As I mentioned in one of my earlier posts on steam power, the technology was originally invented to help pump water out of...get ready for it...coal mines! Coal was used as fuel for a variety of different industries in the past and is still used in the present. So let's take a look at coal and how wonderful it is, and how it is more than just a dark hard rock that disgruntled factory workers shovel into furnaces or what Santa gives you when you've been naughty.
DISCLAIMER: I am NOT a historian and do NOT pretend to be one. If you do find inaccuracies or know better resources for more information, feel free to share.
What is Coal?
As always, let's start with the basics. What is coal? Coal is a sedimentary rock composed primarily of carbon, hence its name which means, "mineral of fossilized carbon". However, coal not only contains carbon but also hydrogen, nitrogen, sulfur, and oxygen. Coal forms in the rock strata in deposits called "coal seams" or "coal beds". As it is a fossil fuel, it originally formed from prehistoric plants that were buried by mud and other vegetation and slowly compressed and heated over time. For most, the definition of standard coal ends at hard black rock, which is perfectly fine and normal. However, there is really no such thing as standard coal.
Types
An important thing to note as we press on is that not all coal is created equal. Coal is ranked using Hilt's law, which says that coal's quality is dependent on the depth of the coal seam. The greater the depth, the greater the materials' exposure to heat and pressure, which allows the process of carbonization to occur. The below coal types are written in order from lowest to highest.
Peat
The above image is one I took while studying abroad in Ireland. This is peat. Think of it as coal in raw form before it is has time to sit in the ground and become proper coal through carbonization. Peat is a spongy substance that is composed of decaying organic matter and other plant material. It has been used as a fuel source in Ireland, Scotland, and Finland for centuries.
Lignite
This is also referred to as "brown coal" or "rosebud coal". Lignite is the intermediate form of coal and is considered the lowest in rank and the lowest in energy content. It has high amounts of volatile matter and a lot more moisture. However, the downside to lignite is that it must be carefully stored and transported since it is susceptible to spontaneous combustion.
Bituminous Coal
This type of soft coal is used primarily for heat and electricity generation, steam power electricity in particular. Bituminous coal also has a higher heating value than lignite. There are three different types of bituminous coal. The first is smithing coal, which is ideal for forges for metalworking. The second type is cannel coal. Cannel coal was used to make coal oil for public lighting in the 19th century and was eventually replaced by kerosene. The third type of bituminous coal is coking coal, which is used in steel manufacturing.
Anthracite
In the hierarchy of coal, anthracite is at the top. It has the highest energy content of any other type. It's a hard coal and is formed deep in the rock strata where there is a great amount of pressure and heat. Given its fine quality, anthracite is not cheap. However, for those who can afford it, anthracite is used in stoves, furnaces, and in water-filtration systems. It has very fine pores that can capture sand and other harmful impurities.
And there you have it, a simple overview of the world of coal. If there is anything to be taken away from this post, it should be that there really isn't such a thing as standard coal and without this lovely little black rock, we wouldn't have been able to power the 19th century or the 21st century. But also keep in mind that coal is a nonrenewable resource. It takes millions of years and the right conditions in order for nature to produce coal and there is a limited amount of it as a result. So one can't help but wonder what will happen when we run out?
To learn more about coal, check out the links below.
Resources
http://en.wikipedia.org/wiki/Coal
http://www.worldcoal.org/coal/
http://www.britannica.com/EBchecked/topic/448229/peat
http://www.geology.ar.gov/energy/lignite.htm
http://education.nationalgeographic.com/education/encyclopedia/coal/?ar_a=1
Types
An important thing to note as we press on is that not all coal is created equal. Coal is ranked using Hilt's law, which says that coal's quality is dependent on the depth of the coal seam. The greater the depth, the greater the materials' exposure to heat and pressure, which allows the process of carbonization to occur. The below coal types are written in order from lowest to highest.
Peat
The above image is one I took while studying abroad in Ireland. This is peat. Think of it as coal in raw form before it is has time to sit in the ground and become proper coal through carbonization. Peat is a spongy substance that is composed of decaying organic matter and other plant material. It has been used as a fuel source in Ireland, Scotland, and Finland for centuries.
Lignite
This is also referred to as "brown coal" or "rosebud coal". Lignite is the intermediate form of coal and is considered the lowest in rank and the lowest in energy content. It has high amounts of volatile matter and a lot more moisture. However, the downside to lignite is that it must be carefully stored and transported since it is susceptible to spontaneous combustion.
Bituminous Coal
This type of soft coal is used primarily for heat and electricity generation, steam power electricity in particular. Bituminous coal also has a higher heating value than lignite. There are three different types of bituminous coal. The first is smithing coal, which is ideal for forges for metalworking. The second type is cannel coal. Cannel coal was used to make coal oil for public lighting in the 19th century and was eventually replaced by kerosene. The third type of bituminous coal is coking coal, which is used in steel manufacturing.
Anthracite
In the hierarchy of coal, anthracite is at the top. It has the highest energy content of any other type. It's a hard coal and is formed deep in the rock strata where there is a great amount of pressure and heat. Given its fine quality, anthracite is not cheap. However, for those who can afford it, anthracite is used in stoves, furnaces, and in water-filtration systems. It has very fine pores that can capture sand and other harmful impurities.
And there you have it, a simple overview of the world of coal. If there is anything to be taken away from this post, it should be that there really isn't such a thing as standard coal and without this lovely little black rock, we wouldn't have been able to power the 19th century or the 21st century. But also keep in mind that coal is a nonrenewable resource. It takes millions of years and the right conditions in order for nature to produce coal and there is a limited amount of it as a result. So one can't help but wonder what will happen when we run out?
To learn more about coal, check out the links below.
Resources
http://en.wikipedia.org/wiki/Coal
http://www.worldcoal.org/coal/
http://www.britannica.com/EBchecked/topic/448229/peat
http://www.geology.ar.gov/energy/lignite.htm
http://education.nationalgeographic.com/education/encyclopedia/coal/?ar_a=1

