Lime kiln

A lime kiln is a kiln used for the calcination of limestone (calcium carbonate) to produce the form of lime called quicklime (calcium oxide). The chemical equation for this reaction is

CaCO3 + heat → CaO + CO2

This reaction takes place at 900 °C (1650 °F; at which temperature the partial pressure of CO2 is 1 atmosphere), but a temperature around 1000 °C (1800 °F; at which temperature the partial pressure of CO2 is 3.8 atmospheres[1]) is usually used to make the reaction proceed quickly.[2] Excessive temperature is avoided because it produces unreactive, "dead-burned" lime.

Slaked lime (calcium hydroxide) can be formed by mixing water with quicklime.

Lime plant, Wyoming
Rotary lime kiln (rust-colored horizontal tube at right) with preheater, Wyoming, 2010
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Traditional lime kiln in Sri Lanka

Early lime use

Because it is so readily made by heating limestone, lime must have been known from the earliest times, and all the early civilizations used it in building mortars and as a stabilizer in mud renders and floors.[3] Knowledge of its value in agriculture is also ancient, but agricultural use only became widely possible when the use of coal made it cheap[4] in the coalfields in the late 13th century, and an account of agricultural use was given in 1523.[5] The earliest descriptions of lime kilns differ little from those used for small-scale manufacture a century ago. Because land transportation of minerals like limestone and coal was difficult in the pre-industrial era, they were distributed by sea, and lime was most often manufactured at small coastal ports. Many preserved kilns are still to be seen on quaysides around the coasts of Britain.

Types of kiln

Permanent lime kilns fall into two broad categories: "flare kilns" also known as "intermittent" or "periodic" kilns; and "draw kilns" also known as "perpetual" or "running" kilns. In a flare kiln, a bottom layer of coal was built up and the kiln above filled solely with chalk. The fire was alight for several days, and then the entire kiln was emptied of the lime.

In a draw kiln, usually a stone structure, the chalk or limestone was layered with wood, coal or coke and lit. As it burnt through, lime was extracted from the bottom of the kiln, through the draw hole. Further layers of stone and fuel were added to the top.[6][7]

Early kilns

LDLimeLimekilnOld
Cross section of typical early kiln

The common feature of early kilns was an egg-cup shaped burning chamber, with an air inlet at the base (the "eye"), constructed of brick. Limestone was crushed (often by hand) to fairly uniform 20–60 mm (1–2 12 in) lumps – fine stone was rejected. Successive dome-shaped layers of limestone and wood or coal were built up in the kiln on grate bars across the eye. When loading was complete, the kiln was kindled at the bottom, and the fire gradually spread upwards through the charge. When burnt through, the lime was cooled and raked out through the base. Fine ash dropped out and was rejected with the "riddlings".

Only lump stone could be used, because the charge needed to "breathe" during firing. This also limited the size of kilns and explains why kilns were all much the same size. Above a certain diameter, the half-burned charge would be likely to collapse under its own weight, extinguishing the fire. So kilns always made 25–30 tonnes of lime in a batch. Typically the kiln took a day to load, three days to fire, two days to cool and a day to unload, so a one-week turnaround was normal. The degree of burning was controlled by trial and error from batch to batch by varying the amount of fuel used. Because there were large temperature differences between the center of the charge and the material close to the wall, a mixture of underburned (i.e. high loss on ignition), well-burned and dead-burned lime was normally produced. Typical fuel efficiency was low, with 0.5 tonnes or more of coal being used per tonne of finished lime (15 MJ/kg).

Lime production was sometimes carried out on an industrial scale. One example at Annery in North Devon, England, near Great Torrington, was made up of three kilns grouped together in an 'L' shape and was situated beside the Torrington canal and the River Torridge to bring in the limestone and coal, and to transport away the calcined lime in the days before properly metalled roads existed.[8]

Sets of seven kilns were common. A loading gang and an unloading gang would work the kilns in rotation through the week.

A rarely used kiln was known as a "lazy kiln".[9]

Great Britain

The large kiln at Crindledykes near Haydon Bridge, Northumbria, was one of more than 300 in the county. It was unique to the area in having four draw arches to a single pot. As production was cut back, the two side arches were blocked up, but were restored in 1989 by English Heritage.

The development of the national rail network made the local small-scale kilns increasingly unprofitable, and they gradually died out through the 19th century. They were replaced by larger industrial plants. At the same time, new uses for lime in the chemical, steel and sugar industries led to large-scale plants. These also saw the development of more efficient kilns.

