UJET VOL. 2, NO. 2, DEC Page 139

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1 UMUDIKE JOURNAL OF ENGINEERING AND TECHNOLOGY (UJET) VOL. 2, NO. 2, DEC 2016 PAGE DEVELOPMENT OF AUTOMATED HOUSEHOLD BIODIESEL BATCH-PRODUCTION PLANT FOR VEGETABLE OIL FEEDSTOCK * 1 Eze C. C. and 2 Obasi R. U. 1 Department of Mechanical Engineering, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. 2 Department of Electrical Engineering, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria. ABSTRACT The automation of an affordable house-hold biodiesel-batch production plant was presented. The system design automation, connection and implementation were done in three stages- an explicit connection of sodium methoxide tank using a motor powered stirrer, the timer and the solenoid valve, the connection of the groundnut oil tank using the heater band, the temperature controller and the solenoid valve and the connection of the reactor using the heater band, temperature controller, solenoid valve, a motor powered stirrer and a timer. Two heater bands and two electric motors were employed for heating and stirring the solenoid-fitted oil and reactor tanks respectively. The 5 minutes period required for the complete dissolution of sodium hydroxide in methanol (leading to sodium-methoxide production) was the same period when the vegetable oil (groundnut oil feedstock used here) was to be pre-heated to the desired 50 o C before use. The solenoids fitted to these two tanks opened at the end of the set 5 minutes to discharge their contents into the reactor. In the reactor tank, stirring and heating at 65 o C went on simultaneously during the next 45 minutes when transesterification reaction automatically stopped and its solenoid valve opened. 94.6% and 3.2g of fatty-acid methyl ester (biodiesel) and glycerol products respectively were discharged. KEYWORDS Automation, transesterification, sodium-methoxide, vegetable oil feedstock, biodiesel 1.0 INTRODUTION Efforts have been made world-wide to gradually replace the use of non-renewable petroleum fuels with renewable biofuels for some obvious reasons. Some recent estimates by BP of world wide proven petroleum reserves of trillion barrels with 80 million barrels as daily production rate predict this petroleum products to last for the next 53.3 years (Andy, 2004). It is estimated that the proven fossil fuel reserves in Nigeria, billion barrels will be exhausted in the next 45 years, (Wikipedia, 2016). The production and use of fossil fuels release a lot of green-house gases into the atmosphere resulting in increased global warming and consequent depletion of the ozone layer (Gaurdian, 2013). To effect this much desired switch over to renewable energy sources in accordance with the yearnings of many nations, researches have been on-going for alternatives during the past couples of decades and biofuel seems to be the winning candidate. Biodiesel is the diesel fuel produced from vegetable oils or animal fats of which transesterification is *Corresponding Author: ezekajikris@gmail.com, one method of producing this biodiesel in the reaction between vegetable oil and alcohol in the presence of a strong alkali catalyst. This fuel has been reported to have offered reduced exhaust emissions, improved biodegradability, reduced toxicity and higher cetane rating which can improve engine performance and reduce emissions (Jimoh, 2012). It can be termed clean fuel as it does not contain carcinogens and its sulfur content is also less than the mineral fuel. Biodiesel does not cause acid rain since it contains little or no Sulfur, being of vegetable oils derivatives. Despite all the advantages of biodiesel over fossil diesel, the efforts to switch over to biodiesel from fossil diesel shall ever remain a mirage unless biodiesel is produced at affordable price. This then requires that researchers find efficient and economical production techniques. Presently, the price of fossil diesel is lower than that of biodiesel worldwide. This implies that the global aspiration to switch over from the use of the former to the latter may not be feasible any time soon. The world wide cost of biodiesel in 2015 was over $1 or N160-N190 per litre, favouring the continued use of fossildiesel which stands at N180 per litre. The relatively higher cost can be attributed principally to the high cost of production; the high cost of production on its own part is UJET VOL. 2, NO. 2, DEC Page 139

