propane - butane

[ken nugent]

Can anyone clarify the following;

 

I have just been told by our local MH dealer here in france not to use Butane gas because it clogs up the jets is this right? or is this just a personal preferance as he says he always uses propane. I know that propane doesnt freeze but its this question about dirt? Our vehicle is a 2007 Dethleffs Globebus with the usual gas appliances.

 

Any info appreciated.

 

Many thanks

 

Ken nugent

[Brambles]

Maybe it is the quality of Butane in France, but in the UK there is no problem. I have been using Calor Butane for 8 years and no problems at all with jets.

Jon

[Randonneur]

Never use anything but Propane in our motorhome.

[david lloyd]

Maybe he is referring to the problems occurring a couple of years ago when regulators were failing due to the tar like substance clogging them up?

 

David

[Neil Hunt]

I thought the problem arose from the reaction of butane/propane with rubber hoses and particularly if the hose was sited beneath the regualtor, no problem with stainless steel hoses.

[hallii]

We are just back from France / Spain and I filled the Gaslow twice using the LPG filling station pumps.

 

My spare is propane so I am able to make side by side comparisons.

 

I noticed that the LPG (GPL Butane) burnt with a yellow tipped flame but the propane burnt clean and hot. The propane seemed to boil the kettle quicker as well.

 

But, the LPG only costs about 70 Euro cents a litre.

 

So it's LPG (Butane) for me.

 

Hallii

 

[Dave Newell]

ken nugent - 2010-10-07 2:58 PM

 

Can anyone clarify the following;

 

I have just been told by our local MH dealer here in france not to use Butane gas because it clogs up the jets is this right? or is this just a personal preferance as he says he always uses propane. I know that propane doesnt freeze but its this question about dirt? Our vehicle is a 2007 Dethleffs Globebus with the usual gas appliances.

 

Any info appreciated.

 

Many thanks

 

Ken nugent

 

Your local dealer is talking out of his bumhole, butane is no more likely to clog jets than propane. Neither gas will freeze until it is well below 0 degrees C, what happens is that butane has a boiling point of around 2 deg C while propane has a boiling point of around minus 42 deg C. In other words butane will not produce any gaseous vapour if it is below its boiling point but propane will continue to give gaseous vapour right down to around the minus 40 deg C mark.

 

D.

[olley]

hallii - 2010-10-07 5:32 PM

 

We are just back from France / Spain and I filled the Gaslow twice using the LPG filling station pumps.

 

My spare is propane so I am able to make side by side comparisons.

 

I noticed that the LPG (GPL Butane) burnt with a yellow tipped flame but the propane burnt clean and hot. The propane seemed to boil the kettle quicker as well.

 

But, the LPG only costs about 70 Euro cents a litre.

 

So it's LPG (Butane) for me.

 

Hallii

 

GPL/LPG isn't Butane, its a mixture of both, usually more Propane than Butane, if it was all Butane in cold weather (below 1c) there would be no pressure to push the liquid along the pipe to the vaporiser.

 

I am lead to believe in the UK its around 90% Propane, but I can't find anything official on that.

 

Olley

[747]

Butane has a higher calorific value than Propane and should boil a kettle quicker. To see a yellow tipped flame on Butane could mean that it is not refined properly or there is something else mixed with it.

[Brambles]

747 - 2010-10-07 6:38 PM

 

Butane has a higher calorific value than Propane and should boil a kettle quicker. To see a yellow tipped flame on Butane could mean that it is not refined properly or there is something else mixed with it.

 

However propane burns with a much higher temperature flame than butane and this may be reason the kettle boiled quicker.

 

 

[747]

Brambles - 2010-10-07 7:31 PM

 

747 - 2010-10-07 6:38 PM

 

Butane has a higher calorific value than Propane and should boil a kettle quicker. To see a yellow tipped flame on Butane could mean that it is not refined properly or there is something else mixed with it.

 

However propane burns with a much higher temperature flame than butane and this may be reason the kettle boiled quicker.

 

 

Sorry brambles but that is not correct.

 

Propane 2220Kj per mol.

 

Butane 2877 Kj per mol.

 

Before you say anything, Yes I did have to look it up as I remember from College that latent energy should show up as actual energy (leaving out efficiency).

 

Nowadays, we use either gas through the same pressure regulator. For better efficiency, we should use a regulator of a lower pressure. It used to be 28 mbar for Butane. This in practical terms made the gas/air mixture more suitable for combustion. At 37 mbar, the Propane will burn more efficiently than Butane at that pressure.

 

Now that 30 mbar is the standard pressure, Butane should be a little better than Propane.

