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Biodiesel thoughts and questions


plasticbadger
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The other day my wife got a leaflet stuck on the Disco offering Biodiesel delivered to the door for £1.10/L and it got me thinking. Now, I've used the search function and read various other things on the web, but it seam there is alot of confusing information around. My thoughts / questions are as follows:

Is Biodiesel suitable for my cars, a 1999 Discovery Td5 and a 2002 Volvo 1.9D? There doesn't seem to be a definative web source on checking whether a vehicle can run on Biodiesel (I'm thinking B100 to EN 14214), so does anybody know if these cars can? Or am I better running a lower percentage mix?

If I bought Biodiesel from a supplier I thought I may keep a 205L barrel in the shed with a hand pump and pipe to fill the cars. Does this sound like a sensible idea, or an enviromental disaster waiting happen?

The main problem I see is that at £1.10/L the saving isn't that great, so I starting looking at making my own DIY Biodiesel processor and sourcing my own vegatable oil, be it from a supermarket or pre-used. Is there greater risks in terms of purity by taking this route, or is it as some people suggest, safer to make it yourself?

Finally, as far as I understand it you don't pay duty on biodiesel made at home if you make less than 2500L per year and if you exceed that amount then the duty is lower than diesel anyway as it's classed as an alternative fuel. If this is the case then the £1.10/L is a rip off!

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Biodiesel should run any diesel engine...providing it is well made. Unfortunately many commercial manufacturers seem to think it's ok just to stir a few chemicals in a bucket and call it bio. There are a few tests you can do: 3/27 test for conversion, and 50/50 for soap content. A Google search will pull them up I'm sure.

I have personal experience of a 2002 Volvo 1.9D on bio - mines done about 10k miles on my homebrew now, and no problems bar the fuel freezing back in December, and a clogged filter. Both my own lazy fault. I can't speak for the Td5 - I've heard of people using it, but I've not got experience there.

You are correct - under 2500 litres/year and you don't pay duty. It's the manufacturer that's taxed - so in the case of your commercial enterprise, they will be paying 48ppl in tax on what they sell you. And probably VAT too.

If you want real savings, then a homebuilt reactor is the way to go. I built mine for £300 ish, and made its money back in about 3 months. You need to be very aware of the risks though - the chemicals used are very toxic, and highly flammable. You need to take every precaution that you (and your property) remain safe. And of course you need to find a source of oil - this is getting more and more difficult.

(Some forum members who read the Sunday Times might have noticed a 1/2 page photo of me and my plant a few weeks ago :lol: )

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I had a lot of trouble with soapy deposits in the bio and stopped using it, the saving i made went on new fuel filters every tank!

£1.10 sounds steep, you won't be saving much but you are helping the environment.

Be careful storing it, it's a bio-alcohol and doesn't keep forever like derv will, it goes off. It also attracts some sort of bacteria that deposits sludge which bungs up the tank.

On the other hand I know people who run on bio very succesfully, even some that make it, and others that just use veg oil mixed with derv.

Apparenlty it causes prpblems with common rail systems. The extra heat in the fuel on a common rail causes oxidation of the fuel, you can buy additives to combat that, plus if it isn't made properly you get lots of ethanol left in the fuel which wrecks fuel pump seals.

In fact I've just been having a very similar conversation in the pub ;)

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I had a lot of trouble with soapy deposits in the bio and stopped using it, the saving i made went on new fuel filters every tank!

That sounds like poorly finished bio. I'm afraid this is more the norm than the exception with commercial bio suppliers.

Be careful storing it, it's a bio-alcohol and doesn't keep forever like derv will, it goes off. It also attracts some sort of bacteria that deposits sludge which bungs up the tank.

It's actually an Ester - not an alcohol. But you are correct, there are some bacteria that thrive in the stuff. Much the same precautions need to be applied as to diesel bug. Ensure that there is no water in the fuel and you should be fine.

Apparenlty it causes prpblems with common rail systems. The extra heat in the fuel on a common rail causes oxidation of the fuel, you can buy additives to combat that, plus if it isn't made properly you get lots of ethanol left in the fuel which wrecks fuel pump seals.

Not quite right. Oxidation stability is an issue with biodiesel. It is particularly easy to oxidise the fuel during the final finishing process.

The theory was that the extremely high pressures in a common rail might cause polymerisation (i.e. turn to plastic like gungy stuff) of the fuel. So far, there seems no evidence of this.

It's actually methanol that's used in biodiesel manufacture (generally). Very chemically similar to Ethanol, except ethanol gets you tipsy, methanol sends you blind, then mad, then dead. It is particularly important to ensure that there is no methanol left - not just for the lifespan of your seals, but the soapy byproduct can remain dissolved in the methanol content of the fuel. If you have MeOH left - chances are you will have soapy fuel, and endless filter clogging problems.

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