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A beehive oven is a type of oven in use since the Middle Ages in Europe. [1] It gets its name from its domed shape, which resembles that of a skep, an old-fashioned type of beehive.
Its apex of popularity occurred in the Americas and Europe all the way until the Industrial Revolution, which saw the advent of gas and electric ovens. Beehive ovens were common in households used for baking pies, cakes and meat. These ovens were also used in industry, in such applications as making tiles and pots and turning coal into coke.
A fire brick chamber shaped like a dome is used. It is typically 4 metres (13 ft) wide and 2.5 metres (8 ft 2 in) high. The roof has a hole for charging the coal or other kindling from the top. The discharging hole is provided in the circumference of the lower part of the wall. In a coke oven battery, a number of ovens are built in a row with common walls between neighboring ovens. A battery consisted of a great many ovens, sometimes hundreds of ovens, in a row. Some mines also employed parallel batteries. [2]
With candle wax wrapped in paper, dry kindling (twigs, small sticks, and/or wood chips), and pine cones, a small fire was made toward the front of the oven. As the fire caught, more kindling was added to produce a thick smoke, which coated the oven with black soot. The fire was then pushed back into the middle of the oven with a hoe. More wood would be added until there was a good, hot fire. After all of these steps were taken, the food would be prepared for baking. [3]
The beehive oven typically took two to three hours to heat, occasionally even four hours in the winter. Breads were baked first when the beehive oven was hottest, with other baked items such as cinnamon buns, cakes, and pies. As the oven cooled, muffins and "biscuits" could be baked, along with puddings and custards. After a day's baking there was typically sufficient heat to dry apples and other fruits, vegetables, or herbs. Pots of beans were often placed in the back of the oven to cook slowly overnight. [3]
While coal was the premier fuel of the industrial revolution, very few raw coals are suitable for making iron in blast furnaces. However many coals can be converted to coke, a hard and highly carbonaceous mineral foam well suited for fueling blast furnaces, by distilling off the volatile components. [4] In the early 1900's, in the US alone, there were several thousand beehive coke ovens employed in making coke. These were typically about 3.6 metres (12 ft) diameter, paired back to back in long banks, enclosed behind an oven high retaining wall and well covered with earth. Each bank had a railed track down the center for the car used to charge the ovens. Each bank face had a oven door sill level platform for holding and cooling coke, above a RR track for shipping it. [5] For a well preserved and exposed example, see the photographs linked to the 'Redstone Coke Oven Historic District' in Google Maps.
Beehive coke ovens were batch processors. Given a hot oven, the coking cycle begins by adding coal from the top and leveling it to produce an even layer of about 60–90 centimetres (24–35 in) deep. The door is then bricked up and sealed, leaving only a small air vent. As the surface coal heats, it undergoes destructive distillation, evolving combustible gasses and vapors which soon ignite, providing the heat for ongoing distillation. Heating is regulated by limiting the amount of air entering the door's vent. Excess distillate escapes through the top and burns above the oven, producing spectacular nighttime displays. Distillation proceeds from top to bottom. As the coal heats, it softens into a tarry mass permeated with bubbles of evolving distillate, which give the coke its characteristic cellular structure. Most of the fixed carbon is retained in the coke, while some of the volatile gasses are cracked, depositing their carbon in the upper layer of coke, giving the "top ends" their prized metallic luster. Complete distillation is marked by much reduced gas production, at which point the top hole is covered until the coke can be withdrawn. As the coke is still hot enough to ignite on exposure to air, it is cooled in the oven by introducing water concurrently with unbricking the door. As the oven remains much too hot to enter, the coke is broken up and pulled out with long handled scrapers. Ideally the next cycle starts immediately after pulling the previous charge, to make maximum use of the oven's retained heat. [5]
Cycle time varied with the raw coal's chemical and physical character, particularly the percentage of volatiles, and with the initial depth of a charge, the rate that air is introduced, and promptness of pulling the coke and recharging. Typical cycle time was 48 hours for blast furnace coke, up to 72 hours for special purpose cokes. Uniform size and fineness of the raw coal promoted uniform and more rapid coking, so the feed was usually slack screened from shipping stock, supplemented by crushed stock. Sulfur and phosphorus, the primary contaminating elements, are retained in coking, so it was highly desirable that the coal be "washed" before coking. This usually used density based concentration techniques to eliminate the heaver iron pyrites and slate. Since exposure to the atmosphere reduces the tendency of any coal to coke, coke ovens tended to be built adjacent to the screening plants. [4] [5]
In the Thirteen Colonies that later became the United States, most households had a beehive oven. Bread was usually baked in it once a week, [ citation needed ] often in conjunction with pies, crackers, or other baked goods. To heat the oven, the baker would heap coals and kindling inside and wait several hours. Requiring strict regulation, the right amount of wood to ash had to be burned and then tested by sticking one's hands inside. Then one had to add more wood or open the door to let it cool to the right temperature.
