Modes Of Occurrence And High-temperature Behaviors Of Mineral Matter In Coals And Their Effects On Ash Fusibility

Coal will continue to be the major energy of our country in a long period of time. The presence of coal ash could lead to the relative reduction of combustible components, which causing the reduction of the calorific value of coal. More importantly, coal ash can cause slagging, fouling, corrosion, wear and other issues, which seriously affect the safety and economy of the boiler. A systematic study on the modes of occurrence and the high temperature behaviors of the mineral matter in coals was conducted in this article. A prediction model for the ash fusion temperatures was also established.Firstly, the relevant analysis and hierarchical cluster analysis were conducted on the complete characteristic data (proximate analysis, elemental analysis, ash composition analysis and ash fusion analysis) of 21 coals. And the reasons for these relations were analyzed. The quantitative characteristics of the mineral matter in coals were determined by the Rietveld method on the low temperature ash samples.Then, the thermal gravimetric analysis and in situ X-ray diffraction method were conducted on the low temperature ash to study the behaviors of mineral matter in coals below 815 ?. The common behaviors of mineral matter at higher temperatures in coals were got from the study on 21 coals.Finally, a large number of samples by mixing of pure minerals were made according to the quantitative characteristics of the mineral matter in coals. The samples were processed according to the national standard on ashing. And the ash fusion temperatures of the samples were tested. A model to predict the ash fusion temperatures was established through the method of principal component regression. And the model was used for the prediction of fusion temperatures of real coal ash, which proved the feasibility of building prediction model based on the mineral compositions in coals. The model not only has the predictive accuracy, but also reflects the behaviors of mineral matter in coals at high temperatures. So the model can be used to guide the regulation of ash fusibility by the method of coal blending and additive.