butane propane mixture as for a bbq
terry
here in australia many vehicles are powered by LPG which is typically
a propane butane mixture and it is quite cheap at about $0.50 per
litre. On the other hand it costs about $1.50 per litre to fill a bbq
gas cylinder with propane gas. It is in fact illegal to fill a bbq
cylinder with autogas, and people are advised it is quite dangerous to
do so, but there seems to be no consistant reason given for this.
Many believe it results in more CO2 produced during burning. Others
say it will be a hotter flame that the bbq was not designed for. I
have even heard an explanation that the propane and butane liquids
will separate in the cyclinder which of course is rubbish.
One thing that would obviously occur is that taking vapour off the
cylinder of mixed propane and butane must lead to the liquid being
enriched in the higher boiling component ie butane as the cylinder
MTs. but why would that matter? surely either butane or propane will
cook my steak quite adequately? ( I know the vapour pressure curves
for both gases and that pure butane will have no pressure in the
cylinder when the temp gets down to about 0 deg C, but thats pretty
rare in this part of the woods, and if its that cold I aint bbqing no
how!
I am no expert but I assume in vehichle use the car takes the liquid
lpg from the cyclinder so the composition wont be changing with time.
Terry
Androcles
"terry" <tfm...@iprimus.com.au> wrote in message
news:1d07e409-f6b2-4eeb...@k23g2000yqa.googlegroups.com...
> Some more holiday curiosity
> here in australia many vehicles are powered by LPG which is typically
> a propane butane mixture and it is quite cheap at about $0.50 per
> litre. On the other hand it costs about $1.50 per litre to fill a bbq
> gas cylinder with propane gas. It is in fact illegal to fill a bbq
> cylinder with autogas, and people are advised it is quite dangerous to
> do so, but there seems to be no consistant reason given for this.
> Many believe it results in more CO2 produced during burning. Others
> say it will be a hotter flame that the bbq was not designed for. I
> have even heard an explanation that the propane and butane liquids
> will separate in the cyclinder which of course is rubbish.
Oil floats on water, water floats on carbon tetrachloride (cleaning fluid).
http://en.wikipedia.org/wiki/Lava_lamp
Why is it rubbish?
terry
oil floats on water and water floats on carbon tetrachloride because
they are immiscible.
propane and butane are perfectly miscible.
Androcles
============================================
Uranium 238 and uranium 235 are even more perfectly miscible
than propane and butane. Iran is unmixing them ("which of course
is rubbish" - they don't want a nuclear weapon, they said so).
All animals are equal, but some are more equal than others - George Orwell,
"Animal Farm".
terry
>
one can quite easily unmix propane and butane also, I do it frequently
in a gas chromatograph, I am simply saying the liquids dont separate
by themselves. ( other than by preferential evaporation). unmixing of
uranium is a subject very dear to my heart. I have invested in Silex
Systems which will soon hopefully have perfected the separation of
U235 and U238 using laser enrichment technology,
Androcles
============================================
So the denser of the two will not sink under gravity (or separate
in a centrifuge to speed up the process), but remain "perfectly"
miscible?
unmixing of
uranium is a subject very dear to my heart. I have invested in Silex
Systems which will soon hopefully have perfected the separation of
U235 and U238 using laser enrichment technology,
====================================
Yes, we desperately need enriched lasers... it sounds very dear
to your wallet. Do you keep it close to your heart? I keep mine
in the back pocket of my pants, very dear to my arse.
Peter Fairbrother
>>> "terry" <tfm...@iprimus.com.au> wrote in message
>>> news:1d07e409-f6b2-4eeb...@k23g2000yqa.googlegroups.com...
>>>> Some more holiday curiosity
>>>> here in australia many vehicles are powered by LPG which is typically
>>>> a propane butane mixture and it is quite cheap at about $0.50 per
>>>> litre. On the other hand it costs about $1.50 per litre to fill a bbq
>>>> gas cylinder with propane gas. It is in fact illegal to fill a bbq
>>>> cylinder with autogas, and people are advised it is quite dangerous to
>>>> do so, but there seems to be no consistant reason given for this.
