I just started working for Alstom power, who owns the former assets of Combustion Engineering, one of the largest builders of fossil fired steam boilers in the country.

Anyhow I was reading thru the company's history which at one time included the locomotive superheater company. Anyhow one of CE's early claims to fame the literature here says was its use of Pulverized Coal (PC) in boilers both on stationary and locomotives.

I was wondering if anyone knew of any steam locomotives that burned PC? Also they started the technologies in the early 1920's so steam locomotives still had a ways to go in their development. Does anyone know why PC never took off in steam locomotives, despite its huge success in the power industry?

Adam [/b]

Have you ever seen what comes out of many stokers on steam locomotives? I've personally witnessed some stoker output that resembles semi-pulverized coal by the time the draft grabs it....... <:-)

But to be a bit more serious, I would suggest it's the difficulty of handling. Imagine pulverized coal in the tender of a steamer, getting wet from the rain, and turning into a caked or muddy mess........

As I recall the union Pacific experimented with a coal fired gas turbine made from the hulk of a Great Northern W series electric, an ALCO Pa for auxiliaries and hostling propulsion, and a centipede tender. It apparently was not a great success as the abrasive qualities of the unburned fuel tended to cause the blades to fail at all too high a frequency. A test engineer is reputed to have commented that it sounded much like any other gas turbine, except for the pinging sound of the bits of turbine blade occasionally coming through the sides.

Its seems to me that there may be some potential for a fluidized bed system with automatic firing however I suspect that such an arrangement might not be cost effective in a locomotive because of the amount of processing equipment that it has to carry with it.

GME

Pulverized coal "dust" was fired in Australia fairly successfully. The burners were sort of like large showerheads, inside of which coal dust was picked up by a jet of steam and blown through holes into the firebox.

dave

There were several attempts around the world; the UP even tried to burn a coal slurry in their gas turbine locomotive. The following will get you started:

http://www.google.com/search?hl=en&q=%2 ... ed+Coal%22

PC has the consistancy of dust. The coal arrives at the plant in large chunks much like locomotive fuel; it is ground up in a bank of pulverizers just before being blown into the boiler by a jet of steam.

You wouldn't want the complexity of carrying pulverizers on the locomotive itself; so the coal would have to be ground beforehand and stored. That is when you encounter you first problem...coal dust is an explosion hazard (think grain elevator explosions.) And it gets everywhere.

Sandy's point about keeping it dry in the tender is next; I think one class of German or British locomotives that used PC loaded the fuel in a closed container. When you needed more fuel, the empty container was lifted out, and replaced with a full one.

A utility boiler is basically a big box, with the walls being made of small water tubes. A set of fans push air (forced draft), pull air (induced draft), or do both (balanced draft); ensuring an even flow of air through the boiler. What's more, the fuel burns in the form of a fireball; the fans and steam blowers blow in at an angle, so the fuel swirls around as it burns. This gives it a decent amount of time in the boiler to be burned completely with little carryover.

Compare this to a steam locomotive that burns fuel on a grate; using a blastpipe to induce air through the boiler. The amount of draft will vary widely; PC would easily be lifted off the grates and blown unburned up the stack. And it would be hard to burn it throughly in a steady fireball in the small confines of a locomotive firebox.

PC, along with steam turbines and high boiler pressures were all tried aboard locomotives in the 1920s and beyond when these technologies all worked in stationary plants and ships and resulted in higher efficiences. But designers quickly found out that the banging, dirty, constanting changing environment of a steam locomotive was way different from the clean, stationary, steady state world of power plants and engine rooms aboard ships; and what worked well in a powerhouse was shaken apart aboard a locomotive. And most such attempts were one-off locomotives that spent most of their time in the back of the shop; waiting for some spare time for the shop forces to sort them out; though there were a few exceptions.

Related to Dave's post, we've had several extensive discussions on the topic of the Australian pulverized coal burners on the Yahoo steam_tech group.

