The Lima Double Belpaire Boiler discussion stimulated a neuron or two regarding un-combusted coal fuel.

With all of the new steam locomotive projects either completed, theorized or in motion at this time (T-1, 4014, Tornado, ATSF 3463 come to mind), what have been the fuel options considered? I know that the Tornado was proposed to burn a fuel oil coal mix but that was abandoned. I’m curious if there has been much consideration to coal (typo "cold" edited) water slurry fuel for a locomotive. I’m not in the power gen or petro business so other than know about it, I’m not familiar enough with it to know if it is even possible (like sure but you’d need tankers of slurry or the BTU output is insufficient).

With solid coal, has there ever been a firebox/”stoker” design that like a power plant that made use of pulverized powdered coal?

Just about any fuel you can imagine has been burned in steam locomotives at one time or another. This includes wood, all forms of coal, oil (Bunker C, diesel, Waste Vegetable Oil, etc.), and more esoteric things like coffee beans, manure, and even mummies.

I'm not sure if coal slurry has ever been tried but I've wondered if it wouldn't be the best of both worlds. Cheap like coal, but handles and fires like oil.

Yes, quite a few pulverized coal fired steam locomotives have been tried in locations including the US, Germany, and Australia. I believe the Australian locomotives, converted near the end of steam to burn pulverized "brown" coal, were by far the most successful.

David Wardale investigated coal firing of locomotives in South Africa in the early 1980's and had extended discussions with a sales engineer from a pulverized firing equipment company. Wardale showed him locomotive plans, discussed operational requirements, and even took him on a cab ride so he could see the kind of conditions the equipment would have to work in. The sales engineer did a lot of work and was confident their equipment could be adapted to work, but steam was officially on the way out and no actual installations were done.

It's not cold-water, it's coal/water -- pulverized coal carried in water to make it flow smoothly.

Boilers can be built to work with slurry firing, but they are not at all the sort on conventional locomotives. A substantial amount of the heat energy of reaction goes into heating up the water before it gets to work raising the transition temperature of the carbon in the coal for combustion ... so the effective flame path has to be longer, with different radiant heat-uptake characteristics. Now, the energy that went into that water is recoverable (contrary to what you may have heard) but you need a much longer 'economizing' gas path, even longer than that represented by a Franco-Crosti setup, to get it out. (See the DOE testing of the Donlee Turbo-Fire XL in the early '80s for a discussion of what's involved.)

With modern materials and coatings, it's (in my opinion) practical to take the flue-gas temperature down past the condensation point of the water in the gas plume... or tap the exhaust flow for FGR at any point its temperature is suitable, taking account of any additional water in the recirculated gas.

Some water in the plume is highly desirable from a NOx-reduction standpoint (on the Donlee boiler this is actually furnished by steam injection, not admixed in the fuel). While there is no present requirement or, apparently, expectation that steam locomotives would have to adhere to Tier 4 final emissions, it might be valuable at some point to know that it could be done.


Pulverized coal firing on locomotives has a rather long history, usually punctuated by critical-mixture dust explosions. One problem with dust explosions is that they can easily be promoted to the equivalent of shockwave detonation, at which point explosion doors or other measures are pointless. The situation with 'furnace puffs' is bad enough in powerplant boilers, where firing is generally near-continuous rate with relatively slow firing changes when turndown is needed. This is NOT what prevails in most railway service, and as equipment ages, seals begin to degrade, people get complacent, etc. eventually -- usually sooner than later -- it will be BOOM time.

I have some information on the '50s experiment with the StuG system, on Victorian Railways in Australia, if anyone remains interested in the cockamamie idea... that was about the best of the attempts. For a rather good example of what to avoid, see the 'Snuff Dipper and the Yellow Dog Blues' that appeared in Trains Magazine (October 1972)

At this point, I'm leaning the other way, using a baseline fire of solid fuel (either light and thin, or 15-particle GPCS) with liquid and/or gas fuel cofiring. PM me for details -- I have no desire to put the whole list to sleep in the middle of a work day.

