Coal drying
The large water content of coal (especially brown coal or lignite) is responsible for the low efficiency and high pollution produced by the coal-fired power plants. Drying the coal before burning it has the following advantages:
- reduction in coal consumption, as coal is not used to evaporate water
- reduction of greenhouse gas emissions for the same power generated
- increase in burning temperature, resulting in less pollutants as SO4, NOx, mercury
- increase of the thermodynamic efficiency of the power plant
- decrease in the plant running power for the pulverised combustion type
The previous coal drying technologies use electric power, steam or heat from the power plant to dry the coal, therefore diminishing the overall performance of the plant. Drying the coal with solar energy provides low grade solar heat for the drying process, therefore does not draw from power plant resources.
We have conducted successful experiments with solar coal drying at small scale and intend to start larger scale drying experiments. Our technology has a decisive advantage over other coal drying technologies because it can provide the least expensive heat, even cheaper than coal heat. This is the fundamental quality that makes our technology economically viable even at very large scale.