G04424249

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IOSR Journal of Engineering (IOSR-JEN) Volume 4 Issue 4 Version 2

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G04424249

  1. 1. IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org ISSN (e): 2250-3021, ISSN (p): 2278-8719 Vol. 04, Issue 04 (April. 2014), ||V2|| PP 42-49 International organization of Scientific Research 42 | P a g e Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel engine in dual fuel mode Biswajit Nayak 1 Department of Mechanical Engineering, KEC, Bhubaneswar-752054, Odisha, India, Abstract : - The present study demonstrates the emission analysis of different blends of Karanja biodiesel and diesel with producer gas in dual fuel mode usinga twin cylinder diesel engine for 2 cases of operations.In case 1, test is carried out using the above test fuels bothin single mode and dual fuel mode operation with constant gas flow rate of 21.49Kg/hr under different load conditions. Similarly, in case 2, test is performed at a constant load of 10 kW under different gas flow rates using the same test fuels in dual fuel mode only. The study reveals that,all blended fuels shows better emissions compared to diesel in both cases of operations. Dual fuel mode operation of all tested fuels shows lower smoke and oxide of nitrogen emissions compared to their single mode operation under all load conditions, whereas, other emission parameters are found to be on higher side. Keywords: - Fossil diesel; producer gas; dual fuel; twin cylinder; emission; biodiesel I. INTRODUCTION Energy is the backbone of India’s economic growth. Since, India being an agricultural country, huge amount of diesel fuel is consumed in agriculture sector. Due to rapid depletion of diesel fuel, its rising prices and hazards emissions from vehicles, an alternative fuel for diesel is critically important for our nation’s economic growth and security. Keeping this in view, more interest is generated to do research work to find out the viable alternative fuel for diesel engine in India. Non-edible vegetable oil i.e. Karanja and its derivatives can be used as an alternative fuel for compression ignition engine. It is renewable, highly available and environmental friendly. Due to higher viscosity of vegetable oil it creates some engine problems like poor fuel atomization, which leads to poor engine performance, ring sticking, injector pump failure and injector deposit etc (Agarwal and Das 2001). To reduce viscosity of vegetable oil and to improve the engine emissions, transestrification andblending with diesel is necessary. The different blends are made by mixing biodiesel with diesel in a proportion of volume/volume ratio or weight/weight ratio. Wang et al. (2006) conducted experiment using vegetable oil blends with diesel and reported that, lower NOx and a small change in CO emission compared to diesel.Senthilkumar et al. (2001) carried out experiment using Jatropha oil-diesel blend and reported that EGT, HC, smoke and CO emissions are higher than mineral diesel.Babu and Devaradjane (2003) conducted experiment using soya bean methyl ester with diesel and reported that reduction of 20.2% for CO, 6.1% for PM and 4.5% increases for NOx emission. Similarly, biomass derived producer gas can be used as an alternative fuel for diesel engine due to their eco-friendly nature (Nwafor 2000a, 2000b). Producer gas when burnt produces insignificant SOxand little NOx, the main constituent of acid rain and smog than fossil fuel (Henham and Makkar 1998). However, due to higher octane number of producer gas, it cannot operate in diesel engine with the help of small amount of injected pilot fuels. Hence a diesel engine needs to be dual fueled. The current dual fuel engine can be operated interchangeably, either on gaseous fuel with diesel pilot ignition or wholly on liquid fuel injection as a diesel engine. Due to this switching over mechanism from dual fuel to single mode operation in a dual fuel engine, it tends to retain most of the positive features of diesel operation(Badr et al. 1999). The advantage of this type of engine is that it can use the difference of flammability of two different used fuels. Again, in case of lack of gaseous fuel, this engine runs according to the diesel cycle by switching from dual-fuel mode. The disadvantage is the necessity to have liquid pilot fuel available for the dual-fuel engine operation (Mansour et al. 2001).The main objective of using dual fuel mode is to reduce NOx and particulate emission (PM). In case of diesel engine it is difficult to reduce simultaneously both NOx and smoke due to the tradeoff curve between NOx and smoke. One suitable method is to solve this problem by using alternative oxygenated fuel which provides more oxygen for combustion. Gasification is the process of conversion of solid/liquid bio fuels in to gaseous fuel in a gasifier by pyrolysis process at high temperature. Producer gas is a low calorific value gas, which is generated by the conversion of high calorific value wood in a gasifier. It is a mixture of carbon monoxide, hydrogen, carbon dioxide, methane and nitrogen. The typical composition of producer gas generated from Babul wood with desired moisture content and properties are shown in Table 1. The sample of wood pieces is shown in figure 1.
