Beehive furnace
A beehive furnace is a closed furnace that is used to produce coke . The furnace was developed in England in the middle of the 18th century, making it one of the oldest types of furnace that was used for coke production. The furnace was given the name beehive furnace because of the similarity of the first models with the shape of a beehive .
construction
The furnace was completely made of bricks and had a circular coking chamber that was arched at the top and closed. The sole of the stove was inclined slightly forward. Later there were also ovens with an oval or square floor plan. The entire walls around the stove were surrounded by an air duct, which meant that the coals to be coked were also heated from the vault. In the middle of the furnace dome there was a breakthrough called the charging opening, which was used to fill the coking chamber. This charging opening remained closed during operation. A door was attached to the front of the furnace through which the finished coke could be drawn out of the furnace. This door was made of iron, but there were also stoves in which this opening did not have an iron door. Another side opening was used to discharge the smoke gases. This opening was connected to a chimney through which the smoke gases were specifically discharged into the atmosphere, so that these could not escape into the open without being directed. Several ovens were connected to one forge. To regulate the air supply, the stove had additional control openings, which were attached around the arch of the door. Beehive ovens had a capacity of two to four tons of hard coal , depending on their size . The ovens were combined into coke oven batteries of eight or more ovens. A mobile coal wagon running on rails was used to fill the furnaces with coal. The furnaces were filled through the charging opening with the aid of a slide on the underside of the car.
business
The furnace was filled with coal through the charging opening. The coal piled up in the furnace was pulled flat with a rake, then the filling opening was closed. During the first coking process, the coal to be coked was ignited with wood or glowing coals. In ovens that had been in operation for a long time, the oven walls were so hot that the coals ignited themselves. After about an hour pale, bluish smoke rose from the openings. You could tell that the stove came on fire from a small explosion. The coal remained on fire for about five hours after it was ignited. The oven door was then closed airtight so that fresh air could only enter the top of the oven. The joints were smeared with a mortar made from sharp-edged sand and sealed. In the case of ovens without a door, the opening was bricked up. After about 48 to 72 hours, the coke was completely baked and could be taken out of the oven. For this purpose, the red-hot coke mass was cooled by injecting water after opening the door. The still hot coke was pulled out of the oven with iron forks and picks.
Raw materials and products
Beehive ovens were the first coke ovens that could also be charged with fine coal. These fine coals, known as fat grist or pits, that are produced when the coal is mined , were previously considered waste and remained underground. By operating the beehive ovens, these coals could still be used advantageously. However, only excellent coals could be used. The heating during coking caused the fine coal particles to bake together to form coke. The coke produced with beehive ovens had a metallic sheen and was preferred by the iron and steel industry. However, the top layer of coke on each furnace filling was spongy and unusable. For this reason, it was recommended that this coke be burned again in the beehive furnace; this enabled the heat required for the coking process to be generated. The by-products produced were not initially obtained. It was not until many years later that the additional substances contained in the coking coal were recovered during the coking process.
Problems
When operating the beehive ovens, there were major problems for the people working in the vicinity of the ovens and a heavy burden on the environment . Since the coals were initially burning during the coking process, a black smoke was created. This smoke and the other vapors released into the open air during the coking process made the surrounding area smoky. After some time, the workers working on the coke ovens developed diseases such as bronchial catarrh. The extreme difference in temperature could also cause rheumatic diseases and by flying coal dust one could with the workers black lung disease develop. In addition, the workers often suffered from eye infections. The tar drained from the ovens contaminated the floors. When the coke was extinguished, hydrogen sulfide was produced , which polluted the environment and endangered workers.
Modifications
Over the years there have been various improvements and further developments to the beehive furnace. The engineers paid particular attention to the extraction of the by-products, in particular the tar and the hydrocarbons produced during coking were to be extracted. Towards the end of the 19th century, beehive furnaces were built in England, with which one could also extract the by-products. In order to better extract the by-products, the company Dr. C. Otto & Comp. the beehive ovens of the mining company Hibernia and Shamrock with air heaters. The combustion products were directed through sole channels embedded in the furnace sole. On July 29, 1880, a patent was granted for a beehive furnace in which the exhaust gases were cooled with water.
Individual evidence
- ↑ a b c Gustav Adolf Wüstenfeld: On the trail of coal mining. Gustav Adolf Wüstenfeld-Verlag, Wetter-Wengern 1985, ISBN 3-922014-04-6 .
- ↑ a b c d e f g h Tobias Nolteklacke: Development of the coking industry in West Germany up to the end of the First World War. Bachelor thesis, ISBN 978-3-640-13996-5 .
- ↑ a b c d e f The book of inventions trade and industry. Fifth volume mining and metallurgy, publishing and printing by Otto Spamer, Leipzig 1899.
- ↑ a b c F. Schreiber: Development and current status of the coking industry in Lower Silesia. Julius Springer's publishing bookstore, Berlin 1911.
- ↑ a b c d e f Ferdinand Fischer: The chemical technology of fuels. Printed and published by Friedrich Vieweg and Son, Braunschweig 1901.
- ^ A b c Rudolf von Wagner: Handbook of chemical technology. Eleventh edition, published by Otto Wigand, Leipzig 1880.
- ^ Ferdinand Fischer: Annual report on the achievements of chemical technology with special consideration of electrochemistry and industrial studies for the year 1896. Otto Wigand publishing house, Leipzig 1897.
- ^ A b Karl Otto Henseling: Origins of the industrial metabolism between man and nature. Newly designed edition, Institute for Ecological Economic Research (IÖW) (Ed.), Berlin 2009, ISBN 978-3-932092-90-9 .
- ^ HE Armstrong: Comments on the methods followed in coking coals and on the extraction of volatile substances . In: G. Krause. (Ed.): Chemiker-Zeitung No. 50, Cöthen June 1885, p. 893.
- ↑ Ernst Friedrich Dürre: The newer Cokes ovens. Baumgärtner's bookstore, Leipzig 1892.