Flue gas waste heat recovery system of Bayer process aluminum oxide production roasting furnace

Abstract

The invention relates to the field of aluminum oxide roasting, in particular to a flue gas waste heat recovery system of a Bayer process aluminum oxide production roasting furnace. The flue gas wasteheat recovery system is provided with a flue gas heat exchanger and an evaporation stock solution heat exchanger, evaporated secondary water sequentially enters the evaporation stock solution heat exchanger and the flue gas heat exchanger to separately exchange heat with evaporation stock solution and flue gas, recovery of flue gas waste heat in a Bayer process aluminum oxide production system isrealized, and economic benefits and environmental protection effects are created; and operation is stable, the equipment failure rate is low, the operation rate is high, and frequent cleaning is not needed.

Description

technical field [0001] The invention relates to the field of alumina roasting, and more specifically, relates to a waste heat recovery system for flue gas of a roasting furnace for Bayer process alumina production. Background technique [0002] In the production of alumina, the reaction temperature of the roasting furnace in the roasting process is above 800 °C, and the temperature of the flue gas discharged through the chimney is at 160 °C. Generally designed for direct discharge to atmosphere. There are two commonly used methods for heat recovery in flue gas: one is to use water (evaporated secondary water or production water) for indirect heat exchange through a heat exchanger, and the other is to use evaporated raw liquid for indirect heat exchange through a heat exchanger . [0003] Use produced water or evaporated secondary water for heat recovery, due to the low temperature, it is easy to cause the moisture contained in the flue gas to condense locally in the heat e...

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Problems solved by technology

[0003] Use produced water or evaporated secondary water for heat recovery, due to the low temperature, it is easy to cause the moisture contained in the flue gas to condense locally in the heat exchanger, and then combine with the flue gas dust to form scaling on the flue and even the blades of the induced draft fan ;Using the evaporated stock solution for heat recovery, due to the entrainment of floating matter (the main component is aluminum hydroxide), it is easy to scar and block the surface of the heat exchanger, and it needs to be cleaned regularly, and the operation is unstable

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