International Conference on Mechanical, Industrial and Energy Engineering 2016 26-27 December, 2016, Khulna, BANGLADESH
ICMIEE-PI-160160
Production of Biodiesel from Palm Oil and Performance Test with Diesel in CI Engine 1
Md. Rafsan Nahian 1*, Md. Nurul Islam 1, Shaheen Mahmud Khan 2 Department of Mechanical Engineering, Rajshahi University of Engineering & Technology, Rajshahi-6204, Bangladesh 2 Department of Mechanical Engineering, Khulna University of Engineering & Technology, Khulna-9203, Bangladesh
ABSTRACT Biodiesel from palm oil has significant potential as an alternative fuel in compression ignition (CI) engine. Early investigations report that biodiesel which is extracted from palm oil by transesterification method has similar properties like diesel fuel. Transesterification is a process of using an alcohol in the presence of a catalyst such as sodium hydroxide or potassium hydroxide to break the molecule of the raw renewable oil with glycerol as a byproduct. It has been reported that for 0.35% sodium hydroxide and 20% methanol biodiesel production is maximum. Experimental studies are conducted on a single cylinder, four stroke, water cooled, naturally aspirated diesel engine fuelled with two different blends, 10% palm oil and 90% diesel (B-10), 20% palm oil and 80% diesel (B-20). The brake thermal efficiency of B-10 is slightly lower than diesel and higher than B-20. Besides Brake specific fuel consumption of B-10 blend is very close to the specific fuel consumption of diesel and slightly lower than B-20. The emission of CO and NOx are slightly lower than conventional diesel fuel. Besides there is no sulphur content. The main concern of this paper is to produce biodiesel from palm oil by transesterification method and test the performance for different blends to analyze the fuel properties. Keywords: Palm oil, Transesterification, Biodiesel, Performance test.
1. Introduction The non-renewable nature and limited resources of petroleum fuels have become a matter of great concern. Bangladesh is an under developing country. Its energy demand is increasing day by day. Her daily demand of diesel fuel is about 109 thousand barrels [1]. The combustion of these fuels in IC engines causes pollution. All these aspects have drawn the attention to conserve and stretch the oil reserves by way of alternative fuel research. Enhanced energy security, depletion of conventional fuel and climate change mitigation are the main drivers for the transformation of the energy system from fossil to renewable sources. As a renewable energy source, the use of palm oil in diesel engines is nearly as old as diesel itself. Many researchers have found that using raw palm oil in diesel engine can cause numerous problems. Palm oil has increased viscosity, low volatility, cold flow properties and cetane number that causes injector cocking, piston ring sticking, fuel pumping problem and deposit on engine. However, the above limitations can be greatly minimized by converting the palm oil into ester through transesterification method which is named as biodiesel [2]. Biodiesel is a biodegradable, nontoxic, and clean renewable fuel with properties similar to conventional diesel. It is produced from renewable resources and has low emission profiles [3]. Biodiesel is still not commonly used in daily life mostly due to the high production cost involved, though this fuel has been developed for about three decades [4]. A cheaper raw material for biodiesel production could be a solution. The raw materials for biodiesel production now mainly include biological sources such as vegetable seed oil, soybean oil and some recovered animal fats [5]. As biodiesel is biodegradable, they do not contain any sulfur, benzene group. As a result, the products of combustion of the biodiesel do not produce * Corresponding author. Tel.: +88-01737967964 E-mail address:
[email protected]
sulfur-di-oxide (SO2) & butadiene. The main advantage of using biodiesel in diesel engine is to reduce CO2 emissions [6]. At present, 100% biodiesel is not used in place of diesel fuel to run the engine. Because 100% biodiesel cause significant reduction of brake thermal efficiency, higher specific fuel consumptions and excessive NOx formation. This problem can be greatly minimized by using diesel-biodiesel blend. The most widely used blend is B-10. Diesel- biodiesel blend doesn’t cause significant increase of NOx and reduction of brake thermal efficiency. Meanwhile the other performance parameter of the engine is like as diesel fuel [7].
2. Materials and Methods To produce biodiesel from palm oil the following materials and methods are used. 2.1 Materials 1 liter palm oil 200 ml methanol (99% pure) 3.5 gm NaOH (Lyn catalyst) Blender machine Measuring beakers for methanol and oil Thermometer Heater 2.2 Methods Palm oil is extracted or pressed to obtain crude oil. This crude oil usually contains free fatty acids (FFA), water, sterols, phospholipids, odorants and impurities. Using this oil in diesel engines can cause numerous problems. The increased viscosity, low volatility and poor cold flow properties of palm oil leads to severe engine deposits, injector coking, piston ring sticking etc. However
converting this crude palm oil into diesel may eliminate these problems. Biodiesel may be produced by following four ways: 1. Pyrolysis 2. Micro emulsification 3. Dilution 4. Transesterification Transesterification: It is the process of using an alcohol (e.g. methanol, ethanol or butanol) in presence of a catalyst such as sodium hydroxide or potassium hydroxide to break the molecule of the raw renewable oil chemically into methyl or ethyl esters of the renewable oil with glycerol as a byproduct. Transesterification process of palm oil is given in figure 1 [8].
