Quality of Pellets Made from Agricultural and Forestry Crops in Costa Rican Tropical Climates

Abstract

Pellets may be produced with different types of agriculture or forestry crops in Costa Rica. This work evaluated the energy, physical, and mechanical properties of pellets fabricated from 12 types of agricultural and forestry crops (Ananas cumosos, Arundo donax, Coffea arabica, Cupressus lusitanica, empty fruit bunch and oil palm mesocarp fiber of the fruit of Elaeis guineensis, Gynerium sagittatum, Pennisetum purpureum, Phyllostachys aurea, Saccharum officinarum, Sorghum bicolor, and Tectona grandis), and similarities among these crops were established by multivariate principal component analysis. High variation was found in the pellet properties. The energy evaluation revealed that C. lusitanica and P. aurea are the crops with the best qualities for fuel use because of their high calorific values (from 16807 kJ/kg and 19919 kJ/kg, respectively) and low ash content (1.03% and 3.39%, respectively). As for physical properties, most crops exhibited values within the range noted by several authors and standards. All 12 pellet crops displayed high durability (from 72.12% to 92.98%) and compression force (from 295.18 N to 691.86 N). Moreover, the evaluation of crop similarities allowed the determination of four group combinations. Within these groups, C. lusitanica, P. aurea, and G. sagittatum had similar energy qualities and the best caloric characteristics.

Physical and Compression Properties of Pellets Manufactured with the Biomass of Five Woody Tropical Species of Costa Rica Torrefied at Different Temperatures and Times

“…For W abs determination, half of the pellet was placed in a desiccator with a saturated solution of potassium nitrate at 22 • C (21% in equilibrium moisture content) for 8 days to obtain constant weight. The details of this procedure are available in Tenorio et al [22]. The samples were weighed before and after being placed in the desiccator.…”

Pellets Evaluation Made from Tropical-Climate Agricultural and Forestry Crops of Costa Rica with a Domestic Stove

“…The pellets were manufactured by Agrep Forestal S. A., which is located in San Carlos, province of Alajuela (Costa Rica). The details of the manufacturing conditions are shown in Tenorio et al [19,20].…”

“…Presently, the technological adaptations to the pellet production process are known for many tropical-climate agricultural crops [18], as are the evaluation of some aspects of the pellet quality and the information about the physical, chemical or energetic characterisation [19,20]. However, the behaviour of these crops in equipment such as domestic pellet stoves, regarding energy efficiency and level of emissions are scarcely known.…”

Evaluación de la combustión de comprimidos cilíndricos fabricados con cultivos forestales y agrícolas en Costa Rica utilizando un quemador doméstico

“…Los pellets fueron fabricados por la empresa PELLETICS S.A. (http://pelletics.com/), ubicada en San Carlos en la provincia de Alajuela (Costa Rica). El detalle de las condiciones de fabricación es mostrado en Tenorio et al (2015aTenorio et al ( , 2015b y Aragón-Garita et al (2015).…”

“…En la actualidad, se conocen las adaptaciones tecnológicas al proceso de producción de pellets para muchos cultivos agrícolas tropicales (Aragón-Garita et al, 2015) (Tenorio, Moya, Tomazello, y Valaert, 2015a) y la información sobre la caracterización física, química o energética (Tenorio, Moya, Tomazello, & Valaert, 2015b). No obstante, el comportamiento de estos cultivos en algunos equipos como quemadores domésticos de pellet, su eficiencia energética y las emisiones producidas es poco conocida.…”