Coke (fuel)
Coke is a solid fuel derived from carbonized coal, known for its unique burning properties that make it a valuable heat source, particularly in commercial applications like steel production and power generation. The use of coke dates back to 1642 when brewery workers in Derbyshire, England, discovered that by heating coal to remove sulfur, they could create a cleaner-burning fuel that improved the quality of beer. This technique was later adapted by Abraham Darby for iron smelting, leading to a significant enhancement in iron production due to the low sulfur content of coke. Over time, the coking process evolved, shifting from labor-intensive beehive ovens to modern methods that optimize efficiency and minimize waste by recovering valuable gases and by-products. While coke was crucial for steel manufacturing during World War I, its demand has since fluctuated, declining in the United States but remaining strong in other countries, where it is primarily used as an energy source. Today, about 80% of the world’s coke production serves this purpose, highlighting its ongoing relevance in global industry.
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Coke (fuel)
Coke is one of several solid energy sources that results from the process of making another fuel source. The name "coke" has generally been used in reference to carbonized coal. Coke that comes from the petroleum manufacturing process is usually known as "petroleum coke," "pet coke," or "petcoke." Coke has its own unique uses that differ from those of coal or petroleum. The way it burns makes it a valuable heat source, especially for commercial purposes such as steel mills and power plants.
Overview
Coal coke's value as a heat source was discovered by brewery workers in Derbyshire, England, in 1642. The wood used to heat the malt mixture during the brewing process was growing increasingly scarce, so workers tried using coal in its place. They discovered, however, that the sulfur in the coal left the beer and ale with an unpleasant taste. They decided to char the coal, or heat it enough to burn off the sulfur, before using it to heat the malt. They found that the resulting product—coke—burned hotter than coal and did not have a negative effect on the brew. Sixty years later, Abraham Darby, a man who had been an apprentice in the brewery, applied this technique to the coal he used to smelt iron in his ironworks. The quality of the resulting iron products, such as pans and cannons, was greatly improved by the low sulfur concentration in the coke. Darby's technique spread and enhanced the production of iron around the world.
Darby's original process for using coke was time consuming and generated such great heat that the insides of his furnaces would burn away and require frequent repair. The more recent coking process for coal involves baking it in a super-hot oven. For many years, these were beehive-shaped ovens tended by crews of men who worked to put in the raw coal and remove the coke through manual labor. The process of heating the coal without allowing it to burn would purify it, burning off substances such as sulfur and oils and leaving behind a product that was nearly pure carbon.
Carbonized coal coke generated greater heat with less waste and quickly became the fuel of choice for many manufacturing purposes. By the 1880s, many American steel manufacturers had adopted its use. When World War I (1914–1919) increased demand for metal, coke was used to manufacture nearly 90 percent of all the steel made in the United States. During the twentieth century, new designs were made for coke ovens and for foundries that recaptured some of the valuable gases and other by-products for reuse.
Demand for coke fuel declined in the United States during the latter twentieth and early twenty-first centuries. However, it remains in great demand in a number of other countries, and much of the coke produced in the United States is sent overseas. Approximately 80 percent of the coke produced in the world is used as a fuel source.
Bibliography
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Valia, Hardarshan S. "Coke Production for Blast Furnace Ironmaking." American Coke and Coal Chemicals Institute, 2021, accci.org/wp-content/uploads/2021/07/coke-production-for-blast-furnace-ironmaking-07-22-2021.pdf. Accessed 3 Jan. 2023.