Design and efficiency of a small-scale woodchip furnace

Abstract

Although advances have been made in combustion efficiency in large-scale woodchip furnaces, less experimental results are available at the <20 kW range. Compact feed systems, as well as optimized grates and combustor chambers, continue to represent a challenge for the wider use of low-cost wood chips. This study describes the design and testing of a small-scale woodchip furnace that operates at a range of 9-18 kW. The efficiency test takes account of the feedstock Eucalyptus nitens, with three moisture contents and the combination of different air excess (λ) and primary/secondary air ratios. The results reveal a maximum of combustion efficiency of 85% for the low moisture content sample (16%) at λ=1,5 and 82% for samples with 29% and 40% moisture content, at λ= 2,0 and 2,1 respectively. The integrated heat exchanger proved to be highly efficient by reducing gas temperature by up to 69% prior to its exit.

Effect of torrefaction temperature on properties of Patula pine

“…Volatiles have high H/C and O/C ratios, implying a reduction in the H/C and O/C atomic ratios of the remaining solid after torrefaction process (Deng et al 2009, Nocquet et al 2014, Prins et al 2006b). Materials with higher heating value and low moisture content can benefit thermochemical processes such as combustion and gasification as the reaction temperatures in those processes can be increased (Pérez et al 2012, Torres-Fuchslocher andVaras-Concha 2015). Other authors have reported results on the changes in biomass composition (at different torrefaction conditions) that are consistent with the findings of this study (Bridgeman et al 2010, da Silva Grassmann et al 2016.…”

Performance evaluation of combustion of palm kernel shell and coconut husk blend in a pilot-scale grate furnace

“…Palm Kernel Shells (PKS) are carbonaceous shell fractions left after processing and crushing of palm fruit. Thermal conversion processes may convert this high carbon content as a source of heat energy (Najmi et al, 2006;Edmund et al, 2014;Husan et al, 2002;Torres-Fuchslocher and Varas-Concha, 2015;Oladosu et al, 2019). Table 1 shows the ultimate and proximate analysis of raw residues PKS carried out by Onochie et al (2017).…”

Untitled

“…Palm Kernel Shells (PKS) are carbonaceous shell fractions left after processing and crushing of palm fruit. Thermal conversion processes may convert this high carbon content as a source of heat energy (Najmi et al, 2006;Edmund et al, 2014;Husan et al, 2002;Torres-Fuchslocher and Varas-Concha, 2015;Oladosu et al, 2019). Table 1 shows the ultimate and proximate analysis of raw residues PKS carried out by Onochie et al (2017).…”