Coke (fuel)
Coke is an important industrial product, used mainly in iron ore smelting, but also as a fuel in stoves and forges.
[4] Some facilities have "by-product" coking ovens in which the volatile decomposition products are collected, purified and separated for use in other industries, as fuel or chemical feedstocks.
Thus, different types of coal are proportionally blended to reach acceptable levels of volatility before the coking process begins.
If the range of coal types is too great, the resulting coke is of widely varying strength and ash content, and is usually unsaleable, although in some cases it may be sold as an ordinary heating fuel.
The hearth process continued to be used in many areas during the first half of the 19th century, but two events greatly lessened its importance.
[citation needed] A fire brick chamber shaped like a dome is used, commonly known as a beehive oven.
For the United States, the Occupational Safety and Health Administration (OSHA) has set the legal limit for coke oven emissions exposure in the workplace as 0.150 mg/m3 benzene-soluble fraction over an eight-hour workday.
The US National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.2 mg/m3 benzene-soluble fraction over an eight-hour workday.
[citation needed] Highland Park distillery in Orkney roasts malted barley for use in their Scotch whisky in kilns burning a mixture of coke and peat.
When heated, the coal decomposes and the bod becomes slightly friable, easing the process of breaking open holes for tapping the molten metal.
It contains phenolic, aromatic, heterocyclic, and polycyclic organics, and inorganics including cyanides, sulfides, ammonium and ammonia.
[citation needed] The solid residue remaining from refinement of petroleum by the "cracking" process is also a form of coke.
[citation needed] Fluid coking is a process which converts heavy residual crude into lighter products such as naphtha, kerosene, heating oil, and hydrocarbon gases.
[30] By 1078 CE, the implementation of coke as a replacement to charcoal in the production of iron in China dramatically increased the industry to 125,000 tons per year.
[33] In 1589, a patent was granted to Thomas Proctor and William Peterson for making iron and steel and melting lead with "earth-coal, sea-coal, turf, and peat".
[34] In 1620, a patent was granted to a company composed of William St. John and other knights, mentioning the use of coke in smelting ores and manufacturing metals.
In 1627, a patent was granted to Sir John Hacket and Octavius de Strada for a method of rendering sea-coal and pit-coal as useful as charcoal for burning in houses, without offense by smell of smoke.
[36] It was considered an improvement in quality, and brought about an "alteration which all England admired"—the coke process allowed for a lighter roast of the malt, leading to the creation of what by the end of the 17th century was called pale ale.
[38] Wilkinson improved the process by building the coal heaps around a low central chimney built of loose bricks and with openings for the combustion gases to enter, resulting in a higher yield of better coke.
The Scottish iron industry expanded rapidly in the second quarter of the 19th century, through the adoption of the hot-blast process in its coalfields.
[9] In 1802, a battery of beehive ovens was set up near Sheffield, to coke the Silkstone coal seam for use in crucible steel melting.
By 1870, there were 14,000 beehive ovens in operation on the West Durham coalfields, producing 4,000,000 long tons of coke per year.
[39] This was not technically possible to achieve until the firebox arch came into use, but burning coke, with its low smoke emissions, was considered to meet the requirement.
[40] In the late 19th century, the coalfields of western Pennsylvania provided a rich source of raw material for coking.
The Minersville Coke Ovens in Huntingdon County, Pennsylvania, were listed on the National Register of Historic Places in 1991.
"The smoke and gas from some ovens destroy all vegetation around the small mining communities", noted W. J. Lauck of the U.S. Immigration Commission in 1911.
[45] Passing through the region on train, University of Wisconsin president Charles Van Hise saw "long rows of beehive ovens from which flame is bursting and dense clouds of smoke issuing, making the sky dark.
The beehive ovens make the entire region of coke manufacture one of dulled sky: cheerless and unhealthful.
"[45] In 2024, an investigation into 17 coke burning facilities in the US could be responsible for an estimated 892 premature deaths every year, as well as increased asthma symptoms and other health impacts for residents.
