Pyrolysis Of Oil Palm Trunk_fairus

Deris, R. R. R., Sulaiman, M. R., Darus, F. M., Mahmus, M. S. and Bakar, N. A. 2006. Pyrolysis Of Oil Palm Trunk (OPT). In: Som, M.A., Veluri, M.V.P.S., Savory, R.M., Aris, M.J. and Yang, Y.C. (Ed.). Proceedings of the 20th Symposium of Malaysian Chemical Engineers (SOMChE 2006), 19 - 21 December 2006, UiTM Shah Alam, Selangor. pp 245 – 250. Shah Alam: University Publication Center (UPENA). ISBN: 983-3644-074

PYROLYSIS OF OIL PALM TRUNK (OPT) R. R. R. Deris1,*, M. R. Sulaiman2, F. M. Darus1, M. S. Mahmud3 and N. A. Bakar1 1

Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia. 2 Faculty of Chemical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia. 3 Faculty of Education, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia. * Corresponding author. Phone: +603-55443650/4540, Fax: +603-55443638 Email: [email protected]

ABSTRACT Thousands of tonnes of Oil Palm Trunk (OPT) will be produced annually in Malaysia. This has a significant effect on the environment, particularly due to the green house gas (GHG) that are released during the decomposition of OPT. OPT was pyrolysed at temperature ranges from 200oC to 600oC with heating rate of 10oC/min. The char yield decreased rapidly with increasing pyrolysis temperature up to 300oC. Above 300oC, the char yield decreased proportionately as the temperature increases. However, the gas yield (includes the loss of fine oil droplets) showed the opposite trend, it increases with increasing reactor temperature. The oil production showed the same trend as gases but the proportions are much lower. The highest percentage of oil produced was at 600oC. At the temperature of 200oC, there was no significant effect on the distribution of the production of liquid, char and gases. It may be because of not enough energy to break down the higher molecules to the smallest one. The study on the effect of particle size on products distribution showed that, there was no major effect on product yields between particles size of 0.25mm to 2.0mm. Gas Chromatography-Mass Spectroscopy (GC-MS) result showed that the highest percentage of compound present in the liquid oil was in the order of Heptadecane (20.6%), Nonacosane (18.2%), Tetracosane (14.8%), Octadecane (14.3%), Decosane (14.3%), 11-butyl (14.3%), Heptacosane (5.2%), Hexacosane (3.3%), Tetratetracontane (3.3%) and Phenol (1.6%). Keywords: pyrolysis, oil palm trunk, GC-MS.

1. INTRODUCTION Biomass is an important contributor to the world economy. Malaysia is the largest producer and exporter of palm oil in the world with market share of about 50 and 58 percent, respectively (Mohd Nasir, 2003). In 1997, Malaysia produced about 13.2 million tones of oil palm biomass including trunk, fronds, and empty fruit bunches (Kamaruddin et.al., 1997). Agriculture and forest products industries provide food, feed, fiber, and a wide range of necessary products like shelter, packaging, clothing, and communications. However, biomass is also a source of a large variety of chemicals and materials, and of electricity and fuels (Chum and Overend, 2001). In developing countries, the use of biomass is of high interest, since these countries have economies largely based on agriculture and forestry (Sensoz et. al., 2006). The use of these materials will depend on the state of the art of safe and economic technologies able to transform them into manageable products (Bridgwater, 1999). In this way, thermochemical biomass conversion processes such as pyrolysis, gasification and liquefaction are the most appropriate (Encinar et al., 1995). In thermal conversion, combustion is already widely practised. Whereas, gasification attracts a high level of interest as it offers higher efficiencies compared to combustion. However, fast pyrolysis is interesting because liquid are produced and this offers advantages in terms of storage, transportation and versatility in applications, even though it is still at a relatively

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early stage of its development (Bridgwater, 2004). The products and applications of these thermal conversion processes are summarised in Figure 1. Pyrolysis involves heating carbonaceous materials in the absence of Oxygen. It is an ancient technology used ages ago to produce charcoal from wood for heating and smelting metals from various ores. Charcoal for barbecues and similar uses has been produced on a small scale in Malaysia at present time. Modern pyrolysis technology is developing predominantly for the maximum liquid production instead of merely charcoal and coke. To enhance the overall applicability of biomass for large scale production, pyrolysis processes offers several options for upgrading biomass. The amount and nature of end products of pyrolysis will depend on the operating temperature, the heating rate, the residence time and the compositions of the biomass. In this study, oil palm trunk (OPT) was chosen as the renewable energy source. Its pyrolysis was conducted under different conditions in a fixed-bed reactor. The aim of the study is to investigate the influence of the final pyrolysis temperature, the particle size and the compositions of bio-oil in order to provide preliminary data for further investigation. Pyrolysis

