Coldry Process
Encyclopedia
Coldry Process is a coal upgrading technology
developed in Victoria, Australia by Environmental Clean Technologies Limited to specifically beneficiate low-rank brown coal (lignite
) and sub-bituminous coal
by removing natural high moisture content and certain pollutants; harden and densify the coal; raise the calorific value of the coal to more than 5800 kcal/kg; and transform the coal into a stable, exportable black coal equivalent
product for use by black coal fired power generators to produce electricity
. The Coldry Process is a commercial method to achieve large scale beneficiation of low-rank coal without a need for government subsidy.
The possibility of creating densified coal was identified following observations made at the Maddingley Mine
near Bacchus Marsh, Victoria
. The mine operator observed that hardened bitumen-like road surfaces formed naturally soon after rain events when trucks had churned up brown coal fines with moisture when they entered and left the mine. In the days that followed a rain event the road surfaces at the mine would harden like tarmac and no longer absorb water. Dr Johns and colleagues identified that a process of low-mechanical shear had occurred where brown coal mixed with a small amount of moisture and subject to low-level mechanical shear had triggered a natural exothermic reaction process within the coal leading to the expulsion of its moisture content. The low mechanical shear process fundamentally alters micro chemical bonds within the coal, naturally reducing moisture content to around 11 per cent; boosting calorific value over 5600 kcal/kg; and creating a new ‘densified coal’ product that is hydrophobic, no longer prone to spontaneous combustion, readily transportable and from a commercial and environmental point of view, a black coal equivalent.
The Coldry Process attritions brown coal in large energy efficient kneaders to produce a coal paste easily extruded to a uniform pellet size. The resulting pellet is dried by evaporative water loss at ambient temperatures to produce a densified brown coal. Water loss is fully recovered and captured as a demineralised (distilled) water. The compressive strength of the densified coal generally equals that of briquettes or hard coals.
As a consequence of water loss, densified brown coal has a calorific value equivalent to that of high rank black coal, establishing Coldry Process pellets as a Black Coal Equivalent. The densified brown coal product emanating from the Coldry Process possesses abrasion resistance and is stable and safe to transport as an export product. The low mineral content characteristic of densified BCE derived from Victorian brown coal gives a distinct advantage over black coals, which by comparison contain higher levels of ash and sulphur. The percentage of Volatile and Fixed Carbon values of raw coal is retained by the Coldry Process, ensuring the chemical reactivity characteristic of raw brown coal is substantially retained in the densified product. Retention of valuable volatile fractions makes densified Coldry BCE an ideal feed for gasification processes.
, and Newcastle New South Wales
Australia.
adb = as dry basis. ar = as received. db = dry basis. wb = wet basis.
Coal upgrading technology
Coal upgrading technology refers to a class of technologies developed to remove moisture and certain pollutants from low rank coals such as sub-Bituminous coal and lignite and raise their calorific values...
developed in Victoria, Australia by Environmental Clean Technologies Limited to specifically beneficiate low-rank brown coal (lignite
Lignite
Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat...
) and sub-bituminous coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
by removing natural high moisture content and certain pollutants; harden and densify the coal; raise the calorific value of the coal to more than 5800 kcal/kg; and transform the coal into a stable, exportable black coal equivalent
Black coal equivalent
Black coal equivalent is a term applied to describe the properties of an export coal product derived from the Coldry Process, a patented coal upgrading technology operated by Environmental Clean Technologies Limited, in Victoria, Australia...
product for use by black coal fired power generators to produce electricity
Electricity
Electricity is a general term encompassing a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena, such as lightning, static electricity, and the flow of electrical current in an electrical wire...
. The Coldry Process is a commercial method to achieve large scale beneficiation of low-rank coal without a need for government subsidy.
