AHEX- A NEW, COMBINED WASTE HEAT RECOVERY AND EMISSION CONTROL SYSTEM FOR ANODE BAKE FURNACES

摘要

Alstom has developed a new Fume Treatment Center (FTC) forimproved emission control of Anode Bake Furnaces. The newcompact FTC eliminates the conditioning tower with its use ofcompressed air and water with a patented heat exchanger system(AHEX) specially developed for the anode baking process. Theadsorbent (alumina) is injected upstream the AHEX. Thiseliminates additional reactor stages downstream, and keeps theheat exchanger tubes free from fouling.The AHEX started up in November 2011 at the anode bake plantat Alcoa Mosj?en, Norway and has demonstrated stable operationwith gas temperatures cooled down to less than 100°C. Emissionmeasurements document 10-20% less PAH-16 and significantlyless HF despite a higher gas to alumina flow ratio in the AHEXsystem compared to the conventional FTC.In addition, the AHEX system enables up to 5000 kW of thermalenergy to be recovered at Alcoa Mosj?en.