Page 301 - Wastewater Solids Incineration Systems

262 Wastewater Solids Incineration Systems

• Breaking off soft slag from rabble arms, drop holes, hearth ceilings, and ther-
mocouples.
• Removal of soft slag and loose brick that jams rabble teeth.
• Calibration, repair, and replacement of thermocouples, analyzers, etc.

1.6 Shutdown Maintenance

Shutdown maintenance can be divided into preventive and emergency maintenance.
A preventive maintenance shutdown is one that is scheduled on a regular interval
(for example, once per year) and includes a predetermined list of work, such as

• Rabble arm teeth replacement.
• Thorough inspection and repair of all internal refractory.
• Repair of sagging hearths.
• Replacement or repairs of rabble arms.

• Center shaft repairs.
• Modifications to improve operations.
• Burner tile cleaning and replacement (with precured burner tile, if available).

To accomplish tile cleaning and replacement, fuel, air, and electrical fittings
can be shut off and disconnected from the burner. The burner can be removed
from the incinerator shell and the exposed burner tile cut out from the adjacent
refractory bricks.
The new burner tile should be slightly undersized from the original dimensions;
®
sheet Kaowool or similar fiber refractory material can be used to fill any gaps
between the new burner tile and the existing tile opening.
It should be noted that emergency shutdown is required for a collapsed hearth,
broken rabble arm, and cracked center shaft.

1.7 External Shell Maintenance
On incinerators, which have external insulation, there is only a small amount of
exposed shell surface that must be inspected. The exposed surface will be in the
immediate vicinity of all operating burners. An operator can detect hot spots from
the burning of the painted surface and by the glowing of the metal. Should a hot spot
be found, the cause must be immediately determined and corrected. Typically, this