Reduction in HFO consumption

Challenge Summary

Heavy Fuel Oil used for combustion in the furnace for Bake oven, consumption of HFO need to optimize with minimum specific consumption.

Challenge Scenario

For aluminum production, primary industry uses electrolytic cells to transform alumina into metallic aluminum. During this process, the cell consumes the anode, a carbon block with specific properties, needing to replace the anode blocks timely to ensure continuous production.

During thermal treatment, Anode Baking Furnaces (Baking Oven) use fuel to generate enough energy for the baking process. Thus, energy efficiency comes as an important process and financial indicator, directly related to the amount of energy (burned fuel) needed to bake a specific anode weight (GJ/MT). Baking oven aims to produce high quality anodes, with lower fuel consumption and not harming furnace refractory life.

Heavy Fuel Oil (HFO) or furnace oil consisting of residues from crude-oil distillation is used primarily for the combustion process (>50%) in modern baking furnaces along with volatiles and packing coke totaling to a combined energy consumption of 5+2 GJ/MT of baked anodes.

During baking, green anodes are heated to temperatures over 1060°C supported by Pitch tar fumes within the furnace. Effective control of pitch burning leads to lower fuel consumption in terms of GJ/Metric ton of baked anodes.

Profile of the End-User

Heavy Fuel Oil firing in the existing Aluminum baking furnaces

Functional Requirements of the End-User

  • Reduction in the overall fuel consumption of the anode baking process by effectively controlling parameters within the furnace such as draft, flue temperature etc. ensuring quality of baked anode at the same time.

Functional & Operational Capabilities

  • Control, optimize internal furnace parameters in real-time based on changes within the baking oven leveraging pre-existent data models for optimal quality of anodes

Operational constraints

  • Proposed system to be compatible and seamlessly integrable to existing PLC + OEM software.
  • Controlled firings need to be optimized with modification in logic
  • Robust system able to withstand high temperatures

Expected Tangible Benefits and Measurable Gains

  • Reduced consumption of HFO for the entire process
  • 90 lakhs per annum saving with reduction of 1 L of HFO per anode

Performance Metrics or Outcomes

  • Amount of HFO conserved during the firing process
  • Quality of the anode produced post baking