Ultimate Analyses for Raw and Torrefied Biomass

CHAPTER 4: RESULT AND DISCUSSION

4.4 Ultimate Analyses for Raw and Torrefied Biomass

type of biomass. It was due to 250-355 µm particle size had larger sample area than 355- 500 µm. As a result, it caused carbonisation to react faster.

Figure42:♦ Hydrogen content for raw and torrefied biomass 0.00

1.00 2.00 3.00 4.00 5.00 6.00 7.00

37.00 87.00 137.00 187.00 237.00 287.00

Hydrogen Content (wt %)

Temperature (° C)

EFB (250-355 um) EFB (355-500 um) PMF (250-355 um) PMF (355-500 um) PKS (250-355 um) PKS (355-500 um)

Figure43: x Oxygen content for raw and torrefied biomass

Figure44: ▲ Nitrogen content for raw and torrefied biomass 30.00

32.00 34.00 36.00 38.00 40.00 42.00 44.00 46.00 48.00 50.00

37.00 87.00 137.00 187.00 237.00 287.00

Oxygen Content (wt %)

Temperature (° C)

EFB (250-355 um) EFB (355-500 um) PMF (250-355 um) PMF (355-500 um) PKS (250-355 um) PKS (355-500 um)

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00

37.00 87.00 137.00 187.00 237.00 287.00

Nitrogen Content (wt %)

Temperature (° C)

EFB (250-355 um) EFB (355-500 um) PMF (250-355 um) PMF (355-500 um) PKS (250-355 um) PKS (355-500 um)

Furthermore, figure 42 to figure 43showed hydrogen and oxygen contents were changed due to release of methane (CH₄), ethane (C₂H₆), carbon dioxide (CO₂) and carbon monoxide (CO) during torrefaction process. The exception was nitrogen content while it was remained unchanged from figure 44.

Figure45:● Sulphur content for raw and torrefied biomass

Besides, sulphur content for figure 45 was below than 0.6 wt%. As a result, it showed that oil palm biomass released less sulphur during combustion into atmosphere. Besides, it reduced health problem caused by sulphur.

0.00 0.10 0.20 0.30 0.40 0.50 0.60

37.00 87.00 137.00 187.00 237.00 287.00

Sulphur Content (wt %)

Temperature (° C)

EFB (250-355 um) EFB (355-500 um) PMF (250-355 um) PMF (355-500 um) PKS (250-355 um) PKS (355-500 um)

Figure46: O/C ratio for different type of biomass

In the order hand, figure 46 showed O/C ratio for all samples. It decreased over torrefaction temperature and resulted improvement of gasification properties of torrefied biomass [2].The decreasing of O/C ratio was due to removal of water and carbon dioxide during torrefaction process [7]. During the torrefaction process oxygen content was reducing while carbon content was increasing. Increasing of carbon content caused high calorific value during the burning. It resulted less smoke and water vapor were formed.

As a result, torrefied products were improved in combustion view.

0.60 0.70 0.80 0.90 1.00 1.10 1.20

200.00 210.00 220.00 230.00 240.00 250.00 260.00 270.00 280.00 290.00 300.00

O/C Ratio

Temperature (°C)

EFB (250-355 um) EFB (355-500 um) PMF (250-355 um) PMF (355-500 um) PKS (250-355 um) PKS (355-500 um)

4.5. Calorific Value fromRaw and TorrefiedBiomass

Figure47: Energy yield for different types of oil palm biomass

Figure 47 result represented three types of oil palm biomass (EFB, PMF and PKS) energy variation for raw and torrefied samples. The energy yield was referred to higher heating value (HHV) for both raw and torrefied samples. The graph was plotted at different particle size, torrefaction temperature and type of oil palm biomass.

The energy yield for EFB, PMF and PKS were increased with increasing torrefaction temperature. For all samples, practically all chemical energy was retained in the torrefied product and the energy yield was depended on that torrefied product. It seems torrefied product contained different amount of carbon content that resulted different energy yield.

