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Show Performance of Third Generation Rotary Kiln Incinerator John Petersen and Mike Keller Callidus Technologies Inc. repeatable manner. If the designer does not have full control of either the fuel or air supply, the consequences will be poor system operation and associated unpredictable emissions and operating conditions. A n examination of rotary kiln operations to include input of both fuels and combustion air highlights several variables that must be considered. First, consider how materials are processed into the kiln. In the ideal world, fuel feeding to the rotary kiln is a smooth continuous operation to deliver thermal energy at a constant rate. However, the rotary kiln is used to process varied types of waste materials that include, but is not limited to sludges, soils, and varied types of trash. Unfortunately, these materials are normally not blended to provide a consistent heating value and are often processed on a batch basis. Mechanical equipment to feed these materials include screw feeders, drop chutes, and ram loaders. These devices are a compromise between the desire to meter material into the kiln evenly and the requirement to avoid feed jams and processing interruptions. In short, feeding of the waste materials is not a smooth continuous process that meters thermal energy into the kiln. On a minute to minute basis, the fuel input rate can be expected to vary significantly. These feed variations can result in very dramatic swings in flue gas production and heat release within the incinerator. A good example is to consider that operators will occasionally feed a whole barrel of waste into the kiln during a short one to two minute period. This barrel of material m a y contain a hydrocarbon sludge with over 6 M M Btu's of available heat which, if not properly controlled, will volatilize and combust within two to three minutes. What this means, in simple terms, is that the downstream equipment, ID fan, scrubber, etc. must be sized to handle instantaneous flows at least 25 percent greater than the calculated heat and material balances in order to ensure proper operating pressures in the primary incinerator at all V-33 2 |