>>>> Many believe it results in more CO2 produced during burning. Others
>>>> say it will be a hotter flame that the bbq was not designed for. I
>>>> have even heard an explanation that the propane and butane liquids
>>>> will separate in the cyclinder which of course is rubbish.
One danger I can think of offhand is that the pressure will drop quite
low when the gas is drawn from the cylinder - at the end it will be
largely butane, with a naturally lower pressure.
The cylinder will also be quite cold, as evaporation and to a lesser
extent expansion of the gas cools it when gas is drawn. You can
sometimes see ice on a cylinder, even in hot weather, if gas has been
drawn fast from it.
Some Aussies etc. use this effect to cool beer for the barbie ...
The low pressure might make the flame go out, but it will still be
leaking gas, which if the barbie is closed means it might fill partly
with gas/air. One spark, and BOOM!
BTW, in practice no-one actually separates butane and propane completely
for fuel purposes, it's too much work. All of the commercially available
liquified gasses sold as propane or butane or LPG are mixtures
containing both butane and propane, plus various isomers of them, and
even pentane and ethane etc.
I recently analysed some "purified lighter fuel butane", and it
contained 11% propane and 16% pentane!
>> propane and butane are perfectly miscible.
> So the denser of the two will not sink under gravity (or separate
> in a centrifuge to speed up the process), but remain "perfectly"
> miscible?
Yes, for all practical purposes.
In a very tall column there might be a very slight difference in
composition between top and bottom, but it would be hard to detect,
never mind measure.
-- Peter Fairbrother
Androcles
"Peter Fairbrother" <zenad...@zen.co.uk> wrote in message
news:4b3de146$0$2490$db0f...@news.zen.co.uk...
I was nit-picking his "perfect" and "of course is rubbish", Peter,
not the practical aspect. Had he said "propane and butane are
miscible" I'd have made no challenge, but "perfect" is an
unnecessary exaggeration and clearly false, in fact, actually,
and that's actually a perfect fact, in fact, so of course his
"perfect" is rubbish, of course, in fact, actually (and any
other adjectives I can add to thoroughly convince me).
Bernhard Kuemel
> Some more holiday curiosity
> here in australia many vehicles are powered by LPG which is typically
> a propane butane mixture and it is quite cheap at about $0.50 per
> litre. On the other hand it costs about $1.50 per litre to fill a bbq
> gas cylinder with propane gas. It is in fact illegal to fill a bbq
> cylinder with autogas, and people are advised it is quite dangerous to
> do so, but there seems to be no consistant reason given for this.
Maybe the connectors are incompatible and an improvised connector might
leak and cause a flash or explosion.
Laws are made by a number of people who may agree on them for various
reasons, but these reasons are not typically included in the laws, so
that's why you don't get consistant reasons. Are you actually sure it is
illegal? What are possible fines for it? Do you know which part of the
law makes it illegal?
Bernhard
Salmon Egg
"Androcles" <Headm...@Hogwarts.physics_q> wrote:
> Oil floats on water, water floats on carbon tetrachloride (cleaning fluid).
> http://en.wikipedia.org/wiki/Lava_lamp
> Why is it rubbish?
If you do not know by now, any rational explanation will be of no use to
you.
Bill
--
An old man would be better off never having been born.
Salmon Egg
Androcles
"Salmon Egg" <Salm...@sbcglobal.net> wrote in message
news:SalmonEgg-CF6DC...@news60.forteinc.com...
> What can you expect from a guy who walks up to lions to pull out thorns?
>
> --
> An old man would be better off never having been born.
You'd be better off never having been born, old man.
So would we, but I'll settle for the next best thing.
You now cease to exist, guppy spawn.