More recently, David Wardale seriously looked at pulverized (or as he said it was more accurately termed, "micronized") coal firing in South Africa in the early 80's. IIRC, he contacted the local agent for Combustion Engineering, explained what he was trying to do, and had the sales engineer take a ride on a mainline steam locomotive so he'd get first-hand knowledge of the application. The rep didn't see any significant problems with adapting their equipment for locomotive applications. Unfortunately no funding was forthcoming so nothing ever came of this. He could see huge advantages for the technology, the chief one being it would at once and forever free the fireman from the burden of maintaining a troublesome firebed. No clinkers, no grate shaking, no ashpan cleaning, no shoveling the back corners, etc. Turn the knob and make more steam.

One guess for why pulverized coal firing never succeeded in wide-spread locomotive applications was that it was tried too early (certainly this would be true in the U.S.). It seems we sometimes had a tendency to try something once and when it didn't work say "the hell with this". The much more mature technology of the late 40's/early 50's might have been much more successful, but by that time, nobody here had much interest in improving steam.

Interestingly, when I was a senior in high school, and friend and I talked our way into a tour the Wisconsin Electric Power Co. (former TMER&LCo.) Lakeside power plant, reputed to be the world's first commercial pulverized coal fired power plant, opened in 1917, IIRC. The tour of the recently decommissioned and cleaned coal handling facilities was a guided tour through the history of PC firing technology. The original installation had all the coal handling and grinding machinery in a separate building far from the main plant, on the theory, I suppose, that if the damned stuff blew up it wouldn't take the generating plant with it. Subsequent revisions to the plant brought the lump coal right to the firing floor, where it was pulverized in what were essentially high speed ball mills just a couple feet from where it was blown into the furnaces with equipment that mimicked oil firing. Indeed the plant had been recently converted to natural gas, (when it was still cheap) with provisions to fire with heavy oil if that became expedient. Indeed, on a subsequent trip up there a couple years later to check out reports that the trolley freight equipment was back in daily service, we found the venerable steeple cab electrics switching tankcars of heavy oil, as the plant was on a gas pipeline, but had no connection for bulk oil.

A PC fired locomotive would need to be set up like an oil burner, with the fuel burning in suspension in the middle of the firebox. I suspect calculating the relative BTU output of the fuels will show that a standard locomotive firebox isn't large enough to obtain the required heat output, and of course the size of the firebox is constrained by factors other than the type of firing equipment.

Am I remembering correctly that the C&O's ill-fated steam turbine electrics 500-502 had enclosed coal bunkers in the nose of the loco and were fueled from a special facility that provided pulverized coal?

I'm pretty sure the C&O STE's used lump coal and conventional stokers. They did have enclosed coal bunkers, but I think that was intended to cut down on fugitive dust emissions. The new coaling facilities may have been cosmetic.

IIRC, the ACE3000 was intended to burn pulverized coal, delivered on board in containers via a forklift truck. Perhaps its designer/promoter might share some information as to how this might have been accomplished.

Who knows, with Diesel fuel approaching $5 a gallon, maybe it's time to dust off those plans.

A very interesting discussion so far with so many responses in such a short time. I am quite amazed at how much response there has been in such a short period of time.

Here's an interesting article I just found from the New York Times back when they wrote nice articles about coal in 1917

http://query.nytimes.com/mem/archive-free/pdf?_r=1&res=9E0DE2DD1538EE32A25757C0A9649C946696D6CF&oref=slogin

It is a really interesting article what it doesn't mention was who was the company behind it and did it ever take off.

From their book "Combustion Fossil Power" which was originally put out by CE, then ABB and now Alstom, it says that CE got into PC in 1918 with Wisconsin Electric's Oneida and Lakeside stations, after capitalizing on a PC system for steam locomotives. Thus I was wondering if anyone knew if this would have been a commercial railroad model or if it was simply the trial mentioned in the article. Since the book says that Combustion Engineering was a subsidiary of The Locomotive Superheater Company, as well as the book mentions CE's real claim to fame was its early adoption of PC burning when most others were still grate burning. So if ever there was a company that was poised to bring PC to the railroad market it would have been CE.

