Thermogravimetric study of interactions in the pyrolysis of blends of coal with radiata pine sawdust

Ulloa, Claudia; Gordon, Alfredo L.; Garcı́a, Ximena

doi:10.1016/j.fuproc.2008.12.015

Cited by 117 publications

(70 citation statements)

References 19 publications

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“…Park et al [64] also noted as Oney et al [115] as well as Gao et al [116], that synergy was more pronounced at higher biomass blending ratio (around 70%). Ulloa et al [117] conducted co-pyrolysis of blends of subbituminous (Bitsch Coal), bituminous (Lemington coal) coals, with Radiata Pine sawdust in a TGA under nitrogen at different heating rates (10, 30 and 50 K/min) to a maximum temperature of 1473 K. Their experiment depicted interaction between biomass and the two coals at temperatures higher than 673 K and up to 1473 K. Their explanation of the interaction was that the synergy between devolatilization of biomass and lignin (which spans from 673 K to 1173 K) coincides with that of coal. However, they identified the role of biomass mineral matter as catalytic agent favoring decomposition of coal/biomass blends by decreasing the formation of char and favoring the generation of more volatile material.…”

Section: Pyrolysismentioning

confidence: 99%

“…While extensive studies have been conducted on free radicals release during coal pyrolysis [115][116][117][118][119][120][121][122][123][124], such studies involving direct in situ observation of radicals released during biomass or biomass components (cellulose, hemicelluloses and lignin) pyrolysis are lacking. Understanding the mechanism of free radicals release during biomass/biomass components pyrolysis can pave the way to improvements in the modeling of coal and biomass blends during co-pyrolysis/co-gasification, and the synergistic effect between coal and biomass; therefore, providing an insight to the prediction of co-conversion of coal and biomass.…”

Section: General Assessmentmentioning

confidence: 99%

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A Review of Thermal Co-Conversion of Coal and Biomass/Waste

2014

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Abstract:Biomass is relatively cleaner than coal and is the only renewable carbon resource that can be directly converted into fuel. Biomass can significantly contribute to the world's energy needs if harnessed sustainably. However, there are also problems associated with the thermal conversion of biomass. This paper investigates and discusses issues associated with the thermal conversion of coal and biomass as a blend. Most notable topics reviewed are slagging and fouling caused by the relatively reactive alkali and alkaline earth compounds (K 2 O, Na 2 O and CaO) found in biomass ash. The alkali and alkaline earth metals (AAEM) present and dispersed in biomass fuels induce catalytic activity during co-conversion with coal. The catalytic activity is most noticeable when blended with high rank coals. The synergy during co-conversion is still controversial although it has been theorized that biomass acts like a hydrogen donor in liquefaction. Published literature also shows that coal and biomass exhibit different mechanisms, depending on the operating conditions, for the formation of nitrogen (N) and sulfur species. Utilization aspects of fly ash from blending coal and biomass are discussed. Recommendations are made on pretreatment options to increase the energy density of biomass fuels through pelletization, torrefaction and flash pyrolysis to reduce transportation costs.

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Section: Pyrolysismentioning

confidence: 99%

Section: General Assessmentmentioning

confidence: 99%

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

2014

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“…3), which constitute the macromolecular structure of the agricultural and other woody materials, are linked together with relatively weak ether bonds (R -O -R, bond energy of 380-420 kJ mol -1 ). It has been reported by Blajez and Kosik, 33) that these bonds are less resistant to heat at temperatures as low as (400-500°C). In contrast, the immobile structure (MC carbon structure), which mostly comprised of dense polycyclic aromatic hydrocarbons linked together by C = C (aromatic ring) bonds with bond energy of 1 000 kJ mol -1 are more resistant to the heat.…”

Section: Effect Of Blending On Gas Phase Reactionmentioning

confidence: 89%

“…Little additional ordering (graphitization) is seen to take place after devolatilization and the previous published literature supports this findings. 33) Graphitization depends on the ability of carbon crystallites to align and coalesce. Mobility is enhanced by hydrogen whereas oxygen hinders mobility by developing highly cross-linked rigid carbon structures.…”

