Briquettes, Peat and peat briquettes

What is peat?

Peat, sometimes known as turf, is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs.The peatland ecosystem covers 3.7 million square kilometres (1.4 million square miles)] and is the most efficient carbon sink on the planet, because peatland plants capture CO2 naturally released from the peat, maintaining an equilibrium. In natural peatlands, the “annual rate of biomass production is greater than the rate of decomposition”, but it takes “thousands of years for peatlands to develop the deposits of 1.5 to 2.3 m [4.9 to 7.5 ft], which is the average depth of the boreal [northern] peatlands”,[ which store around 415 gigatonnes (457 billion short tons; 408 billion long tons) of carbon (about 46 times 2019 global CO2 emissions). Globally, it even stores up to 550 gigatonnes (610 billion short tons; 540 billion long tons) of carbon, representing 42% of all soil carbon and exceeds the carbon stored in all other vegetation types, including the world’s forests.[Across the world, peat covers just 3% of the land’s surface, but stores one-third of the Earth’s soil carbon. Sphagnum moss, also called peat moss, is one of the most common components in peat, although many other plants can contribute. The biological features of sphagnum mosses act to create a habitat aiding peat formation, a phenomenon termed ‘habitat manipulation’. Soils consisting primarily of peat are known as histosols. Peat forms in wetland conditions, where flooding or stagnant water obstructs the flow of oxygen from the atmosphere, slowing the rate of decomposition.

Peatlands, particularly bogs, are the primary source of peat; although less-common wetlands including fens, pocosins, and peat swamp forests also deposit peat. Landscapes covered in peat are home to specific kinds of plants including Sphagnum moss, ericaceous shrubs, and sedges. Because organic matter accumulates over thousands of years, peat deposits provide records of past vegetation and climate by preserving plant remains, such as pollen. This allows the reconstruction of past environments and the study of changes in land use.

Peat is harvested as a source of fuel in certain parts of the world. By volume, there are about 4 trillion cubic metres (5.2 trillion cubic yards) of peat in the world, covering a total of around 2% of the global land area. Over time, the formation of peat is often the first step in the geological formation of fossil fuels such as coal, particularly low-grade coal such as lignite.

The Intergovernmental Panel on Climate Change (IPCC) classifies peat as neither a fossil fuel nor a renewable fuel, and notes that its emission characteristics are similar to fossil fuels.At 106 g CO2/MJ, the carbon dioxide emission intensity of peat is higher than that of coal (at 94.6 g CO2/MJ) and natural gas (at 56.1) (IPCC). Peat is not a renewable source of energy, due to its extraction rate in industrialized countries far exceeding its slow regrowth rate of 1 mm (0.04 in) per year, and as it is also reported that peat regrowth takes place only in 30–40% of peatlands.

Peat/Turf Briquettes.

In Ireland, peat briquettes are a common type of solid fuel, largely replacing sods of raw peat as a domestic fuel. These briquettes consist of shredded peat, compressed to form a virtually smokeless, slow-burning, easily stored and transported fuel. Although often used as the sole fuel for a fire, they are also used to quickly and easily light a coal fire. peat fuel in the form of peat briquettes which are used for domestic heating. These are oblong bars of densely compressed, dried, and shredded peat. Peat moss is a manufactured product for use in garden cultivation. Turf (dried out peat sods) is also commonly used in rural areas.

A briquette (French: [bʁikɛt]; also spelled briquet) is a compressed block of coal dust[1] or other combustible biomass material (e.g. charcoalsawdustwood chips,[2] peat, or paper) used for fuel and kindling to start a fire. The term derives from the French word brique, meaning brick.

Coal briquettes.

Coal briquettes have long been produced as a means of using up ‘small coal’, the finely broken coal inevitably produced during the mining process. Otherwise this is difficult to burn as it is hard to arrange adequate airflow through a fire of these small pieces; also such fuel tends to be drawn up and out of the chimney by the draught, giving visible black smoke.