A lime kiln erected at Dudley, West Midlands (formerly Worcestershire) in 1842 survives to this day as part of the Black Country Living Museum which opened in 1976; although, the kilns were last used during the 1920s. It is now among the last still existing in a region which was dominated by coalmining and limestone mining for generations until the 1960s.[10]

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19th century limekilns at Froghall.

Lime Kiln 1

A preserved lime kiln in Burgess Park, London.

Forrabury and Minster - old lime kiln, Boscastle - geograph.org.uk - 842707

Old lime kiln, Boscastle, Cornwall.

Broadstone limekiln stonework detail

A large limekiln at Broadstone, Beith, Ayrshire.

Annery Kiln, Weare Gifford 1

The Annery kiln in Devon, England.

Limekiln Crindledykes 1992

Large 19th-century single limekiln at Crindledykes near Housesteads Northumbria.

Dumbarton castle and lime kiln

Dumbarton castle in 1800 and functioning lime kiln with smoke in the foreground.[11]

Australia

In the late 19th and early 20th centuries the town of Waratah in Gippsland, Victoria, Australia produced a majority of the quicklime used in the city of Melbourne as well as around other parts of Gippsland. The town, now called Walkerville, was set on an isolated part of the Victorian coastline and exported the lime by ship. When this became unprofitable in 1926 the kilns were shut down. The present-day area, though having no town amenities as such, markets itself as a tourist destination. The ruins of the lime kilns can still be seen today.

Limestone kiln ruins at Walkerville, Victoria, Australia

Limestone kiln ruin at Walkerville, Victoria, Australia

Limestone kiln ruins viewed from Limeburners track at Walkerville, Victoria, Australia

Limestone kiln ruin as seen from bushwalking track, Walkerville, Victoria, Australia

A lime kiln also existed in Wool Bay, South Australia.

Wool Bay lime Kiln

Other countries

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Old lime kilns, Antoing, Belgium

Modern kilns

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Cross section of simple shaft kiln

Shaft kilns

The theoretical heat (the standard enthalpy) of reaction required to make high-calcium lime is around 3.15 MJ per kg of lime, so the batch kilns were only around 20% efficient. The key to development in efficiency was the invention of continuous kilns, avoiding the wasteful heat-up and cool-down cycles of the batch kilns. The first were simple shaft kilns, similar in construction to blast furnaces. These are counter-current shaft kilns. Modern variants include regenerative and annular kilns. Output is usually in the range 100–500 tonnes per day.

Counter-current shaft kilns

The fuel is injected part-way up the shaft, producing maximum temperature at this point. The fresh feed fed in at the top is first dried then heated to 800 °C, where de-carbonation begins, and proceeds progressively faster as the temperature rises. Below the burner, the hot lime transfers heat to, and is cooled by, the combustion air. A mechanical grate withdraws the lime at the bottom. A fan draws the gases through the kiln, and the level in the kiln is kept constant by adding feed through an airlock. As with batch kilns, only large, graded stone can be used, in order to ensure uniform gas-flows through the charge. The degree of burning can be adjusted by changing the rate of withdrawal of lime. Heat consumption as low as 4 MJ/kg is possible, but 4.5 to 5 MJ/kg is more typical. Due to temperature peak at the burners up to 1200 °C in a shaft kiln conditions are ideal to produce medium and hard burned lime.

LDLimeShaftKilnRegen
Gas flows in two cycles of operation of regenerative shaft kilns

Regenerative kilns

These typically consist of a pair of shafts, operated alternately. First, when shaft A is the "primary" and B the "secondary" shaft, the combustion air is added from the top of shaft A, while fuel somewhat below via burner lances. The flame is top-bottom. The hot gases pass downward, cross to shaft B via the so-called "channel" and pass upward to exhaust of shaft B. At same time in both shafts cooling air is added from the bottom to cool the lime and to make exhaust of gases via the bottom of the kiln impossible via maintaining always a positive pressure. The combustion air and cooling air leave the kiln jointly via exhaust on top of shaft B, preheating the stone. The direction of flow is reversed periodically (typically 5–10 times per hour) shaft A and B changing the role of "primary" and "secondary" shaft. The kiln has three zones: preheating zone on the top, burning zone in the middle, and cooling zone close to the bottom. The cycling produces a long burning zone of constant, relatively low temperature (around 950 °C) that is ideal for the production of high quality soft burned reactive lime. With exhaust gas temperatures as low as 120 °C and lime temperature at kiln outlet in 80 °C range the heat loss of the regenerative kiln is minimal, fuel consumption is as low as 3.6 MJ/kg. Due to these features the regenerative kilns are today mainstream technology under conditions of substantial fuel costs. Regenerative kilns are built with 150 to 800 t/day output, 300 to 450 being typical.

