Using Fat to make Bio diesel

[PD1]

Hi I’m fairly new to making Bio diesel , after a few batches I am making bio from cooking oil using the two stage no titration method , I’ve got some fat that I want to use . I’ve been told by a mate that used to make bio that you can mix a bit with oil but not too much , though he used a one stage method. What’s the best way to make the fat I to bio , can I make a batch just from fat ?
Thank in advance

[nigelb]

Hi PD1..you can use whatever quantities of solid fat you like in producing biodiesel. In many cases, using solids can produce better quality BD. However, the temperature it begins to gel at will be higher than fuel made from other sources. This can be problematic as the weather gets colder.

I made a batch many years ago from oil given to me by Oakwoodtv. Pain in the arse to get it liquid enough to process. Great fuel though. It was a good summer challenge.

[Tony]

I think the general solution is to heat up some liquid oil then melt the fat into it.  Oils that are solid at room temp tend to have a higher calorific value than liquids (longer hydrocarbon chains).

That said it's an utter PITA to deal with and I prefer to stick with liquid.

Sometimes I'll take really hot oil, and mix that into whites with some glycerol and that seems to help - but I think in my case the whites are more likely to be oil+water and I'm just removing the water to leave better oil.

And lets not forget that guy in the US, a liposuction surgeon - that got into trouble for converting his patient's fats into fuel for his car...

Edit: found him.  Eww.  https://www.independent.co.uk/life-style/health-and-families/health-news/surgeon-uses-human-fat-to-run-his-cars-1211431.html

[knighty]

save it for summer when temps are higher and it'll stay runny longer in your tank?

[dgs]

I often blend a very small amount of beef fat into my oil (certainly less than 5%) It reduces the gel point in Winter from -9 to -4 degs. I just add a small amount of coldflow which deals with the problem.

[PD1]

Thanks everyone , some good advice, I recognise some of you from another website , I can’t believe that Dr using his patients fat for fuel !
I didn’t realise that it Gels at a lower temperature even when its processed, I might use a small amount as suggested until it starts to get cold , then wait until summer next year .
It does seem a faff but I was given it for free by the guy I got my oil and other bio stuff from , so might as well use it , albeit slowly !
dgs what’s cold flow ?

[nigelb]

Just for the record PD...using solid fats will gel at a higher temperature....not a lower one.

[dgs]

Thanks everyone , some good advice, I recognise some of you from another website , I can’t believe that Dr using his patients fat for fuel !
I didn’t realise that it Gels at a lower temperature even when its processed, I might use a small amount as suggested until it starts to get cold , then wait until summer next year .
It does seem a faff but I was given it for free by the guy I got my oil and other bio stuff from , so might as well use it , albeit slowly !
dgs what’s cold flow ?

It's a Winter additive which suppresses the bio made from fats ability to crystallise.

Making bio from oils/fats reduces the pour/gel point temperature by about 5degs. So for instance if a fat/oil started to gel at say +10degs then the resultant bio would start to gel at +5degs. One of the worst fats that can contaminate feedstock is lamb (kebab) fat which is still solid at between 30 to 35 degs so you can imagine what would happen to bio with an amount of this mixed in.

[PD1]

Thanks everyone , some good advice, I recognise some of you from another website , I can’t believe that Dr using his patients fat for fuel !
I didn’t realise that it Gels at a lower temperature even when its processed, I might use a small amount as suggested until it starts to get cold , then wait until summer next year .
It does seem a faff but I was given it for free by the guy I got my oil and other bio stuff from , so might as well use it , albeit slowly !
dgs what’s cold flow ?

Ok thanks , sounds good
It's a Winter additive which suppresses the bio made from fats ability to crystallise.

Making bio from oils/fats reduces the pour/gel point temperature by about 5degs. So for instance if a fat/oil started to gel at say +10degs then the resultant bio would start to gel at +5degs. One of the worst fats that can contaminate feedstock is lamb (kebab) fat which is still solid at between 30 to 35 degs so you can imagine what would happen to bio with an amount of this mixed in.

[Head Womble]

As dgs mentioned lamb fat (kabab fat) I thought I'd chip in with my experiences, making bio from this has a few other draw backs.
1 it's a real pain to melt.
2 it often contains watery layers as it's pored into the drums when hot and water separates out as it cools.
3 it often contain lumps of meat, tissue paper, fag butts, dead mice etc.
4 as you heat it to get it back to liquid it smells awful, something akin to sick, and if you get it on your clothes the smell will stay no matter how many times they are washed.

I collected around 700L of this wonderful stuff one winter, from a number of shops, all of it was the same.

[dgs]

You poor soul Womble, isn't it just horrible stuff. When Arash mentioned the leg of lamb for next years field roast I remembered  the kebab fat and thought 'I'll pass on the lamb'

[Head Womble]

You poor soul Womble, isn't it just horrible stuff. When Arash mentioned the leg of lamb for next years field roast I remembered  the kebab fat and thought 'I'll pass on the lamb'

Horrible stuff doesn't cover it, I have a pair of jeans and a t-shirt that got this kabab fat on probably 10 years ago, they're now used for working on cars and stuff but the smell is still there.

[PD1]

Oh blimey sounds a pain , let’s hope I don’t have lamb fat !

[Tony]

I'm not precious (in this game you can't be) and I'm quite happy arms deep in a drum chiselling out compacted layers of burnt mush from the bottom, but draw the line at kebab fats.

Can attest to the fact it smells like some kind of creamy vomit.  It's a smell you don't forget, I can pretty much smell it now just thinking about it, and it has been years since I last encountered that stuff.  Never again if I can avoid it.

[kamaangir]

You decadent westerners......tutututut 

The fat is the best bit! or the tripe....

The reason the fat smells disgusting is because it has lots of water in it and has gone rancid. Lamb fat rendered is actually lovely.

We should do some test batches of all the solid fats and see what each one is like as far as viscosity and gel point and how well it burns etc...