Mineral phase characterization and thorough understanding of its transformation behavior during combustion are imperative to know the potential utilization of coal in the thermal industries. The primary objective of t...Mineral phase characterization and thorough understanding of its transformation behavior during combustion are imperative to know the potential utilization of coal in the thermal industries. The primary objective of this work is to analyze the quality of Indian Coals and obtain their mineral species-specific information at different depths. The samples were obtained from Talcher Coalfield, Odisha, India. Coal from four seam sections in the Talcher coalfield, India are mainly high ash coal （〉50 %） and volatile matter deceases along with the seam depth. XRD results show that the major mineral phases present in the coal are quartz and kaolinite. Siderite, illite, and anatase were found in minor quantities. It has been observed that the clay minerals （kaolinite, silimanite, illite） decompose at higher temperature and traces of dolomite, mullite, hematite etc. are formed during the process of combustion. Among the four seams （M2, M12, M24 and M43） studied, ash of M43 has high A1203%, TIO2% and K20% content and low SIO2%, CaO% and MgO% content. High acid- to-base ratios contributed to high ash fusion temperatures （IDT 〉 1500 ℃） and low slagging potential of the coals studied. Relatively low fouling index （〈0.3） was estimated for all the coal seams studied. Furthermore, thermodynamic modeling software, FactSage, have been used to envision the mineral phase transformations that take place between 800 and 1500℃ during coal combustion.展开更多
This kinetic study focuses on determining the thermal gravimetric profile of a particular grade of Indian sub-bituminous coal. A thermogravimetric analyzer (TGA-1000) was employed to investigate the thermal behavior a...This kinetic study focuses on determining the thermal gravimetric profile of a particular grade of Indian sub-bituminous coal. A thermogravimetric analyzer (TGA-1000) was employed to investigate the thermal behavior and extract the kinetic parameters of Jamadoba coal and its corresponding density sepa<span style="font-family:Verdana;color:#000000;">rated macerals. The weight loss was measured in air atmosphere. The coal </span><span style="font-family:Verdana;color:#000000;">samples used in this study were obtained from Jamadoba mines, Jharkhand. Sam</span><span style="font-family:Verdana;color:#000000;">ples of 35 mg and 200 μm mean size were subjected to synthetic air atmos</span><span style="font-family:Verdana;color:#000000;">pheres (21% O</span><sub><span style="font-family:Verdana;color:#000000;">2</span></sub><span style="font-family:Verdana;color:#000000;">). Heating rates of 2, 5 and 7</span><span style="font-family:;" "=""><span style="color:#000000;font-family:Verdana;">°</span><span style="font-family:Verdana;color:#000000;"></span><span><span style="font-family:Verdana;color:#000000;">C/min were applied until the tempera</span><span style="font-family:Verdana;color:#000000;">ture reached 1400</span></span><span><span style="color:#000000;font-family:Verdana;">°</span><span style="font-family:Verdana;color:#000000;">C, which was kept constant until burnout. Low heating</span></span><span><span style="font-family:Verdana;color:#000000;"> rate was preferred so that devolatilization occurs prior to ignition and </span><span style="font-family:Verdana;color:#000000;">combust</span><span style="font-family:Verdana;color:#000000;">ion. Derivative thermogravimetry (DTG) analysis method was applied to </span><span style="font-family:Verdana;color:#000000;">measure the weight changes and rates of weight loss used for calculating the kinetic parameters. The activation energy (</span><i><span style="font-family:Verdana;color:#000000;">E</span><sub><span style="font-family:Verdana;color:#000000;">a</span></sub></i><span style="font-family:Verdana;color:#000000;">) and pre-exponential factor were obtained </span><span style="font-family:Verdana;color:#000000;">from model-free methods by applying non-isothermal thermogravimetry</span><span style="font-family:Verdana;color:#000000;"> analysis.</span></span></span>展开更多
Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The...Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The objective of this paper is to study the changes in organic structure and mineral phase transformation during combustion. Different density fractions were generated and then heated at different temperatures from 200 to 1000 ℃. Petrography, Fourier transform infrared spectroscopy （FTIR） and X-ray diffraction （XRD） were carried out on all the density fractions aimed to accomplish this objective. Here, through petrography, it was observed that the vitrinite and liptinite macerals disappear at higher temperature while porous inertinite is seen. The inertinite structure is exposed which is assumed by the presence of -OH and C-O-C stretches with the aromatic nucleus （CH） and three to four adjacent H from FTIR spectra. Moreover, it can be concluded that aliphatic groups get collapsed at high temperature. In case of inorganic matter, through XRD and FTIR, it is also revealed that with increasing temperature, clay minerals converted into elemental oxides. Hence, this study is suggesting that the structures of coal are altered by the degree of contact metamorphism.展开更多
