Increased Operational Flexibility in CFB Alumina Calcination

Abstract

Operational flexibility with regards to production rates and fuel usage in alumina calcination is becoming increasingly important in today’s market. Outotec has a range of technologies, which can be retrofitted in old plants, or offered as options in new developments, that are aimed at improving the plant flexibility and performance, while maintaining product quality.

Process stability is critical for product quality and energy consumption and also to reduce material and refractory wear, increasing the operational life of the calciner. In the Outotec^® SmartFeed product, the feed and fuel control is automated to reduce temperature fluctuations in the circulating fluidized bed (CFB) furnace. A feed forward function, build into the fuel controller, takes into account any changes in feed rate or hydrate bypass level and adjusts the fuel correspondingly and in advance.

Additional operational flexibility and improved service life can be gained through Outotec’s Burner Management System concept. This system is designed to reduce the downtime of the calciner and to allow maintaining the temperature in the CFB furnace during shutdowns by keeping the pre-heat burner in operation continuously.