Key Points for Selection and Installation of Pulverized Coal Lance

1. Core Selection Parameters

• Coal Injection Volume: High injection volumes require high-flow lances (e.g., Laval type) to prevent coal powder deposition inside the lance.
• Tuyere Diameter: The outer diameter of the lance should be 10-20mm smaller than the inner diameter of the tuyere (e.g., for a 120mm tuyere inner diameter, use a 100-110mm lance outer diameter) to ensure adequate airflow space.
• Airflow Velocity: For conventional conditions, select 100-120m/s; for high coal injection ratios, choose 150-200m/s to prevent coal powder settling due to low velocity.
• Insertion Depth: Typically insert 1/3 to 1/2 of the tuyere length (approximately 200-400mm), adjusted based on the blast furnace raceway position.

2. Installation and Debugging Requirements

• Concentricity: The lance axis must align with the tuyere axis (deviation ≤5mm) to prevent coal powder from biasing to one side and causing localized wear.
• Sealing: Use high-temperature-resistant sealing gaskets (e.g., graphite gaskets) at connection interfaces to ensure no leakage and prevent air ingress affecting coal powder concentration.
• Angle Adjustment: The angle between the lance and the horizontal plane is typically 0-5° (downward tilt) to avoid directing coal powder toward the tuyere cooler, which could cause overheating and damage.
• Trial Injection Verification: After installation, conduct a cold-state trial injection to check the stability of coal injection volume, nozzle atomization effect, and ensure no blockages or leaks.
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Daily Maintenance and Common Issue Handling

The frequency and quality of pulverized coal lance maintenance directly affect the continuity of blast furnace coal injection. Key focus areas include:

1. Daily Maintenance Points

• Regular Inspection: Check each shift for lance bending, deformation, nozzle wear or blockage, and leaks at connection points.
• Clearing Blockages: If the nozzle is blocked, use a steel rod or compressed air (0.6MPa) for reverse purging. Avoid forceful hammering to prevent nozzle damage.
• Replacement Cycle: Replace regularly based on wear conditions—conventional lances every 1-2 months, cooled lances every 3-4 months.
• Parameter Recording: Document the wear location and extent of the lance during each replacement to provide data for optimizing material or structure.