Typical flow sheet for the proportioning and mixing area
One of our proprietary equipment is the Preheating Screw for the continuous Preheating of Anode Dry Mix.
Typical characteristics:
- Slowly rotating low wear hollow flight screws with individual HTM flow rate adjustment
- Heated trough
- Variable speed drive, frequency controlled
Benefits:
- Intensive heat exchange
- Gentle product conveyance, and therefore no product breakdown
- Very high availability
- Compact design, low space requirement
- Well proven
Design features
Heat transfer medium
Liquid heat transfer medium first flows through the core pipe, then enters the last hollow flight at the opposite shaft end and passes back to the outlet through the hollow flights in counter-current to the direction of product flow in the trough
Heat exchange
During the product conveyance brought about by the rotating hollow screws, an intensive heat exchange takes place between the hollow screws and the product. The product is heated exclusively by heat transfer and not by the transformation of mechanical energy.
Rotational speed
Normally, the hollow screws rotate within a range of 2 to 15 r/min. Hence, energy requirements are low and mechanical wear is virtually negligible. Furhermore, the low speed of the screws prevents dust formation in the product area, even in the case of products with low bulk densities
Space requirement
Outotec Preheater Screws are of compact design. Despite their low space requirement, they offer large heat exchange surfaces. It is often possible to integrate them in existing plant installations. When planning new installations, a comparison with other heat exchange systems shows that the low space requirements of preheater screws represent a favourable factor in the cost estimate.
Recent Major References
BALCO
HENAN NAM KWONG
Nalco National Aluminium Co.
Korba, Chattisgarh, India
Yichuan, Henan, India
Angul, Orissa, India
For further information, please contact  aluminum(at)outotec.com
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