*plonk*
Do not reply to this generic message, it was automatically generated;
you have been kill-filed, either for being boringly stupid, repetitive,
unfunny, ineducable, repeatedly posting politics, religion or off-topic
subjects to a sci. newsgroup, attempting cheapskate free advertising
for profit, because you are a troll, because you responded to George
Hammond the complete fruit cake, simply insane or any combination
or permutation of the aforementioned reasons; any reply will go unread.
Boringly stupid is the most common cause of kill-filing, but because
this message is generic the other reasons have been included. You are
left to decide which is most applicable to you.
There is no appeal, I have despotic power over whom I will electronically
admit into my home and you do not qualify as a reasonable person I would
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filed, they amuse me and I retain them for their entertainment value
as I would any chicken with two heads, either one of which enables the
dumb bird to scratch dirt, step back, look down, step forward to the
same spot and repeat the process eternally.
This should not trouble you, many of those plonked find it a blessing
that they are not required to think and can persist in their bigotry
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You have the right to free speech, I have the right not to listen. The
kill-file will be cleared annually with spring cleaning or whenever I
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Update: the last clearance was 25/12/09. Some individuals have been
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I'm fully aware that you may be so stupid as to reply, but the purpose
of this message is to encourage others to kill-file fuckwits like you.
I hope you find this explanation is satisfactory but even if you don't,
damnly my frank, I don't give a dear. Have a nice day and fuck off.
terry
> Androcles wrote:
> >>> "terry" <tfm...@iprimus.com.au> wrote in message
> >>>news:1d07e409-f6b2-4eeb...@k23g2000yqa.googlegroups.com...
> >>>> Some more holiday curiosity
> >>>> here in australia many vehicles are powered by LPG which is typically
> >>>> a propane butane mixture and it is quite cheap at about $0.50 per
> >>>> litre. On the other hand it costs about $1.50 per litre to fill a bbq
> >>>> gas cylinder with propane gas. It is in fact illegal to fill a bbq
> >>>> cylinder with autogas, and people are advised it is quite dangerous to
> >>>> do so, but there seems to be no consistant reason given for this.
> >>>> Many believe it results in more CO2 produced during burning. Others
> >>>> say it will be a hotter flame that the bbq was not designed for. I
> >>>> have even heard an explanation that the propane and butane liquids
> >>>> will separate in the cyclinder which of course is rubbish.
>
> One danger I can think of offhand is that the pressure will drop quite
> low when the gas is drawn from the cylinder - at the end it will be
> largely butane, with a naturally lower pressure.
thats the bit I was unsure of, I know it must get richer in butane
but just how the composition changes from the full cylinder to where
there is no liquid left would be interesting to know.
but dont they have butane barbies in the US? how do they manage this
risk? are they taking off the liquid perhaps?
>
> The cylinder will also be quite cold, as evaporation and to a lesser
> extent expansion of the gas cools it when gas is drawn. You can
> sometimes see ice on a cylinder, even in hot weather, if gas has been
> drawn fast from it.
> Some Aussies etc. use this effect to cool beer for the barbie .
bloody genius's arent we, and all the yanks can do is put men on the
moon.
> The low pressure might make the flame go out, but it will still be
> leaking gas, which if the barbie is closed means it might fill partly
> with gas/air. One spark, and BOOM!
that wouldnt be good.
> BTW, in practice no-one actually separates butane and propane completely
> for fuel purposes, it's too much work. All of the commercially available
> liquified gasses sold as propane or butane or LPG are mixtures
> containing both butane and propane, plus various isomers of them, and
> even pentane and ethane etc.
>
> I recently analysed some "purified lighter fuel butane", and it
> contained 11% propane and 16% pentane!
yes and natural gas around our way contains ethane, propane and
butane
> >> propane and butane are perfectly miscible.
> > So the denser of the two will not sink under gravity (or separate
> > in a centrifuge to speed up the process), but remain "perfectly"
> > miscible?
>
> Yes, for all practical purposes.
>
> In a very tall column there might be a very slight difference in
> composition between top and bottom, but it would be hard to detect,
> never mind measure.
