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                                       Details van artikel 26 van 114 gevonden artikelen
 
 
  Combustion Properties of Macerals from Four Alberta Coals
 
 
Titel: Combustion Properties of Macerals from Four Alberta Coals
Auteur: Gentzis, Thomas
Chambers, Allan
Verschenen in: Energy sources. Part A, Recovery utilization and environmental effects
Paginering: Jaargang 17 (1995) nr. 6 pagina's 655-680
Jaar: 1995-11-01
Inhoud: The combustibility of handpicked vitrinite and inertinite concentrates from four Alberta coals ranging in rank from subbituminous C to low-volatile (LV) bituminous was measured and compared with the parent coal. The combustion properties of the concentrates were studied by routine analysis of the maceral concentrates, examination of low-temperature reactivity on a thermogravimetric analyzer, examination of high-temperature burnout profiles on the entrained flow reactor, and measurement of char combustion reactivity on a single-particle combustor. The structure of partially combusted chars from two of the coals and their maceral concentrates were examined using scanning electron microscopy. Low-temperature oxidation of pyrolysis chars formed from the coals and macerals indicated that all of the samples had similar activation energies of between 29,900 and 35,600 cal / mol. For three of the coals, the inertinite char had lower reaction rates under these conditions. Under entrained flow combustion conditions at 1000°C, the subbituminous and high-volatile (HV) bituminous coals were very reactive, with 90% burnout in air in less than 0·2 s. The initial weight loss of the inertinite maceral during devolatilization was significantly less than the vitrinite maceral or parent coal for the three reactive coals. However, the chars formed from inertinite burned at similar rates to vitrinite char. The similarity in maceral char combustion rates was confirmed on a single-particle combustor; however, the three reactive coals and their macerals burned at the diffusion limit. Although char combustion rates were similar, the low initial weight loss of the inertinite fraction would result in longer combustion times for complete combustion of the inertinite char. Scanning electron microscopy revealed that inertinite chars from the HV bituminous and the LV bituminous coals generally retained their original morphology1 during devolatilization, white the vitrinite macerals went through a plastic phase. The “reactive” HV bituminous coal formed porous, spongelike chars, while the “unreactive” LV bituminous coal developed vesicular chars with low surface area.
Uitgever: Taylor & Francis
Bronbestand: Elektronische Wetenschappelijke Tijdschriften
 
 

                             Details van artikel 26 van 114 gevonden artikelen
 
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