LDLimeShaftKilnAnnul
Gas flows in an annular shaft kiln

Annular kilns

These contain a concentric internal cylinder. This gathers pre-heated air from the cooling zone, which is then used to pressurize the middle annular zone of the kiln. Air spreading outward from the pressurized zone causes counter-current flow upwards, and co-current flow downwards. This again produces a long, relatively cool calcining zone. Fuel consumption is in 4 to 4.5 MJ/kg range and the lime is typically medium burned.

LDLimeRotaryPH
Rotary kiln with preheater: hot gas flows

Rotary kilns

Rotary kilns started to be used for lime manufacture at the start of the 20th century and now account for a large proportion of new installations if energy costs are less important. The early use of simple rotary kilns had the advantages that a much wider range of limestone size could be used, from fines upwards, and undesirable elements such as sulfur can be removed. On the other hand, fuel consumption was relatively high because of poor heat exchange compared with shaft kilns, leading to excessive heat loss in exhaust gases. Old fashioned "long" rotary kilns operate at 7 to 10 MJ/kg. Modern installations partially overcome this disadvantage by adding a preheater, which has the same good solids/gas contact as a shaft kiln, but fuel consumption is still somewhat higher, typically in range of 4.5 to 6 MJ/kg. In the design shown, a circle of shafts (typically 8–15) is arranged around the kiln riser duct. Hot limestone is discharged from the shafts in sequence, by the action of a hydraulic "pusher plate". Kilns of 1000 tonnes per day output are typical. The rotary kiln is the most flexible of any lime kilns able to produce soft, medium, or hard burned as well as dead-burned lime or dolime.

Gas cleaning

All the above kiln designs produce exhaust gas that carries an appreciable amount of dust. Lime dust is particularly corrosive. Equipment is installed to trap this dust, typically in the form of electrostatic precipitators or bag filters. The dust usually contains a high concentration of elements such as alkali metals, halogens and sulfur.

Carbon dioxide emissions

The lime industry is a significant carbon dioxide emitter. The manufacture of one tonne of calcium oxide involves decomposing calcium carbonate, with the formation of 785 kg of CO2 in some applications, such as when used as mortar; this CO2 is later re-absorbed as the mortar goes off.

If the heat supplied to form the lime (3.75 MJ/kg in an efficient kiln) is obtained by burning fossil fuel it will release CO2: in the case of coal fuel 295 kg/t; in the case of natural gas fuel 206 kg/t. The electric power consumption of an efficient plant is around 20 kWh per tonne of lime. This additional input is the equivalent of around 20 kg CO2 per ton if the electricity is coal-generated. Thus, total emission may be around 1 tonne of CO2 for every tonne of lime even in efficient industrial plants, but is typically 1.3 t/t.[12] However, if the source of heat energy used in its manufacture is a fully renewable power source, such as solar, wind, hydro or even nuclear; there may be no net emission of CO2 from the calcination process. Less energy is required in production per weight than portland cement, primarily because a lower temperature is required.

See also

References

  1. ^ CRC Handbook of Chemistry and Physics, 54th Ed, p F-76
  2. ^ Parkes, G.D. and Mellor, J.W. (1939). Mellor's Modern Inorganic Chemistry London: Longmans, Green and Co.
  3. ^ Hewlett, P. C. (Ed.) (1998). Lea's Chemistry of Cement and Concrete: 4th Ed, Arnold, ISBN 0-340-56589-6, Chapter 1
  4. ^ Platt, Colin (1978). Medieval England, BCA, ISBN 0-7100-8815-9, pp. 116–7
  5. ^ Sir Anthony Fitzherbert, Boke of Husbandrye, 1523
  6. ^ Smith, Nicky (May 2011). "Pre-industrial Lime Kilns" (PDF). Introductions to Heritage Assets. English Heritage. Retrieved 21 April 2013.
  7. ^ Siddall, Ruth. "Kiln Architecture and Technology". Materials Science. University College, London. Retrieved 21 April 2013.
  8. ^ Griffith, R. S. Ll. (1971). Annery Kiln, Weare Gifford. Grenville College project. Supervisor Mr. B. D. Hughes.
  9. ^ Hood, James (1928). Kilmarnock Water and Craufurdland Kilm Glenf Ramb Soc. Annals. 1919 – 1930. P. 126.
  10. ^ "The Limekilns - Black Country Living Museum". www.bclm.co.uk. Retrieved 6 April 2018.
  11. ^ Stoddart, John (1800), Remarks on Local Scenery and Manners in Scotland. Pub. Wiliam Miller, London. Facing p. 212.
  12. ^ EU Emissions Trading Scheme Archived 11 December 2009 at the Wayback Machine National Archives Gov UK