2 attributable to the inefficient production processes and reactors. These inefficiencies cause lavish of time, energy and labour during production which ultimately lead to increased production cost and high cost of biodiesel. This work aims at reducing production time, energy and labour by automation processes. The cost of biodiesel is the main hurdle to commercialization of the product (Science Direct, 2016). Automated Processors greatly reduce the hands-on time with the equipment. Automated Processors also help reduce wastage, increase efficient use of resources, and better control when making biodiesel at home. Automation greatly reduces the need for human sensory and mental requirements as well (Biodiesel, 2016). Automation of biodiesel machines over the years involves the use of pumps at various production stages, fluid mixers, heat exchangers, neutralizer and recycling machines which are usually costly. Other production machine components which indeed hike biodiesel cost include the temperature control unit, electric motors, turbine blade mixers, costly stainless steel tanks, dehydration and sedimentation tanks. In particular, this work provides a means to find ways by which the production of biodiesel via transesterification can be both more efficient and economical. Here, the continuous production process prevalent with most biodiesel plants was replaced by batchprocesses. Material transportations involving costly pumps which characterize most biodiesel plants were replaced by gravitational force due to plant configuration. Costly turbine blade stirrers were replaced with simple discs. Thus by incorporating automation on a machine configured to utilize the effect of gravity for material transportation during conversion, and using locally sourced cheap materials, we obtained a house hold machine which offers integral faster processes, cheaper labour input and better energy management in the making of biodiesel to make its cost lower. 2.0 MATERIALS AND METHODS 2.1 Production recipe: From the literature, it can be illustrated that biodiesel could be produced from the transesterification reaction of methanol and groundnut oil using sodium hydroxide base as catalyst as shown below (Ma, 1998). One mole of triglyceride (oil) when mixed with three moles of alcohol in the presence of an alkaline catalyst under certain conditions will yield three moles of biodiesel and one mole of glycerol. Triglyceride + 3MeOH 3 Biodiesel + Glycerol (1) This reaction equation leading to the production of fatty acid methyl ester (biodiesel) is also represented as C 17H35 COOCH 2 + OHCH 3 CH 2 OH Ι NaOH Ι C 17 H 35 COOCH + OHCH 3 3C 17 C 35 COOCH 3 + CHOH Ι Catalyst Ι C 17H35 COOCH 2 + OHCH 3 CH 2 OH 1mole 3 moles 3 moles + 1 mole Triglycerd (oil) Alcohol Biodiesel Glycerol For this work, following the experiments carried out on the reaction kinetics of groundnut oil transesterification and the investigations on the effect of the conversion variables for a batch reactor in collaboration with the literature, the following production recipe was adapted: Oil-to- methanol mole ratio = 1: 6 (Srivasta, 2000) Catalyst concentration = 0.5%wt of oil (Feuge, 1999) Reaction temperature = 65 o C (Meher, 2006) Reaction time = 45 minutes Reactor impeller speed = 300rpm Molar mass of groundnut oil = 846 g which occupies a volume of 961 ml Molar mass of methanol = 32 g (triple mole mass of methanol = 96 g) From eqn. (1), 1mole of oil reacts with 3 moles of methanol By the reaction stoichiometry as in equation (2), 846g oil reacts with 96g CH3OH) For complete reaction, double portion of methanol is required. According to Srivasta (2000), when 100% excess methanol is used, the reaction is at its highest rate. In this condition, the reaction is driven to completion without being starved of alcohol. :. 846g of oil reacts with 2(96)g or 192g of methanol which occupies a volume of ml 961 ml of oil reacts with (258.4 ml of CH3OH + 0.5% wt of oil for NaOH) UJET VOL. 2, NO. 2, DEC Page 140

