Hexachlorobenzene, Incineration

One incinerator that has been evaluated rather extensively and for which test results have been reported is the liquid chemical waste incinerator facility owned by the Metropolitan Sewer District (MSD) of Greater Cincinnati, Ohio (1 ). The MSD facility uses a rotary kiln and liquid injection cyclone furnace to incinerate a wide variety of liquid industrial chemical wastes. The total design heat release rate is 120 million kJ/h (114 million Btu/h). Tests conducted over a wide temperature range ( 900°C to 1300°C) for six Appendix VIII chemicals (carbon tetrachloride, chloroform, hexachlorobenzene, hexachlorocyclo-pentadiene, and hexachloroethane) have shown DREs equal to or very near 99.99%. 

A hazardous waste incinerator operates at a chemical plant to treat a liquid production waste stream. Your manager requests that in preparation for a trial bum, you institute a procedure for compliance with emission regulations. The waste stream feed rate is 800 Ib/h and the stack gas flowrate is 22,760 scfin (60°F, 1 atm). The incinerator is to operate at a destmction and removal efficiency (DRE) of 99.995% for hexachlorobenzene. 

Hexachlorobenzene is dissolved in a combustible solvent and burned in a chemical incinerator equipped with an afterburner and scrubber. 

A hazardous waste incinerator monitored over a 24-hour period took in a total of 1 kg of hexachlorobenzene. Analysis of the exhaust gas from the facility showed levels of 0.25 pg m of hexachlorobenzene at an exhaust gas flow rate of 0.200 m /s. What is the DRE of the process ... 

---