EMISSION CHARACTERISTICS OF DIFFERENT ORGANIC POLLUTANTS FROM WASTE INCINERATION USING O_2/RFG COMBUSTION TECHNOLOGY

摘要

Oxygen/Recycled Flue Gas (O_2/RFG) is one of the new-develop clean combustion technologies, different from general air combustion system, which use high concentration oxygen mixed with recycled flue gas to serve as feed gas for fuel combustion. The exhaust gas can be significantly reduced and the control efficiencies of air pollutant, especially for CO_2, can be much improved. It is usually used for CO_2 recovery in the coal-fired power plants; however, fewer studies apply it for waste incineration as well as investigate the emission characteristics of organic pollutants in such combustion system. As a result, this study applies this O_2/RFG combustion technology for waste incineration in a laboratory-scale fluidized bed incinerator to investigate the effects of different ratios of recycled flue gas and O_2 concentration in feed gas on the emission characteristics of different organic pollutants (PAHs, phenol, alkene and benzene compounds). Experimental results indicated that most high-ring PAHs were present in solid phase while low-ring PAHs were present in gas phase. 2,4-dinitrophenol was the major phenol compounds and the formations of chlorinated phenol compounds were very low. The major alkene compounds were allyl chloride and methacrylonitrile, and the major benzene compounds were BTEX and tricholobenzene. Increasing the O_2 concentration in the feed gas (from 21% to 40%) reduced the concentrations of solid-PAHs and phenol compounds, but increased the concentrations of gas-PAHs, alkene and benzene compounds. As the ratio of recycled flue gas increased, the concentrations of solid-organics (PAHs, phenol, alkene, and benzene compounds) were all increased while that of gaseous-organics were decreased or slightly increased and then decreased. With 75% recycled flue gas, the emission of PAHs was the minimum. These results showed O_2/RFG combustion technology not only improve the destruction efficiency of gaseous organic pollutants but also increase the total combustion efficiency.