Thanks for your constructive help Peter.
terry
definately different and I believe you cant actually buy an autogas
connection unless you are a licensed gas fitter and the connection is
going on a vehicle. And no I have not seen the particular law
myself , nor heard of anyone actually being charged so its quite
possibly just a scare campaign, but if there are good safety reasons
not to do it, I dont have a problem with it. I just want to understand
the technical side of it fully and if I was convined it could be done
safely I would then be quite happy to question the legal basis
further.
Terry
Mark Thorson
>
> Some more holiday curiosity
> here in australia many vehicles are powered by LPG which is typically
> a propane butane mixture and it is quite cheap at about $0.50 per
> litre. On the other hand it costs about $1.50 per litre to fill a bbq
> gas cylinder with propane gas. It is in fact illegal to fill a bbq
> cylinder with autogas, and people are advised it is quite dangerous to
> do so, but there seems to be no consistant reason given for this.
Fuel gases are heavily contaminated and unsuitable for
direct application to food. Here's a collection of
statements about the heavy ends in propane fuels from
the vendors:
Some of these heavy ends (especially if made from
coal) can be aromatics like napthalene, which are
carcinogens and do not burn as readily as short
aliphatics like propane. You'll be painting your
food with carcinogens. Only fools violate the rules.
Peter Fairbrother
> "Peter Fairbrother" <zenad...@zen.co.uk> wrote in message
> news:4b3de146$0$2490$db0f...@news.zen.co.uk...
>> Androcles wrote:
>>
>>>>> "terry" <tfm...@iprimus.com.au> wrote in message
>>>> propane and butane are perfectly miscible.
>>> So the denser of the two will not sink under gravity (or separate
>>> in a centrifuge to speed up the process), but remain "perfectly"
>>> miscible?
>> Yes, for all practical purposes.
>>
>> In a very tall column there might be a very slight difference in
>> composition between top and bottom, but it would be hard to detect, never
>> mind measure.
>>
>> -- Peter Fairbrother
>
> I was nit-picking his "perfect" and "of course is rubbish", Peter,
> not the practical aspect. Had he said "propane and butane are
> miscible" I'd have made no challenge, but "perfect" is an
> unnecessary exaggeration and clearly false, in fact, actually,
> and that's actually a perfect fact, in fact, so of course his
> "perfect" is rubbish, of course, in fact, actually (and any
> other adjectives I can add to thoroughly convince me).
But butane and propane are perfectly miscible.
"Perfectly miscible" is a technical term meaning that they mix at all
concentrations.
Take umbrage at chemists in general if you like ..
-- Peter Fairbrother
terry
> terry wrote:
>
> > Some more holiday curiosity
> > here in australia many vehicles are powered by LPG which is typically
> > a propane butane mixture and it is quite cheap at about $0.50 per
> > litre. On the other hand it costs about $1.50 per litre to fill a bbq
> > gas cylinder with propane gas. It is in fact illegal to fill a bbq
> > cylinder with autogas, and people are advised it is quite dangerous to
> > do so, but there seems to be no consistant reason given for this.
>
> Fuel gases are heavily contaminated and unsuitable for
> direct application to food. Here's a collection of
> statements about the heavy ends in propane fuels from
> the vendors:
>
>
> Some of these heavy ends (especially if made from
> coal) can be aromatics like napthalene, which are
> carcinogens and do not burn as readily as short
> aliphatics like propane. You'll be painting your
> food with carcinogens. Only fools violate the rules.
interesting , I have not yet heard food contact as a reason, and I am
not sure it is valid for the autogas supplied in Australia. I have
forwarded a question to one of our suppliers so it will be interesting
to see if that comes up.
