Palm Oil Sector
Palm oil industry is the pillar to change Malaysia’s economy and plays a major role as the largest exporter of palm oil worldwide and second largest producer after Indonesia. There are few types of palm oil species available globally but in Malaysia, oil is extracted from mesocarp of oil palm species called Elaeis guineensis. Palm oil has become global interest for its renewable and sustainable raw materials. In reality, oil palm agricultural has begun in year 1917 at a slow growth and after last 50 years of plantation, then the development was in rapid pace through large scale investment on that agricultural industry. Thus, production of oil palm is increasing. In 1985, palm tree were planted in 1.5 million hectares and in 2007, it increased to 4.3 million hectares. It has become the most important commodity crop in Malaysia. In 2011 the total hectares palm tree plantation area was 4.917 million. Over the years, palm oil production has showed an increasing from 4.1 million tonnes in 1985 to 6.1 million tonnes in 1990. In 2011 and 2012 showed 18.9 million tonnes and 19.4 million tonnes respectively. http://www.palmoilworld.org/about_malaysian-industry.htmlWaste Generated from Palm Oil Sector
In Malaysia, 94% of biomass enormously produced from palm oil sector and the balance is from agricultural and forestry sector like wood, rice husks and sugar cane (biochar from treated and untreated). Solid oil palm biomass from the palm oil mill throughout the year consist of empty fruit bunch (EPF), mesocarp fibre (MF), palm kernel soil (PKS), oil palm trunk (OPT), oil palm frond (OPF). Each of fresh fruit bunch (FFB) containing 21 % crude palm oil (CPO), 6-7% palm kernel, 13.5-15% MF, 5.5-7% PKS and 22-23% EFB. (biochar from oil palm biomass: a review of its potential and challenges). The oil palm production in year 2012 generated 95.21 million tonnes of oil palm waste which includes 21.90 mtonnes of EFB, 12.38 mtonnes of OPF, 5.71 mtonnes of PKS, and 55.22 mtonnes of mill effluent (POME). (Sustainable Biofuels and Other Related Bio-Products from Palm Cultivations). The average weight of palm fronds that had entered the cutting period is equal to 4 g per dry frond, with total production of palm fronds around 5500 kg hectare per year. (characeristics of activated carbon results from pyrolysis of oil palm fronds powder). Oil palm frond biomass consist of 30.4 % dry wt. of cellulose, 40.4% of hemicellulose, 21.7% lignin, 1.7% extraction and 5.8% ash (biochar from oil palm biomass: a review of its potential and challenge).
Bio-char is known as carboneous material produced from biomass by pyrolysis under zero or limited supply of oxygen to capture combustible gases and usually in low temperature and heating rate. Bio-char consist of volatile matter, ash content, fixed carbon and moisture content. The product yields are influence by the types of feedstock, structural composition, and pyrolysis condition for example residence time, heating rate and temperature of pyrolysis process. Slow and fast pyrolysis is usually be determine from heating rate and residence time and for production of bio-char usually used slow pyrolysis or called as conventional carbonization at long residence time but low heating rate and for fast pyrolysis is vice versa. Bio-char is produced in solid from by dry carbonization, pyrolysis or gasification of biomass, and in slurry form by hydrothermal carbonization of biomass under pressure (recent advances in utilization of biochar). Bio-char can be used in many particular areas; hence the end users of bio-char should considering chemical and physical characterization of bio-char.
Non Direct Method
However, bio-char also can be produced either by direct firing method and non-direct firing method where in non-direct firing method, the heating source not direct contact with the feedstock and heated externally. The combustion of bio-char happens in separate chamber and heat being transferred by conduction Furthermore, by using non direct method, it produced clean air and no pollution occurred.
Palm oil industry in Malaysia has grown quickly cause the waste of this production to increase. However, with the presence of lignocellulose biomass broadly has created cause the major problem in disposal the waste. Palm oil biomass has been abundant without applying proper waste management to minimise and recover the energy from waste. Moreover, the palm oil frond that being cut during harvesting is only being leaved to rot on the ground and this abundance of oil palm frond not fully utilized into product. It has alternative used for economical aspect thus should not be disposed easily. Today, the increasing in global warming through the greenhouse gas emission and increasing in concentration of carbon dioxide in the atmosphere are the greatest threats and challenges faced by mankind. Production of bio-char can potentially lead to environment friendly replacement and enhance sustainability.
