WHB Inlet Duct Lining Erosion

Waste Heat Boiler · Inlet Duct

Problem Details

Background

The waste-heat boiler inlet duct is the throat where hot gas enters the boiler. Gas temperature is high (800–1000℃), dust load heavy (especially incinerator and smelter gas) and velocity high. The inlet lining endures continuous high-velocity dust-laden gas abrasion—the fastest-wearing zone of WHB linings.

Failure Mechanism

Dust-laden gas scouring: high-temperature gas carrying dust abrades the duct wall at high velocity, thinning the surface layer by layer. Local intensified scouring: at elbows, transitions and flow guides, direction changes concentrate scouring far beyond straight sections, forming pits. Thermal shock: boiler start/stop and load swings cause temperature changes; thermal-shock stress worsens lining cracking. Corrosion: acidic gas components condense and attack in cooler zones.

Consequences

After inlet lining wear, vessel walls overheat with leakage risk; worn debris entering the boiler may damage heating surfaces; forced shutdown hurts heat recovery and unit availability.

Solution

Material Selection and Parameters

Select the inlet duct for "high wear resistance + thermal-shock resistance":

Material system: wear-resistant castable (Al₂O₃≥70%) or SiC wear castable (SiC≥50%). SiC's hardness and wear resistance suit the heaviest inlet and elbow zones;
Flow-guide protection: install inlet flow-guide anti-wear plates to direct flow and reduce local scouring; thicken elbows and transitions or fit replaceable wear liners;
Anchors: densified anchors for firm wear-layer bonding.

Installation Essentials

Monolithic placement: cast duct linings monolithically with precise formwork at irregular zones. Vibration: vibrate fully. Water control: keep at the datasheet lower limit for wear strength. Bake-out: follow the curve to prevent wear-layer spalling.

Maintenance

Monitor duct wall temperature and gas resistance; investigate on anomalies. At maintenance, measure inlet and elbow residual thickness and patch or replace zones beyond limits; record wear data to optimize flow-guide structure and wear design.

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