Page 255 - Wastewater Solids Incineration Systems

Incinerator Operations 217

• Auxiliary fuel system.
• Heat recovery system.

• Instrumentation and control system.
• Monitoring and recording systems.
• Air pollution control system.
• Center shaft drive, gear, and shear pin.

• Clinker grinder.
• Process water system.
• Lance ports.
• Ash conveyance system.

• Valves and actuators.
• Outer shell.
In the outer shell, operators should be looking for evidence of “hot spots” or cor-
rosion. Infrared thermography, similar to that used for electrical switchgear moni-
toring, is useful for identifying and quantifying hot spots. Metal thickness testing
may be required to determine if there is interior deterioration of the shell.

2.2 Multiple-Hearth Furnace Startup

There are two types of startup: cold startup and hot standby startup. A cold startup
raises the internal temperature of the incinerator from ambient air temperature to at
least 593°C (1100°F) at the hottest location within the incinerator. The temperature
reached may be higher than 593°C (1100°F), depending on the percentage of solids
and the heat content of the feed. When properly performed, a cold startup will cause
evaporation of all moisture in the refractory without causing any damage.
A hot standby startup raises the temperature of the incinerator from a hot
standby temperature of between 316 and 427°C (600 and 800°F) to at least 593°C
(1100°F) at the hottest location within the incinerator.
For both cold and hot standby startups, the required incinerator temperatures
will vary depending on the quality and quantity of the feed. At the Green Bay Metro-
politan Sewer District, the incinerator temperature typically is set to 704°C (1300°F)
for three hours before feed cake introduction. Once the incinerator has been brought