OCR Text |
Show ) ) combustion product gases with a packed-column scrubber, and an ionizing wet scrubber, followed by an activated carbon bed adsorber and a high efficiency particulate (HEPA) filter. An induced draft fan downstream of the HEPA filter draws a slight vacuum (draft) throughout the incinerator/scrubber system and vents the combustion products via a stack. The research program studied the effects of three operating parameters: feed chlorine content, incinerator temperature, and combustion excess air. A Box-Wilson factorial experimental design specified 18 test conditions which included 5 levels of variation for each parameter. Blends of methanol, carbon tetrachloride, and chlorobenzene in the feed produced the various inlet chlorine concentrations (0 to 33.8 percent). Arsenic and antimony were added to these blends in proportions designed to give constant feed concentrations of 12 and 40 ppm respectively for all tests. These concentrations in the feed material ensure that the worst-case concentrations in the stack gas will never exceed the threshold limit values (TLV), of 0.2 mg As/m3 and 0.5 mg Sb/m3. Furthermore, if all the trace metals leave the incinerator via the scrubber blowdown water, their concentrations will not exceed the EP toxicity limits (5 mg As/L, no limit established for Sb). The liquid feed entered the main combustion chamber via a steam-atomized nozzle at about 45 kg/hr (100 lb/hr). Auxiliary propane maintained the incinerator at the specified temperature which ranged from 1,137° to 1,450°C (2,079° to 2,642°F). Combustion air entered via swirl registers in the burner to produce from 5.9 to 11.7 percent excess oxygen at the incinerator exit. 3 |