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Show - 8 - In this study two bituminous coals were fired with the sewage sludge, one a regular HVB and a regular MVB. These were the same regular coals as fired in the straw co-firing experiments. The experiment s were executed in April/May 1994. The experimental burner was designed to be flexible in terms of geometry and fuel-air mixing, and was based on the design of the IFSB as shown in Figure 3. The burner included of a number of channels for the coal, sewage sludge and coal/sewage sludge blends. Air staging was accomplished by introducing tertiary air through ports on the periphery of the burner (external air staging), and furnace staging with tertiary air injectors located through side ports downstream of the burner. Fuel staging was accomplished by introducing natural gas through the centre of the burner (internal fuel staging), and with gas injectors located through side ports downstream of the burner but upstream of the tertiary air injectors. Furthermore, fuel staging was accomplished by injecting the sewage sludge or a blend through the centre of the burner. For each experimental condition, detailed input/ output measurements were taken which consisted of temperature, 02, C02, CO, NOx and S02, heat transfer and heat flux distributions, and dioxins on a pre-selected flame. Flue gas solid samples were also taken to determine total combustibles burnout. The burner "vas operated \vith nlunicipal sewage sludge in the cofiring range of 0 - 30 0/0, 50 %, 70 % and 100 0/0. Within this range a |
