Recovering Wood Waste to Produce Briquettes Enriched with Commercial Kraft Lignin

Abstract

Aiming to use lignocellulosic biomass as energy source, one of the process that may aggregate values is the densification process, which allows the production of bioenergy using solid fuels, mainly for reducing transportation costs. In this research, solid fuel from co-briquetting of wood residues from sawmill using commercial kraft lignin as binder was investigated. The effects of compression pressure (900, 1200 and 1500 PSI) and briquette formulation (varying wood and kraft lignin proportion) on the quality and characteristics of briquettes were evaluated. The main findings were that briquetting of wood residues with kraft lignin resulted in an improvement of bulk density, strength rupture modulus, low heating value (LHV) and high heating value (HHV). The briquettes using 4% and 6% of kraft lignin, and submitted to 1200 to 1500 PSI, presented higher bulk density and strength resistance, respectively. On the other hand, the heating values showed the highest results with the addition of 2% lignin at 900 PSI, being the legal range for additives in briquettes for many countries such as in European Union.

Evaluation of kraft lignin and residues of sawmill for producing briquettes

“…The briquetting process followed Silva et al (2021) method. The experiment was conducted in a Lippel B-32 piston press machine.…”

“…The analysis of the modulus of rupture and heating values followed the methodology described by Silva et al (2021). The modulus of rupture was performed in an universal machine in accordance to Brazilian standard NBR ISO 11093-9 (ABNT, 2009), and the heating values were determined following the DIN 14918 (2010) standard.…”

“…Sawmills residues are a considerable natural resource, being inefficiently used raw material. According to Silva et al (2021), the waste generated in the log process can achieve 40-60% (Obernberger & Thek, 2004) and generally is burned or discarded into landfills (Ackom et al, 2010). The main problem of selling these wastes to produce energy is their low density, which makes transportation expensive.…”

“…The densification process parameters, as temperature and pressure, and raw material properties directly influence in the properties and quality of the densified biomaterials (Clavijo et al, 2020). Richards (1990); Gilvari et al (2019) and Silva et al (2021) highlighted that parameters of abrasion and impact resistance, compressive strength, and density are important analyze quality characteristics of a densified biomaterial.…”

“…briquettes) enriched with Kraft lignin may be a rational strategy alternative for using these forestry residues as renewable energy sources. It is possible to observe the rise in the number of studies that report the use of compacted biomass with high content of lignin to produce energy or the use of lignin as the binding material in densification processes (Boudet, 2000;Ekeberg et al, 2006;Lurii, 2008;Pereira et al, 2016;Gouvea et al, 2017;Leokaoke et al, 2018;Boschetti et al, 2019;Silva et al, 2021). Ayyachamy et al (2013) affirm that lignin can also have non-fuel applications, related to polymer, resins, adhesives, carbon fibers development, and other bio-refinery uses.…”