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Show Abstract This paper describes results of an investigation of the effect of large amplitude resonant pulsations excited inside an E P A rotary kiln incinerator by a tunable pulse combustor (i.e., the Cello burner) upon puff emissions. Incineration tests were conducted with two surrogate wastes: toluene and polyethylene. Pulsations were excited inside the incinerator by operating the Cello burner at a frequency that equaled a natural acoustic mode frequency of the incinerator. Each test was repeated ten times, and each waste was incinerated with and without the excitation of large amplitude pulsations within the incinerator. The performance of the incinerator was evaluated by determining the total amounts of unburned, gas phase, hydrocarbons, carbon monoxide and soot emitted during the test. Comparison of the incinerator emissions in pulsating and non-pulsating tests revealed that in the pulsations decreased the total amount of emissions (i.e., the magnitude of the puffs) in all tests. Furthermore, the pulsations reduced the soot emissions by amount varying between 30-75%, which is most significant as it is generally more difficult to incinerate the soot in the afterburner and the soot represents a higher health hazard. These analytical results were confirmed by visual observations of conditions inside the incinerator where the "atmosphere" was practically clear in pulsating tests and very smoky in non-pulsating tests. Finally, sampling line oxygen concentration measurements strongly suggest that the observed improvements in incinerator performance were due (at least in part) to the increase in mixing rates caused by the pulsations. Introduction Interest in pulse combustion and its applications has been steadily increasing because of the potential of this technology to reduce fuel consumption and emissions and increase productivity in energy intensive and incineration processes. T o date, the majority of efforts in this area were devoted to the development and commercialization of space and liquid heating applications of pulse combustion. In such an application, energy released by the pulse combustion process is transferred, through the pulse combustor walls, to the heated fluid (e.g., air, water, thermal fluid), which is brought into contact with the exterior walls of the pulse combustor. The advantages of these applications can be directly related to the presence of pulsations within the combustor, and they include: a highly intense and complete combustion process, increased rate of heat transfer from the flame and combustion products to the combustor walls, low C O , unburned hydrocarbons, N O x and soot emissions, and self aspiration of fuel and air. While the reduced emissions alone would made these applications highly attractive, additional economic benefits of these heating applications include lower fuel consumption and smaller system size, which reduces capital investment and operating costs. These advantages are provided by the space heaters and boilers that are currently being successfully marketed by such U S companies as Lennox, Hydrtherm and Fulton a number of successful Japanese and European companies. The realization that the advantages exhibited by pulse combustion heating applications are directly related to the presence of large amplitude pulsations within the system has suggested that similar advantages could be attained in large scale energy intensive and incineration processes if practical means for exciting pulsations within the process could be found. A process for driving such pulsations in an industrial process using a tunable pulse combustor (i.e., the Cello burner) has been recently developed by Sonotech1'2. In a typical application, the Cello burner is designed to operate over a range of frequencies that includes at least one natural acoustic mode frequency of the process. The Cello burner is then retrofitted to the process and tuned on site to operate at one of the natural acoustic mode frequencies of the process. In such an application, the Cello burner supplies a small fraction (e.g., 1-5%) of the process energy and, most importantly, it excites large amplitude, resonant, pulsations within the process. W h e n compared to steady state operation of the process, these pulsations can produce all or a combination of the following benefits: increase the fraction of input energy transferred to the load (e.g., liquid or waste), increase the process 2 V-28 |