anthracite vs bituminous

[bendorsey]

Hi Ya'll:

I'm about to start on a coaling tower that provided both soft coal (bituminous) and hard coal (anthracite). I got to wondering about what the effect would be if the fireman loaded his loco with the wrong stuff.

Its my understanding (I could be wrong here) that anthracite has a higher carbon content and burns slower so a larger firebox is needed for the same BTU production rate. That seems to say a loco accidently loaded with anthracite instead of bituminous would not generate as much heat and would have problems producing enough steam to pull its load. Wouldn't hurt the loco tho (tick the engineer off to no end, lol).

Bituminous burns a bit faster so a loco accidently loaded with bituminous instead of anthracite would produce more heat since it has a larger firebox possibly damaging the loco if the pop off valves failed to work (big fat kaboom).

If the fireman quickly realized his error I'd think he could compensate by changing the rate at which he stoked the firebox. Faster for anthracite in a bituminous loco - slower for a bituminous in an anthracite loco (but it would still tick the engineer off).

Watcha think gents?

Ben

 

[StorkNest]

According to a modeling book I have,
Anthracite has a high heat value around 15,000 BTU per pound
Bituminous has a heat value of at least 10,500 BTU per pound

 

[sethmcs]

Both should work fine. Depending on the quality, bituminous coal can be cleaned to get 18,000btu. Coking coal is above 15,000 btu , Low ash , low sulfur.

 

[bendorsey]

Intresting heat values.

But doesn't Anthracite burn slower? Thats why the fire boxes were so large. Most locos that burned it had wooten fireboxes with the enginer on the right side and the fireman on the front of the tender deck.

Ben

 

[sethmcs]

Intresting heat values.

But doesn't Anthracite burn slower? Thats why the fire boxes were so large. Most locos that burned it had wooten fireboxes with the enginer on the right side and the fireman on the front of the tender deck.

Ben

Yes but it burns longer. Just think of it as pine verse oak.

 

[Enkidoh]

Well, where I live (Western Australia), the only type of coal mined here is the low grade, sub-bituminous Collie coal. It caused nothing but headaches for the WAGR administration, as it not only proved to be a very poor burner (several classes of loco had to be rebuilt with larger fireboxes to compensate), due to it's high moisture content, storage proved a nightmare, as if left in the sun for long periods the moisture would evaporate, reducing the coal to dust.

Hence during the steam era the bituminous coal had to be stored in big ponds in order to keep it moist. It's also the reason for why the last classes of WAGR steam locomotives were fitted with long, deep fireboxes specifically designed to burn it, especially the famous W and V classes.

One interesting attribute of that coal was that it made WAGR steam locomotives famous for only emitting white smoke, not black. Whether the coal is a clean burner or was just because of how much water it contained I'm not sure. But looking at photos from the steam era and my own experiences riding behind preserved locomotives here indeed clouds of thick black smoke are rarely if ever seen above steam locomotives.

 

[jadebullet]

Anthracite all the way. It burns the hottest, and it burns the longest. An Anthracite Wooten Firebox wouldn't have that much trouble with bituminous, but a bituminous burning one would have some problems.

 

[magickmaker]

Technically, you could use either coal in a firebox, but the probable result of using the wrong one, let's say softer coal in a larger firebox, would be that the engine would consume far more coal than it might usually. Not because that coal burns cooler, but because it burns easier. So it's possible, say, for a locomotive that usually uses Anthracite coal to burn the softer coal, but if doing so it might only last half the time.

 

[bendorsey]

My premise was based on the rate at which they produced heat.

Anthractie burned slower and produced less heat per given quantity per minute then bituminous (shovel fulls per minute for example). Anthracite in a loco designed for bituminous wouldn't produce as much heat per minute as the same quantity of bituminous. Bituminous in a loco designed for anthracite would produce more heat if the fireman put the same amount of bituminous in the firebox as he would have of anthracite.

As long as the pop off valves work neither scenario is dangerous (but both would probably get the fireman a swift kick in the rear, lol).

BTW - the coal tower is coming along nicely.

Ben