One thing that wanders through my brain every now and then is the logistics of fueling a steam locomotive.

Coal:

1) Coaling towers: any left in service?
2) Coal Loaders: pretty good if you work from a fixed base, not too good for fan trips. Also need dump truck.
3) Front end Loaders: they don't reach high enough, you have to build a "hill" first. Also need dump truck.
4) Dumping hopper on forklift: not to bad if you have a forklift that will lift high enough. Also need dump truck.
5) Bagged coal on a pallet, on a flatbed, with a small forklift: actually worked pretty good, filling the bags was a little too labor intensive.
6) 1 cubic yard aggregate bags and a crane: Might be workable, labor to fill the bags is still a problem.

Oil:

1) Tank Truck:
3) Tankcar:
4) Oil Tank:

Water:

1) Fire hose: everybody uses it, most don't take care of it, so it rots.
3) Irrigation Pipe: For permanent and semi permanent set ups could work, also maybe you could build a portable standpipe for semi permanent setups
4) Water Tower: Oh you lucky dog.

-Hudson

OK, the real experts have chimed in on the slurry and dry pulverized coal thing. It was done but not widely, for good and rational reasons.

If you are interested in sustainable steam, you have biofuels to consider such as pellets, torrefied wood, veg oil, etc. Also industrial waste products if you can burn them cleanly and efficiently.

I've been toying with how to most cleanly and efficiently use waste oil in a traditional firebox and haven't yet found the right combination of oil cleaning / treatment and burner and firepan engineering to allow it to be used as cleanly and efficiently as more refined light oil fuels which can be very efficiently burned in vaporizing burners which will clog on waste or heavy fuels.

I'm interested in finding out more about this topic, thanks for mentioning it.

dave

Any good railfan steam running has the logistics worked out to handle everything.

You also should consider the steam engine is in motion, vs a stationary boiler.

There are very few coal towers any more, there are some standing ghosts still like the one near New Buffalo, Michigan on the PM.

If you have a GOOD fire you will not have uncombusted coal. Story is on the Big Boys
when they got steaming good, with a good fire, you would have the stoker on continuous, the steam jets running full spraying the coal out, the fire burning hot, and eventually the actual fire would raise above the grates and fully spent fuel hitting the grates. Something to think about if they get the Big Boy going or if they convert to oil. I doubt the Big Boy will be put on serious hauling demands than just passenger hauling but they could put it thru some freight hauling tests like they did with 765.

I think the Hill Country Flyer down in the Austin , Texas area burned used motor oil collected in their SP 2-8-2. James

I was involved with an oil burned that got used oil from a local car dealer. The dealer also dumped in all of the body shop solvents and probably some paint into the waste oil tank. It was not something you wanted to breathe and boy would it make smoke. And of course I was young and dumb and liked to smoke out the highway overpass when we went under. One time I made so much smoke going up the line it laid in the valley an we had to run through it on the way back. Ah, those were the days.

Ho, ho, ho, ho!!! And I can't help but be reminded that there was a Mexican steam locomotive that was also used as an incinerator by a police department down there to dispose of a huge confiscated shipment of marijuana. The town's own incinerator was broken down, and so someone came up with the idea of disposing of the marijuana in the local steam locomotive. It was quite efficient; the locomotive burned up the Mary Jane in about a half hour or less, a job that would have been several times longer in the incinerator. This was done in the passenger station, and the whole facility smelled like a pot party!

About other fuels--the mummy story from Egypt is just a myth, though it's surprising at some of the other things steam locomotives have digested over the years.

Let us also recall the plantation engines that ran on bagasse, the refuse from sugar cane after the sugar juice has been squeezed out of it. This was squeezed into bales that the fireman threw into the firebox. It burned hot enough, but it was also like tinder; it burned so fast the fireman probably had a tougher job than the toughest coal burner around. It was also very prone to making the biggest bunch of sparks you ever saw; there was a reason the cane engines had those spark arrestors so similar to what were worn on wood burners.