3 :. Production recipe = 1000 ml oil : ml CH3OH : 4.4 g NaOH from equation (1) (3) But 4.4 g of NaOH raises methanol volume by (4x4.4) or 17.6 ml Production recipe (chosen) = 1000 ml oil: ( ) ml sodium methoxide (CHONa(aq) 1000 ml oil : ml CHONa(aq, giving reactants volume of ml or 1.3 litre (4) Other production variables include: Volume occupied by reactants = (1.3 L or about ¾ of reactor cylinder volume). :. Reactor volume = 1.73 L (volume for reactants to occupy only ¾ reactor cylinder volume) Stirring impeller type = straight turbine impeller % Free fatty-acid of oil used = 0.98 % Moisture content of oil used = 0.10 Reactor glass- fibre insulator thickness = 5.5mm (determined critical radius of insulation) The % Biodiesel by mass produced was obtained from this expression m M % Biodiesel produced by mass =. X 100 (5) where m = mass of biodiesel produced and M = mass of groundnut oil feedstock used. 2.2 Design considerations: In this design, priority was given to affordability and availability in the selection of the materials for automation. Upon these considerations the components used included three solenoid-valves, three pole contactors with auxiliary contacts and two Anly timers, a single pole circuit breaker, two thermocouples, one temperature controller, and three one-half rolls each of red, green and yellow 3mm diameter wire. and the ports are isolated. The one used for this design is the normally closed type and is rated as follow: Voltage/Hz: 240/50, bars Orifice pipe: 3/4, Maximum media temperature: 90 o C, Current: 5A. Three solenoid valves of this sort were used for the design. One for the sodium methoxide tank, the second for the groundnut oil tank and the third for the reactor tank Pole contactors: The contactor which is an electrically controlled switch used for connecting and disconnecting a power circuit was used here. It is controlled by a circuit which has a much lower power level than the switched circuit. A contactor has three components. The contacts are the current carrying part of the contactor. This includes power contacts, auxiliary contacts, and contact springs. The electromagnet (or coil) provides the driving force to close the contacts. The enclosure is a frame housing the contact and the electromagnet. Enclosures are made of insulating materials like Bakelite, Nylon 6, and thermosetting plastics to protect and insulate the contacts and to provide some measure of protection against personnel touching the contacts. When current passes through the electromagnet, a magnetic field is produced, this attracts the moving core of the contactor. The electromagnet coil draws more current initially, until its inductance increases when the metal core enters the coil. The moving contact is propelled by the moving core; the force developed by the electromagnet holds the moving and fixed contacts together. When the contactor coil is de-energized, gravity or a spring returns the electromagnet core to its initial position and opens the contacts. The two contactors used in this work are rated V, 50Hz., one for the groundnut oil tank heater band, and the other for the reactor tank heater band. 2.3 Component descriptions: The following components were used in the design of the automated machine The solenoid valve: The electromechanically operated solenoid valve is to shut off, release, dose, distribute or mix fluids. If the valve is open when the solenoid is not energized, then the valve is termed normally open (NO). Similarly, if the valve is closed when the solenoid is not energized, then the valve is termed normally closed (NC) Circuit breaker: A circuit breaker is an automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and interrupt current flow. Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation. The circuit breaker contacts must carry the load current without excessive heating, and must also withstand the heat of the arc produced when interrupting (opening) the circuit. UJET VOL. 2, NO. 2, DEC Page 141

4 The circuit breaker used for this work is rated: V, 20A Timer relay: A timer is a specialized type of clock for measuring time intervals. The type of timer used for the design is an electronic Anly delay timer. Rated: AC 220v; 5A; 250VAC P.F-1,Type AH-3. NC = The implication of a normally closed state of a timer is that once the timer coil is energized, the normally closed contact is opened. NO = The implication of a normally open state of a timer is that once the timer coil is energized, the normally open contact is closed. This timer is set to open and cut off current flow at the set time The temperature controller: Temperature control is a process in which change of temperature of a space (and objects collectively there within) is measured or otherwise detected, and the passage of heat energy into or out of the space is adjusted to achieve a desired average temperature. A temperature controller is an instrument used to control operational temperature. It does this by comparing the process temperature (process variable) with the desired value (set value). The difference between these values is known as the error (deviation). Temperature controllers use this error to decide how much heating or cooling is required to bring the process temperature back to the desired value. Once this calculation is complete the controller will produce a signal that effects the change required. It usually works in conjunction with the thermocouple. 2.4 System design and implementation: The design of this project involved coupling the above hardware components and testing at the different stages of the implementation. The system design, connection and implementation were done in three stages. The first stage involved an explicit connection of sodium methoxide tank using the timer (set at 5 minutes) and the solenoid valve. The second stage explained the connection of the groundnut oil tank using the temperature controller and the solenoid valve. The final stage showed the connection of the reactor using temperature controller, solenoid valve and timer. Figure 1: AH3-3 Anly timer (Courtesy- Timer relay: Figure 2: Temperature controller (Courtesy Temperature controller Sodium-methoxide tank connection: The sodiummethoxide tank is designed to completely dissolve sodium hydroxide in methanol in the mixer tank to form sodiummethoxide. For complete dissolution, the electric motorimpeller-shaft system is designed to run for five minutes, and at the end of five minutes the solenoid valve opens to allow the discharge of the sodium-methoxide into the reactor tank. This is achieved with a timer. The timer is set at five minutes and is powered from the mains (neutral and live terminals), labeled N and L to the double pole switch terminals labeled 2 and 7 respectively. When the double pole switch closes, UJET VOL. 2, NO. 2, DEC Page 142

