Title: Feeding properties and behavior of hammer- and knife-milled pine

Abstract

This work reports the rheological characterization of hammer and knife-milled lodgepole pine materials as a function of grind size and moisture content. Characterizations included particle size and shape distributions, bulk density, compressibility at 10 kPa uniaxial pressure, elastic recovery from 10 kPa uniaxial pressure, shear strength, effective angle of internal friction, arching in a custom hopper, and feeding performance in volumetric and gravimetric auger feeders. Particle analysis indicates that the width and length distributions of the 3 mm hammer-milled and the 6 mm knife-milled materials are quite similar, and that all the materials have relatively short aspect ratios (< 4). Compressibility and elastic recovery both increased with increasing moisture content with both values increasing more than 10% and the effect being most severe for the 3 mm grind. Adding 3 kPa of pressure increased the critical arching width for all hopper arching tests, except for the 25 mm grind material with 20% MC, for which the critical arching width actually decreased with increased pressure. Interestingly, for materials with smaller particle sizes, the volumetric feed rate tends to decrease as moisture increases even though the density of the material increases with moisture content and the auger speeds are the same. Timemore » variability of volumetric feed rate increased dramatically with increasing particle size but the impact of moisture content was not as clear. For nearly all tests, gravimetric auger feeding resulted in better feeding control and substantially decreased time variability in the material feed rate. These tests show that material feed rate and volumetric auger feed rate variability are dependent upon material shear strength, bulk density, and particle size. Shear tests indicate that material strength generally decreased with increasing particle size, although the impact of moisture was not entirely consistent.« less

Authors:

Hernandez, Sergio  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-9525-7671"

Westover, Tyler L.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-7828-8436"

Matthews, Austin C.  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-0380-6598"

Ryan, J. Chadron B. ^[1]; Williams, C. Luke  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-1935-0110"

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+ Show Author Affiliations

1. Idaho National Lab. (INL), Idaho Falls, ID (United States)

Publication Date:

Sat Jul 08 00:00:00 EDT 2017

Research Org.:

Idaho National Lab. (INL), Idaho Falls, ID (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1473708

Alternate Identifier(s):

OSTI ID: 1550247

Report Number(s):

INL/JOU-16-39953-Rev000
Journal ID: ISSN 0032-5910

Grant/Contract Number:  

AC07-05ID14517

Resource Type:

Accepted Manuscript

Journal Name:

Powder Technology

Additional Journal Information:

Journal Volume: 320; Journal Issue: C; Journal ID: ISSN 0032-5910

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS; Biofuels; particles; flow; comminution