I seem to recall a story about the last D&RGW eastbound freight over the San Juan Extension in 1968 out of Durango made it to Chama on what little BTUs could be gotten out of the coal dust and dead cat found in the Monero tipple. They reached Chama with less than 100 p.s.i. in the boiler and the tender's coal space empty.

The Grand Canyon Railway uses waste vegetable oil.... http://youtu.be/b95GANkUCDs

Somehow I totally forgot about bagasse yesterday. Porta spent a lot of time in Cuba figuring out how to burn this fuel efficiently. Apparently bagasse was well suited for use with Porta's Gas Producer Combustion System and he did experiments with stationary boilers to work it out. In one of his papers he mentions that it burned a lot like certain grades of coal that tend to get "sticky" as they burn, requiring regular mechanical agitation of the fire bed. His Cuban project locomotive, Minaz #1816, an ALCO 2-8-0. It was modified by Porta with a Lempor exhaust, feed water heater, improved piston valves, etc. but retained the original oil firing. The plan was to convert it to burn bagasse once the initial tuning up had been completed as evidenced by the huge extensions welded to the side of the tender. This engine was intended as the test bed for a series of new construction 0-6-2T 3-cylinder compounds that would have replaced the fleet of ancient US steamers working in Cuba, and they would have burned stoker-fired bagasse (basically a free by-product of sugar cane production) instead of imported oil. These engines were completely designed in Argentina (the plans still exist) but about the time they were ready to go to construction the Cuban proponent of the project died and the price of sugar plummeted, pretty much negating the need for any new motive power.

Paint solvents would at least burn. When I was at Black River with the 148, they were using waste motor oil. The problem was that it came from various sources that apparently mixed coolant in with used motor oil. It was necessary to drain the 'water' out of the bottom of the tank almost every Saturday and Sunday morning, or else you had a tough time getting a fire going. Many a 'first trip' those days was pulled by a diesel.

Logistics play a big factor here. If you are running from a fixed location, coal makes sense, unless you have a NIMBY problem. Your front end loader, conveyor, ramp, dump truck, whatever else you need are there, as is your water. Having been on the road with the 148 a few times, there was a certain beauty about being able to fuel the engine with a hose. Of course, the economics have changed a bit since the mid 1970s.

Also, waste oil is now considered a hazmat, at least in some (all?) locations, and special permits and inspections are required to burn it. Again, times have changed.

The oil from the automotive part of our company is shipped to California and burned in industrial heating. The antifreeze is recycled for automotive use and deicing. The paint latex and oil are separate and recycled to more paint. At first it was all cost to get rid off , now we are paid for it based on how pure it is , and use the money for holiday parties. The engineer on the Hill Country Flyer told me it was a city oil collection program and they had not had any problems with contamination. James

Some ideas on bagasse (and similar 'biomasa') combustion can be obtained in the Babcock and Wilcox 'Steam' handbook. An interesting, if somewhat dated, paper on the principles can be found here: (.pdf download)

(A couple of other interesting papers from the same source can be found at this location.

In general, an 'ideal' way to feed bagasse is in a manner reminiscent of an old Crawford underfeed stoker, with 'tuyeres' providing hot air to evaporate off the moisture in the biomass ASAP. (Then see my previous note about how to recover the heat in the water further down the Rankine cycle...)

One thing potentially advantageous for biomass combustion is a cellular 'windbox' for the primary air. There was an interesting paper from 1935 that described how to do this in detail, which I found interestingly adaptable to GPCS on locomotives with 'computer control' -- I'll provide the reference if I can find it again... someone here will hopefully recognize it first and cite it here.

Successful bagasse burning appears to also involve a substantial thermal reservoir in the furnace refractory. How well this translates to a locomotive boiler may bring up unpleasant rumblings of a certain Bulleid locomotive... but it's possible that with modern materials and design the result could be made 'proof' against necessary thermal cycling and the usual sorts of vibration and shock for locomotives in the anticipated service.