Page 520 - Materials Chemistry, Second Edition

CAT3525_C15.qxd 1/27/2005 12:40 PM Page 491
Incineration of Hazardous Wastes 491
Discharge

Excess air
Fuel
Liquid waste
Excess
air
Seals

Fuel
Waste liquids 1200−2300°F 2000−
Waste solids 2500°F Refractory
Waste
lining

Ash Ash

FIGURE 15.7 Rotary kiln incinerator. (From Oppelt, E.T., J. Air Pollut. Control Assoc., 37, 558–586, 1987.
Reproduced with kind permission of the Air and Waste Management Association.)

FIGURE 15.8 Injection ports for the introduction of liquid hazardous wastes to a rotary kiln.

A long residence time is preferred because the solids bed in the kiln is not thermally uniform. The solids
retention time may be several hours, and can be estimated from (U.S. WPCF, 1988).

θ 0.19L/(NDS) (15.6)

where θ is the retention time (min), L the kiln length (m), N the kiln rotational velocity (r/min), D
the kiln diameter (m), and S the kiln slope (m/m).
The coefficient 0.19 is based on empirical data.