Only fools ( and lazy people) accept rules without questioning
them..
terry
>
if it saves the post degenerating to a flame war, I am happy to remove
the perfect adjective.
terry
I have since found that the regulators on the propane cylinders are
regulated for an output of just 2.75KPag, which surprised me a bit, I
thought it would be much higher. I also found from calculations on
another site that starting with a 50:50 mix by the time you have
consumed about 80% of it you have almost pure butane left, so the
pressure in the cylinder does drop significantly as the contents of a
mix are consumed until it reaches pure butane vapour pressure but if
the output of the regulator is 2.75KPag the barbie doesnt see this,
unless you got to that temperature where the cylinder pressure is
below 2.75 Kpag. ( about 2 deg C) , which seems unlikely on a typical
Aussie bbq day, but I take your point about the effects of
autorefrigeration.
Salmon Egg
Peter Fairbrother <zenad...@zen.co.uk> wrote:
> But butane and propane are perfectly miscible.
>
> "Perfectly miscible" is a technical term meaning that they mix at all
> concentrations.
>
> Take umbrage at chemists in general if you like ..
"Thoroughly" or "mutually soluble" might be better terms.
Bill
Salmon Egg
<1c9eefd2-538d-4de3...@j5g2000yqm.googlegroups.com>,
terry <tfm...@iprimus.com.au> wrote:
> I have since found that the regulators on the propane cylinders are
> regulated for an output of just 2.75KPag, which surprised me a bit, I
> thought it would be much higher. I also found from calculations on
> another site that starting with a 50:50 mix by the time you have
> consumed about 80% of it you have almost pure butane left, so the
> pressure in the cylinder does drop significantly as the contents of a
> mix are consumed until it reaches pure butane vapour pressure but if
> the output of the regulator is 2.75KPag the barbie doesnt see this,
> unless you got to that temperature where the cylinder pressure is
> below 2.75 Kpag. ( about 2 deg C) , which seems unlikely on a typical
> Aussie bbq day, but I take your point about the effects of
> autorefrigeration.
There are many areas in California where LPG is used for heating as well
as cooking. The Mammoth Lakes area is relatively famous for being a ski
center. I have gone fishing in that area fairly often. In our Fall
season, say September or October, I have gone fishing while the sun was
still below the horizon. Without a wind, freezing at 32�F or 0�C can be
very comfortable. I have been there when it was much colder, under 20�F
or -7�C, but still have the heater work well. I do not ski and I
presume it gets much colder during the winter.
I presume, from what was posted, that butane would not be satisfactory
under those conditions.
Androcles
"Rubbish" is a technical term meaning useless waste or rejected matter.
Ref: http://www.merriam-webster.com/dictionary/rubbish
"Useless waste" means cannot be used as a fuel for cooking on the barbie.
The real rubbish is
"It is in fact illegal to fill a bbq cylinder with autogas, and people are
advised it is quite dangerous to do so"
"Illegal" depends on the country, its infrastructure and its tax system.
Russia has now placed a minimum price on vodka (two quid a bottle),
where before it could affordably be used as fuel for the barbie.
Apparently the Russian people thought it more sensible to ingest the
calorific value of the ethyl alcohol directly rather than buy dead flesh
and heat it (which is more efficient?) but their government wasn't
selling enough gas to Ukraine through its pipeline.
One year ago:
http://www.busrep.co.za/index.php?fSectionId=565&fArticleId=4805700
Today:
http://www.google.com/hostednews/afp/article/ALeqM5hyqXJAFb1AyW4vHzkBRaoIzul9mgThe element of truth: it is dangerous to fill a bbq cylinder with anyliquid, you might splash it in your boots while doing so.Take umbrage at the dictionary if you like...
Peter Fairbrother
Probably not - and a similar situation occurs in hot-air balloons if
butane is used.
-- Peter Fairbrother
terry
> In article
> <1c9eefd2-538d-4de3-bb82-02279775e...@j5g2000yqm.googlegroups.com>,
wouldnt get any out of the bottle. I assume propane must have been
used. ( boils at about -42 C which is also about -40 F)
dlzc
On Jan 1, 4:44 pm, terry <tfm...@iprimus.com.au> wrote:
...
> interesting , I have not yet heard food contact as a
> reason, and I am not sure it is valid for the autogas
> supplied in Australia. I have forwarded a question to
> one of our suppliers so it will be interesting to see
> if that comes up.