Production of bio-char was selected for my project as I found that palm oil frond is the highest abundance waste that has potential to be converted into useful products in environment sustainability. Furthermore, this palm oil frond is easily found especially after pruning process. Non-direct firing method was used in my study because it produced clean and dry air and the heater not release carbon dioxide which can be operated in tightly sealed spaced.
The objectives of this research are:
1)To study the optimum parameter to prepare bio-char using double jacket pyrolyzer.
2)To evaluate and characterized of palm oil frond bio-char physical characteristics by using SEM, BET, pH meter and UV-Vis Spectroscopy.
Scope of Research
The scopes of this research study are discussed to ensure the objectives of the research are achieved. Firstly, this experiment were conducted under various activation temperature which are 400 ?C , 600 ?C and 800 ?C of heating temperature under slow pyrolysis for 1 hour in double jacket pyrolyzer. From previous study, production of bio-char under slow pyrolysis showed higher yield of bio-char in term of mass and energy. Would be tested for its physical characteristics using Brunaeuer, Emmett and Teller (BET) method that calculated specific surface area of bio-char by measure the nitrogen gas sorption at 77 K(use of chemical and physical characteristics to investigate) . In addition, the bio-char surface morphology were analysed using Scanning Electron Microscopy (SEM) with an acceleration voltage of 20 kV. Sample preparation involves freeze-drying the samples for 3 days before they were adhered to aluminium stubs using graphite and nickel cement. (use of chemical and physical characteristics to investigate). Bio-char methylene blue (MB) adsorption preparation must be conducted at room temperature and dark space and tested using UV-VIS Spectroscopy at the wavelength of 665 nm (use of chemical and physical characteristics to investigate). The amount of MB adsorbed calculated to determine the suitability as an adsorbent. In order to test for pH, bio-char samples were immersed in deionized water with 1 hour of stirring. Most of the journal showed that bio-char possess common high pH value.
The Significant of Research
The increasing in solid waste produced in Malaysia due to palm oil production has caused many problems. Thus, turning the lignocellulosic biomass into bio-char has been identified as a way in reducing abundance of waste from palm oil. As known, existing charcoal has cause the greenhouse gas emission to environment. Therefore, through bio-char production along with the abundance of the biomass has open the way for mitigation of climate change and improve less fertile soils and increase crop yields.
The procedures of this study were divided into three stages; (1) preparation of palm oil frond samples; (2) production of bio-char and (3) analysis of the physical characteristics of bio-char. Moreover, this experiment is testing based on physical characteristics of the bio-char palm frond based to determine the specific surface area, surface morphology of palm frond biomass and bio-char, pH of solution and adsorption on MB.
Palm Oil Frond
The palm oil frond used is coming from palm oil estate at Tanjung Langsat, Kuala Selangor. The bio-char preparation is from palm frond obtained after the pruning process and basically still in fresh condition.
Methylene Blue (MB)
MB used for the bio-char adsorption study before analysed using UV-Vis Spectroscopy.
Liquified Petroleum Gas (LPG)
LPG use for the combustion of the biomass.
Nitrogen gas purge into double jacket pyrolyzer during the pyrolysis process.
Distilled water used to immerse the bio-char sample before taking the pH reading of the solution.
The equipment used in this study is stated in table 3.2 below:
Oven To dry the palm oil frond sample
Cutting mill To mashed the dried sample into powder
Weighing scale To weight the palm oil sample in gram
Double jacket pyrolyzerTo produce bio-char from biomass
SEM To analysed surface morphology of bio-char and biomass
BET To analysed the specific surface area of sample
UV-Vis Spectroscopy To determine the adsorption reading of bio-char samples
pH meter To determine the pH value of bio-char
Figure 3.2: Flow for the process of preparing palm oil biomass, bio-char and testing methods.
Preparation of Palm Oil Frond Samples
At the preparing stage, the palm oil fronds is collected from the estate are cutting into small pieces and dried in the oven for three consecutive days at temperature 70 ?C to remove the moisture content from the samples. The moisture content should be less than 5% to get better quality of bio-char. After the drying process, the dried product is mashed in cutting mill and sieve using 1 mm size of molecular sieves. The mashed product is store in airtight plastic bag together with silica gel to remove any present moisture in the mashed sample.
