Rotary Dryers and Coolers Rotary Calciners

Adding functionality and value to your products.

Direct Fired & Indirectly Heated Calciners are used for applications where it is necessary to change the "state" of the material. Direct fired units are suited to high-temperature applications and indirectly heated units for dusty, finely divided materials and low to medium temperature applications.

Direct Fired Calciners

Direct Fired Calciner
Direct Fired Calciner

Direct Fired, Refractory Lined Calciners are also supplied for high temperature applications where it is necessary to change the ‘state’ of the material. Since this process usually requires a long residence time, the length to diameter ratio is often in excess of 10:1. In most cases an oil or gas burner fires directly into the discharge end of the unit. The material is heated in three ways - by radiation from the burner flame, conduction from the refractory lining and convection by contact with the hot gases.

Features

Direct fired (usually but not always), refractory lined calcined heat material in three ways - by radiation from the burner flame, conduction from the refractory lining and convection by contact with the hot gases.

Benefits

Suitable for high temperature applications where it is necessary to change the 'state' of the material or drive a chemical or physical reaction.

Process Flow Diagram

Direct Fired Calciners
 

Indirectly Heated Units

Indirect Fired Calciner
Indirect Fired Calciner

Indirectly Heated Rotary Dryers and Calciners are available for dusty, finely divided materials and low to medium temperature calcining applications. The rotary drum is partially enclosed and externally heated by a series of burners mounted in an insulated stationary chamber or jacket. Alternatively, the products of combustion from an external heater may be recirculated to increase thermal efficiency. 

Since heat transfer is by radiation and conduction via the cylinder wall, the internal flights are arranged to distribute the material around the inner periphery of the drum. The entrainment of ‘fines’ is minimal as a low air flow is only required for removing the water vapor, little or no de-dusting equipment is therefore necessary.

Features

In the indirectly heated dryer/calciner, there is little or no contact between the product and the drying gases since heat transfer is mainly via the cylinder wall.

Benefits

This design is therefore more appropriate for fine, dusty materials, including those necessitating an inert atmosphere, or for applications where contamination is to be avoided.

Process Flow Diagram

Indirectly heated rotary calciner
Indirectly heated rotary calciner

Contact

How can we help you?