The key difference between thermal coal and metallurgical coal is that thermal coal is useful in making steam that generates electricity, whereas metallurgical coal is useful in producing carbon used in steelmaking.
Coal is a very important material and can be defined as a comble black or brownish-black sedimentary rock that forms rock strata known as coal seams. Thermal coal and metallurgical coal are two important forms of coal.
CONTENTS
1. Overview and Key Difference
2. What is Thermal Coal
3. What Metallurgical Coal
4. Thermal Coal vs Metallurgical Coal in Tabular Form
5. Summary – Thermal Coal vs Metallurgical Coal
What is Thermal Coal?
Thermal coal or steam coal is coal that is primarily burned in boilers to generate steam to produce electricity or for the processing of heating purposes. We can use it as a direct source to process heat. This term refers to all types of coal that are not classified as coking coal.
However, due to various environmental considerations, the use of thermal coal is limited now. It has become a major cause of global warming. As an evaluation, back in 2014, thermal coal peaked in electricity generation, and it is estimated that this usage will come to a terminal at around 2050 if we attempt to limit global warming. As a result, most companies have stopped investing in new thermal coal production.
What is Metallurgical Coal?
Metallurgical coal or coking coal is exclusively useful as an ingredient for steel production. Generally, this type of coal is baked in a coke oven where coal is forced to remove the impurities and produce coke. This gives a form of almost pure carbon.
Metallurgical coal has a low ash content, low moisture content, and low sulfur and phosphorous content. We can categorize this type of coal as a type of bituminous coal, depending on the chemical composition. Metallurgical coal can produce strong and low-density coke when it is heated in the presence of a low-oxygen environment. During this heating process, the coal softens. The volatile components tend to evaporate, and these components then escape through pores in the coal mass.
During the process of coking (production of coke from metallurgical coal), the material tends to swell, and its volume increases. The ability of metallurgical coal to form coke relates to its physical properties, such as the rank of coal. In contrast to this type of coal, thermal coal cannot produce coke when the material is heated.
The term caking ability describes coking coal because it refers to the suitability of coal to be converted into coke. Different types of coking coal include hard coking coal, medium coking coal, semi-soft coking coal, and pulverized coal.
What is the Difference Between Thermal Coal and Metallurgical Coal?
Thermal coal and metallurgical coal are two important forms of coal. The key difference between thermal coal and metallurgical coal is that thermal coal is useful in making steam that generates electricity, whereas metallurgical coal is useful in producing the carbon used in steelmaking. Moreover, the demand for thermal coal is forecasted to increase at a steady phase throughout the years ahead, whereas metallurgical coal dramatically decreases with the decreased demand for steel.
The below infographic presents the differences between thermal coal and metallurgical coal in tabular form for side-by-side comparison.
Summary – Thermal Coal vs Metallurgical Coal
The key difference between thermal coal and metallurgical coal is that thermal coal is useful in making steam that generates electricity, whereas metallurgical coal is useful in producing the carbon used in steelmaking. Moreover, thermal coal is more expensive than metallurgical coal.
Reference:
1. “Steam coal.” Glossary EIA. US Energy Information Administration.
Image Courtesy:
1. “Massive machinery at work in the open-pit Wyodak coal mine in the coal-rich Powder River Basin outside..” (CC0) via Raw Pixel
2. “Koks Brennstoff” By Stahlkocher – Own work (CC BY-SA 3.0) via Commons Wikimedia