The influence of biomass type on the energy yield was the best observed in figure 47. It showed PMF had highest energy yield followed by EFB and PKS. It was because of increased carbon content that leads towards high calorific value during burning. PMF had highest increasing of carbon content followed by EFB and PKS. Besides, figure 47

8.50E+03 9.00E+03 9.50E+03 1.00E+04 1.05E+04 1.10E+04 1.15E+04 1.20E+04

37 87 137 187 237 287

Energy (J)

Temperature (°C)

EFB (250-355 um) EFB (355-500 um) PMF (250-355 um) PMF (355-500 um) PKS (250-355 um) PKS (355-500 um)

emphasized that particle size gave small influence in energy yield with showing similar trends. Figure 47 most clearly revealed the increase of the energy yield with increasing torrefaction temperature. As proved, torrefaction improved energy density of raw oil palm biomass. (Refer Appendix III for detail result of calorific value for raw and torrefied biomass)

CHAPTER 5: CONCLUSION AND RECOMMENDATION

5.1 Conclusion

The kinetic study from TGA weight loss curve for EFB, PMF and PKS described two steps of reaction involve during torrefaction process. First step was fast hemicellulose decomposition reaction while second step was slow hemicellulose decomposition reaction. Both steps represented hemicellulose decomposition whereas no decomposition of cellulose and lignin. Kinetic model can be used for predicting amount of torrefied product of oil palm biomass from torrefaction process. However, this model limited to EFB, PMF and PKS only with particle size between 250-500 µm.

Torrefaction temperature - Six of torrefaction temperature were applied, i.e. 200, 220, 240, 260, 280 and 300°C for EFB, PMF and PKS. When temperature increased, more weight loss was obtained. From TGA observation, weight loss was resulted from decomposition of hemicellulose only. No cellulose and lignin decompositions were involved. Besides, the hemicellulose decomposition is more significant compare to cellulose and lignin during torrefaction of oil palm biomass since temperature decomposition of hemicellulose between 225-325°C [5].

Type of biomass - Different type of biomass composed different composition of hemicellulose and resulted different weight loss. EFB and PMF composed higher amount of hemicellulose than PKS where both of EFB and PMF torrefied products were resulted more weight loss than PKS.

Particle size - Two particle sizes were used during torrefaction process: 250-355 µm and 355-500 µm. 250-355 µm was resulted higher more weight loss and higher energy density rather than 355-500 µm. It was because of larger sample area of 250-355 µm lead decomposition that subjected to carbonisation, devolatilisation and hemicellulose to react faster than 355-500 µm. EFB, PMF and PKS with 250-355 µm had more weight loss and higher energy density.

Reaction time - During torrefaction process for EFB, PMF and PKS, 2 hours of reaction time was applied for each torrefaction temperature (200, 220, 240, 260, 280 and 300°C).

2 hours of reaction time was enough for EFB, PMF and PKS where there was no more weight loss of sample (weight loss constant). However, reaction time below 2 hours was not suitable for EFB, PMF and PKS. It was due to unfinished reaction showed by TGA for those samples since there was a weight loss (weight loss not constant). It can be concluded that four main parameters give significant to torrefaction process which were torrefaction temperature, type of biomass, particle size, torrefied temperature and reaction time.

Furthermore, applying torrefaction process had resulted towards energy densification for EFB, PMF and PKS. PMF contained highest energy followed by EFB and PKS. Other than that, ultimate analyses for EFB, PMF and PKS showed different carbon, hydrogen, nitrogen, sulphur and oxygen contents before and after torrefaction process.

