Speciation Of Mineral Matter In Daqing Lignite Coal And Formation Of Particulate Matter

The particulate matter derived from pulverized coal combustion is one of the main sources of inhalable particles in the atmosphere. Fine particles (PM2.5, i.e. Particle diameter <2.5μm) are caused great attention as their negative influence on the people's health, as most of trace toxic components deposit on the surfaces of fine particles for their large surfaces. However, due to the complication of the formation mechanism of particulate matter during coal combustion, little information about this aspect has been reported. Therefore, there is scientific and economical significance to study the formation, growth, and controlling of particulate matter during the pulverized coal combustion.An overview of the main progress in the formation of particulate matter during coal combustion was given, followed with the comment and criticism of these research achievements. Then, experiments on Daqing lignite coal were conducted using methods of float-sink, low temperature ash, and sequential extraction to study the speciation of inorganic mineral matter in this specific coal, as the speciation of mineral matter played an important role in the mineral matter transformation and the particulate formation during coal combustion. These experiments helped us to understand the inherent transformation progress of mineral matter during coal combustion significantly.Field experiments in Hongwei power station in Daqing were also carried out. Both of the fly ash before and after ESP were sampled and classified with respect to aerodynamic diameter using low pressure impactor, and then samples were detected and analyzed by FSEM, XRF, and so on. As a result, the mass distribution, the shape, and the inorganic components distribution of the sampled particles were obtained, which could lead to in-depth comprehension of the formation of particulate matter derived from coal combustion.In the end, the most accepted vaporization model of refractory inorganic oxide, which was completely established by Quann, was analyzed and improved. We managed to introduce the CO/CO2 ratio in the surface of char to the model, and found that the improved model could simulate the total vaporization of inorganic matter quiet well, as well as that it could reveal the influence of different combustion parameters on the inorganic oxide vaporization.