If not, why not?
> Only fools ( and lazy people) accept rules without
> questioning them..
Only babies learn about the world around them by putting things from
it in their mouths first...
David A. Smith
terry
> Dear terry:
>
> On Jan 1, 4:44 pm, terry <tfm...@iprimus.com.au> wrote:
> ...
>
> > interesting , I have not yet heard food contact as a
> > reason, and I am not sure it is valid for the autogas
> > supplied in Australia. I have forwarded a question to
> > one of our suppliers so it will be interesting to see
> > if that comes up.
>
> If not, why not?
If food contact was such a critical issue I would expect to be able to
find an Australian standard for propane for cooking use. I cannot
( which of course does not mean it does not exist) whereas I have
been able to find a standard for automotive use. On no official site
of gas suppliers in Australia have I seen a reference to not using
autogas for health reasons.
> > Only fools ( and lazy people) accept rules without
> > questioning them..
>
> Only babies learn about the world around them by putting things from
> it in their mouths first...
I am not sure what you imply by that remark. I am certainly not
advocating anybody try using autogas in a bbq, I am simply trying to
ascertain for sure why it is illegal ( and I have confirmed that it
is ) Real safety is obtained when you understand the science not the
laws.
Salmon Egg
<3f339430-1047-4270...@a15g2000yqm.googlegroups.com>,
terry <tfm...@iprimus.com.au> wrote:
> If food contact was such a critical issue I would expect to be able to
> find an Australian standard for propane for cooking use. I cannot
> ( which of course does not mean it does not exist) whereas I have
> been able to find a standard for automotive use. On no official site
> of gas suppliers in Australia have I seen a reference to not using
> autogas for health reasons.
I had an acquaintance working at our local gas company. Although
originally built for use with artificial gas, the distribution was
converted to use natural gas shortly after WWII. One of the problems was
that the sulfur it contained required that copper tubing no longer be
used. Aluminum (Is it aluminium in Australia?) was OK.
He also told me that they were getting gas from various sources.
Sometimes they got batches with a fair amount of arsenic as an impurity.
One of the fun things as a kid was to stick a piece of meet on a fork
and cook it in an open gas flame. I can se that arsenic in the gas could
be a problem in such a situation.
One of my favorite fishing places in California was Hot Creek. It runs
into the Owens River which has been the principle water source for Los
Angels since about 1913. It contains natural arsenic. The question is
what its oxidation state is. That state greatly affects the toxicity.
I do not believe that anything is done to eliminate arsenic. I think
dilution from other sources is all that is required. The arsenic level
is reported on a regular basis.
This shows that natural products can be a toxic hazard. LPG can
certainly carry phosphine or arsine in addition to other hydrocarbon
based impurities already mentioned here.
dlzc
On Jan 1, 8:41 pm, terry <tfm...@iprimus.com.au> wrote:
> On Jan 2, 1:21 pm, dlzc <dl...@cox.net> wrote:
...
> > > Only fools ( and lazy people) accept rules without
> > > questioning them..
>
> > Only babies learn about the world around them by
> > putting things from it in their mouths first...
>
> I am not sure what you imply by that remark.
I imply that others have raised a question about the safety of the gas
source's constituents as being safe for human consumption. Early in
life, we have parents that make rules we have to follow, until they
can convey (if they know) the reasons behind the rules.
> I am certainly not advocating anybody try using
> autogas in a bbq,
You have implied exactly this. You want to know why the cheaper
source cannot be used. If that was not your intent, then you did not
say that in the first place. I understand you are expending
considerable energy distancing yourself from that interpretation /
intent. You don't need to keep doing this, as I'll quit bitching.
> I am simply trying to ascertain for sure why it is
> illegal ( and I have confirmed that it is ) Real
> safety is obtained when you understand the science
> not the laws.