85 5.2 Recommendation

During carried out this torrefaction project, there are a few recommendation from my side in order to make improvement and variety focus on torrefaction research, so that it becomes completed with deeply investigation. There are:

a) carried out research on determining composition of hemicellulose, cellulose and lignin for raw and torrefied biomass. Significant on doing this research is to know exact composition of hemicellulose, cellulose and lignin after and before torrefaction process. By doing this, we can know exactly which structure decompose during torrefaction process. It might be hemicellulose, cellulose or lignin. Besides, we can know the starting decomposition of hemicellulose, cellulose and lignin during the torrefaction process.

b) carried out at different particle sizes such as 100-250 µm and 100-200 mm. The important is to identify its affect onto weight loss, energy content and ultimate analysis. By doing that, kinetic model that already created can be modified and applied with different range of particle size.

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APPENDICES

Appendix I: Laplace Transform

Appendix II: Ultimate Analyses for Raw and Torrefied Biomass (EFB, PMF, PKS)

Experiment

Content (%)

C H N S O O/C

EFB_250-355_Raw Sample _45.81 _5.74 _0.43 _0.48 47.55 1.04 EFB_250-355_200 46.69 5.12 1.45 0.18 46.56 1.00 EFB_250-355_220 46.77 4.94 1.52 0.07 46.70 1.00 EFB_250-355_240 49.22 4.75 1.64 0.10 44.29 0.90 EFB_250-355_260 51.70 4.09 1.76 0.22 42.23 0.82 EFB_250-355_280 57.17 4.44 1.80 0.12 36.48 0.64 EFB_250-355_300 58.75 3.87 1.24 0.04 36.11 0.61 EFB_355-500_Raw Sample _45.00 _5.60 _0.37 _0.46 48.57 1.08 EFB_355-500_200 44.60 5.99 1.16 0.15 48.11 1.08 EFB_355-500_220 45.06 6.21 1.25 0.08 47.41 1.05 EFB_355-500_240 46.82 5.63 1.27 0.08 46.20 0.99 EFB_355-500_260 48.24 5.06 1.27 0.07 45.36 0.94 EFB_355-500_280 55.16 4.91 1.52 0.10 38.31 0.69 EFB_355-500_300 55.55 4.71 1.43 0.11 38.20 0.69 PMF_250-355_Raw Sample 45.82 5.26 0.57 0.45 47.90 1.05 PMF_250-355_200 47.60 4.03 1.45 0.04 46.88 0.98 PMF_250-355_220 48.12 4.02 0.97 0.06 46.83 0.97 PMF_250-355_240 50.92 4.47 1.33 0.04 43.24 0.85

PMF_250-355_260 51.73 5.09 1.45 0.41 41.33 0.80 PMF_250-355_280 52.72 4.53 0.85 0.08 41.82 0.79 PMF_250-355_300 56.61 4.30 0.99 0.04 38.05 0.67 PMF_355-500_Raw Sample 47.89 5.74 0.63 0.51 45.23 0.94 PMF_355-500_200 46.91 5.06 1.23 0.07 46.75 1.00 PMF_355-500_220 47.65 4.73 1.34 0.06 46.22 0.97 PMF_355-500_240 47.87 4.68 1.43 0.07 45.96 0.96 PMF_355-500_260 50.50 4.53 1.56 0.09 43.32 0.86 PMF_355-500_280 51.09 4.27 1.62 0.07 42.96 0.84 PMF_355-500_300 51.50 3.78 1.65 0.07 42.99 0.83 PKS_250-355_Raw Sample _50.18 _5.55 _0.49 _0.42 43.36 0.86 PKS_250-355_200 46.76 4.78 0.88 0.03 47.56 1.02 PKS_250-355_220 47.08 4.56 0.88 0.08 47.40 1.01 PKS_250-355_240 47.20 4.63 0.85 0.06 47.26 1.00 PKS_250-355_260 47.68 4.47 0.48 0.03 47.35 0.99 PKS_250-355_280 47.91 4.25 0.99 0.03 46.83 0.98 PKS_250-355_300 51.31 4.04 1.03 0.03 43.60 0.85 PKS_355-500_Raw Sample _49.27 _5.46 _0.42 _0.38 44.47 0.90 PKS_355-500_200 46.84 5.21 0.87 0.03 47.04 1.00 PKS_355-500_220 47.49 4.72 0.91 0.02 46.85 0.99 PKS_355-500_240 48.33 4.66 0.89 0.04 46.08 0.95