  2. 2. Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel International organization of Scientific Research 43 | P a g e Fig.1. Sample piece of Babul wood TABLE I Composition and properties of producer gas Composition CO-19±3%, CO2-10±3%, N2-50% H2-18±3%, CH4- up to 3% Density 1.287 Kg/m3 Ref. (Banapurmath, et al. 2008) Calorific value 4186 KJ/m3 Octane number 100-105 Laminar burning velocity 0.5±0.05 m/s Ref. (Banapurmath, et al. 2009) Stoichiometric air/fuel 1.12 Ref. (Banapurmath, et al. 2008) II. PREPARATION OF BIODIESEL 1.First, the crude karanja oil is collected from the crusher mill, which is a clear, viscous and dark brown in colour. Then it is filter with a nylon mesh cloth filter. After filtration, it is applied to degumming process in which phosphorus is removed from crude oil in a chemical processby using suitable chemical like1% v/v phosphoric acid in necessary method. After degumming, it is applied to estrification process which is a chemical process. In this process degummed karanja oil is mixed with 22% volume/volume (v/v) ratio methanol and1% v/v ratio sulphuric acid. The mixture is then stirred for period of one hour at a temperature of 65o C. This esterified mixture is then applied to transestrification process. In this process, acid esterified Karanja oil was taken in transestrification unitin which a reagent mixture is mixed with this esterified oil. A reagent mixture was prepared with anhydrous methanol (22% v/v) and base catalyst KOH (0.5% v/v). The total mixture was then continuously stirred at a constant speed below a temperature of 65o C (i.e. the boiling point of methanol) for about 1.5-2.0 hours. Then the stirring and heating was stopped and the mixture was allowed to settle down for about 24 hours. After settling, glycerol which is dark in colour was obtained in the lower layer and separated through separating valve. The upper layer which is Karanja methyl ester was collected separately. Then water washing of methyl ester was performed 2-3 times to remove extra esters and KOH. It was then heated above 65o C to remove additional methanol to obtained pure Karanja biodiesel. 1.1 Preparation of different blends neat Karanja oil. The Karanja biodiesel was then blended with diesel or fossil diesel (FD) in various concentrations to get their respective blends. In the present work, the blends used are B10, B20 and B30. The blend B10 is prepared by mixing 10% Karanja biodiesel and 90% diesel by weight basis followed by the preparation of other two blends. After preparation of different blends of biodiesel and neat oil, some of the important properties of the fuels were carried out before use in diesel engine. Fuel properties like density, kinematic viscosity, acid value, free fatty acid (FFA), flash point, fire point, cetain number and calorific value etc were estimated using various ASTM methods. The estimated fuel properties of different test fuels are given in Table 2. TABLE II Properties of test fuels Properties Diesel Karanja oil K10 K20 ASTM Methods Density at 25o C(Kg/m3 ) 825 925 832 837 D 1298 Kinematic viscosity At 40o C (cSt.) 2.76 28.69 3.7 4.36 D 445 Acid value(mg KOH/g) - 30.76 - - D 664
  3. 3. Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel International organization of Scientific Research 44 | P a g e FFA (mg KOH/g) - 15.4 - - D 664 Calorific value (MJ/kg) 42.5 34.7 41.7 D 240 Cetane number 47 32.33 - D 613 Flash point (o C) 73 219 89 109 40.9 Fire point (o C) 103 235 119 135 - III. TEST PROCEDURE AND METHODOLOGY The experimental setup consists of a twin cylinder, 14HP, 16:1 compression ratio, 4-stroke water cooled diesel engine with electrical generator and bulb loading devices supplied by Prakash Diesels Pvt. Ltd. Agra, a downdraft type biomass gasifier having rated gas flow rate 25 NM3 /hr, gas cooler, gas filter supplied by Ankur Scientific Energy Technology Pvt. Ltd., Baroda.. The partial combustion of biomass in the