Page 71 - AJWEP-22-6

Pine sawdust biofuel: Quality and temperature optimization

Table 1. Orthogonal test results
Group Forming Moisture Binder addition Heating Relaxed Relaxation Impact
pressure (MPa) content (%) ratio (%) temperature (°C) density (g/cm ) ratio resistance (%)
3
1 20 16 2 150 0.653 1.202 87.594
2 10 10 1 150 0.932 1.301 96.346
3 30 12 3 150 0.889 1.101 96.245
4 40 10 4 150 0.99 1.071 97.939
5 50 14 5 150 0.923 1.032 97.322
6 40 14 1 160 0.856 1.013 96.690
7 10 16 3 160 0.694 1.041 91.685
8 30 10 5 160 0.993 1.063 97.368
9 20 12 4 160 0.932 1.120 96.850
10 50 10 2 160 1.066 1.010 97.214
11 40 10 3 170 1.056 1.059 97.891
12 10 12 5 170 0.889 1.042 96.384
13 50 16 4 170 0.838 1.018 96.497
14 20 10 1 170 1.004 1.063 96.694
15 30 14 2 170 0.914 1.012 96.254
16 30 10 4 180 1.054 1.010 97.272
17 20 14 3 180 0.905 1.040 95.870
18 50 12 1 180 0.962 1.014 95.815
19 40 16 5 180 0.900 1.054 95.445
20 10 10 2 180 0.926 1.032 95.567
21 40 12 2 190 1.012 1.021 96.805
22 30 16 1 190 0.891 1.044 96.008
23 20 10 5 190 0.994 1.025 96.528
24 10 14 4 190 0.883 1.009 95.896
25 50 10 3 190 0.989 1.026 96.798

Table 2. Multivariate fitting models of each These phenomena occur because optimal moisture
dependent variable and temperature conditions minimize elastic

Dependent R 2 Multiple regression fitting model deformation and stress relaxation in densified biofuel,
variables thereby enhancing relaxed density. Conversely,
H1 0.9213 Y=0.9064+0.0492A−0.974B+0.00 excessive moisture content traps steam during extrusion,
79C+0.0491D+0.0048AB+0.0038 inducing substantial elastic deformation and densified
AC−0.0215AD+0.0064BC+0.0446 biofuel expansion that ultimately reduces relaxed
BD−0.0030CD density.
H2 0.8093 Y=1.06−0.0252A−0.0058B−0.007 The interaction between forming pressure and
C−0.0372D+0.0082AB+0.0386AC
−0.0586AD−0.0157BC+0.0222BD heating temperature affects the stability of the densified
+0.0294CD biofuel. Appropriate molding pressure and heating
H3 0.8133 Y=0.9575+0.0115A−0.0147B+0.0 temperature increase the density of the densified biofuel
047C+0.0072D+0.0099AB−0.0048 while causing the binder and lignin in the biomass
AC−0.0063AD+0.0017BC+0.0147 material to melt, resulting in higher stability and lower
BD−0.0043CD relaxation ratio.

Volume 22 Issue 6 (2025) 65 doi: 10.36922/AJWEP025240195