The first briquettes were known as culm bombs and were hand-moulded with a little wet clay as a binder. These could be difficult to burn efficiently, as the unburned clay produced a large ash content, blocking airflow through a grate.

With Victorian developments in engineering, particularly the hydraulic press, it became possible to produce machine-made briquettes with minimal binder content. A tar or pitch binder was used, obtained first from gas making and later from petrochemical sources. These binders burned away completely, making it a low-ash fuel. A proprietary brand of briquettes from the South Wales coalfield was Phurnacite, developed by Idris Jones for Powell Duffryn.[3][4] These were intended to emulate a high-quality anthracite coal, such as that from the Cynheidre measures. This involved blending a mixture of coals from different grades and colliery sources.

East-Asian briquettes

Homemade charcoal briquettes (called tadon ) were found after charcoal production in Japanese history. In the Edo period, a polysaccharide extracted from red algae was widely used as a binder. After the imports of steam engines in the Meiji period, coal and clay became major ingredients of Japanese briquettes. These briquettes, rentan and maintain, were exported to China and Korea. Today, coal briquettes are avoided for their sulfur oxide emission. Charcoal briquettes are still used for traditional or outdoor cooking. Woody flakes such as sawdust or coffee dust are major ingredients of modern mass-consumed briquettes 

  • Bituminous coal, 25%
  • Steam coal, 45%
  • Dry steam coal, 22%
  • Pitch, 8%

Early briquettes were large and brick-shaped. They could be stacked, or even built into walls. The Antarctic expeditions of both Shackleton and Scott took large quantities of these briquettes with them and used them to build pony stables. As the ponies were eaten, as planned, the stables could be dismantled and used for fuel. Phurnacite briquettes later adopted a squared oval shape. This regular shape packed well as a good firebed, with plentiful airflow. They are also easy to mechanically feed, allowing the development of automatically controlled heating boilers that could run for days without human intervention.

Biomass briquettes. Biomass briquettes are made from agricultural waste and are a replacement for fossil fuels such as oil or coal, and can be used to heat boilers in manufacturing plants, and also have applications in developing countries. Biomass briquettes are a technically renewable source of energy and their emissions do not constitute an anthropogenic greenhouse gas, unlike emissions from traditional coal briquettes, as any carbon released was taken directly from the atmosphere in recent history, not sequestered deep in the earth during the Carboniferous period as with coal.

A number of companies in India have switched from furnace oil to biomass briquettes to save costs on boiler fuels. The use of biomass briquettes is predominant in the southern parts of India, where coal and furnace oil are being replaced by biomass briquettes. A number of units in Maharashtra (India) are also using biomass briquettes as boiler fuel. Use of biomass briquettes can earn Carbon Credits for reducing emissions in the atmosphere. Lanxess India and a few other large companies are supposedly using biomass briquettes for earning Carbon Credits by switching their boiler fuel. Biomass briquettes also provide more calorific value/kg and save around 30-40% of boiler fuel costs.

A popular biomass briquette emerging in developed countries takes a waste produce such as sawdust, compresses it and then extrudes it to make a reconstituted log that can replace firewood. It is a similar process to forming a wood pellet but on a larger scale. There are no binders involved in this process. The natural lignin in the wood binds the particles of wood together to form a solid. Burning a wood briquette is far more efficient than burning firewood. The moisture content of a briquette can be as low as 4%, whereas green firewood may be as high as 65%.

Environmental impact

Briquetted paper has many notable benefits, many of which minimize the impact of the paper waste generated by a shredding system. Several manufactures claim up to 90% volume reduction of briquetted paper waste versus traditional shredding. Decreasing the volume of shredded waste allows it to be transported and stored more efficiently, reducing the cost and fuel required in the disposal process.

In addition to the cost savings associated with reducing the volume of waste, paper briquettes are more useful in paper mills to create recycled paper than uncompressed shredded material. Compressed briquettes can also be used as a fuel for starting fires or as an insulating material.