Bio-fuel

Gasification

Fuel Gas

Storage option

Chemicals, transport fuels, Hydrogen

Turbine

Engine Combustion

Heat

Boiler

Electricity

Heat

FIGURE 1: Products from thermal biomass conversion

2. MATERIALS AND METHODS 2.1 RAW MATERIAL The biomass sample used in this study was Oil Palm Trunk (OPT) obtained from an oil palm farm at Kampung Tanjung Berembang, Pulau Pinang, Malaysia. The proximate and ultimate analysis of the OPT is presented in Table 1. For the study purposes, five different feedstocks sizes 0.25mm, 0.50mm, 0.75mm, 1.0mm and 2.0mm were used. The feedstocks were cut into cubic shape, oven dried at 110 overnight and ground prior to pyrolysis. 2.2 EXPERIMENTAL PROCEDURE The experimental system used was a fixed bed pyrolysis unit (Fig.2). The size of the reactor was 70 mm in diameter and 380 mm in length, constructed of stainless steel with a temperature controller. The reactor was heated externally and nitrogen gas was supplied to maintain the inert atmosphere in the reactor and also to drive the pyrolyze vapor product to the condensers. The OPT sample of 150g was loaded in the reactor vessel. The temperature range for the reactor was 200 – 600 0C. The retention time was fixed for 2 hours in order to allow the sample to go through a complete pyrolysis process (R. R. R. Deris, 2006). The liquid product was collected at the liquid collector point. The effect of temperature was analysed by increasing the temperature and fixing the particle size to determine the optimum condition of product yield. The condensable products (liquid) were collected in a series of traps maintained at room temperature. These liquid products contained an aqueous and oil phase, which were weighed and run through GC-MS analysis. The char was also removed from the reactor and weighed.

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TABLE 1: Proximate and ultimate analyses of OPT Proximate analysis Wt% Moisture content 5.89 Volatile matter 76.84 Fixed carbon 11.42 Ash content 5.85

Elemental analysis Carbon (C) Hydrogen (H) Nitrogen (N) Oxygen (O) Sulfur (S) Colorific value (MJ/kg)

Wt% 40.64 5.09 2.15 53.12* 17.27

*By difference

CONDENSOR

EXTRACT

HEATER 1 DATA LOGGER WATER FURNACE

NITROGEN HEATER 2 To

SAMPLES BOAT OIL TEMPERATURE CONTROLLER

OIL CONTAINERS

FIGURE 2: Fixed Bed Pyrolysis Unit

3. RESULTS AND DISCUSSION 3.1 RAW MATERIAL CHARACTERISTICS The main criterion of the suitability of the feedstock to be used for pyrolysis conversion is high volatile content with low ash and sulfur content. Table 1 shows the characteristics of OPT, it appears that the high volatile content, low ash and sulfur content, therefore it is suitable for pyrolysis conversion. Table 2 shows a comparison of characteristics of fresh OPT and char obtained from pyrolysis at 600oC. It revealed that colorific value (CV) was doubled (28.18 MJ/kg) from the original sample (17.27 MJ/kg). Also, proximate analysis shows that fixed carbon and ash content increased but volatile content decreased to almost half of the original sample. Since the CV of the char is low (28.18 MJ/kg) but high ash content (25.68 wt %), therefore it is not suitable for charcoal fuel production. These results supported a finding in K. O. Lim and K. S. Lim, 1991. But OPT is suitable for pyrolysis conversion because it contains high volatile content (76.84 wt %). 3.1 PRODUCT YIELD The products obtained from pyrolysis of OPT are bio-oil, solid char and gas. The maximum liquid product was found at an operating temperature of 600oC and 1 mm feedstock size. 3.2 EFFECTS OF OPERATING TEMPERATURE The products distribution of different pyrolysis temperature is shown in Fig. 1. It is learn that bio-oil started to produce at temperature above 200oC. This is because at 200oC and below the heat was not high enough for a complete pyrolysis to take place thus yielding less liquid product or no liquid at all. As the operating temperature increases, the liquid yield increased significantly up to 600oC at a product yield of 18.7 wt%. The solid (Char) yield decreased rapidly from 90 wt% (at temperature of 200oC) to 42 wt% (at temperature of 300oC). As operating temperature increases from 300oC to 600oC, the char yield decreased slightly from 42 wt% to 30 wt%.

