Oil Firing

Explosion risk I suppose. Can you imagine a firebox full of gas exploding? Propane and butane are also fossil fuels. The NYMR method with rapeseed oil would be a better route for the Bluebell.

 

Well it's one thing to call something BS, especially if you don't understand it, but you can't prove it, can you?

 

The issue is that its expensive

BUT based on what I know about balloons no pumping involved - you may need to nitrogen pressurise in winter* so it sounds promising

Balloon burners use liquid propane the pressure to force the fuel into the burners comes from the vapour in the tanks. In cold weather less gas evaporates hence lower pressure so instead you can pressurise the tank with nitrogen.

 

I have never heard of one exploding, either, not even in a crashed LPG-fuelled car, so the concern expressed in an earlier seems a bit alarmist.

 

When using gas on a live steam model it is possible to get an impressive "Whoomph!" explosion if not handled correctly. I would not like to be around if scaled up to full-size!

 

It is. But on a quick skim through the article, the form of analysis looked designed to produce an answer, and to be pitched to a target audience to be able to wield as a proof text. It struck me as alarmist absolutism, and to be making some significant assumptions about how the costs and benefits would fall that are collapsed into a simplistic headline. In particular, I didn't see any suggestion that income earned now might have a positive value to offset against longer run costs - but I recognise that this may be a level of detail too much for a newspaper report; nor did I see any discussion of where the different sources of money might come from.

More generally, it suffers from the "in the long run we're all going to be dead issue", and isn't terribly helpful about policy choices now to deal with short term energy supply and cost challenges.

 

Manoeuvring the scaled-up propane can over the cab and pushing down the valve into the tank would be quite something too... not to mention the 14' long match over the chimney...

I think pilot light system and adequate venting would minimise that particular risk.
The usual concern is pooling around an unknown leak in a storage facility where it can build up. That may actually be the killer - who's going to want to carve up the tender so the gas tank is exposed?

 

The containers are pressurised and the internal pressure is contained by the thick wall of the container, which is generally circular. If you scale up to sufficient fuel to maintain a supply over a period of several hours sufficient to maintain enough steam pressure to move maybe 400 tons throughout that period then you need either multiple cylinders about the same size as currently available; or a very large and difficult to accommodate cylinder to contain all the fuel needed. The large cylinder is difficult to accommodate as it must be circular, but the hoop strength reduces with the increase in diameter so the metal would need to be much thicker. The standard size cylinders are already heavy for the gas they carry; how heavy would a much larger one be? Bear in mind how much gas would be provided by a burner large enough to maintain steam pressure at 200 p.s.i. in, say, an Ivatt Class 2 boiler, hardly the biggest in use. Or do you just carry a supply of standard cylinders and change them regularly and often throughout the day?

 

I would have a feeling energy density might be an issue.
Storage of the propane/butane as well. You don't need pressurised tanks for coal or oil firing.

 

Somewhere, I believe in Scotland there is a LPG fired Sentinel steam waggon, I'm told that the burner is controlled by a smart phone, the firebox is recently made to the 1920's 'Spiral tube nest' Super Sentinel design.

Among my 'collection' is a propane fired steam car, no automatic burner controls and only a pilot light to keep things alight. On one occasion I fitted a piezzo to light the pilot, made things easier than crawling underneath with a match, BUT one time the pilot blew out, I clicked the piezzo and got a most impressive 'whoomf' and the 'Smokehood' landed in the road.

 

Looks like the Bure Valley doesn't intend to stop steam traction for another fire-risk summer:

 

Very useful that they can convert from oil to coal and vice versa in a quoted 72hrs.

 

Thinking about LPG as a fuel, a number of USA railroads have tried liquified natural gas as a fuel for diesel locos, possibly 15 years ago. I don't recall the details but the locos ran in pairs with a "tender" of a flat wagon conveying two or three 20 foot tank containers with the lng fuel. I'll ask my North American contacts how it all worked out.
Cheers, Neil

 

There is an American entertainer, Jay Leno who has a large collection of Historic Vehicles, amongst which is a Peerless traction engine that has been 'Converted' to LPG firing.

 

Twenty-odd years ago when converting cars to run on LPG was popular, CNG (compressed natural gas) was also mooted at an alternative. This is stored at a higher pressure than LPG so the pressure vessels would need to be more substantial, but the fuel was cheaper. There would also need to be a means of compressing the gas. It might be worth thinking about. I think it didn't take off for cars due to the lack of infrastructure. Although LNG (liquified natural gas) has been mentioned above it needs to be stored at very low (i.e. cryogenic) temperatures, which would require highly insulated tanks, and would also need a means of liquifying the gas, which would add to the challenge.