gasifier reactor is converted in to high temperature producer gas, which enter in to the gas cooler. The moisture, tar and dust particle is removed by passing through a two set of filter. At the outlet of the filter pipe a mechanical valve is provided to control the gas flow rate. For gas flow measurement, an orifice meter is connected to surge tank. Manometers are used to measure the air and gas flow separately. The producer gas and air are mixed in the intake pipe and then the mixture enters into the engine cylinder. The engine was always operated at its rated speed of 1500 rpm, injection timing of 23o before top dead centre (BTDC) and injection pressure of 220 bars. The AVL make 5-gas analyzer (model no. AVL Digas 444) and smoke meter (model no. AVL 437 C) with accuracy ±1% is used to measure emission parameters. The 2-cases of operation are described as follows: Case 1. The test is carried out by using the test fuels FD, B10, B20 and B30 in single mode operation and with producer gas at a constant and optimum flow rate of 21.49 Kg/hr in dual fuel mode operation under different load conditions of 0, 2, 4, 6, 8 and 10 kW respectively. Case 2. The test is performed using the above test fuels under dual fuel operation at different gas flow rates starting from zero to maximum substitution i.e. 0, 10.74, 15.21, 18.61 and 21.49 Kg/hr respectively at a constant and optimum load of 10 kW. IV. RESULT AND DISCUSSION 4.1. Carbon monoxide (CO) emission At 10 kW load
  4. 4. Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel International organization of Scientific Research 45 | P a g e The CO emissions in dual fuel mode operation of all test fuels in case 1 are found to be higher compared to their single mode operation at all load conditions (figure 2). This is due to incomplete combustion and presence of CO in producer gas under dual fuel operation. However, with increase in load, CO emission decreases and at highest load it increases for all test fuels. This is due to better combustion at higher load as a result of higher charge temperature, but at highest load, due to fuel richness incomplete combustion occurs, hence, higher CO emission. Again, with increase in blend percentage in diesel, CO emission decrease in both modes of operations compared to diesel. This is due to complete oxidation of biodieselas a result of presence of oxygen.The CO emission in case of dual fuel operation of diesel is 87.4% higher than its single mode operation at highest load. Similarly, the figure 3 indicates that with increase in gas flow rate, CO emission increases linearly for all test fuels in case 2. The reason may be due to the presence of CO in producer gas composition. Hence, more amount of gas flow rate means more amount of CO emission. At highest gas flow rate, the CO emission for FD is 0.66% and that of B30 is 0.531% which is the lowest among all blended fuels. This may be due to lower carbon to hydrogen ratioand higher oxygen in B30 blend compared to other fuels. 1.2. Hydrocarbon (HC) emission The HC emission trends are similar with CO emission. A significant reduction of HC emission of all blended fuels compared to diesel in both modes of operation (figure 4)is due to more complete combustion of blended fuels.The HC emission in dual fuel operation of diesel is 39.7% higher than its single mode operation due to incomplete combustion as a result of slow combustion producer gas in dual fuel mode at highest load. Again, with increase in gas flow rate in case 2 for all test fuels, HC emission increase. This may be due to incomplete combustion as a result of slow burning nature of producer gas. However, with increase in blend percentage in diesel, HC emission decreases compared to diesel (figure 5) due to better combustion of biodiesel fuel as a result of higher cetane number and presence of oxygen in biodiesel. At highest gas flow rate, diesel shows 68 ppm and B30 shows 48 ppm of HC emission.
