Hammer mill operating and biomass physical conditions effects on particle size distribution of solid pulverized biofuels

Gil, Miguel; Arauzo, Inmaculada

doi:10.1016/j.fuproc.2014.06.016

Cited by 43 publications

(19 citation statements)

References 28 publications

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“…It shows very good agreement for particles larger or equal 0.5 mm. That supports the observation of Gil et al [40] that sieving data mainly describe the width of particles, especially for the large size fractions. However, sieving seems to underestimate the fraction retained on the 0.25 mm and 0.09 mm sieves.…”

Section: Precision Testing Of Isokinetic Sampling Equipmentsupporting

confidence: 92%

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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: Precision Testing Of Isokinetic Sampling Equipmentsupporting

confidence: 92%

“…It is a two-parameter distribution function expressed as a cumulative percent (undersize) distribution. Previous studies [38][39][40] showed good correlation between RRBS fit parameters and measured milled particle sizes. The RRBS equation is [41]:…”

Section: Discussionmentioning

confidence: 65%

Wood pellet milling tests in a suspension-fired power plant

Masche

Puig-Arnavat

Wadenbäck

et al. 2018

Fuel Processing Technology

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“…In particular, milling [6][7][8], densification [9,10] and thermal treatment [11 -13] affect particle size and shape distribution, bulk density and energy density. With specific reference to solids from particulate biomasses, handling and feeding present further difficulties due to peculiar properties both at particle level and at bulk level that make these materials even more unpredictable than other granular materials traditionally processed by industry, especially in terms of flow reliability and control [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Assessment on bulk solids best practice techniques for flow characterization and storage/handling equipment design for biomass materials of different classes

Berry

Larsson

Lestander

et al. 2015

Fuel Processing Technology

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This paper shows the results of a collaborative project in which four different laboratories have carried out complementary characterization tests on samples of the same set of lignocellulosic biomass materials with the objectives of better understanding their properties and identifying any critical features of the different characterization procedures. Three different types of material were used as model biomasses: 1) Scots pine wood chips, as an example of a coarse and flaky particulate biomass with some elastic properties; 2) chopped straw of reed canary grass as a nesting biomass having long and flaky fibers; 3) Scots pine wood powder as a fine particulate with elastic and cohesive properties. Particle size and shape analyses were carried out with; calipers, 2D image analysis, 3D image analysis (ScanChip) and through mechanical sieving. Applications and validity limits of each of these techniques are evaluated and discussed. The flow function and internal friction 2 were determined with a Schulze ring shear tester, a Brookfield powder flow tester and a large ring shear tester. No significant differences in the results generated by these shear testing techniques were found. Wall friction measurements were carried out with a Schulze ring shear tester; a Brookfield powder flow tester; a large Jenike shear tester and a Casagrande shear box. Results, in this case, showed significant differences with a higher wall friction coefficient obtained with the larger shear cell. Additionally, tensile strengths of biomass materials were measured by the use of a novel measurement technique. Arching tests were carried out in a pilot scale plane silo with variable hopper geometry and results were compared with those predicted by applying the Jenike procedure and a modified procedure which assumed tensile strength was the controlling material property (rather than unconfined yield strength). Finally, safety of handling and storage was assessed by carrying out explosion tests on dusts from Scots pine and reed canary grass.KEYWORDS: lignocellulosic biomass, particle size, particle shape, flowability, arching, explosion RESEARCH HIGHLIGHTS: Suitable test methods were classified for three biomass classes  Different particle sizing methods give a wide range of results  Shear tests do not discriminate flowability differences between the biomass classes  Arching behavior depends more on tensile strength than on compressive strength  Scots pine and reed canary grass dusts are flammable

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“…The Rosin-Rammler function is widely used for size distribution descriptions of various particles, including biomass particles [21][22][23][24], expressed as [25]:…”

Section: Mathematical Modelmentioning

confidence: 99%