Sciencemadness Discussion Board

BP 'Opal' fuel

Panache - 27-8-2008 at 02:53

BP has developed an 'unsniffable' fuel for spark ignition engines to help combat the problem of petrol sniffing in central Australia called 'Opal'. it is subsidised by our federal government.
Basically they remove the aromatics (toluene xylene benzene etc) which makeup approx 25% of petrol (or 'gas' if you are US).
The question is what do they replace it with, i have been curious. Not surprisingly the data on the MSDS and fact sheets gives away nothing except this little quote

'Does not contain oxygenates added as components'

Which i assume means alcohols and nitro compounds?? There was speculation that the nitro functionilised short chain paraffins had been the replacement for the aromatics to help with the RON and vapour pressure, but i am just repeating something already said and read.
However i thought that the nitro compounds where in themselves effective inhalants and ethanol well that also an intoxicant so ????

ScienceSquirrel - 27-8-2008 at 03:05

There is a pdf giving a fairly complete specification for the fuel here;

http://www.bp.com/liveassets/bp_internet/australia/corporate...

Petrol tends to vary a bit depending on what is coming out of the refinery and often there are winter and summer mixes.
Basically Opal is a mixture of saturated aliphatic octane isomers.

Panache - 27-8-2008 at 03:22

Quote:
Originally posted by ScienceSquirrel
There is a pdf giving a fairly complete specification for the fuel here;

http://www.bp.com/liveassets/bp_internet/australia/corporate...

Petrol tends to vary a bit depending on what is coming out of the refinery and often there are winter and summer mixes.
Basically Opal is a mixture of saturated aliphatic octane isomers.


That dry assessment of yours is hardly conducive to starting a conspiracy theory involving mystery additives, genocide and corrruption.
Unfortunately its probably correct. That link was where i pulled the quote from i mentioned. Its about 1% oxygen though the fuel, i wonder what 'normal' fuel is.

ScienceSquirrel - 27-8-2008 at 03:34

My esteemed colleague Secret Service Squirrel could 'sex it up a bit' for you :D

not_important - 27-8-2008 at 06:20

I agree with ScienceSquirrel on the composition, moving to a fancy grade of petroleum ether.

Note that in the US and some other countries, aromatics have been at a fairly low for some time, more from pollution control issues than worries about huffing.

Oxygenates are general alcohols or ethers, acetals have been used as well. In Southern California the oxygen level is required to be 2%, with is around 5,5% ethanol.

Magpie - 27-8-2008 at 19:55

In the US methyl tert-butyl ether (MTBE) was tried for a few years as an oxygenate in gasolines. But as people are wont to do this got into the ground water through spills, causing much mayhem. I suppose that is due to the resistance of the ether to biological degradation.

As not_important stated the level of toluene and benzene are quite low in US fuels. I think we are geting the oxygenates through ethanol, and the octane rating through branched and cyclic aliphatics.

Perhaps the Opal recipe is based on the US formulations. It is amazing to what lengths the Australian government is going to protect its citizens. Baning this, reformulating that, etc. Australia must be vying for the world's leading nanny state.

unionised - 28-8-2008 at 10:55

Now this is an amusing tale.
Way back in ancient history they used petroleum fractions as gasoline, These were faily pure alkanes but they knocked like crazy. They added alkyl lead componds to fix the knocking but they were very toxic and persistent. So they replaced them with arromatics like toluene and xylene.
Now someone has noticed that these too are toxic so we move on to branched chain aliphatics.

Long ago they used branched chain alkyl sulphonates as detergents- but these were found to be non-biodegradable so we replaced them with straight chains.

How long before we get back to using strightforward patroleum distilates as gasoline again?

Also, if I read this right; and the branching doesn't make too much difference to the effectiveness; the mixed octane isomers will get you stoned if you sniff them anyway.
http://www.anesthesia-analgesia.org/cgi/content/abstract/77/...

panziandi - 28-8-2008 at 13:11

i remember reading somewhere that a furan can be prepare from fructose (or perhaps it was a pyran from glucose?) by acid hydrolysis and was insoluble in water thus avoiding problems that are encountered with ethanol. But these would also contain oxygen and be classed as oxygenates! That may have been on this forum somewhere try searching for dimethylfuran i think, if i find thread i'll add it in here.

Panache - 28-8-2008 at 23:48

So given some people know about fuels here could someone explain why dimethyl ether is an excellent diesel alternative, seems so completely different in physical properties but i'm sure there is a reason. I have mentioned elsewhere that china is building a plant to run its buses and i think some Canadian city is trialing buses on the fuel also.

ScienceSquirrel - 29-8-2008 at 02:25

Quote:
Originally posted by Panache
So given some people know about fuels here could someone explain why dimethyl ether is an excellent diesel alternative, seems so completely different in physical properties but i'm sure there is a reason. I have mentioned elsewhere that china is building a plant to run its buses and i think some Canadian city is trialing buses on the fuel also.


Not a bad explanation here.

http://www.nykomb.se/index.php?s=Chemicals

I suppose it is no worse than LPG from a safety standpoint.

not_important - 29-8-2008 at 04:49

For diesel fuel what matters is the energy content and cetain number, which is basically how easy is it to get the fuel to self-ignite under compression. For health reasons completeness of combustion, and lack of formation of polynuclear aromatics and soot are important.

Panache - 12-9-2008 at 01:15

why would opal fuel then need government subsidisation for its supply, if it just your normal mix, albeit a more 'american' blend.