But they never mention this in the videos.

[DavidA]

I have been making small amounts of bio for a long time. Usually everything goes ok, and the only trouble I have ever had was when the seal on my Roto-Diesel pump started to leak a bit.

I never bothered to wash my bio. It seemed such a laborious process. Some swear by it, some against it; some swear at each other. Anyway, it almost seemed like a soapy certainty if you were not very careful indeed.

But as you will have noticed, I am now trying to get a bit more professional in my approach, hence the soap test saga.

I read the wiki on the subject.



That nice man from Utah Biodiesel shows how it's done very clearly. So I follow the process.
Graydon gets a colour change after a few drops of 0.01HCL.

I am still adding HCL After 5 mL and thinking I'm doing something wrong.
I start checking everything in sight. (Forgot to check the phase of the Moon, damn) but can't see anything wrong.
It's no good, I am clearly a bum shade-tree chemist. Need to go back to buying Diesel at the pumps.

But wait ! what's this.

A video by Springboard Biodiesel.

Daniel Bowen using the same chemicals. May as well watch it.

He adds 11mL HCL to his sample before it changes.  ELEVEN ! Graydon added 0.15 mL to his.  I stopped at 5 mL assuming I had cocked up.

I haven't seen it anywhere that you could expect to get such a large number.

I can only assume that Graydon is using thrice washed bio while Daniel is using rough old wvo.

Maybe it could be added to the wiki that these large numbers can be expected with wvo.

Amendment,

No, Daniel says it's processed biodiesel.

https://www.youtube.com/watch?v=tzIXwL9GKuQ

[countrypaul]

So had you washed you bio all? Either water washed, or demethed and left to settle?
Had you tried a 50/50 water test to check if there was easily visible soap before titrating?
If the Bio still has methanol in it, that will allow it to hold onto large amounts of soap.

[dgs]

David, its all a case of having experiance of the approx soap level. For high results just use a 1ml sample. You are wasting your titrant using a 10ml sample size on high soap levels.

TIP use a 1ml sample size and if you don't get or hardly get a colour change then add the other 9 or 10 mls. Don't waste your reagents.

Well bubbled and settled bio is approx 300ppm soap (about a 1ml titration) then after woodchips it is usually zero.

Bio after the 5% prewash or similar should be around 1 to 200ppm then after water washing its zero.

Bio won't emulsify during the water wash if the soap is 500ppm or below, no matter how aggressive the wash is.

[DavidA]

I didn't do anything to the bio before the test (as per Graydon Blair suggestion), I'm going to have a wash session today; after I get some heat into the shed.
I avoided washing in the past primarily due to having to get the bio fully dewatered afterwards.

[dgs]

I didn't do anything to the bio before the test (as per Graydon Blair suggestion),

David Smiiths suggestion is Graydon is wrong, whats the point of testing very high levels of soap. Maybe he's trying to sell more reagents.

[DavidA]

There does seem a massive difference between the two examples.

Anyway, I did a small wash test.  Just around 100cc in a 250ccbottle. Used the same amount of water.

I did seven washes in finest Tilly fashion. Water was grey and showing that it couldn't be far from being ready for the newspaper test.
Went to the shop, on coming back gave the bottle a shake.

Big mistake.

I'm now waiting for the bio to clear. Maybe by morning.

[nigelb]

Soap testing...for me...is all about quantifying the process you've adopted. Wherever you end up....at the point you test...for soap and ultimately....fuel quality...you need to be satisfied whether your fuel is good enough for your tank.

The bottom line is this....is your fuel methanol free, soap free and converted to FAME. If it meets these 3 criteria put it in your vehicle and enjoy the savings.

[nigelb]

There does seem a massive difference between the two examples.

Anyway, I did a small wash test.  Just around 100cc in a 250ccbottle. Used the same amount of water.

I did seven washes in finest Tilly fashion. Water was grey and showing that it couldn't be far from being ready for the newspaper test.
Went to the shop, on coming back gave the bottle a shake.

Big mistake.

I'm now waiting for the bio to clear. Maybe by morning.

David.....now you have your process sorted in a jug...upscale to the process.

I dont think that water washing can be done as a sample. Do it in the wash tank but do it gently to begin with.

[nigelb]

You now need to decide whether to pump wash, bubble wash or mist wash......or to wbd ( whole batch demeth) or even go through a resin tower.

Which way to go!!!

