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FLOW PROPERTIES OF SHORT ROTATION EUCALYPTUS BIOMASS Dustin Till & Oladiran Fasina
Biosystems Engineering, Auburn University
ABSTRACT
INTRODUCTION
METHODOLOGY
RESULTS
DISCUSSION
CONCLUSIONS
OBJECTIVES
v Short rota(on Eucalyptus trees are a prime candidate for biomass. They have a rapid growth rate, are very adaptable, and have high energy content.
v In the effort to produce biofuels on a larger scale, the
problems associated with the storage, pre-‐processing, and handling, of woody biomass have become visible.
v Reliable and consistent flow of biomass out of storage
equipment is crucial in the downstream conversion into biofuels.
v To ensure this, flow proper(es of the material must be known in order to design storage bins, silos, hoppers, and feeders correctly.
v Physical proper(es are also needed for design of
storage and handling equipment. v Moisture content is one of the proper(es that affect
the flowability and physical proper(es of biological materials.
The objec(ves of this research are to (1) inves(gate the effect of harves(ng condi(ons (with or without bark), age (2 yr. and 7 yr.), and moisture content on the flowability and physical proper(es of ground Eucalyptus trees and; (2) to compare this to 7 yr. old loblolly pine clean chips.
v Experimental samples (2 yr. old and 7 yr. old) were ground through a 1/8” screen hammer mill. v Flow proper(es (cohesion, flow func(on, angle of wall fric(on, angle of internal fric(on, hopper half
angle, compressibility, and flow index) and physical proper(es (par(cle density and bulk density) of the ground Eucalyptus samples and ground 7 yr. old loblolly pine clean chips were measured at 10%, 20%, and 30% moisture contents (wet basis).
v All experiments were performed in duplicate.
Texture Analyzer
v Cohesive strength slightly decreased with increase in age and with bark (Fig 1). As moisture content increased, cohesion slightly increased.
v Age, bark, and moisture content had significant effects (p<0.05) on compressibility (decreasing, increasing, and increasing, respec(vely) (Fig 2).
v Even though not significant, angle of internal fric(on increased with age, bark, and moisture content (Fig 3).
v Age, bark, and moisture content significantly increased the angle of wall fric(on (Fig 4).
v Hopper half angle was lowered as moisture
content increased and with the presence of bark (Fig 5).
v Par(cle density was significantly affected by moisture content, age, and bark, while bulk density was not affected by these factors (Table 1).
v Flow index indicated all samples were cohesive
(Table 1). Moisture content, age, and bark reduced the cohesiveness (or flowability) of the samples.
v Age, bark, and moisture content have significant effects on the flow proper(es and flowability of ground Eucalyptus biomass.
v 2 yr. old samples had slightly be]er fric(onal
proper(es than 7 yr. old, but not significantly. Bark and increasing moisture content caused a greater decrease in flowability.
v Results show that discharge aids will be needed for this material because it cannot be handled using gravity alone.
Understanding flow proper(es of ground biomass is important in correctly designing storage equipment such as silos, bins, and hoppers. Since biomass is a bulk material, it will have the typical flow problems associated with bulk materials. The objec(ves of this research is to quan(fy the effect of age (2 yr. old vs. 7 yr. old), whether it has bark or not, and moisture content on flow proper(es (cohesion, angle of internal fric(on, angle of wall fric(on, hopper half angle, and compressibility) and physical proper(es (bulk density and par(cle density) of ground Eucalyptus biomass. Age, bark, and moisture content had a significant effect on the fric(onal proper(es that were measured.
TERMINOLOGY 2E8NB 2 yr. old Eucalyptus without bark
2E8WB 2 yr. old Eucalyptus with bark
7E8NB 7 yr. old Eucalyptus without bark
PCC8 7 yr. old loblolly pine clean chips
Samples used in this experiment
Fig. 1: Sample type and moisture effect on cohesion
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2E8NB 2E8WB 7E8NB PCC8
Cohe
sion
, kPa
10% 20% 30%
Fig 3: Sample type and moisture effect on angle of internal fricRon
0
10
20
30
40
50
60
2E8NB 2E8WB 7E8NB PCC8
Angle of In
ternal Fric
Ron
10% 20% 30%
Fig. 5: Sample type and moisture effect on hopper half angle
0
5
10
15
20
25
30
35
40
45
2E8NB 2E8WB 7E8NB PCC8
Hopp
er Half A
ngle
10% 20% 30%
Fig. 2: Sample type and moisture effect on compressibility at applied pressure of 6 kPa
0
5
10
15
20
25
30
35
40
45
2E8NB 2E8WB 7E8NB PCC8
Compressibility, %
10% 20% 30%
Fig. 4: Sample type and moisture effect on angle of wall fricRon (mild steel)
0
5
10
15
20
25
30
2E8NB 2E8WB 7E8NB PCC8
Angle of W
all Fric
Ron
10% 20% 30%
Moisture Content (w.b.) Sample Name ParRcle Density
(kg/m3) Bulk Density (kg/m3) Flow Index
10%
2E8NB 1315.25 178.31 3.22 2E8WB 1303.53 139.80 3.03 7E8NB 1263.67 204.49 3.33 PCC8 1421.72 221.67 2.63
20%
2E8NB 1335.70 165.52 2.94 2E8WB 1334.15 131.75 2.63 7E8NB 1285.94 187.91 2.94 PCC8 1429.34 211.48 2.50
30%
2E8NB 1180.29 154.69 2.78 2E8WB 1180.04 126.97 2.33 7E8NB 1166.85 184.24 2.70 PCC8 1402.35 204.95 2.63
Table 1: Physical properRes of samples at 10%, 20%, and 30% M.C. (wet basis)
ACKNOWLEDGEMENT Support of the REU fellow by the Na(onal Science Founda(on Compe((ve Grant no. 1149940 is gratefully acknowledged.
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