International Journal of Metallurgical Engineering 2016, 5(1): 15-20 DOI: 10.5923/j.ijmee.20160501.03 Performance Evaluation of Suitability of Carbonized Palm Kernel Shell (PKS) as a Veritable Alternative to Coal and Charcoal in Solid Fuel Fired Furnaces Ndubuisi I. Mbada1,*, Pethuel O. Atanda2, Ola Aponbiede3, Abiodun A. Abioye2, Michael I. Ugbaja4, Ayo S. Alabi3 1Department of Transport Technology, Nigerian Institute of Transport Technology (NITT), Zaria Nigeria 2Department of Materials Science & Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria 3Department of Metallurgical & Materials Engineering, Ahmadu Bello University, Zaria, Nigeria 4Department of Polymer Technology, Nigerian Institute of Science and Leather Technology (NILEST), Zaria, Nigeria Abstract Methods: PKS were carbonised in other to drive off the organic matter, and obtained a clean solid fuel. Leco 350 Bomb Calorimeter was used to determine the heating value of the fuel; while adiabatic flame temperature and mass of air/ Kg of fuel were calculated for different conditions of excess air ratio ‘n’. The carbonised PKS was used to melt aluminium. Results: The higher heating value of PKS was 26541.204KJ/Kg. The lower heating value of PKS was 24457.9592KJ/Kg. The adiabatic flame temperature at n = 1 and 1.3 were 2082°C and 1679°C respectively. The air/fuel ratio is directly proportional to n. Discussion: The higher heating value of carbonised PKS was comparatively higher than those of firewood, peat and lignin but less than bituminous and anthracite coals. Keywords Adiabatic flame temperature, Carbonisation, Heating value, Palm kernel shell, Crucible furnace However, there are currently, various species resulting from 1. Introduction genetic modifications of the two traditional species [1]. Historically, the origin of the oil palm could be traced to Many activities of men including driving, power West Africa, with Nigeria, as the leading growers of oil palm generation and production of equipment, in the modern age in the 1950s and late 1960s [9]. Other countries, especially in are fuels dependent [1, 2]. Consequently, the insatiable the Asia sub-region, such as, Malaysia and Indonesia now demand for fuels, fuel efficiency and performance guarantee cultivate oil palm as a chief cash crop produce [9]. and calls for environmental friendly alternative fuels sources, The production of palm oil from the fruit bunch generates while not over relying on fossil fuels [1-3]. Literature is a lot of solid waste product on a large tonnage. These wastes replete with alternative fuels, biomass content, carbon may come from the palm fruit fibre, the palm kernel shell and content and calorific values. the empty fruit bunch [10]. The utilization of palm kernel Palm Kernel Shell (PKS), as a waste product of oil mill shell for thermal energy production by combustion of the which poses considerable environmental problem in terms of palm kernel as a solid fuel mass is well documented in the disposal, has been employed in a number of applications literatures [10]. Okoroigwe [4] highlighted three thermo [4-7]. PKS is an economic and environmentally sustainable chemical processes that can be used to convert PKS to raw material with potential for renewable energy industry [5]. renewable energy, these methods includes- gasification, A study by Okoroigwe [4] on the bio-energy potential of torrefaction and fast pyrolysis. Carbonisation is the term PKS found higher heating value of PKS on a dry and dry ash used for the conversion of organic substances to carbon or free basis using bomb calorimetric method as 22.94 and carbon containing residues through pyrolysis, the process 25.75MJ/Kg. Similarly, other researchers have reported the liberates hydrogen, tar and other gaseous substances [12, 13]. heating values of PKS [6, 7]. Ogbimi [14] advocates that the design and construction of Palm kernel shells are waste products of oil palm. The two crucible furnace using carbonized PKS as an intermediate major species of oil palm are the Dura and Pisifera [8]. technology, is a step towards localization and institutionalization of technology in Africa. * Corresponding author: [email protected] (Ndubuisi I. Mbada) Crucible furnaces are the oldest and cheapest type of Published online at http://journal.sapub.org/ijmee furnace, employed in foundry. Basically the crucibles are Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved made of high temperature resisting materials for instance 16 Ndubuisi I. Mbada et al.: Performance Evaluation of Suitability of Carbonized Palm Kernel Shell (PKS) as a Veritable Alternative to Coal and Charcoal in Solid Fuel Fired Furnaces graphite crucible, the furnace can be fired by solid fuels, Table 1. Ultimate Analysis of Palm Kernel Shell (PKS) liquid and gaseous fuels several works have been done on Components Content% evaluation and performance of some of these fuels for C 56.97 crucible furnace [15]. Olalere et al [16] and Osarenmwinda H 9.18 [17] constructed