ToolFusion
📋 Case Study

All-Electric Lime Kiln Conversion in Ontario Quarry

Inability to meet Tier 3 emission limits with natural gas; lime quality variation due to flame instability

🏗️ Project Overview

Full electrification of vertical shaft lime kiln using staged resistive + microwave hybrid heating

🎯 Challenge

Inability to meet Tier 3 emission limits with natural gas; lime quality variation due to flame instability

🔧 Design Approach

Zoned resistive heating (lower zone) + 2.45 GHz microwave cavity (upper calcination zone) with moisture-sensing feedback

📐 Design Diagram

Resistive Zone P/A = 1.8 kW/cm² Microwave Zone 2.45 GHz, dₚ = 12 cm Feed Lime Product Moisture Sensor Tier 3 Emission Limits Unmet Flame Instability → Lime Quality Variation All-Electric Lime Kiln Conversion Ontario Quarry

AI-generated project design illustration

📐 Key Calculations

Microwave Penetration Depth

d_p = λ₀ × √ε' / (2π × ε'')
Result: 12 cm
Confirmed full penetration through 30 cm limestone charge

Resistive Zone Power Density

P/A = σ × E²
Result: 1.8 kW/cm²
Kept below 2.0 kW/cm² to avoid refractory spalling

📊 Results

Zero stack emissions; CaO purity increased from 92.4% to 97.1%; CAPEX payback in 6.8 years (incl. $1.2M provincial clean-tech grant)

💡 Lessons Learned

  • •Microwave coupling efficiency dropped >30% when feed moisture exceeded 8% — added upstream fluidized-bed dryer
  • •Resistive elements required active water-cooling despite refractory lining

✅ Key Takeaways

  • 1Microwave coupling efficiency dropped >30% when feed moisture exceeded 8% — added upstream fluidized-bed dryer
  • 2Resistive elements required active water-cooling despite refractory lining