Quality effects caused by torrefaction of pellets made from Scots pine

Shang, Lei; Nielsen, Niels Peter K.; Dahl, Jens Peder; Stelte, Wolfgang; Ahrenfeldt, Jesper; Holm, Jesper; Thomsen, Tobias Pape; Henriksen, Ulrik Birk

doi:10.1016/j.fuproc.2012.03.013

Cited by 93 publications

(60 citation statements)

References 13 publications

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“…Grindability is usually expressed by the Hardgrove Grindability Index (HGI) that measures the level of difficulty in the grinding solid (Wu et al, 2012). The higher the value of HGI, the more easily a solid fuel can be reduced to the fine powder (Shang et al, 2012;Wu et al, 2012). The value of HGI of the torrefied biomass increases with the residence time and the torrefaction temperature (Wu et al, 2012).…”

Section: Grindabilitymentioning

confidence: 99%

“…Wu et al (2012) speculates that the rearrangement of the structure and the depolymerization of different molecules during the thermal treatment are one of the reasons of producing such hard and brittle product. Shang et al (2012), on the other hand, reported that the removal of the hemicellulose during the torrefaction process is the main reason of increasing the HGI value of the torrefied product than the raw biomass.…”

Section: Grindabilitymentioning

confidence: 99%

“…Shang et al (2012) noted that the strength of pellets from Scot Pine torrefied at 250 °C was significantly reduced, and the pellets are brittle, uneven, and non-uniform in the physical appearance. The brittle torrefied pellets are difficult to handle and transport because they are easily breakable, and produce dust (Gilbert et al, 2009).…”

Section: Pelletizationmentioning

confidence: 99%

See 2 more Smart Citations

A Comprehensive Review on Biomass Torrefaction

Nhuchhen¹,

Basu²,

Acharya³

2014

IJREB

170

143

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Biomass is a versatile energy resource that could be used as a sustainable energy resource in solid, liquid and gaseous form of energy sources. Torrefaction is an emerging thermal biomass pretreatment method that has an ability to reduce the major limitations of biomass such as heterogeneity, lower bulk density, lower energy density, hygroscopic behavior, and fibrous nature. Torrefaction, aiming to produce high quality solid biomass products, is carried out at 200-300 °C in an inert environment at an atmospheric pressure. The removal of volatiles through different decomposition reactions is the basic principle behind the torrefaction process. Torrefaction upgrades biomass quality and alters the combustion behavior, which can be efficiently used in the co-firing power plant. This paper presents a comprehensive review on torrefaction of biomass and their characteristics. Despite of the number of advantages, torrefaction is motivated mainly for thermochemical conversion process because of its ability to increase hydrophobicity, grindability and energy density of biomass. In addition to this, torrefied biomass could be used to replace coal in the metallurgical process, and promoted as an alternative of charcoal.

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Section: Grindabilitymentioning

confidence: 99%

Section: Grindabilitymentioning

confidence: 99%

See 1 more Smart Citation

A Comprehensive Review on Biomass Torrefaction

Nhuchhen¹,

Basu²,

Acharya³

2014

IJREB

170

143

View full text Add to dashboard Cite

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“…However, whether the grindability of untreated and torrefied material or non-torrefied and torrefied pellets are compared, increasing the degree of torrefaction should result in lower SGE. Shang et al [35] reported an exponential decrease of the grinding energy for pine pellets exposed to increasingly higher torrefaction temperatures when using a coffee grinder as laboratory mill (0.55 kW; similar grinding forces as the IM). However, a comparison between the grindability of torrefied pellets and pellets from torrefied material may only partly apply (see discussion on bonding mechanisms during densification in Section 3.2).…”

Section: Particle Size Distributions After Grindingmentioning

confidence: 99%

Torreﬁed Biomass Pellets—Comparing Grindability in Different Laboratory Mills

et al. 2016

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Abstract:The firing and co-firing of biomass in pulverized coal fired power plants around the world is expected to increase in the coming years. Torrefaction may prove to be a suitable way of upgrading biomass for such an application. For transport and storage purposes, the torrefied biomass will tend to be in pellet form. Whilst standard methods for the assessment of the milling characteristics of coal exist, this is not the case for torrefied materials-whether in pellet form or not. The grindability of the fuel directly impacts the overall efficiency of the combustion process and as such it is an important parameter. In the present study, the grindability of different torrefied biomass pellets was tested in three different laboratory mill types; cutting mill (CM), hammer mill (HM) and impact mill (IM). The specific grinding energy (SGE) required for a defined mass throughput of pellets in each mill was measured and results were compared to other pellet characterization methods (e.g., durability, and hardness) as well as the modified Hardgrove Index. Seven different torrefied biomass pellets including willow, pine, beech, poplar, spruce, forest residue and straw were used as feedstock. On average, the particle-size distribution width (across all feedstock) was narrowest for the IM (0.41 mm), followed by the HM (0.51 mm) and widest for the CM (0.62 mm). Regarding the SGE, the IM consumed on average 8.23 Wh/kg while CM and HM consumed 5.15 and 5.24 Wh/kg, respectively. From the three mills compared in this study, the IM seems better fit for being used in a standardized method that could be developed in the future, e.g., as an ISO standard.

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“…Cuando los pellet son producidos a partir de biomasa diferente a la madera, son denominados pellets de biomasas mixtas, y es a partir de la mezcla de distintos residuos agrícolas que se está demostrando la posibilidad de producir sóli-dos que poseen la suficiente dureza y resistencia al transporte y un poder calorífico cercano al de los pellets de madera [31].…”

Section: Pellets De Biomasas Mixtasunclassified