can sharpen up my operation. I realise that there are no guarantees, and am only asking for opinions.

Best Regards,

Neil.

I am new but think I have understood most of the current science. If you use the same KOH in titration, then you don't need to compensate for purity. About menthanol, the presenters at the conf. in Colorado showed papers to support 25% as ideal which is equal to twice as many meth molecules as triglyceride molecules at the start of the reaction. Tests show this conc. allows the highest degree of conversion. Have you tried 2 stage base/base yet? Some report higher conversion with all else left the same.

Andrew

I have made two recent batches, one which is all the way clear on 3/27 and one which is slightly cloudy. Does anyone else get a slightly cloudy result on this test? What do you think it indicates? Why do you think that?

Thanks Andrew for the reply,

While I am reluctant to go to the trouble of an extra stage, I am certainly considering bumping the methanol up to 22%, and entering the KOH purity value on the "biodieselmatic" spreadsheet to 100%, instead of the 90% I normally use.

Do we still recommend the 5% prewash to pass this test?

I would have tried it today on some old samples, but got roped into building a chook pen (chicken coop) for the wife.

Could the guru's enlighten me on this one?

Cheers,

Neil.

Neil,

I don't have experience with prewash. I am not certain about it with 2 stages. The 2 stage does not add much to the process though. Just let it sit 20 min. at the remainder and let it run.

Lots of people swear by the prewash. As far as I know, it is still a reccomened process. Girl Mark suggested that I try it, but that I'd have to add back glycerol, since I use 2 stage currently.

About your KOH #, I am considering doing more research on higher #'s for myself. At the conference, I interviewed as many people as I could. The range of base # pre titration was from 5-15 for KOH. The 15 was a commercial producer. He uses high cat to drive the reaction and says the trade off is worth it since he MUST exceed ASTM. (reduced yeild and higher soap). I have not done this. I think it is key to have DRY oil. So, if you change your KOH #, compare batches. Higher may be better, in terms of conversion.

Let us know what you find with the comparative tests.

Andrew

Gas Chromatography is considered the only reliable test for completion of reaction - actually it used to test for mono, di, and triclycerides. In ASTM, total glycerol allowed is .24%, I am pretty sure.

Andrew

Actually, this isn't correct. High Performance Liquid Chromatography (HPLC) or Gel Permeation Chromatography (GPC) both give the same detailed information that GC does. The only difference is that GC is the mandated analytical technique in ASTM and ISO biodiesel standards. So, HPLC or GPC can be used to accurately determine biodiesel purity, just not in accordance with the current standards.

quote:

Originally posted by Andrew Morris:
Gas Chromatography is considered the only reliable test for completion of reaction - actually it used to test for mono, di, and triclycerides. In ASTM, total glycerol allowed is .24%, I am pretty sure.

Andrew

I stand corrected. The other parts of what I said are right though?

Do you have any sources to get tests performed with those techniques? Is it cheaper than GC? Have you used them? Do you know how the limits of accuracy/reliability/significance compare to GC testing for glycerol?

Thanks!

Andrew

Yes, I've used both GC and HPLC/GPC, and found both work fine for determining the presence of mono- and di-glycerides and total glycerol. HPLC and GPC also work well, similar accuracy and reliability. The cost of analysis is probably similar. Most university chemistry or chem eng. departments should have suitable HPLC/GPC systems for this work. It really just gives you another option - if you have HPLC/GPC available but not GC, you can still accurately analyse oil composition. You'll still need to complete GC testing at some stage though if you want to show conformity to ASTM or ISO standards.

Other than ASTM, is there any reason to prefer one above the others?

Thanks for the info guys. I appreciate it.

Hi VegeHilux,

You surprise me, Is your wife comfortable in the Chicken Coop. The things we do for our wives Phew!!!
rgds

Dillyman

Dillyman,

I am concerned that the chicken coop could turn out to be my own little "camp x ray" if I don't behave.

Hey microwav, where abouts in the good part of Oz are you?

Could someone help with my previous questions please?

Neil.

Vegehilux, not a guru by any means but here goes:

Methanol, it has been said many times that the percentage can vary anywhere from 17% up. 20% may give good conversion, 22% better yet. 25% is recommended to obtain the best possible conditions for conversion to occur. It is said that 12% methanol is required tomake the bio, the rest is to push the reaction further to completeion (Whilst never getting there). You may well make on spec fuel with 25% but you may also if your good enough do it down to perhaps 22% if your real good.