Preparation of bio-char
This experiment conduct is batch experiment. The start-up procedure is done by ensure the valve and supply wire is connected properly and 500 gram of palm frond biomass is fed into char combustion chamber located in the middle of double jacketed pyrolyzer. The liquefied petroleum gas (LPG) from gas cylinder is supplied to the burner located in the separate area from char chamber in pyrolyzer because the indirect method has been applied. The compressor in started to help the heating process. Then the nozzle of burner is positioned in its place after the flame already turns into blue colour. The pyrolysis temperature should be at 400 ?C, 600 ?C or 800 ?C before starting the time for one hour. The heating rate is used at 20 ?C /min. The temperature indicator is used to indicate the temperature of the process. When the temperature is reached at the desired temperature, nitrogen gas is purged into the double jacket reactor to ensure no or low oxygen in the process. With the present of oxygen, the biomass will be converted into ash. The valves need to be controlled manually to adjust the flow of nitrogen and LPG purging into system. If the time has reached 1 hour, the shutdown process is being carried out by close the valve of LPG and nitrogen, shut off the compressor and let the bio-char to cool down until temperature reach at 70 ?C before collect it.
Analysis of Physical Characteristics
There are four types of physical characteristics analysis to be analysed and study which are Scanning Electron Microscopy (SEM) for the surface morphology study, Brunaeuer, Emmett and Teller (BET) for specific surface area of porosity, pH reading to determine alkalinity or acidity of solution using pH meter and adsorption of methylene blue tested using UV-VIS Spectroscopy.
Scanning Electron Microscopy (SEM)
SEM analysis used is Hitachi S-4100 FE-SEM operates at 20 kV to analyse the differences of surface morphology of the oil palm frond before and after pyrolysis; which the pores has been carbonized and activated after the carbonization process. The major components of palm frond would be cellulose, hemicellulose and lignin where lignin has been reported to fuse on pyrolysis and forms macropores of ~25 ?m to ~100 ?m in size. Bio-char porosity consists of micropores ;20 nm, mesopores between 2 – 50 nm and macropores ;50 nm. Micropores will absorb small molecules such as gas while mesopores will absorb large molecules such as colour (palm frond biochar production and chatacter). From the previous study, it shows the pores structure formed which result from evaporation and breakdown of the non-carbon compounds in the biomass during pyrolysis. Bio-char has activator that enlarges its porosity, causing the bio-char has more rough surface and irregularity. (charateristics of ac from pyrolysis of OPF)
pH meter used is Model 420 Thermo Orion (thermo Fisher Scientific pH meter) to analyse the pH of the bio-char suspension. Bio-char sample is immersed in deionized water ratio of 1:2 (w/v) and stirred for 1 hour. (production and characteristics of slow pyrolysis biochar: influence of feedstock type and pyrolysis)
Brunaeuer, Emmett and Teller (BET)
BET used to measure the surface area of the bio-char using Autosorb-1 Surface Area Analyzer (Quantachrome Instruments) at 0.162 nm2 N2 absorption and 77 K. BET theory aims to explain the physical adsorption of gas molecules on a solid surface and serves as the basic for an important analysis technique for the measurement of the specific surface area of a material. For this study, BET analysis is to determine the effectiveness of different process temperature. Higher surface area of bio-char will increase the adsorption efficiency of charcoal. Samples were degassed at 100 ?C under continuous nitrogen flow for 24 h prior to analysis. (production and characteristics of slow pyrolysis biochar: influence of feedstock type and pyrolysis)
UV-Vis Spectroscopy used to determine the potential of adsorption for different carbonisation temperature to produce palm frond bio-char. First, the samples were dried for one night at 60 ?C in an oven to remove the existing moisture. The concentration used from 3-15 g L-1 at 50 mg L-1 of methylene blue (MB) concentration. Then, to study the adsorption process, the samples is placed in the incubator shaker for 25 ?C, 120 min and speed 120 rpm. (Adsorption of methylene blue on biochar microparticles derived from different waste materials). The sample is separated by filtration and methylene blue adsorption is determined by UV-Vis Spectroscopy at wavelength 665 nm. (carbonisation activation of oil palm kernel shell to produce ac and methylene blue adsorp).