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Coal to Liquids |
AIMR 2009 |
Coal to Liquids
The production of liquids from coal requires the breakdown of the chemical structures present in coal with the simultaneous elimination of oxygen, nitrogen and sulphur and the introduction of hydrogen to produce a stable liquid product. Coal can be converted into a variety of products including petrol, diesel, jet fuel, plastics, gas, ammonia, synthetic rubber, naptha, tars, alcohols and methanol. There has been extensive research into converting coal to a liquid but basically there are three approaches; pyrolysis (direct method), hydrogenation (direct method) and gasification and synthesis (indirect method).
Coal to Liquids technology (CTL) was developed in the early 20th century and was used in Germany in the 1930s and 1940s. Since 1955 in South Africa, SASOL has operated a CTL plant and in late 2008 the Shenhua Group commissioned a CTL plant at Ordos in China. In Australia from 1955 to 1969, a Lurgi gasification plant produced gas for the Melbourne market from briquetted Yallourn brown coal. From 1985 to 1990 a Japanese consortium operated a CTL pilot plant at Morwell which demonstrated that hydrogenation of La Trobe Valley brown coal was technically feasible.
Synthetic gas (syngas) can be produced also by underground or in-situ coal gasification. In this method fuel gases are produced underground when a coal seam gets sufficient air to burn but insufficient for all consumable products to be consumed. Carbon dioxide, carbon monoxide, hydrogen and methane are produced to yield a gas of low but variable heat content. Air is pumped into the burning coal bed through a well and the gas is drawn off through another well from a point behind the 'fire-front'. The gasified coal can then be used to produce liquid fuels (or electricity). The power station at Angren in Uzbekistan has the only operating underground coal gasification project in the world. At present, many projects are in various stages of development in Australia, the USA, Canada, South Africa, India, Vietnam, New Zealand and China to produce electricity, liquid fuels and syngas. A problem associated with this form of extraction is the collapse of the coal bed and surface subsidence.
Resources
In Australia in 2008 no CTL projects were considered economically viable given that there are only two operating projects in the world and those in Australia are in the demonstration phase of development. Because CTL technology is well established, the CTL resource of 16.3 billion barrels is considered a paramarginal demonstrated resource. Operating mines were not included except at New Acland where the New Hope Corporation plans to develop CTL alongside its conventional coal operation. If CTL projects ever become viable in Australia the resource life at current rates of oil consumption is about 50 years. At present, the location of coal which has been considered suitable and available for CTL conversion includes coals from the Surat, Clarence-Moreton, Oaklands and Gippsland Basins.
Industry Developments
New Hope Corporation: The company is considering constructing a CTL pilot plant near the New Acland mine in Queensland (Qld)which would process some 185 000 tonnes per annum (tpa) of coal into 75 million litres of fuel.
Altona Resources plc: A 10 million barrels a year CTL plant and 1140 MW power plant is proposed to be constructed near the Wintinna coal deposit in South Australia (SA). The project would cost about US$3.0 billion and require a 10 million tonnes per annum (Mtpa) open-cut mine.
Ambre Energy Ltd: Ambre plans to demonstrate coal gasification technology at the Felton coal deposit in Qld. If successful Ambre proposes to expand the plant to process 3.8 Mtpa of open-cut coal for an annual production of 0.8 Mtpa of dimethyl ether and 200 Megawatts (MW) of electricity.
Monash Energy: In December 2008 the proposed Monash Energy project in Victoria (Vic) was postponed. The project was planned to include a $300 to $400 million brown coal to liquids demonstration plant and, if viable, a $5 billion 60 000 barrels per day CTL operation was planned to be built.
Spitfire Oil Ltd: A 3.5 Mtpa open-cut mine at Salmon Gums in Western Australia (WA) is planned to be developed to provide feed to a brown coal to liquids plant producing about 7.3 million barrels of oil and distillate per annum, mainly for the Kalgoorlie market.
Blackham Resources Ltd: Blackham propose to develop a CTL operation at the Scaddan brown coal deposit in WA. Based on 30 000 barrels of fuel per day the operation could provide feedstock for 40 years.
Hybrid Energy Australia: A feasibility study is being conducted into a CTL plant located at Kingston in SA. The FuturGas Project plans to use about 3.2 Mtpa of open-cut brown coal to produce 3.7 barrels of synthetic fuel per annum and 40 MW of low emission electricity.
Syngas Ltd: Plan to produce 15 000 to 30 000 barrels of diesel per day from an open-cut mine at the Clinton brown coal deposit in SA.
Underground Coal Gasification:
Linc Energy: In June 2008 Linc Energy and SAPEX merged to develop potential coal resources in SA's Arckaringa Basin using Linc's underground coal gasification technology. In October 2008, the first diesel was produced from the Chinchilla project in Qld. In April 2009, the demonstration gas-to-liquids plant at the Chinchilla Underground Coal Gasification project was officially opened.
Carbon Energy: In October 2008 construction of surface facilities was completed for an Underground Coal Gasification trial at Bloodwood Creek in Qld. In January 2009, trial syngas production commenced.
Cougar Energy: The company plans to trial underground coal gasification near Kingaroy in Qld during 2009. Cougar propose to build a $500 million 400 MW power station.
