Heat energy required in conventional fluidized bed dryer was supplied by fluidization media, i.e, fluidization gas has to meet two requirements simultaneously:

(1), Dynamic conditions required by materials being dried;

(2), Heat energy needed by materials being dried;

For lower inlet fluidization gas temp, the flow rate of fludization gas required is higher, the energy loss from exhaust is higher, which leads to lower drying efficiency, large equipment size and higher capital investment.

Fluidized bed dryer with immersed steam heat exchanger was developed based on conventional fluidized bed dryer: steam heat exchaner is built inside drying chamber and is immersed completely with fluidized materials, the heat energy required by materials being dried is supplied by steam heat exchanger mostly. Main function of fluidization gas is to meet the dynamtic condition required by materials being dried. Therefore, dynamic condition and heat energy are independent. flow rate of fluidization gas can be reduced to minimum degree, resulting in smaller equipment size, lower capital investment and energy consumption.

It is ideal drying process for lignite coal drying in power plants as it needs steam:

Low pressure can be extracted from turbine;

Plant efficiency can be improved as LP steam for drying process is low grade energy.

More details http://www.coaldryingtech.com/ ■