Effect of particle size and addition of cocoa pod husk on the properties of sawdust and coal pellets

Abstract

The continuous increase of the world energy demand, the rise of fossil fuels costs, and the strong environmental policies around the globe are some of the reasons for the wood pellets industry increase. However, there are some other available biomass feedstocks capable of being densified for energy production. Among the various options, the use of mixed biomass pellets is becoming remarkable due to the wide variety of species, although more research is needed in order to enhance the mechanical properties of these pellets. This study aims to identify the effect of particle size on the mechanical properties of sawdust and coal pellets when cocoa pod husks are used as an additive. Cocoa pod husks have a similar composition to sawdust and less sulfur and nitrogen than coal. Thus, the use of this additive might decrease the environmental impact during coal pellets combustion. Results show an attractive potential of cocoa pod husks grinds for pellet production, an increase of the durability of coal pellets mixed with this raw material, and similar performance between cocoa pod husks and sawdust pellets. The compression ratio, the compressive and impact resistance varied linearly with the addition of cocoa pod husks.Keywords: Biomass, coal, cocoa pod husks, densification, pellets, sawdust. RESUMENEl incremento en la demanda de energía a nivel mundial, el alza en los precios de combustibles fósiles y las fuertes políticas ambientales son algunas de las razones del crecimiento de la industria de los pellets de madera. Sin embargo, existen otras materias primas disponibles que pueden ser densificadas para la producción de energía. Dadas las diferentes opciones, el uso de pellets mixtos de biomasa se ha convertido en una opción favorable, a pesar de que es necesaria una mayor investigación con el fin de mejorar las propiedades mecánicas de los pellets. Este estudio tiene como objetivo identificar el efecto del tamaño de partícula sobre las propiedades mecánicas de los pellets de aserrín y carbón cuando la cáscara de cacao se usa como aditivo. Las cascaras de caco tienen una composición similar al aserrín y menos contenido de azufre y nitrógeno que el carbón. Por lo tanto el uso de este aditivo puede disminuir el impacto ambiental durante la combustión de pellets de carbón. Los resultados muestran un potencial atractivo para la producción de pellets con cacao molido, un incremento de la durabilidad de los pellets de carbón mezclados con esta materia prima y un rendimiento similar entre los pellets de cacao y aserrín. La relación de compresión, la resistencia a la compresión y al impacto variaron linealmente con la adición de cáscara de cacao.

The Bioenergetic Potential of Four Oak Species from Northeastern Mexico

“…The values of volatile material for barked and debarked sawdust were found to be in the range of 82% to 91% (Figure 4), and they were similar to values reported by different authors [6,75,[80][81][82][83]. Values below the average reported here were found by Forero-Núñez et al [84] (76.82%) and Demirbas [85] (66.6%). The fact that barked sawdust had less volatile material was reported by Feng et al [86].…”

“…This can be attributed to the presence in the bark of significant amounts of lignin and extracts [29,37], which have a slow devolatilization rate [87], occurring in higher temperature ranges than those recorded during pelleting [88,89]. It is known that volatile matter takes part in the combustion process of biomass, directly affecting the performance and physical stability [50,84]. Thus, a high content of volatile matter would imply a rapid ignition of the biofuel, but also its conversion into powder [6,84], which is a disadvantage.…”

Peer Review #1 of "Physical, mechanical and energy characterization of wood pellets obtained from three common tropical species (v0.1)"

“…Thus, measuring this parameter for pellets indicates their market values. The values of the impact resistance index were higher than the ratio of 33 to 50 % reported by Forero-Nuñez et al (2015). Pellets with a percentage higher than 97.5% as defined by ASABE Standard S269.4 (2006), are considered a high quality biofuel because the particles have good adhesion forces that allow pellets withstand transportation stress before reaching to the end users.…”

“…Fixed carbon has been reported to influence the gross calorific value (Tenorio et al, 2014). Also, in relation to the potential of energy production, this property is the most valuable parameter, since raw materials with high fixed carbon have higher heating values (Forero-Nuñez et al, 2015). The ash content ranged between 2.41 to 3.22%, which is promising for the species studied.…”

Ingeniería básica y de detalle para la instrumentación de una planta prototipo de gasificación de lecho fijo

“…La humedad se estableció siguiendo la norma ASTM E871-82 [7], el material volátil de acuerdo con la ASTM E872 [8], contenido de ceniza mediante la norma ASTM E1755-01 [9] y el carbón fijo fue calculado por balance [10]. Los análisis últimos se llevan a cabo de acuerdo con la metodología descrita en trabajos previos.…”