Most people are not capable or are not interested in understanding the
"science" behind safety. That is why there *are* laws. In lieu of
having a hungry mind such as yours appears to be, "real safety" comes
from following the laws. You don't need to fabricate homilies to
justify getting your answers.
There is an orifice in gas-fired appliances, that is sized for a
certain heat rate. Its sizing is based on an assumption of the fuel
being evaporated, and the heat rate the appliance can safely produce.
Putting in a different fuel can:
1) clog the works, or damage the seals;
2) produce a very sooty flame, since atmospheric-pressure ignition
temperatures might not be suitable for the mix;
3) produce too much flame, since too much fuel might be allowed to the
burners;
4) more (such as contaminants, which I find uncompelling since all
fuel sources are "dirty");
5) not paying the appropriate taxes, allowing people to eat without
Big Brother knowing they are, or more likely using subsidized
transportation fuel for cooking.
I don't find #4 or #5 to be particularly compelling, but I do believe
there to be "mechanical" reasons why it might be a bad idea to cook
with a different blend of (eventually) gaseous fossil fuels.
In general, laws have some justification written into or recorded
"adjacent" for their existence. I'd suggest you go to the text of the
law, to seek out the basis of the law.
David A. Smith
terry
> Dear terry:
>
> On Jan 1, 8:41 pm, terry <tfm...@iprimus.com.au> wrote:
>
> > On Jan 2, 1:21 pm, dlzc <dl...@cox.net> wrote:
> ...
> > > > Only fools ( and lazy people) accept rules without
> > > > questioning them..
>
> > > Only babies learn about the world around them by
> > > putting things from it in their mouths first...
>
> > I am not sure what you imply by that remark.
>
> I imply that others have raised a question about the safety of the gas
> source's constituents as being safe for human consumption. Early in
> life, we have parents that make rules we have to follow, until they
> can convey (if they know) the reasons behind the rules.
yes and I appreciated that input and said that I would look into it,
in fact I have already sent off an email to a supplier who sells both
propane and autogas . And yes I agree babies and children should
just
accept what their parents tell them. but I am not a child, I am an
adult and a trained chemist. I ought to be to know why the law is in
place, and frankly I feel a bit embarrassed that I dont, especially
considering I work in the petrochemical industry.
>
> > I am certainly not advocating anybody try using
> > autogas in a bbq,
>
> You have implied exactly this. You want to know why the cheaper
> source cannot be used. If that was not your intent, then you did not
> say that in the first place. I understand you are expending
> considerable energy distancing yourself from that interpretation /
> intent. You don't need to keep doing this, as I'll quit bitching.
I think you have misunderstood. I am not distancing myself from
anything. Of course I want to know why the cheaper source cannot be
used, its a perfectly logical question to ask, My point was I would
not advocate to anybody else when I do not know myself (yet) whether
there is in fact a danger.
> > I am simply trying to ascertain for sure why it is
> > illegal ( and I have confirmed that it is ) Real
> > safety is obtained when you understand the science
> > not the laws.
>
> Most people are not capable or are not interested in understanding the
> "science" behind safety. That is why there *are* laws. In lieu of
> having a hungry mind such as yours appears to be, "real safety" comes
> from following the laws. You don't need to fabricate homilies to
> justify getting your answers.
Most people are not qualified chemists and dont read this forum. I am
really lost as to where you are coming from. it seems to me you are
trying to create points of difference that dont exist in order to stir
up an argument. I dont disagree that people should follow the laws,
but law abiding people still get injured in all sorts of accidents
every day. Many of these accidents could have been avoided by having
a better understanding of the science of what they are doing.
Thats all I meant to imply.
And people will always choose to break laws, if they didnt we wouldnt
need police, At least if they understand the reason for the law they
are going to break they are less likely to hurt themselves or others.
For example if we just promulgate the idea that autogas cant be used
for the bbq just because of a food contact reasons, someone might
think it is therefore OK to use it for a gas fired lighting apparatus,
and if in fact if it was the CO problem they are still in danger if
they set the light up in their unventilated garage.
