New process control system applied on a closed baking furnace

In 2004 the Ardal Carbon plant increased total baked anode production with 30 % through retrofit of Furnace #3. Using the latest technology of the Hydro baking furnace design, annual capacity of a two fire-zone furnace was increased from 50.000 to 105.000 tons. The closed top furnace technology has traditionally higher tar content in the flue-gas than furnaces of open type design. At plants with electrostatic precipitators the major part of uncombusted volatiles are collected as tar that has been dealt with either by deposition, recycling or combustion. With this retrofit, flue gas treatment is now based on the technique of regenerative thermal oxidation. The paper demonstrate the improvements achieved with a new process control system and evaluate the most relevant parameters of the baking process such as combustion of volatiles, energy consumption and quality consistency.