Section: Effect Of Chemical Propertiesmentioning

confidence: 99%

Structural Transformation of Agricultural Waste/Coke Blends and Their Implications during High Temperature Processes

et al. 2011

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With a sharp increase in demand and production, palm oil wastes, (i.e. empty fruit bunches, fibre and shells) are generated, out of which a large amount ends up in landfill. In such a context, alternative solutions are needed to reduce the impact of these agricultural wastes on the environment. The present paper investigates the effect of addition of agricultural waste materials on the combustion behavior of its blends with metallurgical coke (MC). Two types of agricultural waste materials, palm shell and coconut shell, were mixed in different proportion with MC, while the gas phase reactions were studied at 1 200°C in a drop tube furnace (DTF). In the tested conditions, the blends containing agricultural waste materials indicated higher combustion efficiencies compared to MC alone. Carbon structure analysis were performed through 13 CP/MAS NMR spectroscopy showing various groups of carbons present in the agricultural waste samples ranging from aliphatic to aromatic carbons. The morphology of the samples was studied through Scanning Electron Microscope (SEM). SEM provided a qualitative description of the pore structure in the raw samples as well as the changes occurring following the gas phase reactions in the DTF. It was found that the particles derived from the wastes became increasingly deformed and lost their cell lumen. Surface area measurements were found to be in good agreement with the SEM images, supporting the higher combustion efficiency of the blends in comparison to coke alone. The present study suggests that agricultural waste materials have the potential to partially replace MC, as an auxiliary fuel in metallurgical processes.

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“…Two years later, Moghtaderi et al (2004) arrived at the same conclusion using volatile yield determinations, obtained during the pyrolysis of coal-biomass blends in a DTF reactor. Ulloa et al [2009] concluded that volatile yields increased in the last stages of pyrolysis, particularly for blends of biomass and lowranking coal. This phenomenon was attributed to the occurrence of demethoxylation reactions in the presence of aliphatic compounds and inorganic elements, favoring the formation of volatiles and diminishing the formation of char.…”

Section: Introduction 12mentioning

confidence: 99%

Burnout synergic or inhibiting effects in combustion of coal-sawdust blends

Ulloa

Garcı́a

2014

ing.inv.

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The co-firing of coal and biomass was studied using DTG assays. Blends of coal of different ranks and pine charcoal (obtained through pyrolysis of biomass at 1000°C) were prepared. Combustion profiles and characteristic temperatures (IT, PT and BT) were obtained and compared. To detect deviations, the experimental burnout curves for each blend were compared with weighted averages calculated from the conversion profiles obtained for the individual fuel samples and the blend composition. Positive and negative deviations were obtained which can be predicted from the differences in the reactivity of the blend components and their relative proportions. Keywords:Coal-biomass co-firing, Biomass, Coal, DTG. RESUMENSe estudia la combustión de mezclas de carbones de diferente rango con carbonizados de pino (pirolizados a 1000ºC) mediante ensayos DTG. Se registraron perfiles de combustión y temperaturas características (IT, PT y BT). Para detector desviaciones en el quemado de las mezclas, se compararon las curvas experimentales de conversión con aquellas obtenidas a partir del promedio ponderado calculado a partir de la conversión de los combustibles individuales y la composición de la mezcla. Estos ensayos revelaron que existen tanto desviaciones positivas como negativas en la conversión. Los factores clave en la predicción de estas desviaciones corresponden a las diferencias de reactividad entre los componentes de la mezcla y su proporción relativa.

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Thermogravimetric study of interactions in the pyrolysis of blends of coal with radiata pine sawdust

Cited by 117 publications

References 19 publications

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

A Review of Thermal Co-Conversion of Coal and Biomass/Waste

Structural Transformation of Agricultural Waste/Coke Blends and Their Implications during High Temperature Processes

Burnout synergic or inhibiting effects in combustion of coal-sawdust blends

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