Exergen has developed a breakthrough clean coal technology that, teamed with modern coal-fired power station technology, has the potential to deliver a 40% reduction in emissions. The technology is currently known as the Continuous Hydrothermal De-watering (CHTD) of brown coal (lignites) and high moisture subbituminous coal.
Core to the Exergen CHTD technology is a vertical autoclave (Figure 1) that uses gravitational head pressure and a small amount of energy to transform the molecular structure of brown coal to remove up to 80% of its moisture content.
Exergen CHTD is a significant step towards overcoming the social and economic challenges posed by many nations' continued reliance on subbituminous coals for energy production.
Exergen prioritised this application because of the urgency of the global need to limit emissions from brown coal energy production.
By removing moisture from brown coal at previously unattainable levels of efficiency, the need to bleed off large amounts of power station energy to thermally dry fuel prior to combustion is obviated.
The significant gains in emissions levels and water recovery delivered by Exergen CHTD will extend the social license of brown coal-fired power generation for decades to come. The technology itself has a small physical and environmental footprint.
The technology is proven and now ready for application to existing and new technology, brown coal-fired power generation plant.
The Exergen CHTD process offers scope to bring high moisture stranded lignites to a product that can be exported for the thermal coal market. At 10% moisture an Exergen CHTD coal ex Latrobe Valley has a GAR of 5700-5800 kcal/kg.
|Schematic showing moisture in brown coal before and after the Exergen process
(designated moisture levels approximate only, and raw material specific).