> There is an orifice in gas-fired appliances, that is sized for a
> certain heat rate. Its sizing is based on an assumption of the fuel
> being evaporated, and the heat rate the appliance can safely produce.
> Putting in a different fuel can:
> 1) clog the works, or damage the seals;
> 2) produce a very sooty flame, since atmospheric-pressure ignition
> temperatures might not be suitable for the mix;
> 3) produce too much flame, since too much fuel might be allowed to the
> burners;
> 4) more (such as contaminants, which I find uncompelling since all
> fuel sources are "dirty");
> 5) not paying the appropriate taxes, allowing people to eat without
> Big Brother knowing they are, or more likely using subsidized
> transportation fuel for cooking.
>
> I don't find #4 or #5 to be particularly compelling, but I do believe
> there to be "mechanical" reasons why it might be a bad idea to cook
> with a different blend of (eventually) gaseous fossil fuels.
there are certainly heat value differences between butane and propane
but these are small compared to the difference between say methane and
propane , which requires the use of smaller jets in gas burning
appliances. Butane requires 6.5 vs 5.0 parts by volume compared to
propane for complete combustion so it is possible that more CO will be
produced and a sooty flame if enough oxygen is not drawn in by the
burner. but that is something that could be quite easily tested for
( I have access to CO measuring instruments) I have also read many
personal accounts of people already using autogas for cookers etc with
no apparent problems ( which of course doesnt mean there isnt any...
most people would not have access to CO measuring instruments) and it
could well be a significant problem if people were to use it indoors
or without good ventilation.. but again I want to know for sure.
Tax is not an issue here, the high cost of propane vs autogas is
related to the excess of butane available in Australian refineries and
the much larger volumes involved with autogas compared to propane. I
have also since ascertained that the standard for autogas in
Australia dictates a vapour pressure btween 800 and 1530 Kpag at 40
deg C. This would allow anywhere between 0 and about 50 % butane in a
butane / propane mix.
> In general, laws have some justification written into or recorded
> "adjacent" for their existence. I'd suggest you go to the text of the
> law, to seek out the basis of the law.
I have, but there is no basis given it is simply stated that it is an
offence to fill a portable cyclinder with autogas.
Thanks for your input.
Herman Family
> Some more holiday curiosity
> here in australia many vehicles are powered by LPG which is typically
> a propane butane mixture and it is quite cheap at about $0.50 per
> litre. On the other hand it costs about $1.50 per litre to fill a bbq
> cylinder with autogas, and people are advised it is quite dangerous to
> Many believe it results in more CO2 produced during burning. Others
> say it will be a hotter flame that the bbq was not designed for. I
> have even heard an explanation that the propane and butane liquids
> will separate in the cyclinder which of course is rubbish.
>
> cylinder of mixed propane and butane must lead to the liquid being
> enriched in the higher boiling component ie butane as the cylinder
> MTs. but why would that matter? surely either butane or propane will
> cook my steak quite adequately? ( I know the vapour pressure curves
> for both gases and that pure butane will have no pressure in the
> cylinder when the temp gets down to about 0 deg C, but thats pretty
> rare in this part of the woods, and if its that cold I aint bbqing no
> how!
>
> I am no expert but I assume in vehichle use the car takes the liquid
> lpg from the cyclinder so the composition wont be changing with time.
> Terry
The laws have to be written for the general case or the worst possible case.
They may be very concerned that liquid butane gets past the regulator at
some point. It could either get by as a liquid or condense after it gets
by. While butane gas does indeed burn hotter than propane, butane liquid
contains something like 100 to 200 times the energy per unit volume as
butane gas. That could lead to a rather warm stove or funace should it be
ignited.
The car may take liquid, but it is designed with something to vaporize it at
the right rate. Your bbq does not have a vaporizer, but rather relies on
heat transferred from the container walls.
Given that the worst possible case is a boiling liquid butane fire and a
bleve from the tank, I'd say that this is probably a reasonable regulation.
Michael