Mechanical Properties of Solid Biomass as Affected by Moisture Content

Abstract

The objective of the study was to examine the influence of moisture content on the mechanical properties of solid biomass, which is important for storage and handling. Mechanical properties involving powder flowability were determined with a Jenike shear tester. The materials tested were powdered biomass: sunflower husks, apple pomace, dried distillers grains with solubles (DDGS), and meat and bone meal. In static operations in which powdered biomass is generally under a significant load, such as in silos, moisture deteriorates the mechanical properties of biomass and increases its cohesion. In the case of DDGS, an additional slight decrease in stress was observed for samples with the highest moisture content, which was above 20%. For meat and bone meal and sunflower husks, a lubrication phenomenon was clearly observed, in which biomass samples with increased moisture content manifested better flowability, requiring lower boundary shear stresses than less moist samples. For apple pomace samples, with normal stresses above 50 kPa, the addition of moisture above 10% did not change the values of the observed shear stresses, indicating the stability of their properties. The use of powdered biomass with higher moisture contents, at above 10%, should be avoided, as such material can lead to overhangs in tanks and silos.

Numerical Investigation on Flowability of Pulverized Biomass Using the Swelling Bed Model

“…The regular and systematic increase in the gential stresses is particularly evident in the range of higher normal stresses. The l the normal stresses, the less the moisture has an effect on the values of the tange The results of the study of the effect of the moisture content on the mechanical characteristics were presented similarly to the experimental studies [19] in the form of a flow condition, i.e., the dependence of the tangential stress τ, that is, the strength of the deposit, on the normal load σ n , i.e., the degree of consolidation of the powder material deposit.…”

“…Changes in the moisture content also do no nificantly affect the course of tangential stress changes; the only noticeable differen the maximum value of the tangential stress, which, as in most cases of laboratory increases with increasing moisture content. The results of the study of the effect of the moisture content on the mechanical acteristics were presented similarly to the experimental studies [19] in the form of a condition, i.e., the dependence of the tangential stress τ, that is, the strength of the dep on the normal load σn, i.e., the degree of consolidation of the powder material depos…”

“…The investigations of the influence of the moisture content on the flowability of pulverized biomass are based on experimental data previously published by the authors of this manuscript [19,20]. The materials selected for the study were as follows: corn dried distillerʹs grains with solubles (DDGS) (5-600 µm) from the Goświnowice Ethanol Plant, Nysa, Poland; meat and bone meal (MBM) (150-2000 µm) from SARIA Sp.…”

“…The higher the line of the yield locus and the larger its angle of inclination, the worse the flowability of the material. Details of how to perform shear strength measurements with a Jenike apparatus and details of the sample preparation and characterization can be found in the authors' previously mentioned published papers [19,20].…”

“…The exceptions were sunflower hulls and apple pomace, for which the consolidation stress was assumed equal to σ n = 80.3 kPa, and the normal stresses were σ 1n = 72.5 kPa, σ 2 = 54.3 kPa, σ 3 = 33.2 kPa, and σ 4 = 13.0 kPa. The detail of the selection of the mentioned parameters were described in a previous paper [19].…”