Experimental Study On On-line Monitoring Of PCDD/Fs Indicator Using TOF-MS

Energy shortage and environment pollution become more and more important after entering 21st century. Waste clean utilization is a hot issue currently. Incineration is widely used as a waste management technique, but the pollutant emission is a big problem. Especially the dioxin-like compounds are high toxic persist organic pollutants which lead to international attentions.The emission control and combustion optimization call for a fast online-monitoring technology. This research based on the technique of time-flight-mass-spectrometer, developed the equipment that can be used for monitoring the indicator of PCDD/Fs during incineration process. The correlation between PCDD/Fs and its indicator is studied in the paper. VUV-TOFMS is used for monitor these indicators, and the quantitative analysis has been achieved. Real-time monitoring for PCDD/Fs emission has been applied in lab-scale.Reviews techniques of PCDD/Fs monitoring, the on-line monitoring that use TOFMS has been evaluated. Introduction of development of the equipment based on ionization mode and inject system. The VUV-TOFMS that used for PCDD/Fs indicator monitoring has been developed. The inject system and ionization parameters has been optimized for specific indicators.Polycyclic aromatic hydrocarbons (PAHs) and chlorobenzene compounds (CBs) have been selected as indicators, the correlation between these indicators and PCDD/Fs emission has been evaluated in 3 different waste incinerators. High correlation coefficient from CBzs to PCDD/Fs TEQs is founded before flue gas purification system. The emission of PAHs is highest, but the correlation coefficient from PAHs to PCDD/Fs is low.VUV-TOFMS is used for monitoring of Cl1Bz,1,2-Cl2Bz and PAHs including naphthalene, fluorene, phenanthrene, anthracene and pyrene in certain concentration. A good correlation between the signal intensity and real concentration has been found. The quantitative analysis of indicators has been achieved.Fly ash collected from real waste incinerator is reacted in different conditions to generate PCDD/Fs. Parallel testing of on-line monitoring and off-line collection has been done. Comparison of the signal and PCDD/Fs emission data shows that the signal intensities of Cl1Bz and Cl2Bz could reflect the variation of PCDD/Fs emission and TEQs. The trend of PCDD/Fs emission and accumulation of signal of Cl1Bz and Cl2Bz is completely fixed.