文摘Mineral phase characterization and thorough understanding of its transformation behavior during combustion are imperative to know the potential utilization of coal in the thermal industries. The primary objective of this work is to analyze the quality of Indian Coals and obtain their mineral species-specific information at different depths. The samples were obtained from Talcher Coalfield, Odisha, India. Coal from four seam sections in the Talcher coalfield, India are mainly high ash coal （〉50 %） and volatile matter deceases along with the seam depth. XRD results show that the major mineral phases present in the coal are quartz and kaolinite. Siderite, illite, and anatase were found in minor quantities. It has been observed that the clay minerals （kaolinite, silimanite, illite） decompose at higher temperature and traces of dolomite, mullite, hematite etc. are formed during the process of combustion. Among the four seams （M2, M12, M24 and M43） studied, ash of M43 has high A1203%, TIO2% and K20% content and low SIO2%, CaO% and MgO% content. High acid- to-base ratios contributed to high ash fusion temperatures （IDT 〉 1500 ℃） and low slagging potential of the coals studied. Relatively low fouling index （〈0.3） was estimated for all the coal seams studied. Furthermore, thermodynamic modeling software, FactSage, have been used to envision the mineral phase transformations that take place between 800 and 1500℃ during coal combustion.
文摘This kinetic study focuses on determining the thermal gravimetric profile of a particular grade of Indian sub-bituminous coal. A thermogravimetric analyzer (TGA-1000) was employed to investigate the thermal behavior and extract the kinetic parameters of Jamadoba coal and its corresponding density sepa<span style="font-family:Verdana;color:#000000;">rated macerals. The weight loss was measured in air atmosphere. The coal </span><span style="font-family:Verdana;color:#000000;">samples used in this study were obtained from Jamadoba mines, Jharkhand. Sam</span><span style="font-family:Verdana;color:#000000;">ples of 35 mg and 200 μm mean size were subjected to synthetic air atmos</span><span style="font-family:Verdana;color:#000000;">pheres (21% O</span><sub><span style="font-family:Verdana;color:#000000;">2</span></sub><span style="font-family:Verdana;color:#000000;">). Heating rates of 2, 5 and 7</span><span style="font-family:;" "=""><span style="color:#000000;font-family:Verdana;">°</span><span style="font-family:Verdana;color:#000000;"></span><span><span style="font-family:Verdana;color:#000000;">C/min were applied until the tempera</span><span style="font-family:Verdana;color:#000000;">ture reached 1400</span></span><span><span style="color:#000000;font-family:Verdana;">°</span><span style="font-family:Verdana;color:#000000;">C, which was kept constant until burnout. Low heating</span></span><span><span style="font-family:Verdana;color:#000000;"> rate was preferred so that devolatilization occurs prior to ignition and </span><span style="font-family:Verdana;color:#000000;">combust</span><span style="font-family:Verdana;color:#000000;">ion. Derivative thermogravimetry (DTG) analysis method was applied to </span><span style="font-family:Verdana;color:#000000;">measure the weight changes and rates of weight loss used for calculating the kinetic parameters. The activation energy (</span><i><span style="font-family:Verdana;color:#000000;">E</span><sub><span style="font-family:Verdana;color:#000000;">a</span></sub></i><span style="font-family:Verdana;color:#000000;">) and pre-exponential factor were obtained </span><span style="font-family:Verdana;color:#000000;">from model-free methods by applying non-isothermal thermogravimetry</span><span style="font-family:Verdana;color:#000000;"> analysis.</span></span></span>
文摘Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The objective of this paper is to study the changes in organic structure and mineral phase transformation during combustion. Different density fractions were generated and then heated at different temperatures from 200 to 1000 ℃. Petrography, Fourier transform infrared spectroscopy （FTIR） and X-ray diffraction （XRD） were carried out on all the density fractions aimed to accomplish this objective. Here, through petrography, it was observed that the vitrinite and liptinite macerals disappear at higher temperature while porous inertinite is seen. The inertinite structure is exposed which is assumed by the presence of -OH and C-O-C stretches with the aromatic nucleus （CH） and three to four adjacent H from FTIR spectra. Moreover, it can be concluded that aliphatic groups get collapsed at high temperature. In case of inorganic matter, through XRD and FTIR, it is also revealed that with increasing temperature, clay minerals converted into elemental oxides. Hence, this study is suggesting that the structures of coal are altered by the degree of contact metamorphism.