PKS_355-500_260 49.63 4.51 0.97 0.03 44.88 0.90 PKS_355-500_280 49.84 4.53 0.89 0.03 44.71 0.90 PKS_355-500_300 51.56 4.19 0.93 0.03 43.29 0.84

*Notation for CHNS Experiment: Sample Name_Particle Size_Torrefaction Temperature

Appendix III: Calorific Value for Raw and Torrefied Biomass (EFB, PMF, PKS) Experiment Sample Weight

(g)

Calorific Value (J/g)

Energy Yield (J) EFB_250-355_Raw Sample 0.5 17377.00 8.69E+03

EFB_250-355_200 0.5 17534.00 8.77E+03

EFB_250-355_220 0.5 17844.00 8.92E+03

EFB_250-355_240 0.5 18847.00 9.42E+03

EFB_250-355_260 0.5 19761.00 9.88E+03

EFB_250-355_280 0.5 21669.00 1.08E+04

EFB_250-355_300 0.5 22592.00 1.13E+04

EFB_355-500_Raw Sample 0.5 18035.00 9.02E+03

EFB_355-500_200 0.5 18443.00 9.22E+03

EFB_355-500_220 0.5 18897.00 9.45E+03

EFB_355-500_240 0.5 19377.00 9.69E+03

EFB_355-500_260 0.5 19893.00 9.95E+03

EFB_355-500_280 0.5 22180.00 1.11E+04

EFB_355-500_300 0.5 22415.00 1.12E+04

PMF_250-355_Raw Sample 0.5 18093.00 9.05E+03

PMF_250-355_200 0.5 19129.00 9.56E+03

PMF_250-355_220 0.5 19671.00 9.84E+03

PMF_250-355_240 0.5 19986.00 9.99E+03

PMF_250-355_260 0.5 20214.00 1.01E+04

PMF_250-355_280 0.5 21914.00 1.10E+04

PMF_250-355_300 0.5 23102.00 1.16E+04

PMF_355-500_Raw Sample 0.5 18161.00 9.08E+03

PMF_355-500_200 0.5 19341.00 9.67E+03

PMF_355-500_220 0.5 19667.00 9.83E+03

PMF_355-500_240 0.5 20092.00 1.00E+04

PMF_355-500_260 0.5 20751.00 1.04E+04

PMF_355-500_280 0.5 22046.00 1.10E+04

PMF_355-500_300 0.5 23732.00 1.19E+04

PKS_250-355_Raw Sample 0.5 19191.00 9.60E+03

PKS_250-355_200 0.5 19702.00 9.85E+03

PKS_250-355_220 0.5 19715.00 9.86E+03

PKS_250-355_240 0.5 19856.00 9.93E+03

PKS_250-355_260 0.5 20351.00 1.02E+04

PKS_250-355_280 0.5 21085.00 1.05E+04

PKS_250-355_300 0.5 21542.00 1.08E+04

PKS_355-500_Raw Sample 0.5 19160.00 9.58E+03

PKS_355-500_200 0.5 19481.00 9.74E+03

PKS_355-500_220 0.5 19581.00 9.79E+03

PKS_355-500_240 0.5 20026.00 1.00E+04

PKS_355-500_260 0.5 20833.00 1.04E+04

PKS_355-500_280 0.5 20913.00 1.05E+04

PKS_355-500_300 0.5 21856.00 1.09E+04

*Notation for Bomb Calorimeter Experiment: Sample Name_Particle Size_Torrefaction Temperature

Appendix IV: Raw Data for TGA a) -Type of biomass: EFB

-Particle size : 250 – 355 µm -Reaction time : 2 hours