[Brambles]

747, I am correct in what I say, the propane will burn at a higher flame temperature than butane. Flame temperature is not the same as the calorific value. The temperature of the flame may be higher, but the denisty of the gasious elements in the flame is lower hence less over all heat output. Think of it has a smaller hotter flame. To achieve the same heat output for propane then a higher flow rate from the jet is required.

But back to why should a smaller hotter flame with less calorific heat speed up the boiling of a kettle when all every logical thought says it shouldl be slower.

Because it is a hotter flame and with less gasious mass then less heat will convect around the sides of the kettle being an open heating system and more absorbed into the base of the kettle. In a closed more efficient heating system like a boiler or heat exchanger type air heater then the butane flame will produce more heat transfer as there will less possibility for heat to 'escape'.

 

 

 

[Guest peter]

Yea o/k Brambles....... we believe you. You've baffled us with science. :D

[747]

Well he aint baffled me. If you read my post more closely, you will find that he has broadly said the same as me. Maybe in a more baffling way. :D

[Brambles]

747, you think butane will heat a kettle quicker, I offered an explanation, all be it baffling, as to why I think Propane will heat it quicker.

 

[Brambles]

Re read the the bit about the yellow tipped flame. The yellow tipped flame will be an innefficient flame and not being a complete combustion will be producing less heat than it could...... see what you are saying now 747.

[747]

If you read my post Brambles you will see that I also said there was something wrong with the yellow flame.

 

The 2 gases are different and each will have a different optimum gas/air/pressure mix.

 

28 mbar was the standard for Butane and now it is different. This means it is not as efficient. The fuel with the greater calorific value will always perform better at its optimum setting.

 

My van was originally 50 mbar. There is still a sticker to that effect in the gas locker. I have an Alugas bottle with a 30 mbar regulator and a non refillable backup with a 37 mbar regulator. The original equipment (fridge, hob and heating system) performs in a satisfactory manner.

 

Nobody can say one gas performs better than another when the set up is no longer a standard one. Also, if you go back to my post, you will find that I said that Propane should work better because the fixed regulator pressure is more suited to Propane ie; higher than the Butane optimum.

 

If this is getting into a slanging match then I will leave it alone. I hate repeating myself because others jump in without taking note of anything I have said.

 

 

[Derek Uzzell]

olley - 2010-10-07 6:12 PM

 

hallii - 2010-10-07 5:32 PM

 

We are just back from France / Spain and I filled the Gaslow twice using the LPG filling station pumps.

 

My spare is propane so I am able to make side by side comparisons.

 

I noticed that the LPG (GPL Butane) burnt with a yellow tipped flame but the propane burnt clean and hot. The propane seemed to boil the kettle quicker as well.

 

But, the LPG only costs about 70 Euro cents a litre.

 

So it's LPG (Butane) for me.

 

Hallii

 

GPL/LPG isn't Butane, its a mixture of both, usually more Propane than Butane, if it was all Butane in cold weather (below 1c) there would be no pressure to push the liquid along the pipe to the vaporiser.

 

I am lead to believe in the UK its around 90% Propane, but I can't find anything official on that.

 

Olley

 

You might want to look at this earlier thread.

 

http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=13575&posts=7

 

As I understand it, when 'autogas' is used as a vehcle fuel (which is, of course, what it's intended for, not running leisure-vehicle domestic appliances) the LPG is pumped to the motor in liquid form, where it is filtered/heated, etc. and it's only when it enters the motor that it's in gaseous form. So a high percentage of butane in the autogas mix (as is the case in France) will be much more significant where motorhome usage is concerned and vaporisation pressure from the gas reservoir is important, than for vehicle fuelling.

 

As far back as I can remember (long before the Truma/GOK regulator debacle), there have been letters in French motorhome magazines complaining about 'dirty' gas clogging up fridge and heater gas-valves/jets, and the "Use propane, not butane" (and vice versa!) advice was often trotted out, as was "Use this 'make' of gas, not that one".

 

There have also been plenty of claims that modern LPG refinement processes tend to produce 'oily residues' that household domestic appliances/heating systems can easily tolerate, but more finicky leisure-vehicle gas heaters/fridges are less able to (presumably due to the lower gas-flow rate), but I don't think this has ever been proved.

 

If there is to be a choice between butane or propane for motorhome use, I'd favour the latter gas a) for its all-seasons capability and b) because much of the gas-fired kit on modern motorhomes comes from countries (like Germany) where use of propane for leisure vehicles is the norm. Logically, if (say) Truma is designing a heater, they will target their own leisur-vehicle market as a priority and, when that market normally uses propane, it's not unreasonable to assume that Truma heaters may 'prefer' propane to butane.