External links

Wainmans Double Arched Lime Kiln – Made Grade II Listed Building – 1 February 2005

Details & Image: http://cowlingweb.co.uk/local_history/history/wainmanslimekiln.asp

Alderford Common

Alderford Common is a 17.5-hectare (43-acre) biological Site of Special Scientific Interest north-west of Norwich in Norfolk.The common has a thin layer of glacial sands and gravels over chalk. Habitats include bracken heath, scrub, woodland and ponds, together with species rich grassland in former chalk quarries. An old lime kiln is used by bats and a wide variety of birds breed on the site.There is access to the site from Reepham Road, which passes through it.

Birdsall Lime Kiln

Birdsall Lime Kiln is a historic structure located northeast of Decorah, Iowa, United States. Built in 1877, the kiln is 24 feet (7 m) high, and composed of irregularly-cut undressed limestone and exterior wood bracing. Its inside walls are lined with locally produced firebrick. The lime was produced from abundant native limestone. It was used in mortar for masonry construction, and by the Winneshiek Paper Company of Freeport, Iowa in its paper-making processes. The structure was listed on the National Register of Historic Places in 1979.

Griggsville Landing, Illinois

Griggsville Landing, also known as Phillips Landing or Phillips Ferry, was located in Flint Township, just south of Valley City, Illinois. It is a former town site on the Illinois River in Pike County. The town was a steamboat stop which began sometime in the 1830s. There was a lime kiln there that was part of a commercial lime operation prior to post-Civil War industrial intensification in the lime industry. The town at Griggsville Landing was home to a boat yard, a grist mill and a hotel in addition to the Griggsville Landing Lime Kiln, built around 1850, which is still standing as of 2007. The town was eventually abandoned, rendering it a ghost town. Griggsville Landing is adjacent to the Ray Norbut State Fish and Wildlife Area.

Griggsville Landing Lime Kiln

The Griggsville Landing Lime Kiln is located near village of Valley City, Illinois in Pike County. The periodic lime kiln is listed on the National Register of Historic Places, a designation it gained in August 1999. It is actually within the boundaries of the Ray Norbut State Fish and Wildlife Area. The kiln represents an example of an 1850s lime kiln, one of the best-preserved examples of such a kiln. In its heyday the kiln's raw product would have been quicklime. The kiln is one of twelve Pike County sites included in the National Register of Historic Places. Some other examples are the Lyman Scott House, in Summer Hill and the New Philadelphia Town Site, somewhere near Barry, Illinois.

Grove Lime Kiln

Grove Lime Kiln is a disused 19th century lime kiln on the Isle of Portland, Dorset, England. It is located close to HM Prison Portland and The Grove village. Owned by the prison service, the lime kiln has been Grade II Listed since 2009.The Grove Lime kiln is one of a few remaining lime kilns on the island. A 19th-century lime kiln at Easton Lane, now a residence, is another Grade Listed II example. Another kiln is found opposite, while at New Ground, another well-preserved example exists, but is hidden by undergrowth. Finally at Avalanche Road, within the Southwell village, remains another surviving kiln.

Lime (material)

Lime is a calcium-containing inorganic mineral composed primarily of oxides, and hydroxide, usually calcium oxide and/ or calcium hydroxide. It is also the name for calcium oxide which occurs as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta. The word lime originates with its earliest use as building mortar and has the sense of sticking or adhering.These materials are still used in large quantities as building and engineering materials (including limestone products, cement, concrete, and mortar), as chemical feedstocks, and for sugar refining, among other uses. Lime industries and the use of many of the resulting products date from prehistoric times in both the Old World and the New World. Lime is used extensively for wastewater treatment with ferrous sulfate.

The rocks and minerals from which these materials are derived, typically limestone or chalk, are composed primarily of calcium carbonate. They may be cut, crushed, or pulverized and chemically altered. Burning (calcination) of these minerals in a lime kiln converts them into the highly caustic material burnt lime, unslaked lime or quicklime (calcium oxide) and, through subsequent addition of water, into the less caustic (but still strongly alkaline) slaked lime or hydrated lime (calcium hydroxide, Ca(OH)2), the process of which is called slaking of lime.

