TL;DR
Red river and snowman formation are caused by uneven airflow across the grate. Rebalance the compartment air pressures and adjust the cooler grate speed to spread the clinker bed evenly.
What you might see
- asymmetric temperature across the cooler grate
- clinker piling at the kiln discharge end
- underaeration zones visible in the clinker bed
- cooler exit clinker temperature above setpoint
Likely causes
Uneven air pressure distribution across the grate compartments allowing hot clinker channels
Kiln burning zone instability causing lumpy or fine-rich clinker surges
Insufficient cooling air total volume for the clinker throughput rate
Grate speed too fast for current clinker production, thinning the bed and creating short-circuit airflow
Required tools
- Access to the DCS or SCADA trend display for cooler compartment pressures
- Clinker exit temperature probe
- Radiant-heat face shield and aluminized PPE for near-kiln work
Safety first
- The kiln discharge end of the clinker cooler involves extreme thermal radiation. Use radiant-heat PPE and never approach without it.
- Hot clinker can flow rapidly if a snowman collapses. Keep all non-essential personnel clear of the cooler discharge area.
Procedure
- 1
Read the cooler grate pressures for each undergrate air compartment from the control system.[1]
- 2
Identify compartments with pressure significantly below adjacent compartments. Low pressure indicates a thin or absent clinker bed above that zone.[1]
- 3
Reduce the grate speed by 10-15% to build up the clinker bed thickness and improve air distribution.
- 4
Increase the cooling fan total air flow if the clinker exit temperature is above the target.
- 5
Rebalance individual undergrate fan dampers to equalize undergrate pressure across the width.
- 6
Monitor the kiln nose ring temperature and inlet clinker granulometry. Notify the kiln operator if the burning zone is unstable and sending lumpy clinker.
- 7
If a snowman has formed at the kiln discharge, stop the cooler grate and use the manual pneumatic lances (if fitted) to break it up before restarting.
Warning: Thermal radiation hazard when working near the kiln discharge. Use appropriate radiant-heat PPE and maintain maximum practical distance.
Sources
FLSmidth FLSmidth Cross-Bar Clinker Cooler general technical documentation, FLSmidth
FLSmidth clinker cooler operation and maintenance documentation, cooler airflow balancing and snowman prevention procedures (general)
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