  5. 5. Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel International organization of Scientific Research 46 | P a g e 4.3. Carbon dioxide (CO2) emission The figure6 indicates that, the CO2 emissions in dual fuel mode of all test fuels are higher than their single mode operations under all load conditions. This is because of as producer gas is a mixture of CO and CO2 its combustion increases the CO2 emission (Ramadhas et al. 2006).However, CO2 emissions in case of all blended fuels are lower than diesel in both modes of operation. Shankar et al. (2005) reported that biodiesel is an oxygenated fuel which burns clearly to produces less CO2 emission. Again, with increase in load, CO2 emission increases for all test fuels for both modes of operations due to better combustion as a result of higher charge temperature. The CO2 emission in dual fuel mode operation of diesel is 36.1% higher than its single mode operation at highest load. Similarly, with increase in gas flow rate, CO2 emission for all test fuels increases (figure7). This is because of producer gas is a mixture CO and CO2, its combustion increases the CO2 emission. Again, with increase in blend percentage in diesel, CO2 emission decreases at all gas flow rates.At highest gas flow rate, diesel shows 6.41% CO2 emission and B30 shows 5.7%CO2 emission which is lowest among all blended fuels. 4.4. Nitrogen oxide (NOx) emission
  6. 6. Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel International organization of Scientific Research 47 | P a g e The NOx emission values in dual fuel mode operation of all test fuels are found to be lower than their single mode operation (figure 8).This is because of lower adiabatic flame temperature and absence of organic nitrogen in producer gas (Banapurmath et al. 2009) in dual fuel mode. Also with increase in load, NOx emission increases due to increase in energy input for both mode of operation for all test fuels. However, with increase in blend percentage in diesel, NOx emission decreases. This could be attributed to the lower peak combustion temperature as a result of lower energy released during pre-mixed combustion phase due to larger droplet size of blended fuel compared to diesel. This result is agreed with the result reported by Sureshkumar et al. (2008).Again,with increase in gas flow rate (case 2),NOx emission decreases for all test fuels (figure 9). This is attributed to the lower adiabatic flame temperature and absence of organic nitrogen in producer gas.At highest gas flow rate, diesel shows highest NOx emission i.e. 172 ppm and B30 shows 56 ppm followed by other blended fuels. 4.5. Smoke opacity At 10 kW load
  7. 7. Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel International organization of Scientific Research 48 | P a g e The variation of smoke opacity values with load for both modes of operation for all test fuels are shown in figure 10 (case1). The figure reveals that smoke opacity in case of dual fuel mode of all test fuels are lower than their single mode operation. This may be due to clean burning of producer gas and decrease in percentage of injection of pilot fuels in dual fuel mode. Again, with increase in load, the smoke opacity values of all test fuel increases in both modes of operation. This may be due to incomplete combustion as result of insufficient air with increase in load. Also with increase in blend percentage in diesel, smoke opacity decreases at all load conditions. This may be due to better combustion as a result of higher cetane number and presence of oxygen in biodiesel. Again, with increase in gas flow rate in case 2 for all test fuels, smoke opacity decreases (figure 11). This may be due to clean burning of producer gas in dual fuel mode. With increase in blend percentage in diesel, smoke opacity decreases compared to diesel due to better combustion of blended fuels with producer gas as a result of presence of oxygen. At highest gas flow rate, diesel shows highest value of smoke