title: Proximate analysis, backwards stepwise regression between gross calorific value, ultimate and chemical analysis of wood.
abstract: The gross calorific value (GCV), proximate, ultimate and chemical analysis of debark wood in Portugal were studied, for future utilization in wood pellets industry and the results compared with CEN/TS 14961. The relationship between GCV, ultimate and chemical analysis were determined by multiple regression stepwise backward. The treatment between hardwoods-softwoods did not result in significant statistical differences for proximate, ultimate and chemical analysis. Significant statistical differences were found in carbon for National (hardwoods-softwoods) and (National-tropical) hardwoods in volatile matter, fixed carbon, carbon and oxygen and also for chemical analysis in National (hardwoods-softwoods) for F and (National-tropical) hardwoods for Br. GCV was highly positively related to C (0.79 * * *) and negatively to O (-0.71 * * *). The final independent variables of the model were (C, O, S, Zn, Ni, Br) with R(2)=0.86; F=27.68 * * *. The hydrogen did not contribute statistically to the energy content.
authors.affiliation: University of Trás-os-Montes and Alto Douro (UTAD), Forestry Department, Quinta dos Prados Apartado, 1013-5001-801 Vila Real, Portugal. telmimore@hotmail.com
authors.forename: C
authors.initials: C
authors.lastname: Telmo
authors.forename: J
authors.initials: J
authors.lastname: Lousada
authors.forename: N
authors.initials: N
authors.lastname: Moreira
mesh_terms: D018533:Biomass; D012044:Regression Analysis; D014934:Wood / Q000737:chemistry*