Development of Methods for the Determination of Major and Minor Elements and Hydrocarbon Residues in Solid Combustion Products

摘要

Methods for the determination of inorganic constituents in coal fly ash by glow discharge spectrometry (GDS) and for the extraction of the organic compounds from coal and ash by supercritical fluid extraction (SFE) at temperatures below 150°C are reviewed. The inorganic elements studied included Al, Ca, C, Cu, Fe, Mg, Mn, P, S, Si and Ti. The organic compounds were measured by weight loss of the sample. The goal of this research was to find easier and faster ways to measure the concentration of inorganic elements in coal ash and to measure extractability of the coal itself, to make coal conversion and utilization more efficient and convenient. The results of this research indicated that for inorganic element determination, graphite can be used as the host material to make the coal ash pellets. When 90% graphite and 10% ash were mixed together and compressed under 20 tons of pressure, the pellets had suitable conductivity and mechanical strength, and the calibration curves for most of the elements were linear, especially for Al and Si. Copper was also used as the host material. In copper pellets the intensities of all elements were much larger than those in graphite, indicating that copper is more promising for pellet preparation. For supercritical fluid extraction, temperature is an important factor for extraction efficiency. The pressure and kinds of modifiers used were also important for extraction. The weight loss by supercritical fluid extraction of coal was much smaller than by soxhlet extraction, indicating that it is difficult to extract organic compounds from coal by SFE at temperatures below 150°C.