opacity i.e. 70% and B20 shows lowest value i.e. 35% followed by other blended fuels. V. CONCLUSIONS From the above experimental analysis it is concluded that the emission parameters like NOx and smoke opacity values are found to be lower in dual fuel mode operation of all tested fuels compared to their single mode operation. However,the other emission parameters like CO, CO2 and HC values of all tested fuels in dual fuel mode are higher side than their single mode operation under all load conditions. All the blended fuels of biodiesel shows better emissions compared to diesel at all load conditions. Again with increase in producer gas flow rate in dual fuel mode, the emission parameters like NOx and smoke opacity decrease, whereas, CO, CO2 and HC emission values are increases for all test fuels. Hence, producer gas can be used as a potential fuel to reduce NOx and smoke opacity. VI. ACKNOWLEDGEMENT The authors are thankful to the Department of Mechanical Engineering, KEC, Bhubaneswar, for providing the experimental setup to complete this experimental work. REFERENCES [1] Agarwal, A.K. and Das, L.M. 2001. Biodiesel development and characterization for uses a fuel in compression ignition engine. J Eng Gas Turb Power, 123, 404-7. [2] Babu, A.K. and Deveradjane, G, 2003. Vegetable oil and their derivatives as fuels for C.I. Engine. An overview, SAE 2003-01-0767. [3] Badr, O., Karim, G. A. and Liu, B. 1999. An examination of the flame spread limits in a dual fuel engine. Applied Thermal Engineering, 19(10), 1071-1080. [4] Banapurmath, N.R., Tewari, P.G. and Hosmath, R. S. 2008. Performance and emission characteristics of Compressionignition engine operated on Honge, Jatropha and sesame oil methyl esters. Renewable Energy, 33, 1982-1988. [5] Banapurmath, N. R., Tewari, P.G., Yaliwal, V.S., Kambalimath, S. and Basavarajappa, Y.H. 2009. Combustion characteristics of a 4-strokeci engine operated on Honge oil, Neem oil and Rice Bran oils when directly injected and dual fueled with producer gas induction. Renewable energy, 34, 1877-1884. [6] Henham, A. and Makkar, M. K., 1998. Combustion of simulated biogas in a dual-fuel diesel engine. Energy Conversion Management, 39, 2001-2009. [7] Mansour, C., Bourif, A. and Aris, A. 2001. Gas–diesel (dual-fuel) modeling in diesel engine environment, Int J Thermal Science, 40 (4), 409–24. [8] Nwafor, O.M.I. 2000a. Effect of choice of pilot fuel on the performance of natural gas in diesel engine. Renewable Energy, 21,495-504. [9] Nwafor, O.M.I. 2000b. Effect of advanced injection timing on the performance of natural gas in diesel engine. Sadhana, 25 (1), 11-20 [10] Ramadhas, A. S., Jayaraj, S. and Muraleedharan, C. 2006. Power generation using coir-pith and wood derived producer gas in diesel engine. Fuel processing technology, 87, 849-53. [11] Shankar, K.S., Raghavendra Bhat, Sudhir, C.V. and Mohanan, P. 2005. Effect of blend ratios of coconut methyl ester in diesel on the performance and emission of CI engine. Proceedings of the 19th National conference on I.C. engine and combustion, held in Annamalai University, Chidambaram, December 21- 23, 59-63. [12] Senthil kumar, M., Ramesh, A. and Nagalingam, B. 2001. Experimental investigation on Jatropha oil- methanol dual fuel engines. SAE 2001-01-0153. [13] Sureshkumar, K., Velraj, R. and Ganesan, R. 2008. Performance and exhaust emission characteristics of CI engine fueled with Pongamia pinnata methyl ester (PPME) and its blends with diesel’, Renewable Energy, 33, 2294-2302.
  8. 8. Emission analysis of different blends of Karanja biodiesel with producer gas in a twin cylinder diesel International organization of Scientific Research 49 | P a g e [14] Wang,Y.D., AL-Shemmeri, T., Eames, P., McMullan, J. Hewitt, T. and Huang, Y. 2006. An experimental investigation of the performance and gaseous exhaustemission of a diesel engine using blends of a vegetable oil”, Applied Thermal Engineering, 26, 1684-91.

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