Reducing emissions and energy costs

THE OBJECTIVE

SOLAFT was approached by a Canadian Aluminium smelter to find a way to lower electricity consumption and operating costs on-site by reducing filter bag cleaning frequency and improving GTC uptime.

THE ISSUE

The smelter had reached its limits in relation to Air-to-cloth ratio, as result it had a high pulse frequency as they struggle to maintain a constant gas flow. The higher pulsing lead to increased electrical costs and shorter bag life due to wear and stress.

WHAT WE DID & THE SOLUTION

An extended surface filter bag, which SOLAFT trademarked, StarBags™ was proposed. The StarBags™ delivered an increased filtration surface area of 85% without any modifications to the cleaning system or cell plate.

OUTCOME

After a successful implementation and testing, the benefits to the Aluminium smelter were:

Operating Condition 1 – maintained constant gas flow

  • 50% drop in Pulse Frequency ($204K p.a. savings)
  • 25% reduction in Differential Pressure

Additional benefit

  • 50% reduction in Gaseous HF Emissions from the GTC

Operating Condition 2 – Increased gas flow by ~ 8%

  • Drop in Pulse Frequency with significant energy savings ($163K p.a. savings)
  • Extended bag life due to less pulsing

Additional Benefits

  • Reduced HF(g) Emissions of 0.01 kg F/t Al (stack)
  • Reduced HF(g) Emissions of 0.04 kg F/t Al (roof vents)