Page 310 - Wastewater Solids Incineration Systems

Incinerator Maintenance 271

2.1 Slag Formation

Areas where slag buildup occurs include, but are not limited to, the sand bed below
auxiliary fuel lines, burner tiles on freeboard burners, thermocouples, and offgas
ducting. A detailed discussion on the formation and removal of slag and determina-
tion of fusion temperature is contained in the MHF section of this chapter.
If slag formation is observed during normal operation the incinerator should be
shut down and cooled and the slag removed.

2.2 SLAG REMOVAL
Care should be taken when removing slag from the refractory to minimize damage
to the refractory. As a result, guidelines should be prepared for operators based on
the refractory manufacturer’s recommendations.

2.3 MAINTENANCE ISSUES
2.3.1 Thermocouple Repair and Replacement
Thermocouples within the incinerator must be cleaned, calibrated, and repaired on a
regular basis. The thermocouples should be replaced on an as-needed basis.
2.3.2 Calibration, Repair, and Replacement of Analyzers
Oxygen analyzers, THC analyzers, and carbon monoxide analyzers have to be cali-
brated on a daily basis and repaired as necessary.
2.3.3 Tuyere Inspection, Cleaning, and Replacement

Tuyeres allow air to exit the wind box and fluidize the sand bed. Tuyeres need to be
inspected and cleaned on an annual basis and replaced as needed.

2.3.4 Arch Repair and Replacement
The arch separating the wind box from the sand bed needs to be checked on a regular
basis. If the arch is made of refractory, both the arch and the refractory need to be
checked regularly. If the arch is made of stainless steel, it needs to be checked for
cracks and signs of stress and corrosion regularly.

2.3.5 Removal of Sand Bed and Sand in the Wind Box
It is good practice to remove the bed sand every two or three years. This removal is
done by operating the fluidizing air blower and opening the bed drain valve. All
inspection doors must be kept closed to prevent filling the building with sand.