So to answer your question, you will have to play with it. Too many other variables go into the process of making bio that altering one at a time is the only real test. Keep your process constant and test each batch for compliance. Only then will you ascertain if your process allows to meet specification. Expensive I know.

5% prewash is a misnomer, its a 5% wash with water after the reation and before full washing and is only done as far as I know to free trapped biodiesel from the glycerol layer, to maximise yields. That's all.

I hope it helps, I am investigating a LCMS (Liquid chromatography Mass Spectometer?) that will give you a graphical and numerical readout of your mono, di and tri glycerides as well as the makeup of your esters, C14,16 18 etc.

All this is available in the large city to your south. PM me to discuss, I will be going in for it too withmy fuel and I am vitally interested to find out how I am doing as I run a new common rail engine on my fuel, Peugeot not a VW.

Matt

Not inteding to hijack this thread but Microwav how do you calculate total glycerol from a make up of the mono di and triglycerides?

I may have access for a small cost ($150 per test) to an LCMS. Would it be worth it to get a print out with the integration done for you under the respective peaks for mono, di and tri glycerides as well as the ester in terms of the C14, C16 and C18 breakdown with each identified and again an integrated calculation of the area under the curve to give relative %.

Matt

That is great information! Can't wait to get home and try it on unwashed made yesterday and final product in storage tank.

Tried both clockwise and anti clockwise swriling methods and got reverse results. Will take G5 down below equator to test further.

Thanks Matthew,

Hey I bought a new Ford courier, not the VW (unfortunately).

It just worked out heaps cheaper, and I couldn't get a Caddy van passed for mines spec, which is what I need.

It has a mechanical fuel pump, so the pressures off, but I will play with your recommendations as my process seems very consistent.

Contact me if you are headind north.

Neil.

quote:

I stand corrected. The other parts of what I said are right though?

i dont believe the information about the volumes of methanol toward the top of this page are correct with respect to the number of molecules needed for best conversion.

high compression and rick da tech, hello. when your adding adding more sample to the methanol , as high as 20:27 and 1:1 are these at elevated temperatures? or is the chemist wrong when he says 1:4 max?

also does the unreacted material of a failed batch still fall out at near 1:1? or higher as plugy sugested? this would fill in a missing piece to the puzzle of how to process wvo of higher than 50% ffa. current backyard technolgy (see www.worldenergy.org-wec-geis-congress-papers-rachmaniah0904ys.pdf) is a complete b-i-t-c-h to continue base processing to achieve astm standards. i use about 1:1 methanol anyways so the way i figure why not seperate out the awful mixed glycerides in the first place?

Hi,

Are you suggesting that we use 50% methanol in our reaction? Or in the test to see how complete our conversion is. I am not sure I understand your post.

The 25% methanol as optimal comes from one of the research papers - U of Iowa I think. Those papers showed that each of these variables influenced the reaction: temp., mixing, amnt. of cat., amount of meth., time of reaction. I would add ffa content and water content of oil to the list too. So, IN THEORY, the better we do in one area, we may need a little less in the others, up to a point.

What recipe do you use for what oil?

Andrew

no. use - depending on how you do your math- 16.7-25.0 %volume menthanol. since rick da tech said he used only 50% volume methanol instead of 900% and got no oil/bio settling i was asking him if he was doing it at high temperature and if he'd ever had anything(that should have) drop/settle from a test at that 1:1 ratio.

if u of iowa says to use 25% methanol that would be what i use too on on strait base reaction- unless i had a recovery system and wanted too make certain very high conversion (which the 25% im sure already does done right.)

what i tought i was bringing attention too was the two menthanol molecules for every triglyceride molecule which you might want to bring to the attention of those giving the seminar. i guess some of the more experienced tech content editors are on vacation or wish this thread to die.

you dont want to know what recipe i use for my oil - or see i picture of my kithen, unless for laughs.

just in case you or anyone reading wants to know the best recipe formula put forth by u of iowa using base and methanol this i believe is it - 6 moles methanol to 1 mole oil. they usually give a four page chart or something like that showing a bunch of differnt lipid molecules that you could indentify by gas chromatgraph from a sample of your feedstock, calculate the true number of moles in your oil and thus have the EXACT amount of methanol needed, based on (the obviously rouded for convienance and measuring accuracy of 2.0) times the amount of methanol molecules needed to give complete reaction. which is 3:1 (rounded again to 10% v/v). 333 ml methanol per 1000 ml oil is 25% v/v or 33%PURITY-METH?? on this site.