Casting Bay Fume Abatement Improvement Project Sakura Ferroalloys, Malaysia

Abstract

Sakura Ferroalloys (SFA) operates a Manganese Ferroalloy smelter complex in Sarawak Malaysia, consisting of two 81 MVA closed submerged arc furnaces. Tapping of the alloy is done into ladles which are cast into one of eight open casting bays, using the layer casting method. Unwanted emissions were generated during the casting process. An opportunity to lower Sakura’s impact on the environment was identified and a project was launched in conjunction with Resonant Environmental Technologies (RET) to reduce emissions. Key project milestones were:
• Conceptualisation of potential solutions
• Investigating the opportunity to utilise existing fume abatement equipment
• Computational Fluid Dynamics (CFD) analysis of concepts
• Detail analysis and design of chosen concept
• Construction and commissioning
• Post implementation process evaluation

After consideration of various concepts, the decision was made to continue with a concept of capturing the fumes by making use of the installed tap hole fume abatement system. The evaluation of the existing tap hole fume extraction system proved that the system could be utilised for the casting bay fume extraction project with only minor modifications. Conceptual models that were evaluated using CFD revealed that casting bay fume extraction efficiencies of up to 75% could be achieved depending on the concept being analysed. Based on the analyses a partially closed casting bay was chosen with a theoretical efficiency of 63%. The design presented a number of challenges such as the selection of materials of construction and the maintainability of the complete system. Construction was to happen with the furnaces operating at full capacity and careful planning of the construction phase was required to ensure the safety of the construction crew while not impacting on production. The project was successfully commissioned in July 2019. Based on actual flow measurements, the CFD models were validated, indicating that the expected results were achieved. Fume energy capture based on peak energy showed capture efficiencies up to 68% which exceeded the CFD modelled efficiencies. Fume capture video analysis furthermore showed visible reductions in plume volume by around 81%.

Keywords: casting bays, fume extraction system, CFD, plume volume