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348 Lawrence K. Wang et al.

Fig. 1. Schematic of a thermal incinerator. (From US EPA.)

the heat generated during incineration is recovered and stored. The packed beds store the
heat energy during one cycle and then release it as the beds preheat the incoming organic-
laden gas during the second cycle. Up to 95% of energy in the flue gas can be recovered in
this manner (1). The discussion in this chapter focuses on the more common recuperative-
type incineration system. A detailed discussion of regenerative thermal incinerators is
provided elsewhere (2).
In this chapter, a methodology is provided to quickly estimate thermal incinerator
design and cost variables (2–12). The approach taken in this chapter is somewhat less
detailed than the approach given in other US Environmental Protection Agency (EPA)
references, but it allows for a relatively quick calculation of design and operational
parameters. This approach enables the readers to obtain a general indication of design
and cost parameters without resorting to more detailed and complex calculations.
When an adequate amount of oxygen is present in the combustion chamber, organic
destruction efficiency (DE) of a thermal incinerator is determined by combustion temper-
ature and residence time. Furthermore, at a given combustion temperature and residence
time, DE is also affected by the degree of turbulence, or mixing of the emission stream
and hot combustion gases, in the incinerator. DE in an incinerator depends on the types
of organic pollutants as well. Halogenated organic compounds are more difficult to oxi-
dize than unhalogenated organics; hence, the presence of halogenated compounds in the
emission stream requires higher temperatures and longer residence times for complete
oxidation. Depending on the goals of emission stream control, thermal incinerators can
be designed achieve a wide range of DE. Discussion in this chapter will focus on the
processes with organic DE of 98–99% and higher.
The incinerator flue gases are discharged at high temperatures and contain valuable
heat energy. Therefore, a strong economic incentive exists for heat recovery. Typical
recovery methods include the use of flue gas to preheat the emission stream that is
going to be incinerated, to preheat combustion air, and to produce hot water or steam
for other heating requirements. In most thermal incinerator applications, the available
heat energy in the flue gases is used for preheating the emission stream. Discussion