Influence of mill type on densified biomass comminution

Williams, Orla; Newbolt, Gary S.; Eastwick, Carol; Kingman, S.W.; Giddings, Donald; Lormor, Stephen; Lester, Edward

doi:10.1016/j.apenergy.2016.08.111

Cited by 56 publications

(57 citation statements)

References 47 publications

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“…xc,min stands for the shortest maximum chord of a 2D particle projection measured from all measurement directions, and thus represents the width of a particle projection. Preliminary tests and a previous study [17] show that this parameter gives the closest results to those obtained by sieve analysis. Camsizer ® X2…”

Section: Pellet Milling Behaviormentioning

confidence: 53%

“…The Camsizer ® definition of the circularity is the ISO 9276-6:2008 standard definition squared [35]. Both shape factors are commonly used for describing comminuted wood particle shapes [12,17]. The aspect ratio (AR) ranging between zero and one is defined as follows:…”

Section: Pellet Milling Behaviormentioning

confidence: 99%

“…The energy needed for milling biomass depends on the feed moisture, particle size reduction ratio, feedstock characteristics [14], feed rate and mill operating parameters [15]. Comminuting fibrous and orthotropic elastic wood that is capable of absorbing energy before size reduction [16] requires more energy than coal regardless of mill type [17].…”

Section: Introductionmentioning

confidence: 99%

“…The cut size is based on Stokes' law [22] that is only valid for the drag force of a spherical particle [23]. Williams et al [17] found that the classification system of a ring-roller mill for the comminution of densified biomasses followed the Stokes' law, indicated by an increasing sphericity with decreasing particle size. In largescale mill classifiers, there are particle size limits for coal suspension-firing.…”

Section: Introductionmentioning

confidence: 99%

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Wood pellet milling tests in a suspension-fired power plant

Masche

Puig-Arnavat

Wadenbäck

et al. 2018

Fuel Processing Technology

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This paper investigates the milling behavior of two industrial wood pellet qualities (designated I1 and I2 as per ISO 17225-2:2014) in large-scale coal roller mills, each equipped with a dynamic classifier. The purpose of the study was to test if pellet comminution and subsequent particle classification (i.e., the classifier cut size) are affected by the internal pellet particle size distribution obtained after pellet disintegration in hot water. Furthermore, optimal conditions for comminuting pellets were identified. The milling behavior was assessed by determining the specific grinding energy consumption and the differential mill pressure. The size and shape of comminuted pellets sampled from burner pipes were analyzed by dynamic image analysis and sieve analysis, respectively. The results showed that the internal pellet particle size distribution affected both the milling behavior and the classifier cut size. I2 pellets with coarser internal particles than I1 pellets required more energy for milling, led to a higher mill pressure drop and showed a larger classifier cut size. Comminuted pellet particles sampled from burner pipes were notably Masche et al. / Wood Pellet Milling Tests in a Suspension-Fired Power Plant / 2 finer than internal pellet (feed) particles. At similar mill-classifier conditions, characteristic particle sizes of 0.50 mm for comminuted I1 pellets (compared to 0.83 mm for material within I1 pellets) and of 0.56 mm for comminuted I2 pellets (compared to 1.09 mm for material within I2 pellets), respectively, were obtained. Pellet comminution at lower mill loads and lower primary airflow rates reduced the mill power consumption, the mill pressure drop, and the classifier cut size. However, this was at the expense of a higher specific grinding energy consumption. Derived 2D shape parameters for comminuted and internal pellet particles were similar. Mill operating changes had a negligible effect on the original elongated wood particle shape. To achieve the desired comminuted product fineness (i.e., the classifier cut size) with lower specific grinding energy consumption, power plant operators need to choose pellets with a finer internal particle size distribution.

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Section: Pellet Milling Behaviormentioning

confidence: 53%

Section: Pellet Milling Behaviormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wood pellet milling tests in a suspension-fired power plant

Masche

Puig-Arnavat

Wadenbäck

et al. 2018

Fuel Processing Technology

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“…The cumulative retained undersize is the mass passed from the previous sieve, minus the mass retained on the current sieve [20]. Sieving was conducted for 15 min at 3 mm amplitude [21].…”

Section: Particle Size and Shape Characterizationmentioning

confidence: 99%

One way of representing the size and shape of biomass particles in combustion modeling

Trubetskaya

Beckmann²,

Wadenbäck

et al. 2017

Fuel

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a b s t r a c tThis study aims to provide a geometrical description of biomass particles that can be used in combustion models. The particle size of wood and herbaceous biomass was compared using light microscope, 2D dynamic imaging, laser diffraction, sieve analysis and focused beam reflectance measurement. The results from light microscope and 2D dynamic imaging analysis were compared and it showed that the data on particle width, measured by these two techniques, were identical. Indeed, 2D dynamic imaging was found to be the most convenient particle characterization method, providing information on both the shape and the external surface area. Importantly, a way to quantify all three dimensions of biomass particles has been established. It was recommended to represent a biomass particle in combustion models as an infinite cylinder with the volume-to-surface ratio (V/A) measured using 2D dynamic imaging.

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Mechanochemical Pretreatment for Waste‐Free Conversion of Bamboo to Simple Sugars: Utilization of Available Resources for Developing Economies

Ekwe

Tyufekchiev

Salifu

et al. 2022

Advanced Sustainable Systems

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In this work, mechanochemical pretreatment of Bambusa vulgaris is evaluated for waste‐free production of renewable sugars for subsequent fermentation. After a 60 min mechanochemical pretreatment followed by enzyme hydrolysis at 50 °C, 62% of the available carbohydrate can be recovered as fermentable sugars, primarily in the form of glucose and xylose. Structural and chemical analysis finds that mechanochemical pretreatment increases accessible surface area and amorphizes the crystalline cellulose present in bamboo, both of which increase reactivity. The experimental results are then used for a systems‐level analysis of ethanol production in Nigeria. The energy required for mechanochemical pretreatment is estimated to be 0.5–5.6 MJ per kg of bamboo; this energy can be provided by solar power, while still satisfying existing needs for stationary power. Ethanol production on marginal land alone is projected to be sufficient to replace nearly 80% of Nigeria's current gasoline usage while reserving sufficient land area for solar power generation to meet current electricity needs, meaning that bamboo cultivation followed by mechanochemical pretreatment can play an important role for utilizing locally available resources without generation of new chemical wastes.

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Influence of mill type on densified biomass comminution

Cited by 56 publications

References 47 publications

Wood pellet milling tests in a suspension-fired power plant

Wood pellet milling tests in a suspension-fired power plant

One way of representing the size and shape of biomass particles in combustion modeling

Mechanochemical Pretreatment for Waste‐Free Conversion of Bamboo to Simple Sugars: Utilization of Available Resources for Developing Economies

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