Origin
The Coldry Process evolved from theoretical and test work in the Department of Organic Chemistry, University of Melbourne, Victoria, in collaboration with CRA Advanced Technical Development, Melbourne in 1989. This work was based on earlier theoretical work around Densified coal undertaken by the Department of Organic Chemistry, University of Melbourne in 1980-81.The possibility of creating densified coal was identified following observations made at the Maddingley Mine
Maddingley Mine
Maddingley Mine near Bacchus Marsh Railway Station, Victoria, Australia contains a concentration of a particular brown coal formation called Leonardite. A relatively high altitude formation, Maddingley brown coal is distinguished as having 60 per cent moisture content and a rich fulvic acid and...
near Bacchus Marsh, Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
. The mine operator observed that hardened bitumen-like road surfaces formed naturally soon after rain events when trucks had churned up brown coal fines with moisture when they entered and left the mine. In the days that followed a rain event the road surfaces at the mine would harden like tarmac and no longer absorb water. Dr Johns and colleagues identified that a process of low-mechanical shear had occurred where brown coal mixed with a small amount of moisture and subject to low-level mechanical shear had triggered a natural exothermic reaction process within the coal leading to the expulsion of its moisture content. The low mechanical shear process fundamentally alters micro chemical bonds within the coal, naturally reducing moisture content to around 11 per cent; boosting calorific value over 5600 kcal/kg; and creating a new ‘densified coal’ product that is hydrophobic, no longer prone to spontaneous combustion, readily transportable and from a commercial and environmental point of view, a black coal equivalent.
History
For some years the Maddingley Mine provided brown coal to an adjacent manufacturing plant located to the south of Bacchus Marsh. The plant and the mine were decommissioned in the late 1980s. In 1990 the Calleja Group transport company acquired the mine and the business park and became aware of the possibility of densified coal. The company acquired Intellectual Property rights for the densified coal process around 1994. Under the leadership of David Calleja and David Wilson the company invested in the process of developing and commercialising the densified coal methodology and succeeded with bench tests by 1997. At this time the technology process became known as the Coldry Process. For some time the company sought without success to include the Coldry Process as a technology worthy of review, investment and development by the government funded Cooperative Research Centre for Lignite program. Subsequently the Calleja Group invested in the establishment in February 2004 of a large scale working 16,000 tonne per annum pilot plant to demonstrate the process. By April 2004 the Coldry plant rapidly established itself as a viable commercial method to dewater brown coal without need for government subsidy or producing hazardous byproducts. The operation of the pilot plant was assigned to Asia Pacific Coal & Steel Pty Ltd (APCS) in June 2004 when APCS was given responsibility to commercialise the technology. In March 2005 APCS was acquired by ASX listed company Environmental Clean Technologies Limited, which took responsibility for commercialising the Coldry Process. An expanded pilot plant has since been established at the Bacchus Marsh site and testing of more than 300 coal types from around the world has been achieved. Additional improvements include a water recovery process funded by the Victorian government in 2007. Since 2009 ECT Limited has focused on attracting investment partners and investment to fund the establishment of a 2 million tonne per annum Coldry production plant in the Latrobe Valley.Densified brown coal
The Coldry Process produces Densified coal using raw brown coal with an as-mined water content as the sole material. Only the water originally present in the coal is removed by the drying process. This is a distinct advantage over all other known current and planned procedures aimed at producing a dewatered product. Recovered clean, distilled water is the only by-product of the Coldry Process.The Coldry Process attritions brown coal in large energy efficient kneaders to produce a coal paste easily extruded to a uniform pellet size. The resulting pellet is dried by evaporative water loss at ambient temperatures to produce a densified brown coal. Water loss is fully recovered and captured as a demineralised (distilled) water. The compressive strength of the densified coal generally equals that of briquettes or hard coals.
As a consequence of water loss, densified brown coal has a calorific value equivalent to that of high rank black coal, establishing Coldry Process pellets as a Black Coal Equivalent. The densified brown coal product emanating from the Coldry Process possesses abrasion resistance and is stable and safe to transport as an export product. The low mineral content characteristic of densified BCE derived from Victorian brown coal gives a distinct advantage over black coals, which by comparison contain higher levels of ash and sulphur. The percentage of Volatile and Fixed Carbon values of raw coal is retained by the Coldry Process, ensuring the chemical reactivity characteristic of raw brown coal is substantially retained in the densified product. Retention of valuable volatile fractions makes densified Coldry BCE an ideal feed for gasification processes.