Adam

ACE definitely did not plan on using pulverized coal. One of its selling points was that "run-of-mine" coal could be loaded directly into the containers/packs sitting on flat cars (no special coaling facilities required). The flat cars with containers would have been stored at engine servicing facilities, and the packs would have been loaded onto the engines with rubber-tired loaders.

The advance the ACE locomotives would have included in the combustion process was L. D. Porta's Gas Producer Combustion System (GPCS), which significantly reduces emissions of unburned fuel and increases combustion efficiency.

Not really. Everyone else is looking to coal gassification to produce everything from motor fuel to aviation grade fuel. Bottom line is that all energy prices are going up-it's just a matter of how quickly. Also consider the demand for steel and its byproducts. Coal and coke are required by certain processes, creating additional demand.

Giving the NY Times article a quick read, I see they make a big deal out of burning "waste coal", the stuff "used to backfill mines." When PC firing caught on in the electric utility industry, the fuel was no longer waste, which I'm sure changed the economics more than a bit.

1918 was also just at the cusp of the development of high HP boilers for railway use. Even if they were successful in their railway experiments and could fire a mainline locomotive of that era (the article doesn't seem to give any details of what sort of locomotive they tried to fire with PC) it's not a foregone conclusion that they would have been successful firing the superpower of a dozen years later.

I don't have the references, but it might be interesting comparing the BTU output needed to fire an AC-12 or Santa Fe 5000 on Bunker C, and then see if it is even possible to duplicate with PC in the confines of North American loading gauge. That may give you the answer right there.

Interesting discussion. I thought I would add my experiences with fine, or slack coal use on the Cedar Point Amusement Park railroad in the late '70's.

The locomotives had originally been designed to operate at higher maximum boiler pressures than the park wanted to run them at (around 100 psi was the desired goal). The standard way to cut boiler pressure had come to be cutting grate firing area by laying down a heel under the firebox door of tamped down small, fine pieces of coal that had been sorted out of the coal bunker, using coal forks to separate the larger lumps that had been broken up from the large lumps delivered to the railroad by the truckload. Yes, it was a very labor intensive operation, day shift filled five gallon buckets (like 20 per engineer and fireman - done on breaks from actually running the trains), and night shift refilled the tenders by bucket brigade at the end of the evening. The fireman then used the hammer on each engine to further bust up the lump coal during the day to the desired size for each shovel full.

Each engine had a pile of this slack coal on a tender leg from busting up lumps, that the fireman would occasionally shovel into the bank to keep the heel solid. I think around the second season I was there, '79, someone came up with the idea of using the injector cooling hose at the station to wet down the slack coal to make for a more solid bank - essentially turning to a concrete-like consistency after being fired at operating temperatures.

Once the evening shift crews were given the two round-trips left warning near the end of the night, the fireman would start breaking up the bank with a firebox rake, and gradually thin out the fire in preparation for shutting down the engines for the night. All of the fire was dumped and the boiler topped all the way to overflowing the injector. Often the engines were still popping off (around 125 psi) when shutting down, and often had 15 -20 pounds on them in the morning. They also used to really push the re-firing in the morning with a huge, old Ingersol-Rand compressor to get steam up in a little over an hour. (I think most of the engines still running in the park today have since been reboilered.)

It was suggested by an engineer a couple of years before I got there that the stacks should be capped overnight like an oil-burner's to keep the heat in for the night. That was discontinued after I left, since it seemed to accelerate flue problems with the engines. To this day I don't know how true the cause-and-effect of that was. Perhaps Messrs. Moedinger or Conrad could chime in on that.

Thought this might be interesting to some.