CDQ Slant Channel Castable Damage

CDQ Vessel · Slant Channel

Problem Details

Background

The slant channel (annular gas duct) of a CDQ (coke dry quenching) furnace is the key circulation path for cooling gas. Gas carrying coke fines flows through at high velocity, continuously scouring the lining. Slant-channel lining wear and fall-out directly hurt circulation flow and cooling efficiency.

Failure Mechanism

Coke-fines gas scouring: circulation gas carrying coke fines abrades the lining at high velocity in the annular duct. Uneven flow distribution: local high-velocity zones in the slant channel intensify scouring. Thermal shock: charging, discharging and gas-temperature fluctuations shock the lining. Mechanical stress: structural stress and lining expansion mismatch form cracks.

Consequences

After slant-channel fall-out, circulation flow and distribution deteriorate, cooling efficiency drops and coke quality fluctuates; fallen blocks may jam the slant channel or enter the circulation system, forcing shutdown for repair.

Solution

Material Selection and Parameters

Select the slant channel for "high wear resistance + thermal-shock resistance":

Material system: wear-resistant castable (Al₂O₃≥70%) or SiC wear castable (SiC≥50%). SiC's wear resistance suits the heaviest scouring zones of the slant channel and annular duct;
Anchors: densified anchors for firm wear-layer bonding;
Flow optimization: optimize slant-channel and annular-duct structure to improve flow distribution and lower local velocity.

Installation Essentials

Monolithic placement: cast slant-channel linings monolithically with staggered joints. Vibration: vibrate fully. Water control: keep at the datasheet lower limit. Bake-out: follow the curve to prevent wear-layer spalling.

Maintenance

Monitor circulation flow and pressure distribution; investigate on anomalies. At maintenance, measure slant-channel and annular-duct residual thickness, patching or replacing zones beyond limits; record wear data to optimize flow design and wear grade.

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