5 current flows through wires 2 and 7 to energize the timer. The energized timer carries time signal from the timer to the coil of the mixer motor of the sodium-methoxide tank through the normally closed (NC) lines 8 and 5 of the timer. The timer therefore indicates when the electric motor (that causes shaft/impeller rotation) starts and stops rotation. The electric motor is thus powered from (NC) terminal of the timer 8 and 5 of figure 1. When the time of 5 minutes set reaches, the normally closed NC contacts of the timer (8 and 5) disengages thereby energizing the NO of the timer 1 and 6 (which now closes for Figure 3: Circuit diagram of the sodium methoxide tank connection Groundnut oil tank connection The objective here is to raise the temperature of the groundnut oil feedstock to 50 o C before introducing it to the reactor without human interference. A heater band is used to achieve this. Glass filings insulator is wrapped round the tank to reduce heat loss to the outside. From L and N lines (figure 4), a double pole switch (2) takes power to the contactor coil k2. Power goes to the coil at terminals 1 and 3 of the contactor k2; neutral line N goes to terminal 5. These terminals 1, 3 and 5 are normally open (NO) but meanwhile no current flows through them. current to flow). From fig 3, it shows that 8 and 5 terminals form NC, and 1 and 6 form NO of the timer; also, 1and 4 loop form the NC and 3 and 2 form the NO of the mixer motor coil. Upon the engagement of 1-6 of the timer, the 1-4 loop disengages and the 3-2 loop of the mixer engages. The solenoid valve which is connected to the NO (1-6 loop) of the timer now receives current and becomes energized. The energized solenoid valve therefore opens thereby allowing its content to discharge. Below is the circuit diagram of the sodium-methoxide tank connection described. Terminals 2 and 4 of the contactor k2 go to the heater band coil H1 from where power goes via the thermocouple to terminals 1 and 2 of the temperature controller coil, these terminals 1 and 2 being the terminals provided on this controller for the thermocouple connections and where it senses the temperature of the heater band. The temperature controller is powered through its terminals labeled 3 and 5. Thus current flows from line L to terminal 3, then, through to terminal 7. Terminal 7 is looped to terminal 8. As terminal 8 receives power, the contactor coil k2 s energized contacts 1, 2, 3, 4, 5 and 6 close and become energized, prompting the heater H1 into action. The neutral line from the mains go to the heater band via terminals 5 and 6 of the contactor coil. As the heater band heats the groundnut oil, the thermocouple senses the heat and when the oil temperature reaches the desired 50 o C, the temperature controller deenergizes or cuts off energy supply to terminal 7-8 loop. This implies that NC contact 7-8 disengages causing current to stop flowing; and 7-6 loop NO is connected or energized. The solenoid valve is powered from loop 7-6 (NO) terminal of the temperature controller even though current will not go through it until loop 7-8 NC is de-energized to energize loop 7-6 (NO). Upon energizing this NO loop, the solenoid valve S2 receives current and responds by opening its valves to discharge the heated groundnut oil into the reactor. Figure 4 is the circuit diagram showing the connection. UJET VOL. 2, NO. 2, DEC Page 143

6 Figure 4: Groundnut oil circuit diagram The Reactor tank connection: The reactor is designed to mix the sodium-methoxide and the pre-heated groundnut oil during the 45 minutes reaction duration. The reactor tank heater band heats up the reacting mixture to the desired 65 o C and the temperature controller keeps it steady at that. The automated reactor tank system generally consist of the stirrer, heating controller and electronic timer. It is connected from live (L) and neutral (N) line (figure 5). The N is connected to terminals 1and 2 while L is connected to the looped contactor 3 and 5 respectively. The heater band is powered via the contactor which is in turn powered from the mains (supply). The temperature controller is powered through its 240 terminals labeled 3 and 5 while the thermocouple senses the temperature of the heater band and is connected to the temperature controller terminals labeled 1 and 2. The coil of the contactor is powered from the terminal of the temperature controller labeled 6. The heater is set to take (5) minutes for the temperature of the 30,000 ml of oil used to reach 65 o C (causing a simultaneous siphoning of both sodium methoxide and oil into the reactor), and for heating to continue for another 40 minutes before the timer signals the solenoid valve to open to discharge its content. The circuit diagram showing the connection is shown in figure 5. Figure 5: Circuit diagram of the reactor tank UJET VOL. 2, NO. 2, DEC Page 144

7 Figure 6: Integrated circuit of the automation connections. UJET VOL. 2, NO. 2, DEC Page 145

8 Figure 7: Tank A- Sodium methoxide tank showing the stirrer Figure 8: Tank B- the oil tank UJET VOL. 2, NO. 2, DEC Page 146