Characteristics of Coldry densified coal
The chemical and calorific values of densified coal derived via the Coldry Process from typical Victorian brown coal with a natural average moisture content of 60 per cent by weight compares well with typical high grade black coal exported from Tarong QueenslandQueensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, and Newcastle New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
Australia.
Chemical composition
| Name | C Carbon % | H Hydrogen % | N Nitrogen % | O Oxygen % | S Sulfur % |
|---|---|---|---|---|---|
| Victorian Brown Coal (Lignite) | 26.6 | 1.93 | 0.21 | 9.4 | 0.39 |
| Densified Brown Coal (Coldry ) | 59 | 4.24 | 0.46 | 21 | 0.85 |
| QLD Black Coal (Export) | 52 | 2.59 | 0.74 | 11 | 0.25 |
| NSW Black Coal (Export) | 48.9 | 3.29 | 1.19 | 10.1 | 0.81 |
Comparison of calorific values
| Name | Moisture % | Volatiles % | Fixed Carbon % | Ash % | Sulfur % | Net Weight Specific Energy |
|---|---|---|---|---|---|---|
| Morwell Brown Coal (Lignite) | 59.3% wb | 20.0% wb | 19.86% wb | 0.9% wb | 0.3% db | 2006 kcal/kg ar 8.4 Mj/kg ar |
| Tarong Black Coal (Export coal) | 15.5% adb | 22.5% wb | 44.1% wb | 17.9% wb | 0.42% wb | 4800 kcal/kg adb 20.1 Mj/kg adb |
| Densified Brown Coal (Coldry) | 12.0% adb | 48.9% wb | 49.1% wb | 2.4% wb | 0.3% wb | 5874 kcal/kg adb 24.6 Mj/kg adb |
| Percent by weight | ||||||
adb = as dry basis. ar = as received. db = dry basis. wb = wet basis.
See also
- Bituminous coalBituminous coalBituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen. It is of higher quality than lignite coal but of poorer quality than Anthracite...
- Bergius processBergius processThe Bergius Process is a method of production of liquid hydrocarbons for use as synthetic fuel by hydrogenation of high-volatile bituminous coal at high temperature and pressure...
- Coal assayCoal assayCoal Analysis techniques are specific analytical methods designed to measure the particular physical and chemical properties of coals. These methods are used primarily to determine the suitability of coal for coking, power generation or for iron ore smelting in the manufacture of steel.-Chemical...
- Coal upgrading technologyCoal upgrading technologyCoal upgrading technology refers to a class of technologies developed to remove moisture and certain pollutants from low rank coals such as sub-Bituminous coal and lignite and raise their calorific values...
- Energy value of coalEnergy value of coalThe energy value of coal, or the fuel content, raj is the amount of potential energy in coal that can be converted into actual heating ability. The value can be calculated and compared with different grades of coal or even other materials...
- Orders of magnitude (specific energy density)Orders of magnitude (specific energy density)This is a table of specific energy densities by magnitude. Unless otherwise noted, these values assume standard ambient temperature and pressure....
- Fischer-Tropsch processFischer-Tropsch processThe Fischer–Tropsch process is a set of chemical reactions that convert a mixture of carbon monoxide and hydrogen into liquid hydrocarbons. The process, a key component of gas to liquids technology, produces a petroleum substitute, typically from coal, natural gas, or biomass for use as synthetic...
- Karrick processKarrick processThe Karrick process is a low-temperature carbonization and pyrolysis process of carbonaceous materials. Although primarily meant for coal carbonization, it also could be used for processing of oil shale, lignite or any carbonaceous materials. These are heated at to in the absence of air to...
- LeonarditeLeonarditeLeonardite is a soft waxy, black or brown, shiny, vitreous mineraloid that is easily soluble in alkaline solutions. It is an oxidation product of lignite, associated with near-surface mining...
- Maddingley MineMaddingley MineMaddingley Mine near Bacchus Marsh Railway Station, Victoria, Australia contains a concentration of a particular brown coal formation called Leonardite. A relatively high altitude formation, Maddingley brown coal is distinguished as having 60 per cent moisture content and a rich fulvic acid and...
- List of CO2 emitted per million Joule of energy from various fuels