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Show THIRD GENERATION ROTARY KILN SYSTEM Since the advent of R C R A and SuperFund registration in 1985, the industry has progressed through at least three generations of rotary kiln incineration equipment for site remediation. The early projects were utilized on asphalt plant type kiln or small modular kiln systems. These devices were originally designed for a single predictable feed (asphalt), without consideration to an overall combustion process. Perhaps as important for commercial hazardous waste incinerator operation, this equipment was designed for batch operation and the effect of 24 hour-per-day, 7 day-per-week operation on mechanical equipment was significant. Combustion efficiencies and DRE's were marginal and down-times were appalling. Second generation equipment, primarily developed from calcining technologies, improved the mechanical operation characteristics of this equipment. The rotary kiln was designed for continuous operation. Calcining equipment, however, generally was not designed to optimize the combustion process and produce the high destruction and removal efficiencies (DRE's) required to meet today's stringent hazardous waste regulations. Rotary kiln incineration is a solid fuel (waste) combustion process in which it is not unusual for one hour's worth of fuel to be in the combustion zone at a given time and for the composition of the fuel (waste) to vary dramatically. The kiln system is expected to predictably combust these varying wastes without excess emissions. The third generation kilns were designed to expressly address these operating concerns. Equipment designs balance the need to achieve high production levels with the need to operate at an even, controlled combustion rate. In any combustion system, the designer prefers to have control of both the fuel supply and the air supply to the unit, but he must be able to control either the air or the fuel to make the combustion system operate in an efficient and l |