9 Figure9:Tank C- the ractor Figure 10: The structural framework bearing the process tanks and operational gadgets Figure 11:The first angle projection of the machine UJET VOL. 2, NO. 2, DEC Page 147

10 The connections are shown in the electrical circuit diagrams of figures 3 TO 5 Plate 1: Side view of the automated biodiesel production machine 3.0 RESULTS AND DISCUSSIONS 3.1 RESULTS: In two test runs drawn from equation (1) done at a reaction temperature of 65 o C, 1:6 oil : methanol ratio, 0.5% wt of oil for catalyst, 300rpm stirring speed and 45 minutes reaction time, shown in table 1, the material inputs and products were shown. Table 1-Biodiesel and glycerol produced by the automated production machine. Runs Groundnut oil used (880.3g) or (1000ml) CH3OH used (ml) NaoH 0.5% wt of oil (g) Fatty acid methyl ester(biodiesel) produced by mass (g) Biodiesel produced (%) Average Glycerol produced (g) 3.2 DISCUSSION: Table 1, presents the average biodiesel and glycerol produced by the automated production machine. From the table, it may be observed that on the average, 832.7g (volume equivalent of ml) of biodiesel was produced. This gives an average percentage of 94.6 at the end of 45 minutes reaction duration. At the same time, 3.2 g of glycerol was produced. Sodium methoxide obtained when sodium hydroxide pellets were dissolved in methanol is toxic and corrodes mild steel containers. Aluminum is recommended for both the reactor and the mixer tanks. It was observed that every 1g of NaOH catalyst dissolved in methanol raised its volume by 4 ml. Thus, 4.4g sodium hydroxide (NaOH) catalyst used increased the sodium methoxide volume by (4.4 x 4) = 17.6 ml. Sodium methoxide is a solution of sodium hydroxide and methanol. Figures 7 bears the stirrer. It may be observed that sodium hydroxide do not easily dissolve in alcohol The pellets can only dissolve by the application of vigorous agitation. A stirrer powered by an electric motor is thus provided. In figure 8, a stirrer is also provided. Stirring is very vital for oil and sodium methoxide to react since oil and alcohol based compounds are not miscible. This stirring was set to last for the 45 minutes when transesterrification reaction was to end. A heating source was also provided as experiments show that transesterification reaction is best achieved at temperatures close to the boiling point of alcohol used. In this work, the reaction temperature used was 65 o C since the boiling point of methanol used is 64.5 o C. 4.0 CONCLUSIONS Automation was achieved using cheap and locally available materials. It makes both the fuel and production machine affordable to the people. Indeed when biodiesel production becomes less labour intensive and the machine less costly so that consumers can acquire them and carry out production at household and smaller family unit levels, then users will patronize the fuel commodity and a switch over to this renewable diesel fuel from the conventional diesel shall become a reality. The machine may be scaled up and any vegetable oil feedstock may be used, being guided by equation (1) for a new recipe and a corresponding new fuel quantity depending on the user s diesel demand. UJET VOL. 2, NO. 2, DEC Page 148

11 REFERENCES. Andy, J. (2014) Oil Price Latest.Retrieved on 12/03/2016. Biodiesel-kits-online. processor.html:automated biodiesel production for continuous production. Retrieved on 13/01/16 Feuge, R.O, Gros A.T. (1999). Modification of Vegetable Oils VII Alkali Catalysed in Transestrification of Pea-nut Oil with ethanol.j.am Oil chemical society. 26(3):97. Guardian. Copenhagen (2013). Climate conference,(09/06/13). deal. Jimoh, A., Odigure, J., Odili, U., Abdulkareem, A.and Afolabi, A (2012). Production and Characterization of Biofuel from Refined Groundnu oll. DOI: /52443: Department of Chemical Engineering, School of Engineering and Engineering Technology, Federal University of Technology, PMB 65 Minna, Niger State, Nigeria. Ma, F., Clement, L.D. and Hanna, M.A. (1998). The effects of Catalyst, Fatty Acids and Water on Transesterification of Beef Tallow Transesterification. Meher L.C. (2006). Renewable and Sustainable Energy Reviews.10(2006) pp ScienceDirect etrieved on 14/2/2016 Srivastava, A. and Prasad, R. (2000). Triglycerides-Based Diesel Fuels, Renewable and Sustainable Energy Reviews, 4, pp Wikipedia-Oil Reserves in Nigeria: Retrieved on 13/01/2016 UJET VOL. 2, NO. 2, DEC Page 149

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