When the term is encountered in an agricultural context, it usually refers to agricultural lime, which is crushed limestone, not a product of a lime kiln. Otherwise it most commonly means slaked lime, as the more dangerous form is usually described more specifically as quicklime or burnt lime.

Lime Kiln Creek

For the creek in England, see Lime Kiln Creek, Kingston upon HullLime Kiln Creek is a stream within Tulare County in central California. An alternative name for this creek is Dry Creek.

Lime Kiln Field Day

Lime Kiln Field Day (also known as Lime Kiln Club Field Day or Bert Williams: Lime Kiln Field Day) is a 1913 American black-and-white silent film produced by the Biograph Company and Klaw and Erlanger. This is believed to be the oldest surviving film to feature African American actors.

Lime Kiln Halt railway station

Lime Kiln Halt is the only intermediate railway station on the narrow gauge Groudle Glen Railway in the Isle of Man; it also serves as the line's temporary terminus on certain occasions. It is situated at the midpoint of the short line, above the nearby beach and car park.

Lime Kiln Light

The Lime Kiln Light is a functioning navigational aid located on Lime Kiln Point overlooking Dead Man's Bay on the western side of San Juan Island, San Juan County, Washington, in the United States. It guides ships through the Haro Straits and is part of Lime Kiln Point State Park, which offers tours during summer months.

Lime Kiln Mountain

Lime Kiln Mountain is a long ridge in Taney County in the Ozarks of southern Missouri. The ridge reaches an elevation of 1,330 feet (410 m) at 36°36′13″N 92°53′22″W. US Route 160 traverses the ridgeline from Rueter in the southeast to Hilda in the northwest for a distance of approximately 7.5 mi (12.1 km). Cane Creek runs roughly parallel to the ridge along the northeast.Lime Kiln Mountain was named for a lime kiln which was active in the 19th century.

Lime Kiln Point State Park

Lime Kiln Point State Park is a 42-acre Washington state park on the western shore of San Juan Island in the San Juan archipelago. The park is considered one of the best places in the world to view wild orcas from a land-based facility. Due to the unique bathymetric properties of the site, visitors on the shore can be within 20 feet of whales jumping out of the water (breaching and spyhopping). The park was the site of lime kilns beginning in 1860, and one kiln has been restored as a public exhibit.

Lime Kiln Valley AVA

The Lime Kiln Valley AVA is an American Viticultural Area located in the larger Cienega Valley AVA in San Benito County, California. This appellation spans 2,300 acres (931 ha) and was granted AVA status in 1982. The soil in the region is composed of foundations of limestone and dolomite with sandy, gravelly loam above. The area has a wide diurnal temperature variation of up to 50 °F (28 °C), with daytime temperatures in 85 °F (29 °C) to 95 °F (35 °C) range during the summer growing seasons. The AVA is home to old vine Mourvedre plantings.

Little Blakenham Pit

Little Blakenham Pit is a 3.4 hectare biological Site of Special Scientific Interest in Little Blakenham in Suffolk.A 127 metre long tunnel from one of these chalk pits is used by hibernating bats, and it is one of the largest underground roosts known in Britain. Around 450 bats use the tunnel, mainly Daubenton's. Bats also share a lime kiln with a badger sett. The site also has chalk grassland.The site is private land with no public access.

Meybod Lime Kiln Company

Meybod Lime Kiln Company (Persian: شركت توليدي كوره اهك ميبد‎ – Sherkat-e Towlīdī Kūreh Āhak-e Meybod) is a village and company town in Bafruiyeh Rural District, in the Central District of Meybod County, Yazd Province, Iran. At the 2006 census, its population was 37, in 7 families.

National Register of Historic Places listings in Clark County, Indiana

This is a list of the National Register of Historic Places listings in Clark County, Indiana.

This is intended to be a complete list of the properties and districts on the National Register of Historic Places in Clark County, Indiana, United States. Latitude and longitude coordinates are provided for many National Register properties and districts; these locations may be seen together in a Google map.There are 19 properties and districts listed on the National Register in the county. Another property was once listed but has been removed.

Properties and districts located in incorporated areas display the name of the municipality, while properties and districts in unincorporated areas display the name of their civil township. Properties and districts split between multiple jurisdictions display the names of all jurisdictions.

This National Park Service list is complete through NPS recent listings posted October 11, 2019.

Sing Lei Hap Gei Lime Kiln Factory

The Sing Lei Hap Gei Lime Kiln Factory is an abandoned lime production facility on the island of Peng Chau in Hong Kong.

Wellington Caves

The Wellington Caves are a group of limestone caves located 8 kilometres (5.0 mi) south of Wellington, New South Wales, Australia.

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