crucible furnace fired with spent engine oil, O 33.11 while Ighodalo et al [18] carried out a performance evaluation study of charcoal-fired furnace for recycling of S 0.08 aluminum. This study was aimed to evaluate the suitability N 0.48 of carbonised PKS fired crucible furnace for non-ferrous W 0.17 melting. In other to assess the suitability of PKS as a viable Total 100 solid fuel, its calorific value, adiabatic flame temperature, excess air ratios, and the mass of air per Kg of fuel at 2.5. Determination of Adiabatic Temperature of Burning different combustion ratios were determined. Adiabatic temperature was found under the assumption that all the heat evolved through combustion is spent only to raise the temperature of combustion product, in other words, 2. Materials and Methods calorimetric temperature of combustion was determined for 2.1. Materials adiabatic conditions only [19]. The Stoichiometric equations of combustion product are as follows: The following materials were used for the construction of C + O = CO (1) the crucible furnace: Refractory (fire clay), steel crucible, 2 2 steel pipe, blower (bellow), carbonized palm kernel shell, H2 + 1/2O2 = H2O (2) thong, mould, hose connector. S + O2 = SO2 (3) 2.2. Methods From the stoichiometric equations above: 1Kmol of Carbon reacts with 1Kmol of Oxygen to form 1Kmol of CO2 The furnace outer shell is made of cylindrical metal. A therefore, = 4.75KmolO , 2 circular opening was cut out on the side of the cylindrical similarly we have 2.295KmolO2 + 0.0025KmolO2 metal shell, to serve as the inlet of the blower pipe. The basic -1.035KmolO2 from H2, S and O2 respectively. The Number function of the pipe was to supply oxidant or air for 9.18 0.17 of Mole of CO =4.75Kmol, while that of H O= ( + ) combustion of the fuel mass. The inner wall of the furnace 2 2 2 18 was lined with pre-baked or pressed clay, a locally sourced 4.5994Kmol and SO2=0.0025Kmol, total mole of Oxygen = refractory material. The refractory was a fire clay material 6.0125KmolO2. basically of an alumina-silicate compound. The clay was Dry air contains 21 percent Oxygen while Nitrogen sourced from Omoshio quarry site in Ado-Ekiti, Ekiti-State, accounts for almost all the remaining 79 percent. Thus, the Nigeria. The clayey masses were prepared by finely grinding content of Nitrogen in air is 79/21 = 3.762 times the amount and sieving the mass to obtain good particle distribution, of Oxygen. Hence Kmole N2 = 3.762 × 6.0125 = which was then mixed with little amount of water to obtain a 22.619Kmole plus 0.017KmolN2 from the fuel. thick pasty solid that was moulded unto the inner wall of the The total mole of combustion product was 31.9879Kmole. cylindrical shell. The furnace chamber was allowed to dry It follows from the fact that 1mole of any gaseous substance 3 and then fired. With this stage completed the furnace occupies 22.4 , thus the volume of combustion product is 3 chamber was now ready for use. found by multiplying 31.9879Kmole by 22.4 = 716.5290m3 = 7.1653m3/Kg. 2.3. Carbonization To determine the Calorimetric Flame Temperature the The basic procedure in carbonizing the fuel is as follows: following assumptions were made: the shells were packed in steel rectangular compartment i. We neglect the SO2 component of the combustion called retort or coke oven. The shell was heated in the product as the SO2Kmole is negligible. absence of air to decompose the organic matter in the shell. ii. We assume that the stoichiometric equation of The carbonized shell was subsequently quenched and left to combustion is complete, that is, there is no CO as a cool in the compartment. result of incomplete combustion. iii. Theoretical Air-Fuel ratio (least required amount of 2.4. Determination of Calorific/ Heating Value and air) is used for the calculation of the calorimetric Ultimate Analysis flame temperature. The determination of heating value was carried out at iv. We also assume that there is no heat loss to the National Metallurgical Development Centre, Jos, Nigeria. surroundings and the system, that is, the combustion The instrument used for the determination was Leco 350 products, does not work on the surroundings. Bomb Calorimeter. The calorific value of the PKS obtained The adiabatic temperature of combustion , that is when in this study was 6343.5cal/g or 26541.204KJ/Kg. there is no heat exchange with the surrounding is given by International Journal of Metallurgical Engineering 2016, 5(1): 15-20 17 the formula: H2O.............................1.8389×0.1438 = 0.2644 N2................................1.4470×0.7077 = 1.0240 = iv) (4) 3 Total ............................= 1.6394 KJ/ (m .°C) � Therefore, the adiabatic flame temperature is estimated by 3 Is the lower heating value of fuel, KJ/m or KJ/Kg substituting all the parameters into the equation: 3 Volume of combustion products per unit of fuel, m 24457 .9592 = = = 2082.0970°C Is the volume specific heat of combustion product, 7.1653×1.6394 3 KJ/(m .°C).