Refillable Gas Cylinders - LPG Quality

[Uncle Bulgaria]

I'm contemplating going over to refillable gas cylinders as my 2x 6 Kg propane bottles are marginal for extended touring. One bit of information I've picked up on is that LPG does not burn as well as pure propane. It tends to have a yellowish flame and can leave sooty combustion deposits which can affect the performance of appliances, particularly the fridge. Can any member advise me whether this is a significant problem, and are some brands of LPG better "quaity" than others, being higher in purity of propane/butane mix with less other associated heavier hydrocarbon? Advice and guidance welcome.

 

Richard.

[JohnP]

I have been using LPG for about three years now in a previous and my existing van.

My understanding is that in the UK LPG is 100% propane and in Europe it is a mix of Propane and Butane.

Having used the UK version in my Knaus over the last sixteen months I have noticed little or no difference in the burn quality. However I have yet to fill-up abroad.

No doubt others will comment.

[Den]

We've been using lpg filling up here and in France for 5 years with no problems. When having the MH serviced there have been no comments of any build up of sooty deposits. We now use the GASLOW with the new gauges, very handy.

[trickydicky]

hi, we have a van with lpg and have filled up here and in sweden.the only problem we have encountered is actually finding lpg.we drove through denmark into sweden and after a lot of searching finally found lpg in gothenberg.we didn't find any difference in it at all. while i'm on here does anyone know how difficult it is to get lpg in spain.

[crinklystarfish]

LPG is (essentially) a variable mix of propane and butane, the proportions of which may differ from country to country and season to season. Although horror stories abound, finding an actual 'victim' of ‘bad’ lpg is about as easy as finding someone who has actually been subject of the fabled 'gas attack'.

Bottom line is that it simply works. Any 'gumming' of the system is more likely attributable to plasticiser issues from the post 2004 regulator system.

I’ve filled up all over and never had a minute’s grief. I did though custom build my system to use the ‘old’ style propane regulators mounted directly to POL fittings on my twin refillable cylinders.

Refillable LPG in Spain/>/> isn’t easy. There are some publications available including the Dutch ‘LPG Gids’ Book (easy to understand) that help. I always fill up in France/>/> on my way down.

[Derek Uzzell]

crinklystarfish:

 

I know of one instance where a user of a refillable gas-bottle definitely ended up with adulterated autogas.

 

This was in the UK and the bottle was replenished shortly after the service-station's bulk tank had itself been refilled. It was speculated that the liquid that went into the refillable bottle comprised residues that normally lay at the bottom of the bulk tank but had been stirred up when the tank had been refilled. The gas-bottle's user experimented with the liquid in the bottle, but was unable to decide what the contaminant actually was. He told me it definitely wasn't water and, although it would evaporate quite quickly when some was tipped from the bottle, none of his motorhome's appliances would function using it. In fact, the episode had made him sufficiently apprehensive that he had reverted to exchangeable bottles and was selling the refillable gas-bottle.

 

For what it's worth, I also noticed recently that, after the autogas in my own composite refillable gas-bottle had been completely used up (ie. a gas heater would no longer work from that bottle), there was still some liquid remaining within the bottle. However, when the bottle's gas-valve was opened, no 'hissing' took place. When I tipped out the liquid it evaporated and smelled badly. Conversely, a Calor propane bottle that was similarly used up proved to be totally empty after the gas heater had ceased working.

 

My own view is that, where leisure-vehicle domestic appliances are concerned, logically there's a higher likelihood of autogas being less suitable 'purity-wise' than bottled LPG because the logistics, delivery system and design-usage (specifically to fuel vehicles using the LPG in liquid form not vaporised) of the former suggest this should be so. I suspect the risk of getting duff autogas is pretty small (and, in any case, I've no way of quantifying the risk or guarding against it), so I choose to ignore it. However, that doesn't mean the risk doesn't exist and, as I'm sure you are aware, Dometic now warn against using autogas to fuel their fridges.

[Bill Ord]

I’ve filled up all over and never had a minute’s grief. I did though custom build my system to use the ‘old’ style propane regulators mounted directly to POL fittings on my twin refillable cylinders

 

I think Crinklystarfish has a point here. Most of my travelling is done in France and I use French exchange gas bottles. I prefer to buy butane as it tends to be cheaper and there is more in a bottle for any given volume. However I've had to clean the burner in my fridge as it was becoming unreliable to light-up and my Tuma combi has had to be cleaned as well. I'm now considering going back to old style dedicated regulators for butane and propane as I've noticed that the flame on my cooker is noticeably more blue when on propane; butane produces a very slight yellow tip to the flame. I put this down to the fact that you can't have one pressure for both butane and propane and be correct, I believe the appliances in my Rapido are biased to propane on the 30mb fixed regulator so it's either go over to propane or revert to separate regulators, I've yet to decide. Anybody else found a similar experience?

 

Bill Ord

[crinklystarfish]

I accept that there is potential for a higher probability of contamination from forecourt supplies given the additional logistics and ‘housekeeping’ issues. Indeed, I’ve certainly had contaminated unleaded petrol from a local forecourt. I could also be persuaded that the ‘purity’ demands might not be so high, given the primary intended usage of liquid take off tanks supplying internal combustion engines. 

It must have been frustrating for the poor fellow that actually suffered real problems, and I modify my position to acknowledging that we do have a living example. 

Balanced though, against the incalculable number of litres burned by countless leisure users without incident, I’m of the view that the probability of unreliability or system degradation is so remote, as not worthy of a second thought.

Quite what the residual liquid was in Derek’s bottle I have no idea, and it would be interesting to know whether such a phenomenon has been routinely noted in steel, as opposed to composite bottles. 

Dometic’s stance is interesting and the logic behind the company’s advice may be revealing. 

Certainly it’s the case that the refillable solution has so many advantages, that I wouldn’t even consider going back to ‘exchange’ bottles given my own experiences. I do reiterate though that I wouldn’t be keen to run any lpg of any provenance via high pressure pre-regulator pig tails and a 'compromised' pressure regulator. Therein, I think, lays the cause of most of the problems that people unfortunately encounter.

[Uncle Bulgaria]

Thanks for the contributions. The risk assessment therefore appears to indicate a low risk of any detrimental effects occuring, but a significant inconvenience/cost if an unwanted effect does occur.

 

I've just been reading a bit on the Wikipedia web site. Here is an extract.

 

"Varieties of LPG bought and sold include mixes that are primarily propane, mixes that are primarily butane, and the more common, mixes including both propane (60%) and butane (40%), depending on the season—in winter more propane, in summer more butane. Propylene and butylenes are usually also present in small concentration. A powerful odorant, ethanethiol, is added so that leaks can be detected easily. The international standard is EN 589."

 

So, does propylene and butylene vaporise or is it left in the bottle, and if it is carried over in the main gas stream does it vaporise and does it burn cleanly? Any organic chemists or combusion experts in our midst?

 

Richard.

[Derek Uzzell]

Richard,

 

Having looked at Wikipedia entries for propylene and butylene, it appears that both chemicals will react similarly to their big brothers propane and butane - that is, when in pressure-liquified form they will vaporise when the pressure is reduced and will burn easily in vaporised state. So I doubt that any residues remaining in a gas bottle are propylene/butylene.