[Brambles]

Thanks Derek and for links to previous threads, makes interesting reading and more to this than it first seems, especially in cold weather.

[dikyenfo]

France also does a mix in bottles so that winter use is OK. These bottles are in dual colour green/gray for Primagas but others may be different. We did find as camp managers that bottles were sometimes overfilled which got a bit exciting at times but some bottles had a greasy deposit forming content that was a problem but ok once you shook it up a bit.

[tonyishuk]

hallii - 2010-10-07 5:32 PM

 

My spare is propane so I am able to make side by side comparisons.

 

I noticed that the LPG (GPL Butane) burnt with a yellow tipped flame but the propane burnt clean and hot. The propane seemed to boil the kettle quicker as well.

 

But, the LPG only costs about 70 Euro cents a litre.

 

So it's LPG (Butane) for me.

 

Hallii

 

A passing thought makes me wonder if the GPL Propane / Butane mixes at the pumps are altered in the winter to take account higher altitudes and colder weather ?

 

I seem top recall reading (MMM ?) of French motorhomes being taken into the Alps using the left over summer diesel rather than winter diesel. Unfortunately the diesel waxed up and the m/homes had to be taken away to be warmed, fuel emptied and winter fuel put in.

 

Rgds

[Derek Uzzell]

dikyenfo - 2010-10-08 11:21 AM

 

France also does a mix in bottles so that winter use is OK. These bottles are in dual colour green/gray for Primagas but others may be different. We did find as camp managers that bottles were sometimes overfilled which got a bit exciting at times but some bottles had a greasy deposit forming content that was a problem but ok once you shook it up a bit.

 

A new one on me and there's no sign of a dual-colour bottle on the Primagaz website.

 

I believed all exchange-only gas-bottles would contain either butane or propane. The European 30mbar standard that permits butane or propane to be used interchangeably to fuel gas appliances applies only to leisure vehicles. For all other applications the traditional 28mbar(butane)/37mbar(propane) standard remains in force. So any exchange-only bottle containing a butane/propane mixture could logically only target the leisure-vehicle market and I would have thought this wouldn't be commercially viable. Primagaz does offer a "carburation" bottle to power fork-lift trucks and the like, but that contains propane only.

[derek500]

We use 13kg butane bottles at home for hot water and cooking as we do in the MH.

 

The bottles are outside and it gets quite cold at night during the winter (often below freezing).

 

We never have any problems, except in the winter, the boiler stops working when the bottles are nearly empty. We then transfer them to the cooker and we get another week or so using the hob.

 

We have overnighted in many places well below freezing and never have any problems with butane.

[Derek Uzzell]

Besides the cold-weather factor, it needs to be appreciated that butane and propane have very different vaporisation characteristics.

 

Compared to butane, propane’s vaporisation is far more ‘violent’ and the pressures involved are much higher. This makes propane more suitable for high-demand applications like fuelling a household central heating system or hot-air balloon burners. If you own a leisure vehicle with high-demand gas appliances, you would be wise to use propane as you can then be confident that the gas will always be able to ‘keep up’ with the appliances’ demands.

 

Its vaporisation characteristics also make propane potentially much more dangerous than butane. Butane bottles may be used (relatively) safely within confined spaces in a domestic environment to fuel individual gas appliances (eg. SuperSer-type room heaters, holiday-home ovens/hobs), whereas propane bottles should never be used inside a house and should always be stored in the open air.

 

Although derek500’s household systems work OK on ‘open air’ butane bottles in Valencia’s winter weather, you’d be hugely optimistic to expect the same in (most of) the UK. His motorcaravan experience of using butane is typical of the gas, with vaporisation output diminishing as the temperature falls.

 

It certainly is possible to get away with butane when motorcaravanning for short periods in below-freezing conditions, as the gas-locker will usually provide the gas-bottles with useful insulation and there may well be some heat-soak into the locker from within the motorhome’s interior. But, if you hang around long enough for the temperature of the gas in the bottles to drop to that of the outside air, nothing gas-fuelled in the motorhome is going to function.

[olley]

Contrary to what some people believe Propane and Butane do mix, and the percentage of each effects the boiling point of the whole mixture. What this means in practice is that if you have a 50/50 mix you will not be left with half a tank of Butane in cold weather. Have a look at this site: http://www.engineeringtoolbox.com/propane-butane-mix-d_1043.html

 

For a real in depth discussion down to molecular level try this one: http://www.bushwalking.org.au/FAQ/FAQ_Mixtures.htm

 

Olley