Geir Wedde

SO2 Emission Control in the Aluminium Industry

SO2 emissions from the aluminium industry are modest on a worldwide and national scale. Large modern smelters using high-sulphur petroleum coke in anodes and smaller smelters with topographical unfavourable locations may, however, be significant sources locally. This has lead environmental regulators to again review local legislation. Currently SO2 emission legislation is in force in Scandinavia and in some parts of the US. The ongoing review of SO2 emissions may lead to stricter legislation forcing smelters outside these areas to install SO2 control systems. The electrolysis represents approximately 80% of the released SO2 for prebake smelters and approximately 95% for Soderberg smelters.

AHEX‐A New, Combined Waste Heat Recovery and Emission Control System for Anode Bake Furnaces

Alstom has developed a new Fume Treatment Center (FTC) for improved emission control of Anode Bake Furnaces. The new compact FTC eliminates the conditioning tower with its use of compressed air and water with a patented heat exchanger system (AHEX) specially developed for the anode baking process. The adsorbent (alumina) is injected upstream the AHEX. This eliminates additional reactor stages downstream, and keeps the heat exchanger tubes free from fouling.

HEX Retrofit Enables Smelter Capacity Expansion

Aluminium Bahrain (Alba) is one of the largest producers of primary high quality aluminium in the world, and continues to consider further expansions such as the planned new line 6. In parallel the amperage on the existing AP30 pot lines 4 and 5 will be increased further.

Innovative Distributed Multi‐Pollutant Pot Gas Treatment System

Gas Treatment Centers (GTC) are traditionally arranged in the courtyard between pot rooms and handle vast quantities of pot gas (3 – 4 million m3/h) in a large number of filter compartments (15–30) with demanding space requirements and challenging control of operation.

Abart CDS — A New Compact Multi-Pollutant Pot Gas and Alumina Handling System

A new modular Abart CDS has been developed that integrates silos, alumina handling, heat exchangers, fans, SO2 scrubber and stack into a compact and efficient multi-pollutant pot gas treatment and recovery technology with incomparable footprint. The system is based on standardized modules that allows for short delivery time and early start-up. Each module includes an individual fan and optional SO2 scrubber located directly on top of the module. This compact design reduces overall pressure drop and energy requirements for operation of the fans. This paper updates the previously reported experiences from the first full scale installation in Norway with new results on the integrated SO2 scrubbers that were retrofitted in 2012/13.

Experiences with Alstom’s new Alfeed system at Emal

Alstom’s new pot feeding system (Alfeed) was successfully installed and commissioned on Emal’s 756 pots during 2009–2010.