Air backheating and multi-stage waste heat recovery method for aluminum oxide gaseous roasting furnace

Abstract

The invention discloses an aluminum oxide gaseous roasting furnace air backheating and multi-stage waste heat recovery method, which is characterized in that a multi-stage mixed heater is mounted on a flue between an outlet of a roasting furnace suction fan and a chimney, roasting furnace waste heat is used for heating air for combustion, the smoke dew point is improved, high-temperature hot water is recovered, and the hot water is used for producing low-pressure steam through graded waste heat utilization. Urban heat supply network water heating; according to the method, sensible heat of smoke and latent heat of vaporization of steam are recycled, moisture in the smoke is recycled, the efficiency of the roasting furnace can be improved by 30% by recycling high-temperature waste heat in summer, and the efficiency of the roasting furnace can be improved by 17.2% by recycling low-temperature waste heat in winter.

Description

technical field [0001] The invention belongs to the field of cascaded utilization of heat energy, and in particular relates to an air reheating and multi-stage waste heat recovery method of an alumina gaseous roasting furnace. Background technique [0002] In the production of alumina, the gas suspension roaster is widely used in the industry due to its advanced technology and efficient use of energy. See the process flow Figure 1 . At present, the fuel of the gas suspension roaster adopts producer gas, natural gas and other gas fuels, and adopts multi-stage heat exchange to recover heat, and the energy conversion efficiency is high. However, the exhaust gas temperature of the conventional roaster is high, reaching above 160°C. The roaster dehydrates aluminum hydroxide at high temperature to form alumina. The moisture in the exhaust smoke of the conventional roaster is very large, reaching 44% by volume, and the water vapor contains a lot of heat. , accounting for more tha...

AI Technical Summary

Problems solved by technology

However, the exhaust gas temperature of the conventional roaster is high, reaching above 160°C. The roaster dehydrates aluminum hydroxide at high temperature to form alumina. The moisture in the exhaust smoke of the conventional roaster is very large, reaching 44% by volume, and the water vapor contains a lot of heat. , accounts for more than 60% of the calorie input of the roaster, and a large amount of water vapor heat in the flue gas discharged by the roaster is wasted in vain, and the efficiency of the roaster is relatively low

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