The supplier-specified heating schedule, with set ramp rates and holds, that removes free water from a new castable or plastic lining near 100 to 150 C and chemically bound water from the cement hydrates at roughly 250 to 550 C. Ramp rates are often 15 to 50 C per hour depending on thickness and castable type, with holds at each critical range. Thermocouples at the hot face and in the gas track it, and every deviation is logged.
Dry-out chart says hold at 120 for eight hours, then 25 an hour to 540, don't let the burner guy skip ahead.
The schedule is written for the coldest, thickest section in the vessel, not the thermocouple that reads hottest. Pace the burners to the slowest spot.
Also heard as
- bake-out
- heat-up schedule
- dryout
Related terms
Explosive spalling
Violent failure of a castable during first heat-up when trapped steam pressure blows the lining apart.
Cure
To hold freshly placed castable moist and at moderate temperature so its cement can fully hydrate.
Burnout fibers
Plastic fibers mixed into castables that melt during dry-out, leaving channels for steam to escape.
Green
Describes refractory that has been formed or placed but not yet fired, dried or heated in service.