Solid fuels and steam operations
What would alternative fuel talk be without discussion of solid fuels (wood and coal) and steam. First the energy unit I will use is BTU (British thermal unit) which is defined as the amount of energy needed to raise one pound of water one degree F. at 60 degrees F. (from 60 to 61 is the measure). One BTU is ~1055 joule.
First we address the BTU values of some common fuels. It will help us understand why there is a loss of power resulting in increased consumption with fuels such as the alcohols. These figures are in BTU per unit of measure, usually gallons or pounds.
Gasoline 125000 /gal
Fuel Oil 149690 /gal (household heating fuel)
Kerosene 135000 /gal (also known as light distillate)
Diesel fuel 138690 /gal (medium distillate)
Ethanol 84400 /gal
Methanol 62800 /gal
Crude Oil 138095 /gal
Liquid Pet. Gas 95475 /gal
Natural Gas 1008 /Cubic foot
Electric 3413 /kilowatt
Coal per pound
Anthracite 12500 (hard coal found primarily in Pennsylvania)
Bituminous 12000 (most common high value coal used for coke in steel mills)
Sub-bituminous 9000 (what they’re mining in Wyoming)
Lignite 7000 (brown coal)
Common Representative wood, air dried values, green wood is about 75% value of dry wood.
Hickory 5800
Oak 5790
Pine 6390
I addressed steam engines for locomotives in another post, but stationary use of steam for such things as mill operations (sawmill, cotton gins, and electric plants) would be coming back I think. What made me think of the was Chico’s mention of clearing roads in the South, where they were going to just burn it, why not burn it for fuel to help industry and heat the homes?
A rule of thumb for steam operation taken from Lacy 1913 (old but applicable I think) for simple steam (as verses compounds). There is one pound of coal per six gallons of water used. I would base it on bituminous, the most common of coals in use, especially when this was written. So how much water do you use. There are some variables, so I have taken the highest value found for consumption to ‘over estimate. Water consumption is ~30 pounds of water per hour per horsepower. Most common found semi-portable steam engines of the era mentioned and most easily reconstructed are the 30-70 hp.
Using a 75 hp Case steam tractor for an example, this engine would consume ~2250 gallons of water per hour. LOTS of water, and it needs to be GOOD clean water to keep maintenance down if possible. It would require 375 pounds of bituminous coal per hour as well. Not really feasible for a sawmill to haul in coal, so typically slab wood was burned. Let’s assume they are cutting hardwood such as hickory, a very common tree across the entire eastern US. Bituminous coal has ~12000 BTU/pound, where as the hickory has only ~5800 BTU/pound if dry. The wet would have ~4350 BTU/pound. It would take ~1030 pounds of green hickory per hour. Hickory has a density (dry) of ~50 pounds/cubic foot or using our measure ~70 pounds/CF wet. That’s ~15 CF of wood/hour.
A mill of the size this engine can run should be able to put out at least 44,000 board feet of rough-cut lumber a day with a crew (including the woodsmen) of 45. (This is based on the old Engineer Sawmill teams. Use to have the TO&E for that unit. Nice set up too.) This is equivalent to ~140 18†x 20-foot saw logs. Each of these logs will produce ~312 board foot of useable lumber, while leaving ~0.45 cubic feet of slab. Operating ten-hours per day, that’s ~14 logs per hour for a short fall of ~9 CF per hour in wood. But there is plenty of top slash, etc from the operation. Yes it requires transporting, but mules, oxen, or horses can be used. And I would ‘rush’ a rail operation into the mix if at all possible. Even slow moving land trains (each tractor pulling 2-4 trailers depending on the grades). If you can get ahead of the game, there is no speed march needed to get the fuel in as long as it’s ahead.
A steam engine can burn all sorts of things, from wood and coal, to grass, straw, cottonseed hulls, solid waste, and if you have it oil that doesn’t need high refining. Just some thoughts again.
Grae
PS. I will send a pdf copy of Ludy's Steam Engines to anyone interested. It doesn't seem to want to attach here, perhaps too large.
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