Aromatic PICs Formation and Destruction in a Laboratory-Scale Incineration System

• Main Authors: Liu,Shu-Fen, 劉恕芬
• Other Authors: Lin, Chieh
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/92505650257408813065

碩士 === 國立屏東科技大學 === 環境工程技術研究所 === 86 === Aromatic compounds are benzene and compounds that resemble benzene in chemical behavior. In the list of the princile organic hazardous compounds made by U.S. EPA, aromatic compounds take priority of the controlled items. Since aromatic offer many adventages like high energy density and high knock rating, these compounds are added to gasline and jet fuels to improve the engine effency. The purpose of this research is to use a laboratory scalecombustor to simulate the actual incineration process and obtain some fundamental data. Under the design condition, combustor performance in termof fuel burnoff fraction,and destruction and removal efficenc(DRE) as well as the products of incomplete combustion(PICs) is the thrust of this investigation. The spouted bed combustered as one of the most innovative reactors with which to obtain such data. A model fuel- toluene premixed with air are combusted in our spouted bed combustor. The equivalence ratio is the primary operating parameters to be investigated. Experimental results on the fuel lean regime, the stoichometric and the fuel rich regime will be reported. Those data related to the toluene o xidation mechanism and predict the primary pathhway of aromatic PICs formation. Results showed that the highest DRE happen when the equivalence ratio wa snear to the stoichiometric condition. The concentration profile of fuel resid uesbetween the center of the reactor and the wall of the reactor showed the formation and destruction of PICs continuously change during the post flame regi ion(theabove bed surface 33-52cm). In oxidation process of toluene, the signif icant paths of inital propagation process were benzyl radical formation involving abstraction of an H, and benzene andmethyl radical formation by displacement of the side chain. It is interesting to note that the level of ethylbenzene, xylenes and PAHs emissions are high in the fuel regime than in the fuel lean condition.Based on the comparison between the derived kt values and the calculated residencetime, the catalytic effect on the aromatic PICs formation in the heterogeneous environment is demonstrated clearly. The kt value will help to identify the primary operating parameter control the formation and/or the destruction of PICs whenthe residence time distribution is complex in the reactor. The observed rates of aromatic PICs formationn will be used to provide qu antitative information to themodeling study of heterpgenous combustion in the future.