[DavidA]

Soap testing...for me...is all about quantifying the process you've adopted. Wherever you end up....at the point you test...for soap and ultimately....fuel quality...you need to be satisfied whether your fuel is good enough for your tank.

The bottom line is this....is your fuel methanol free, soap free and converted to FAME. If it meets these 3 criteria put it in your vehicle and enjoy the savings.

For me it is just something that I never bothered with in the past and think it is something I aught to do.

I could just carry on as I have done for years and put the results straight into the tank. My Citroen seems quite happy running on it. Or I could try and analyse the stuff more closely and make it a bit higher quality.

An example is that the (apparent) 100% conversion batch, when subject to washing, seems to shrink.  So I have to assume that a lot of the fuel is actually soap.

My biggest batch would be fifteen Litre as that is easily managed in a 25 Litre drum. Still undecided on the best method to adopt for washing.
I don't want to waste Methanol if I can recover it from the Glyc; and whole batch washing would make that more difficult. I understand that only about 5% of the Methanol is likely to be in the Bio. So whatever way I go it will probably involve draining off the Glyc first.
That seems to rule out using a 5% pre-wash. Which I'm informed will make the next wash easier.

It's all choices.

But I don't use much fuel, So I can play about with small test batches and feed the results into the car until I decide on a final approach.

I have a lot of sheet steel and a variety of welding equipment. Just need a plan of action.


Quick addition.

That troublesome wash sample has passed the 'newspaper test'  after nine washes. I'll give it some time to settle out completely then do a soap test on the bio

[countrypaul]

If you can demeth your bio once it passed the 27/3 (90/10) test then allow to settle that should drop the soap level significantly, as Nigel says maybe to around 300ppm. If you want you can then water wash and dry which should get the soap level right down quite possibly below 40ppm.

If you don't have the ability to drive off the methanol and recover it (distillation and condensing) then the simplest method given you are dealing with relatively small amounts would be to bubble the methanol off. If once your reaction is complete and the majority of the glyc removed you leave the (still warm/hot) bio with an aquarium bubbler blowing air through it overnight that should remove most of the methanol. Leave that to settle for a few days and you should find a layer of soap/glyc forms at the bottom of the vessel in which you bubbled the methanol off. This needs to be done in well ventilated environment without any sources of ignition for the methanol fumes, so no electrical switches for example.

If you have a methanol recovery ability such as with a GL processor, then recover as much methanol as you can (this follows a law of diminishing returns once) once you get past about 70C the methanol recovery rate drops significantly.  It is still worth bubbling any remaining methanol off overnight as the lower the methanol level in the bio the quicker and more completely the soap/glyc drops.

You can recover methanol with a whole batch demeth (bio and glyc still present) this allows you to recover more methanol - I don't bother. Another way to make use of the methanol in the glycerol is to use the glycerol from the previous batch to dry the oil for the current batch. Because there is still unused reagent present in the glycerol this can also significantly reduce the acid level of the oil, in addition alot of remaining food particles in the oil are washed out, and often some conversion of the oil to bio (probably mainly di and monos glycerides) can take place. I don't remember ever seeing any definitive figures for this, but I believe Dave (DGS) might have some to give you an idea.  This method still works even if you have used a reduced level of methanol for the reaction and with some excess it is almost impossible to get the conversion required.

[dgs]

 
Quote from countrypaul.
You can recover methanol with a whole batch demeth (bio and glyc still present) this allows you to recover more methanol - I don't bother. Another way to make use of the methanol in the glycerol is to use the glycerol from the previous batch to dry the oil for the current batch. Because there is still unused reagent present in the glycerol this can also significantly reduce the acid level of the oil, in addition alot of remaining food particles in the oil are washed out, and often some conversion of the oil to bio (probably mainly di and monos glycerides) can take place. I don't remember ever seeing any definitive figures for this, but I believe Dave (DGS) might have some to give you an idea.  This method still works even if you have used a reduced level of methanol for the reaction and with some excess it is almost impossible to get the conversion required.
[/quote]

It's not so much the excess chemicals that does good in the glyc wash, more the release of tied up bio that is released into the oil (this accounts for most of the increased volume of oil we see) For every litre of soap that goes into the glycerol it takes with it two litres of biodiesel.

This is why recovering methanol either from glyc or WBD is such a waste of time as it leaves the bio still in the glycerol (about 5 litres of bio in every 20 litres of glyc) Whereas doing a glyc wash recovers most of both chemicals and bio.