Friday, March 27, 2009

I knew King Coal

As did many Americans my age or older, I had a personal relationship with coal. In 1951, the year before I was born, coal peaked as the primary energy source for homes and businesses. Over 50% used coal for either boilers or forced air heat. The elementary schools I attended had coal-fired boilers for heat, and many of my friends lived in houses with coal furnaces. Until I entered junior high, so did I.

By the time I graduated from high school in 1970, the use of coal for heating homes and businesses had fallen to single digits. It’s used in less than two-tenths of a percent of homes today, but making a bit of a comeback as oil prices rise.

Living with a coal furnace required more than a turn of a thermostat to keep things warm in the winter. Although modernized in several ways, it was still an physically interactive experience.

Rather than throwing shovels of coal into the fiery maw of a furnace, coal was shoveled into a hopper box a few feet away. At the bottom of the hopper was an auger, a screw-like mechanism turned by an electric motor to grind the coal into smaller, more efficiently burnable pieces and move them into the fire box. The most sophisticated systems had sensors that fed as needed, others required a human to start and stop the motor.

At some point it became my daily chore in winter to check the hopper before going to school and when I got home and top it off if it needed more coal to keep the fire burning. Depending on what was available and the quality we could afford it might be hard, glittering, black anthracite I shoveled, soft, layered, dark bituminous or crumbly, dull, brown lignite. The harder and blacker the coal the longer and hotter it burned because it higher carbon and lower water content so the fewer shovelfuls had to be loaded into the hopper. So instead of ten minutes of indentured servitude loading lignite or lower grade bituminous I could be done in 5 with anthracite.

It also became my chore to clear the burnt cinder or clinkers from the clinker box under the furnace. I had a long handled iron rod with a 90 degree bend at the end that I used to coax the still warm clinkers into a bucket, then I’d have to drag the bucket out of the basement and dump it on the clinker pile in the back yard. If it was cold and we were burning lots of coal, I’d have to make more than one trip. Every spring my Dad would have to figure out what to do with the clinker pile. I’m not sure where it got rid of it.

On a massive scale, the generation of electricity and manufacturing have to deal with the same issues we dealt with in the basement of my house. The coal is poured into a hopper and ground, often into a fine dust for more even burning. After the energy is extracted in burning, there is slag. And after a while your backyard pile gets too big and you have to do something with it. But before we get to that part, I’m going to spend some time looking at how coal gets out of the ground.

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