Fig.1 Transesterification of fatty acid and typical chain structure of fatty acid methyl ester The conversion of component triglyceride to simple alkyl esters with various alcohols reduces high viscosity of oils and fats. Base catalysis of the transesterification with reagents such as sodium hydroxide is preferred over acid catalysis because the former is more rapid. Transesterification is a reverse reaction. Methyl esters are the most popular esters for several reasons. One reason is the low price of methanol compared to other alcohols. Besides, esters have significantly lower viscosities than the parent oils and fats. They improve the injection process and ensure the better atomization of the fuel in the combustion chamber. Another advantage of the esters is possibly more benign emissions. 3. Preparation of Biodiesel Biodiesel from palm oil is prepared by the following steps. 3.1 Biodiesel manufacturing process Palm Oil
Methyl Alcohol
Transesterification
NaOH (Catalyst)
1 liter of palm oil is poured into a bowl. Then it is put on the heater and allowed to heat. Oil is heated up to 70oC. Then the heated oil is allowed to decrease its temperature to 55oC. During this time, it is checked that the blender is clean and dry and the blender components are tightly fitted. 200 ml of methanol is measured and poured into 1 liter container by a funnel. Methanol absorbs water from the atmosphere. So it is done quickly and the lid of the methanol container is replaced tightly. After that, NaOH is carefully added to the container via funnel. The container is shaken for a few times. It is swirled round rather than shaking it up and down. The mixture gets hot from the reaction. It is swirled thoroughly until NaOH completely dissolved in the methanol, from sodium meth-oxide. Then heated oil is poured into the blender. When the blender still switched off, sodium meth-oxide is carefully poured from the container into the oil. The blender lid is tightly fitted and then switched on for at least 20 minutes. During the blending, the jar is covered with a wetted cloth (cold water) to decrease the heat of the jar. After completion the process, the mixture is poured from the blender into a 2 liter pet bottle for settling and screwed on the lid tightly. It is allowed to settle for 24 hours. Darker colored glycerin as byproduct is collected in a distinct layer at the bottom of the bottle, with a clear line of separation from the pale liquid above, which is the Biodiesel. 3.2 Washing of Biodiesel Biodiesel should be washed to remove soap, catalyst and other impurities. If it passes the wash test, then the rest of biodiesel should be washed. For washing, the biodiesel is poured into one of the wash bottles and half liter fresh water is added for each four wash required. The cap is screwed tightly. The bottle is turned on its side and rolled it with the hands until oil and water is well mixed and homogeneous. 4. Economic of Biodiesel production from palm oil It is estimated that the cost of biodiesel production from palm oil by transesterification process is slightly higher than the conventional diesel fuel. 1 liter palm oil is needed to obtain 1 liter biodiesel. After the transesterification process, the amount of the byproduct in form of glycerin is up to 0.40 ml.
Heating Crude Biodiesel Separation
Glycerin
Pure Biodiesel
Fig.2 Steps of biodiesel manufacturing process from palm oil ICMIEE-PI-160160-2
Table 1 Cost analysis of biodiesel Materials Cost (BDT) 1 liter palm oil 61 200 ml methanol 100 3.5 gm NaOH 3.5 Raw glycerin (Salable) (-8) Net cost for 1 liter biodiesel 156.5 The cost will be reduced significantly when it will be produced in large scale. 5. Properties of Biodiesel The engine performance greatly depends upon the chemical reaction between induced air and the fuel in the combustion chamber, which permits the release of heat energy. For this reason a fuel should possess a number of properties for using it in diesel engine. The main properties are given in Table 2. Table 2 Properties of diesel, biodiesel, palm oil and diesel. Name of Density Calorific Pour the sample (kg/m3) value (kJ/kg) point (oC) Diesel 830 42418.48 -10 Palm oil 883 34294.68 17.2 B 100 862 38356.58 11.7 B-20 840 41606.10 -5 B-10 838 42014.38 -6.8
6. Engine performance, Results and Discussions The performance of the engine at different operating conditions are given below. 6.1 Performance parameters Engine performance indicates the effect of a fuel in the engine. It is necessary to determine engine brake power, brake specific fuel consumption and brake thermal efficiency. The performance parameters can be calculated by following equations [9]. Engine Brake power: Engine brake power (P) is delivered by engine and absorbed load. It is the product of torque and angular engine speed where P is engine brake power in kW; N is angular speed of the engine in rpm as: P=
