Proceedings of The 9th Joint Conference on Chemistry ISBN 978-602-285-049-6

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Biofuel from Light Tar Resulted from Coconut Shell Pyrolysis by

Distillation Process

Uswatun Hasanaha,b* Bambang Setiajib, Triyonob, Chairil Anwarb

Abstract

Light tar resulted from the coconut shell was fractionated by distillation to obtain proper fractions as fuel. The light tar obtained from the distillation of coconut shell liquid pyrolysis resulted from Integrated Coconut Processing Industry PT. Tropica Nucifera Industry in Yogyakarta. The physical properties of fractionation products as fuel were determined including: density by ASTM D 4052, pH with a pH meter, flash point COC with ASTM D-92; kinematic viscosity by ASTM method D-445 and the calorific value by the bomb calorimeter, while the tar composition was analysed using as Chromatography Mass Spectrometer (GCMS). in this process, four fractions were produced with the boiling ranges, 50-100 °C Consisting of 2 phases, the top (22%) and lower (8%); 100-130 °C (2%) and above 130°C (68%). The best results as a fuel is the fraction with boiling point above phase 50-100 °C yellow light (ASTM colour scale 1), the calorific value of 10736 kcal/kg, pH 3.5, kinematic viscosity of 6.14 cSt and flash point of less than 10 °C. The GCMS analysis detected 50 compounds with the highest single component were methyl acetate (15.9% area) and hydrocarbon compounds (accumulatively 30.5% area). This fuel is suitable for ignition or alternative liquid to butane.

Keywords: Biofuel, coconut shell light tar, biomass pyrolysis, bio-oil distillation.

a Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Brawijaya; Jl. Veteran 65145 Malang, Indonesia, kimia@ub.ac.id

b Department of Chemistry, Faculty of Mathematics and Natural Sciences, Gadjah Mada University

Corresponding author e-mail address: uswahas@ub.ac.id

Introduction

Light tar is a by-product of coconut shell pyrolysis untapped. The tar isdark brown in colour, flammable with a flash point of less than 27 °C containing organic oxygenate compounds and hydrocarbon (Hasanah et.al. 2012), but producessoot when burned. Soot is the result of incomplete combustion oligomerat aromatic compounds or phenolics derived from lignin (Demirbas, 2009; Frenklach, 2002), which are found mainly in coconut shell. Soot is not desired in ignition of fuel because polycyclic aromatic hydrocarbons that are precursors of soot, are carcinogenic (Younes Chhiti et al., 2013). in this research, the light tar was fractionated by distillation to produce better fuel.

Methodology

Light tar liquid was from the distillation of coconut shell pyrolysis at PT. Tropica Nucifera Industry in Yogyakarta. Distillation was conducted using a Vigreux column and the distillate was collected in a certain temperature range. The characterization of fractions was determined as the physical properties including: viscosity (ASTM D 445), density (D 369), moisture

content (ASTM D 95) with a calorific value of bomb calorimeter, pH with pHmeter and colour (ASTM Luvibond scale). The composition of the fractions was determined by gas chromatography mass spectrometry (GCMS).

Results and Discussion

The experimental results show that the first drop of distillate occurred at a vapour temperature of 50 °C and condensate produced bright yellow. The vapour temperature continued to increase along with the formation of distillate liquid.Phase separation or the forming of 2-phase liquids started to occur at vapour temperature 70 °C until the temperature reaches 100 °C (Table1).

Condensate in the vapour temperature with the range of 50-100 °C then immediately separated using a separating funnel.The upper phase was fraction 1, then the fraction below was fraction 2. Fraction 3 was formed in the temperature range of 100-130 °C and the residue was fraction 4. Percentage results of each fraction of the coconut shell tar samples used in the experiments were presented in Table 1.

Proceedings of ISBN 978-602-285-049-6 The 9th Joint Conference on Chemistry

206|P a g e Green Chemistry Section 2: Physical Chemistry, Uswatun Hasanah, et al.

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Table 1.Physical-chemical properties of the coconut shell light tar fractions

Boiling point, °C 50 – 100 100-130 >130

Fraction 1 top Fraction 2 below Fraction 3 Fraction 4

% 22 8 2 68

Moist. content, %v 8 58 - -

pH 3,5 3,00 3,35 3,5

Calorific value, kcal/kg 10736 8219 9761 9468

Flash point, °C <10 <10 - 88,5

Table 2. The main components based on GCMS analysis in each fraction light tar fractionation result

The main components % Area

Fraction 1 Fraction 2 Fraction 3 Fraction 4

Methylacetate 15.90 22.7 2.05

Acetic acid - 33.15 21.93 -

Methanol 4.14 12.93 - -

Propanoic acid 6.93

Ethylacetone 3.34

2-Furaldehyde - 6.01 -

Methyl butanoic 4.14

Indonaften 6.14 - -

2-Butanone 11.85 15.09

4,6-Dimethyl phenol - - - 5.85

Guajol - - 4.73 8.79

p-creosol - - - 5.13

Phenol - 1.27 17.91 25.39

4-Ethylguaiacol - 6.48

Table 3 Summary results of the composition analysis by GCMS results of fractionation of coconut shell light tar