Beehive ovens were also used in iron-making. Before this time, iron-making utilized large quantities of charcoal, produced by burning wood. As forests dwindled dangerously, the substitution of coke for charcoal became common in Great Britain, and the coke was manufactured by burning coal in heaps on the ground in such a way that only the outer layer burned, leaving the interior of the pile in a carbonized state. In the late 19th century, brick beehive ovens were developed, which allowed more control over the burning process. [6]
The number of beehive ovens between 1870 and 1905 skyrocketed from about 200 to almost 31,000, which produced nearly 18 million tons of coke in the Pittsburgh area alone. [7] One observer boasted that, loaded into a train, "the year's production would make up a train so long that the engine in front of it would go to San Francisco and come back to Connellsville before the caboose had gotten started out of the Connellsville yards!" The number of beehive ovens in the Pittsburgh seam peaked in 1910 at almost 48,000. [8]
Although they made a top-quality fuel, beehive ovens poisoned the surrounding landscape. After 1900, the serious environmental damage of beehive coking attracted national notice, even though the damage had plagued the district for decades. "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. [9] 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. By night the scene is rendered indescribably vivid by these numerous burning pits. The beehive ovens make the entire region of coke manufacture one of dulled sky, cheerless and unhealthful". [9]
In China, beehive ovens were not banned until 1996, and this ban was not fully effective until 2011. [10]
A forge is a type of hearth used for heating metals, or the workplace (smithy) where such a hearth is located. The forge is used by the smith to heat a piece of metal to a temperature at which it becomes easier to shape by forging, or to the point at which work hardening no longer occurs. The metal is transported to and from the forge using tongs, which are also used to hold the workpiece on the smithy's anvil while the smith works it with a hammer. Sometimes, such as when hardening steel or cooling the work so that it may be handled with bare hands, the workpiece is transported to the slack tub, which rapidly cools the workpiece in a large body of water. However, depending on the metal type, it may require an oil quench or a salt brine instead; many metals require more than plain water hardening. The slack tub also provides water to control the fire in the forge.
Coke is a grey, hard, and porous coal-based fuel with a high carbon content. It is made by heating coal or oil in the absence of air. Coke is an important industrial product, used mainly in iron ore smelting, but also as a fuel in stoves and forges.
Outdoor cooking is the preparation of food in the outdoors. A significant body of techniques and specialized equipment exists for it, traditionally associated with nomad in cultures such as the Berbers of North Africa, the Arab Bedouins, the Plains Indians, pioneers in North America, and indigenous tribes in South America. These methods have been refined in modern times for use during recreational outdoor pursuits, by campers and backpackers.
Coal gas is a flammable gaseous fuel made from coal and supplied to the user via a piped distribution system. It is produced when coal is heated strongly in the absence of air. Town gas is a more general term referring to manufactured gaseous fuels produced for sale to consumers and municipalities.
An oven is a tool which is used to expose materials to a hot environment. Ovens contain a hollow chamber and provide a means of heating the chamber in a controlled way. In use since antiquity, they have been used to accomplish a wide variety of tasks requiring controlled heating. Because they are used for a variety of purposes, there are many different types of ovens. These types differ depending on their intended purpose and based upon how they generate heat.
A stove or range is a device that generates heat inside or on top of the device, for local heating or cooking. Stoves can be powered with many fuels, such as electricity, natural gas, gasoline, wood, and coal.
Dry distillation is the heating of solid materials to produce gaseous products. The method may involve pyrolysis or thermolysis, or it may not.
Destructive distillation is a chemical process in which decomposition of unprocessed material is achieved by heating it to a high temperature; the term generally applies to processing of organic material in the absence of air or in the presence of limited amounts of oxygen or other reagents, catalysts, or solvents, such as steam or phenols. It is an application of pyrolysis. The process breaks up or 'cracks' large molecules. Coke, coal gas, gaseous carbon, coal tar, ammonia liquor, and coal oil are examples of commercial products historically produced by the destructive distillation of coal.
Pocahontas Coalfield, which is also known as the Flat Top-Pocahontas Coalfield, is located in Mercer County/McDowell County, West Virginia and Tazewell County, Virginia. The earliest mining of coal in the coalfield was in Pocahontas, Virginia in 1883 at Pocahontas Mine No. 1, now on the National Register of Historic Places.
