Study On The Reaction Performances And On-line Detecting Of Dioxin Indicator

Nowadays, study on fast and accurately detection of dioxin has become a hot issue in the field of environmental pollution detection all over the world. The prevailing method of dioxin measurement and analysis has many disadvantages, such as complicated sampling and purification process, long test cycle and high analysis cost. In recent years, lots of researches on the subject of on-line detecting had been studied abroad. Because the dioxin in environment is a trace substance, witch is difficult to be detected by on-line analysis technique directly, so it becomes the mainstream of current research around the world to find a substitute compound (namely dioxin indicator) which has some correlations with dioxin for on-line detecting.A review of current accomplishments in the research on theories of dioxin indicators is given at the first section of the dissertation. Several factors such as reaction progress, chemical structure, combustion condition and emission characteristics, were discussed respectively, too. All these factors had great influence on the selection of dioxin indicators. By comparison, some substances which met the requirement can be selected as potential indicators of dioxin.Moreover, some polycyclic aromatic hydrocarbons (PAHs) had been chosen as a typical potential indicator to study its reaction performances in different metal compounds (CuCl₂, CuO, FeCl₃), different heating rate (10K·min^-1,20K·min^-1 50K·min^-1), and different reaction atmosphere (with or without Cl₂) by thermogravimetry. The characteristic of the fly ash, which was simulated by the mixture of PAHs with different structure and CuCl₂ was also studied at the same time.The advanced time of flight mass spectrometry (TOFMS) method was adopted in this experiment. Several potential dioxin indicators including PAHs (Acenaphthene, Fluorene, Anthracene, Naphthalene, Biphenyl et al.), Trichlorobenzene (TCB) and Trichlorophenol (TCP) were chosen to carry out on-line measurement respectively. After that, the quantity of Acenaphthene was achieved by Origin and the Least Square Method.In order to checkout the feasibility of on-line measurements on real substances with this method mentioned above, more experiments with other substances, such as PE, PVC, coal, mud et al had been carried out by TOFMS.At last, the method which combined the tunable diode laser absorption sensor (TDLAS) and the TOFMS to detect dioxin and its indicators in smoke was presented. This method applies a beneficial reference to the future studies.