Group of compounds Total area, %

Fraction 1 Fraction 2 Fraction 3 Fraction 4

Hydrocarbon 30.53 0 6.89 2.33

Aldehyde 2.11 2.43 6.01 2.09

Ester 26 22.83 3.16 3.95

Ketone 27.37 23.11 14.25 13.47

Alcohol/phenolic 5.27 14.2 29.47 68.59

Ether 5.52 1.54 6.21 5.91

Acid 7.07 35.89 31.14 0

The water content in the fraction 2 as shown in Table 1 is high relatively 58% v/v. According to Czernik et al. (1994)high water content occur not only from evaporation, but also from reactions that produce water as by product such as: condensation,

etherification and esterification that occurs between the compounds with functional groups hydroxyl, carbonyl and carboxyl.)Methyl acetate and methyl butanoic was the main component of esterification

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presented in the fractions 1 and 2 as shown in the summary of the GCMS analysis (Table 2 and 3).

Phase separation occurred because of the differences in polarity between fractions 1 and 2. This can be seen in the summary of the results of the analysis of the composition in Table 2. Non-polar organic compounds was hydrocarbon group that cumulatively has quite large percentage in fraction 1, while oxygenate compounds were semi-polar ester groups, ketones, alcohols, ethers and acid distributed into the fraction 1 and 2.

Figure 1 shows that the higher the boiling point the darker the colour of fractions or in other words ASTM colour scale increased as the increasing boiling point. This indicated that the distillation has been able to separate the volatile compounds from the compounds forming the dark, oligomeric aromatic compounds lignin derivated from the light tar, for example: phenolic compounds such as dimethylphenol, creosole, guajol and others (Table 2).

The tendency of the change of colour of the fractions of coconut shell light tar distilled apparently corresponds to the tendency of soot formation (Figure 2). So the darker the colour of the oil, the more soot is formed. The formation of soot is the main constraint for coconut shell tar used directly as a fuel. Frenklach (2002) reported that there are several types of species proposed by some previous researchers as early soot formation in fuels such as polyacetylene, species-species ionic or polycyclic aromatic hydrocarbons, but most researchers agree that polycyclic aromatic hydrocarbons as the main precursor for soot (Younes Chhiti et al. 2013).

Figure 1. ASTM colour scale versus boiling point of fraction

Figure 2. Percentage of soot versus boiling point of

fraction, % Jbb = percentage of soot on the number of initial fuel and % Jtb = percentage of soot on the

amount of fuel burned

Figure 3. Density versus boiling point of fraction

Figure 4. Viscosity versus boiling point of fraction.

The higher the boiling point then the density was increasing (Figure 3).According to Oasmaa et al. (1997), the density of the liquid pyrolysis of biomass is a function of water content. in pyrolysis liquids, density on top phases is different with below phase because the water content. This is because the extractive compound is concentrated at the top while the bottom phase with compounds was dissolved in the water (Oasmaa and Peacocke, 2010). Fractions 3 and 4 show a higher density because the content of organic compounds of relatively high molecular weight classes of phenolic compounds are relatively more than the fractionsand 2 (Table 2). The amount of the of high molecular weight compounds relatively also affected the volatility and viscosity, that is shown by a relatively

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208|P a g e Green Chemistry Section 2: Physical Chemistry, Uswatun Hasanah, et al.

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higher flash point (Table 1) and higher the kinematic viscosity (Figure 4)

Thus the fraction 1 is the best fraction with the highest calorific value (Table 1) and the lowest ASTM colour scale and soot.

Conclusions

The best biofuel was the fraction 1 (top phase, the boiling point 50-100 °C) with the results as much as 22% of the sample light tar, bright yellow (ASTM colour scale 1), the calorific value of 10.736 kcal/g, pH 3.5, 6.14 c St kinematic viscosity and flash point of less than 10 °C. The GCMS analysis of this fraction detected 50 compounds with the highest single component of 15.9% methyl acetate and hydrocarbon compounds of 30.5% cumulatively. The fraction has a very low flash point compared to the other fractions, the fraction so that fraction 1 was the best for lighter or lighter fluid filler as an alternative liquid to butane.

Acknowledgments

Thanks to PT. Tropica Nucifera Industry in Yogyakarta which has helped providing the research samples

References

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Hasanah, Uswatun, Bambang Setiaji, Triyono, Chairil Anwar, 2012,’The Chemical Composition and Physical Properties of the Light and Heavy Tar Resulted from Coconut Shell Pyrolysis’J. Pure App. Chem. Res.,1 (1), 26-32

Oasmaa, A., Leppämäki, E., Koponen, P., Levander, J. & Tapola, E. 1997. Physical characterisation of biomass-based pyrolysis liquids. Application of standard fuel oil analyses. Espoo, VTT Publications 306. ISBN 951-38-5051-X.

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