Bartlett-Snow™ rotary dryers are offered in two basic designs, directly and indirectly heated. These designs are readily adaptable to a wide variety of processing applications and are offered as stand-alone units or as part of complete thermal processing systems.
Bartlett-Snow™ Directly Heated Rotary Dryers
The direct heat dryer design consists principally of an inclined rotating cylinder with internal flighting. This type of design brings process material into direct contact with the drying medium, either in a concurrent or countercurrent flow configuration. The drying medium may be products of combustion tempered with air, heated clean air or special gases. Direct heat rotary dryers are most appropriate when product characteristics reflecting particle size range, specific gravity, and shape permit reasonable drying air velocities through the cylinder, as well as for applications involving product temperatures upwards to 930°F / 500°C.
Typical materials processed in direct rotary dryers:
Alumina , Ammonium Nitrate, Ammonium Phosphate, Granulated Fertilizers, Urea, Food Products, Titanium Dioxide, Proppants, Sand, Clay, Metal Scrap, Pigments
Bartlett-Snow™ Indirectly Heated Rotary Dryers
The indirect heat rotary dryer design provides for heating under oxidizing, reducing, or inert atmospheric conditions. The rotary dryer design consists principally of a rotating cylinder that is enclosed in a furnace along its active length. With heat transfer indirect and through the cylinder wall, the gas velocities within an indirect dryer are low as compared to a direct heat dryer, and correspondingly, the off-gas system is smaller and more economical.
Applications that are appropriate for indirect heat rotary dryers involve a wide variety of fine powders, granular materials, pellets and extrudates that require product temperatures to 930°F / 500°C, bed temperature profiling and special atmospheres. Should the process require inert, reducing or special atmospheric considerations the dryer can be provided with gas-tight seals.
In order to get maximum utilization of radiation heat transfer, the interior of the dryer cylinder is fitted with agitating flights or special internals to gently handle and promote even heat transfer to the process material.
- Automatic temperature, pressure and electrical controls with furnaces featuring multiple gas, oil or dual fuel burners, or electrical heating elements arranged in zones.
- Available in sizes ranging from 6-120in / 152-3048mm in diameter with lengths from 10 to over 100ft / 3.04 to over 30.48m.
Typical materials processed in indirect rotary dryers:
Alumina, Activated Carbon, Metallic Oxides, Rare Earth Compounds, Manganese Oxide, Catalysts, Coke, Coal, Ferrites, Nuclear Materials, Metal Scrap, Pigments