VEG OIL Has any body.....

Not really, it can only be processed by some chemistry.

Steve

I sounds as if it came from a chip shop, some use palm oil which is solid at room temperature, so unless you heat it will stay solid! now where were those plans for that heated tank?

There use to be a law that fuel that was solid at 17deg C IIRC did not need to pay duty, I suspect it was aimed at coal. I used to wonder if you used a heated tank and shovelled the stuff in once heated it would run fine through most pumps....

Different oils go solid at varying temperatures, rapeseed oil goes down to freezing, whereas olive oil and Soya oil start to cloud at about 8deg C Though if it was well used, it could have a fair proportion of animal fat through it, though I would expect some of it still to be liquid

And Biodiesel made from different oils follows the cloud point as a local haulage contractor near me found to his cost!!!

Des

There's a s*it load of info on the net on how to convert oils and fats into biodiesel. It needs to be treated with caustic soda and other chemicals and heated to obtain a biodiesel that won't solidify at low temps.

Steve W (in Aus)

AFAIK, Fully transesterified Oil is a different animal, and is much less temperature sensitive.

Steve

Thanks all for the coments, Buggering around with caustic soda does not sound fun, you are quite correct, was given it from local chinese chip shop who are having difficulties in disposing and being a bit of a tight wad (some people say I squeek when I walk), HA I thought cheap fuel!

I will investigate further to see if it is worth while,

Regards

John

You COULD do it, but buggering around with heated fuel lines, special sequencing, valves is probably more work than the caustic/methanol approach.

Steve

If you do make Biodiesel from it, will be OK for use during warm summer weather!! having had about 8 years of making biodiesel from various Oils, rapeseed is the best for winter months but even that, doesn't like much below freezing, and at -6C a BX started to misfire! Somewhere on the net, I can't find the link ATM there is a site giving cloud points for most oils and their Biodiesel equivalents..

We use Potassium Hydroxide instead of Caustic, need a bit more but is easier to get rid of as a fertiliser....

Des

Whats left is glycerine +methanol anyway isn't it ?

Steve

Correct me if I'm wrong but I think that's Caustic potash, same as sodium hydroxide is caustic soda...... so how are you using that instead of caustic? :-) It's also known as TRF I think. I never was much good at chemistry though so ICBW.

Martin

You are making sodium or potassium methoxide - the thing is a catalyst, and not actually used up in the manufacture.

Steve

That is what bugs me about the process the chemist in me says I should be able to extract the methoxide for reuse as it is just a catalyst.Yet I have not seen a ( small scale) process which does.Leaving the problem of neutralising the methoxide or risking damage to seals ( and I don't mean the 'cuddly' fish eating bastards).No doubt some enterprising soul will come up with a cartridge style catalizer and all the problems will be solved. Interestingly I found that a chinese team have had some success with zinc oxide doped with potassium flouride one step on the way tho' I am a bit wary of using Flourine salts. Derek

It's the Hydroxide bit that does the job,

The methoxide is used up in the reaction, I know there has been some experiments recovering the excess methanol by vacuum,, the methoxide is neutralised by water, Our tame chemist seems to understand the process better than me!!

Water washing appears to remove any impurities, though our method is more akin to "Bucket chemistry"!

Des

Des

Aye but vacuum evap is not a practical solution in a domestic setting and if the methoxide was 'used up' by the reaction then it is not a catalyst (chemists are fussy about terminology - I've been out of the lab for 30 some years btw) it is only used up in so far as to not be practicable to recover. The other thorny question is how much heat are you prepared to put into the equation ( looks evilly at greenhouse as a source of free heat ) I am sure that in time a proper reusable catalytic system will evolve in the same way platinised mesh is used in industrial process but there are so many researchers on the trail it may come from out of the blue-even nanotechnology is being towted. Derek

I can't see how the catalyst can be consumed - look at the reaction equations.

Steve

As I understand it the catalyst is mostly used up by the reaction, most of it appears to be.. In the early stages the reaction is reversible, which is why you use more methanol to make the split complete You are then left with methyl-ester (biodiesel) and glycerol. The glycerol appears to hold any unused catalyst, (residual Alkali and methanol) which can be neutralised with water.

I agree with the heat input, we use a 3KW immersion heater which is running for less than an hour (depending on ambient temperature) to heat 180L of oil to 50C. and there are many other factors to consider, the production of methanol , etc More efficient ways of production will come with technology and more to the point investment (money).....

We only use waste oil so all in all I believe our carbon footprint is better than using diesel, and it saves us a fortune !!!

Des

By definition a catalyst is *not* used up in the reaction(s). It is still there but wether it is economically recoverable is another matter...

Technically I don't think it is a catalyst reaction, the methoxide actually splits the triglyceride and swaps a methyl group for each of the three glycerides which then attach themselves to a hydroxyl group to form the glycerol, the sodium will still be floating around as ions but in a more watery solution by the time the biodiesel is washed out.

I'm also told the home brew method is not quite the same as proper transesterification but I didn't understand the reason.

Either way the resultant liquid is about 10% derived from the methanol.

AJH

">>>>>

I can't argue with your principals every bit is helping.I'm going to keep watching the interweb for the time being and using 25% SVO in the disco until I find a viable small scale process and a source of runny waste veg oil. Sadly my mate with the chippy is using that dammed solidfying oil .When economics dictate no doubt he will consider liquid veg oil if he has a cost saving in disposal. I like the idea of the nanotube cats that looks a like the answer once production issues are resolved .