2πNT 60×1000
Brake specific fuel consumption: Brake specific fuel consumption (BSFC) is the comparison of engine to show the efficiency of the engine against with fuel consumption of the engine in kg/kW/hr. where (mf) is the fuel consumption rate in kg/hr. as: BSFC=
Fuel consumption rate Engine brake power
Brake thermal efficiency: The percentage of brake thermal efficiency of the engine is related to engine brake power and total energy input to the engine. Efficiency=
Brake power× 3600 Fuel consumption rate× Higher calorific value
6.2 Experimental setup The experiment is conducted with conventional diesel fuel, palm oil methyl ester. The rpm is measured directly by the tachometer. Fuel consumption is measured by a burette attached to the engine fuel. A stopwatch is used to measure the fuel consumption time for every 10 cc of fuel. The engine is electrically loaded. The full experimental setup is given in Fig 3. Fuel Burette Fuel Tank
Temperature Exhaust Gas
Cooling water in
Electric Heater
Air Box
Manometer RPM
Eddy Current Dynamometer
Engine
Engine torque
Flywheel
Manual Cranking Cooling water out
Fig.3 Schematic arrangement of experimental setup 6.3 Engine specifications Performance of oil is carried out through PETTER diesel engine. Table 3 Engine specifications Engine type 4- stroke diesel engine Bore × Stroke 80×110 mm Swept volume 553 cc Compression ration 16.5:1 Rated power 4.476 kW (at 1800 rpm) 14 MPa (at low speed, 900-1099 rpm) Fuel injection pressure 20 MPa (at high speed, 1100 to 2000 rpm) Fuel injection timing 24o BTDC Three test fuels have been taken for the performance test. These are 100% diesel fuel, 90% diesel with 10% biodiesel (B-10), 80% diesel fuel with 20% biodiesel (B20).
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Table 4 Performance data of diesel engine with diesel, B-10 and B-20. Brake Brake Efficiency specific fuel Sample power (%) consumption (kW) (Kg/kW/hr.) 0.294 11.3 0.750 Diesel 0.406 15.5 0.546 0.508 18.3 0.456 0.294 10.5 0.820 B-10 0.406 14.2 0.600 0.508 17.3 0.490 0.294 10.2 0.850 B-20 0.406 14.0 0.640 0.508 16.9 0.550
diesel and it increases as blending is increased from B-10 to B-20. This is because of higher calorific value of diesel than the other blends. On increasing the biodiesel proportion in the blend, BSFC increases due to the reduced calorific value of these blends. So, B-10 shows lower BSFC than B-20 because of its higher calorific value.
7. Conclusion In the presented study, it is found that biodiesel which is extracted from palm oil has almost similar properties like diesel fuel and able to replace diesel fuel in small engine. Blends of B-10 gives better results than B-20. Following are the conclusions based on the experimental results obtained while operating in a single cylinder diesel engine with diesel-biodiesel blends.
Efficiency Vs Brake Power
I.
Efficiency (%)
19 Diesel
17 15
B-10 13 11
II. III.
B-10 blends can be utilized directly in diesel engine without any engine modification. The brake thermal efficiency of B-10 is slightly lower than diesel fuel but higher than B-20. Brake specific fuel consumption of B-10 blend is very close to the specific fuel consumption of diesel but slightly lower than B-20.
B-20
So it is advisable to use B-10 rather than B-20 in CI engines.
9 0.2
0.3 0.4 0.5 Brake Power (kW)
0.6
Fig.4 Variation of efficiency with respect to brake power The effect of blending on brake thermal efficiency for various fuel combinations is depicted in figure 4. The brake thermal efficiency of engine is low at low load as compared to the engine running at higher load. This is due to relatively less portion of the power being lost with increasing load. The efficiency of diesel is higher than the other blends. This is because of fuel properties such as viscosity and density is lower than the blends. The efficiency of B-10 is higher than B-20 due to its lower density, viscosity and higher calorific value. BSFC Vs Brake Power
NOMENCLATURE B-10 : 90% diesel+ 10% biodiesel B-20 : 80% diesel+ 20% biodiesel Gm : Gram hr. : Hour BSFC: Brake specific fuel consumption, Kg/kW/hr. cc : Cubic centimètre MPa : Méga Pascal rpm : Révolution per minute mm : Milli meter kW : Kilo watt BDT : Bangladeshi Taka
BSFC (kg/kW/hr.)
0.9 Diesel
0.8 0.7
B-10
0.6 0.5 0.4
B-20
0.3 0.2
0.3
0.4
0.5
0.6
Brake Power (kW)
Fig.5 Variation of BSFC with respect to brake power Figure 5 shows the effect of blending on brake specific fuel consumption (BSFC) for various fuel combinations. The BSFC is observed to decrease sharply for all fuels at higher load. For a certain brake power, the specific fuel consumption is found to be the lowest in case of pure
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