Content maintained by Ron Sait
Coal to Liquids (CTL) |
AIMR 2008 |
Coal to Liquids (CTL)
The production of liquids from coal requires the breakdown of the chemical structures present in coal through the simultaneous elimination of oxygen (O), nitrogen (N) and sulphur (S) and the introduction of hydrogen (H). This action produces 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 there are basically three approaches, pyrolysis (direct method), hydrogenation (direct method) and gasification and synthesis (indirect method).
CTL technology was developed in the early 20th century and was used in Germany in the 1930's and 1940's. Since 1955 in South Africa, the SASOL company has operated the only CTL plant in the world to date. However, the Senhua Group expect a CTL plant to start in late 2008 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.
Underground Coal Gasification: Syngas can also be produced by underground or in-situ coal gasification. In this method fuel gases are produced underground when a coal seam gets enough 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 from a point behind the fire-front through another well. A problem is the collapse of the coal bed and subsidence on the surface. The gasified coal can then be used to produce liquids or electricity. The power station at Angren in Uzbekistan has the only operating underground coal gasification project in the world.
Resources
In 2007 no CTL projects in Australian were considered economic given that there is only one operating project in the world and all those in Australia are in the demonstration phase of development. Since CTL technology is well established, the CTL resource of 16,300 million barrels is considered paramarginal or PDR. Resources from operating coal mines were not included in CTL resources because the coal resources already have uses in other markets. 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 that has been considered suitable and available for CTL conversion includes coals from the Surat, Clarence-Moreton, Oaklands and Gippsland Basins.
Industry Developments
Monash Energy: In the La Trobe Valley (Vic.) construction of a $300 to $400 million brown coal to liquids demonstration plant is expected to commence in 2008 with commissioning in 2010. If viable a $5 billion 60,000 barrels per day CTL operation is planned to be built by 2016.
New Hope Corporation: New Hope is considering constructing a CTL pilot plant near the New Acland mine (QLD) which would process some 185,000 tpa of coal into 75 million litres of fuel.
Altona Resources plc: A feasibility study is being conducted into a 10 million barrels a year CTL plant located near the Wintinna coal deposit in South Australia.
Spitfire Oil Ltd: A 270 million litres per annum brown coal to liquids plant is proposed to be located at Salmon Gums in Western Australia.
Linc Energy: In 2007 construction commenced on a demonstration gas to liquids plant at the Chinchilla underground coal gasification project in Queensland. It is expected to start production in 2008.