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The gas (includes the loss of fine oil droplets) result showed an opposite trend of solid yield. It showed a rapid increase from 10 wt% (at temperature of 200oC) to 42 wt% (at temperature of 300oC). From the temperature of 300oC to 600oC the gas yield showed a gradual increase from 42 wt% to 51.3 wt%. TABLE 2: Characteristics of Oil Palm Trunk (OPT) Test Parameters Moisture Content

Raw Material (Wt %) 5.89

Proximate Analysis Ash Content Volatile Content Fixed Carbon Ultimate Analysis Carbon Hydrogen Nitrogen Oxygen Sulfur Colorific value (MJ/Kg) *By difference

Char (Wt %) 1.59

5.85 76.84 11.42

25.68 30.92 41.82

40.64 5.09 2.15 53.12* 0.00 17.27

42.68 1.79 2.48 53.05 0.00 28.18

Effect of operating temperature on product yields 100.0 90.0

Product yields (wt%)

80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 200

300

400

500

600

Temperature (oC) liquid

char

gases

FIGURE 3: Effect of temperature on solid, liquid and gas yield

3.3 EFFECTS OF FEED PARTICLE SIZE ON PRODUCT YIELDS Figure 4 represents the percentage mass of liquid, solid and gas products in relation to the mass of OPT feed for different particle size at 600oC. It was observed that at the products proportion with particle size of 0.25 mm, 0.50 mm, 0.75 mm and 1.0 mm, there was no significant effect. However, larger particle size (2.00 mm) produced slightly more liquid (18 wt %) compared to the smaller ones.

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Effect of particle sizes on product distributions 60

Product yields (wt%)

50

40

30

20

10

0 0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

Particle size Liquid

Char

Gases

FIGURE 4: Effect of particles sizes on the product yield TABLE 3: Identification and quantification of chemical compound in OPT pyrolysis oil Peak no. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

RT(Min)

Component

% Area

3.35 6.53 7.90 9.01 9.92 10.05 17.89 21.06 26.99 47.77 49.02 51.00 57.25 59.45 62.12 62.52 64.25 64.49 65.79 66.27

2-Furanmethanol Phenol 1,2-Cyclopentanedione, 3-methyl Phenol, 2-methylPhenol, 4-methylPhenol, 2-methoxyPhenol, 4-ethyl-2-methoxyPhenol, 2,6-dimethoxyPentadecane 1-Tricosene Hexacosane Heptacosane (C27H56 MW=380) Heptacosane Octadecane Tetracosane 2,6,10,14,18,22-Tetracosahexaene,2,6,10,15,19,23-hexamethylNonacosane (C29H60 MW=480) Heptacosane Nonacosane Heptacosane Total

0.19 1.59 0.13 0.11 0.04 0.31 0.04 0.18 0.04 0.16 3.33 5.23 7.11 14.33 14.83 0.39 18.19 0.15 20.57 1.43 88.35

3.4 CHEMICAL CHARACTERISATION Since this is a preliminary study, only GC-MS is used to study the chemical characterisation of the biooil produced by pyrolysis process. GC-MS analysis was carried out in order to get an idea of the nature and type of organic compounds in bio-oil products. Table 3 lists the tentative compound of pyrolysis liquid products obtained from pyrolysis of OPT at 660oC, 2 mm feed size. Due to the lack of an appropriate standard mixture calibration, this data obtained without calibration of the MS detector and these compounds identified by comparing chromatogram with data stored in library database. Based on components identified as shown in Table 3, it can be seen that the chemical compositions of pyrolysis bio-oils from OPT are very similar to the inclusion of a lot of aromatics and oxygenated compounds such as carboxylic acids, phenols, ketons, etc. 249

Conclusion Oil palm trunk was successfully converted into bio-oil, char and gas by means of pyrolysis. The liquid product was maximum (18.7 wt% of OPT feedstock) at a reactor temperature of 600oC with particle size of 2 mm. Distribution of products was not affected by the size of feedstock. GC-MS analyses have shown that carboxylic acid, phenol, alcohol and branched oxygenated hydrocarbon are the main compounds of bio-oil. Based on observation, there was significant amount of water contained in the liquid products. Therefore, it needs to be removed for biofuel production or chemical feedstock.

Acknowledgements The authors would like to thank the University Teknologi MARA (UiTM), for giving the opportunity and providing the facilities to successfully perform this study.

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