A delayed coker is a type of coker whose process consists of heating a residual oil feed to its thermal cracking temperature in a furnace with multiple parallel passes. This cracks the heavy, long chain hydrocarbon molecules of the residual oil into coker gas oil and petroleum coke.
A fireplace insert is a device that can be inserted into an existing masonry or prefabricated wood fireplace. Fireplace inserts are invariably made from cast iron or steel. Typically, fresh air enters through vents below, circulates around the main chamber, where it is heated up, then exits through the chimney. They have insulated glass doors that allow the fire to be viewed while closed, improving fuel efficiency and heat output. Air is directed across the interior surface of the glass to prevent the buildup of ash.
A cupola or cupola furnace is a melting device used in foundries that can be used to melt cast iron, Ni-resist iron and some bronzes. The cupola can be made almost any practical size. The size of a cupola is expressed in diameters and can range from 1.5 to 13 feet. The overall shape is cylindrical and the equipment is arranged vertically, usually supported by four legs. The overall look is similar to a large smokestack.
The history of gaseous fuel, important for lighting, heating, and cooking purposes throughout most of the 19th century and the first half of the 20th century, began with the development of analytical and pneumatic chemistry in the 18th century. These "synthetic fuel gases" were made by gasification of combustible materials, usually coal, but also wood and oil, by heating them in enclosed ovens with an oxygen-poor atmosphere. The fuel gases generated were mixtures of many chemical substances, including hydrogen, methane, carbon monoxide and ethylene. Coal gas also contains significant quantities of unwanted sulfur and ammonia compounds, as well as heavy hydrocarbons, and must be purified before use.
The Pittsburgh coal seam is the thickest and most extensive coal bed in the Appalachian Basin; hence, it is the most economically important coal bed in the eastern United States. The Upper Pennsylvanian Pittsburgh coal bed of the Monongahela Group is extensive and continuous, extending over 11,000 mi2 through 53 counties. It extends from Allegany County, Maryland to Belmont County, Ohio and from Allegheny County, Pennsylvania southwest to Putnam County, West Virginia.
The Dunlap coke ovens are the remnants of a coke production facility near Dunlap, in the U.S. state of Tennessee. Built in the early 1900s, the facility consists of five batteries of 268 beehive ovens, which operated under various companies until the early 1920s. The ovens are now listed on the National Register of Historic Places, and are maintained by the Sequatchie Valley Historical Society as part of Dunlap Coke Ovens Park.
Visakhapatnam Steel Plant is the integrated steel plants of Rashtriya Ispat Nigam Limited in Visakhapatnam. Founded in 1982, the plant focuses on producing value-added steel, producing 5.773 million tonnes of hot metal, 5.272 million tonnes of crude steel and 5.138 million tonnes of saleable steel in the 2021-2022 financial year. According to the India Daily Times, the plant is expected to skyrocket in terms of production in the nearest future.
The Cherry Valley Coke Ovens consisted of 200 coke ovens built by the Leetonia Iron and Coal Company around 1866, near Leetonia, Ohio, United States. The function of the "beehive" coke ovens was to purify coal and turn it into coke. The coke was burned in furnaces that produced iron and steel.
Klondyke Coke Ovens are heritage-listed beehive ovens at Parker Lane, Brassall, City of Ipswich, Queensland, Australia.It is also known as Klondyke Beehive Coke Ovens and Klondyke Coking Ovens. It was added to the Queensland Heritage Register on 3 December 2007.
The primitive clay oven, or earthen oven / cob oven, has been used since ancient times by diverse cultures and societies, primarily for, but not exclusive to, baking before the invention of cast-iron stoves, and gas and electric ovens. The general build and shape of clay ovens were, mostly, common to all peoples, with only slight variations in size and in materials used to construct the oven. In primitive courtyards and farmhouses, earthen ovens were built on the ground.
A coking factory or a coking plant is where coke and manufactured gas are synthesized from coal using a dry distillation process. The volatile components of the pyrolyzed coal, released by heating to a temperature of between 900°C and 1,400 °C, are generally drawn off and recovered. There are also coking plants where the released components are burned: this is known as a heat recovery process. A layer of ash then forms on the surface of the resulting coke. The degassing of the coal gives the coke a highly sought-after porosity. The gases are broken down by fractional condensation into hydrocarbon tars, sulfuric acid, ammonia, naphthalene, benzol, and coke gas; these products are then purified in further chemical reactors. Germany still has five coking plants in operation to meet the needs of its domestic industry.