Electronic Resource
Combustion characteristics of high ash South African coal reserves.
| العنوان: | Combustion characteristics of high ash South African coal reserves. |
|---|---|
| المؤلفون: | Everson R.C., Fourth International Conference on Clean Coal Technology Dresden, Germany 18-May-0921-May-09, Kalibantonga P.D., Neomagus H.W.J.P., Wagner N.J. |
| بيانات النشر: | London IEA Clean Coal Centre 2009 |
| نوع الوثيقة: | Electronic Resource |
| مستخلص: | Characterisation was carried out of the chemical, structural, reflectance, maceral, microlithotype, carbominerite, and minerite properties of thirteen different high-ash coal samples. The coals were found to be bituminous and of medium rank (reflectance 0.58%-0.78%) with compositions (by volume) of 7%-66% pure inertinite, 2%-31% pure vitrinite, 11%-42% bi- and tri-macerites, 9%-33% carbominerites and 7%-34% minerite. Raw coals were combusted in a reactive gaseous medium with experimental conditions similar to those used in fluidised bed combustion. The initial devolatilisation period was found to be very rapid, depending on the coal type and temperature, and was distinctly different to the combustion period. The conversion of coal and char was found to increase only slightly over the high temperature range, which indicated that diffusion effects become important. The reactivity of the coals increased slightly with increasing ash composition and decreased with increasing inertinite composition. A shrinking core model involving transport of oxygen to the outer surface of the coal particle, diffusion of oxygen through the porous ash layer, and reactions on the coal surface was found to agree very well with combustion experimental results. The ash diffusion coefficients and reaction rate constants can be used in a fluidised bed combustion process model. Characterisation was carried out of the chemical, structural, reflectance, maceral, microlithotype, carbominerite, and minerite properties of thirteen different high-ash coal samples. The coals were found to be bituminous and of medium rank (reflectance 0.58%-0.78%) with compositions (by volume) of 7%-66% pure inertinite, 2%-31% pure vitrinite, 11%-42% bi- and tri-macerites, 9%-33% carbominerites and 7%-34% minerite. Raw coals were combusted in a reactive gaseous medium with experimental conditions similar to those used in fluidised bed combustion. The initial devolatilisation period was found to be very rapid, depending on the coal type and temperature, and was distinctly different to the combustion period. The conversion of coal and char was found to increase only slightly over the high temperature range, which indicated that diffusion effects become important. The reactivity of the coals increased slightly with increasing ash composition and decreased with increasing inertinite composition. A shrinking core model involving transport of oxygen to the outer surface of the coal particle, diffusion of oxygen through the porous ash layer, and reactions on the coal surface was found to agree very well with combustion experimental results. The ash diffusion coefficients and reaction rate constants can be used in a fluidised bed combustion process model. |
| مصطلحات الفهرس: | COAL, COMBUSTION, COMPOSITION, FLUIDISED BED COMBUSTION, LABORATORY STUDY, MODELLING, NON-METALS EXTRACTION, OXYGEN, PROPERTIES, QUANTITATIVE MINERALOGY, REACTION KINETICS, REFLECTION SPECTRA, SOUTH AFRICA, TEMPERATURE, text |
| URL: | %C% |
| الاتاحة: | Open access content. Open access content |
| ملاحظة: | und |
| Other Numbers: | UKMMM oai:icon.iom3.org:119938 URN:ISBN:978-92-9029-467-2 1309248098 |
| المصدر المساهم: | INSTITUTE OF MATS MINERALS & MINING From OAIster®, provided by the OCLC Cooperative. |
| رقم الانضمام: | edsoai.on1309248098 |
| قاعدة البيانات: | OAIster |
| الوصف غير متاح. |