Thermal plants generate a large amount of electricity by burning coal. Higher the calorific value, the better the energy gained from each unit of coal. For achieving high calorific value, the moisture content of the coal has to be less. Thermal power plants usually dry the coal in open which is not efficient and can take days on end to reduce the moisture.
Oorja medium temperature Industrial process heaters (XCPC) and Oorja direct solar air heaters (CPC) can be used to dry the coal, reducing the moisture content and increasing the calorific value.
The advantages are:
1. By reducing the moisture content by 40%, we can increase the Gross Calorific Value of coal by 50%.
2. The amount of energy generated by burning a unit mass of coal increases.
3. The drying time can be significantly reduced compared to direct sun-drying by using dedicated solar air heaters.
4. Significant reduction in transportation costs due to reduced moisture content.
5. Reduction in GHG emissions due to increased calorific value.
The drying is done using Oorja compound parabolic collector (CPC). It is a solar concentrator technology which can utilise both diffused and direct radiation for producing temperatures up to 120 °C from direct air heating. It consists of a CPC with a parabolic reflector on the bottom. The air is directly passed on to the tubes and heated.
For higher temperature drying, the process can be supplemented by Oorja XCPC which is a high-temperature thermic fluid heater. The heat from the thermic fluid can later be transferred to air through a heat exchanger.