CHAPTER 3 MATERIALS AND EXPERIMENTAL WORKS

Transcription

1 66 CHAPTER 3 MATERIALS AND EXPERIMENTAL WORKS 3.1 MATERIALS AND METHODS Materials The material sources were: waste cooking palm oil is collected from local restaurants with high FFA content and fresh palm oil is purchased from local oil mill. MgSO 4.7H 2 O of 99.0 % purity, Al 2 (SO 4 ) 3.16H 2 O of 98.0 % purity, Al(NO 3 ) 3.9H 2 O of 99.8 % purity, Mg(NO 3 ) 2.6H 2 O of 99.8 % purity and Na 2 CO 3 of 98 % purity were purchased from Nice chemicals, Kerala. Methyl alcohol of 99.9 % purity, ethyl alcohol of 99.9 % purity, propyl alcohol of 99.9 % purity was purchased from SD Fine Chemicals, Mumbai. The catalysts like KOH pellets of 98.2 % purity, NaOH pellets of 97 % purity, CH 3 OK of 98 % purity, CH 3 ONa of 98 % purity were purchased from Nice Chemicals, Kerala Methods Heterogeneous catalysts were characterized and analyzed by following methods. XRD powder technique is used to identify the crystal size and structure, FTIR Technique is used to identify the functional groups which may be present in the catalyst and also used to identify the carboxylic, alcohol, ester, methyl ester, ketone, hydrocarbon in waste cooking oil as well as Biodiesel. SEM describes morphological phenomena; TGA analysis can describe thermal effects with respect to the weight changes and also identify reaction may be exothermic or endothermic one. Surface area can be identified by BET theory. Waste cooking palm oil was characterized by: Gas

2 67 Chromatographic (GC-MS) technique is used to identify the fatty acids profile of waste cooking palm oil as well as Biodiesel oil. 3.2 CATALYST OPTIONS Catalysts are used to accelerate a chemical reaction by reducing the activation energy, which is the energy needed to initiate the reaction. There are two different types of catalyst systems, viz, heterogeneous and homogeneous systems (Vicente et al 2004). The heterogeneous catalyst system includes: Enzymes Titanium silicates Alkaline-earth metal compounds Anion exchange resins Guanadines heterogenized on organic polymers Currently, heterogeneous catalysts are not very popular due to high cost or inability to complete the degree of reaction required by the ASTM specification standard (Gerpen et al 2004). Homogeneous system includes acids and bases. Genrally, acid catalysts are not preferred compared to base catalysts due to a much slower transesterification process of triglycerides into fatty acid methyl ester. However, acid catalysts are commonly used for pretreating high free fatty acid feedstocks. During this pretreatment, fatty acids are converted to fatty acid ester (Gerpen et al 2004). Although different kinds of base and acid catalysts are available for transesterification processes, virtually almost all commercial biodiesel producers use base catalysts. The most common alkali catalysts are: Sodium hydroxide (NaOH) Potassium hydroxide (KOH)

3 68 Sodium methoxide (CH 3 ONa) Potassium methoxide (CH 3 OK) Methoxide ion has been described as the preferred catalyst for the transesterification process of biodiesel production. Methoxide ions can be obtained via several different methods (Jackson, 2006). The traditional method entails preparation of the catalyst solution within the biodiesel plant by mixing either sodium hydroxide or potassium hydroxide with methanol as shown below. NaOH + CH 3 OH H 3 CO - + Na + + H 2 O (3.1) KOH + CH 3 OH H 3 CO - + K + + H 2 O (3.2) Another method is to place sodium methoxide in a methanol solution as shown below. Sodium methoxide is known by many names, such as alcholate, methoxide, and methylate. CH 3 ONa methanol solution CH 3 O - + Na + (3.3) The main advantage of using sodium methoxide over sodium hydroxide is the virtually water free character of the catalyst solution. When mixing traditional hydroxides with methanol, water is generated, leads to unwanted side reactions, such as, saponification. Heterogeneous base catalysts like Mg/Al based sulphate and nitrate compound and also used for this project work. Because of Heterogeneous catalysts recycling is very easy one and also more than 5 times they can be used and also it can increase the ph of the Biodiesel. So, both of the

4 69 homogeneous and heterogeneous catalysts are used for biodiesel production from waste cooking palm oil Preparation of Heterogeneous Catalyst Mg/Al-SO 4 Hydrotalcite-Co-Precipitation Mg/Al-SO 4 based Hydrotalcite were synthesized by using Co- Precipitation technique of Mg 2+ and Al 3+ ions in an alkaline solution containing NaOH. 1.0 M solution of MgSO 4.7H 2 O (0.3M) and Al 2 (SO 4 ) 3.16H 2 O (0.1M) were drop wise mixed in 3:1 ratio with 1M NaOH and while mixing time P H was maintained between 9-12 and the reaction was maintained in nitrogen atmosphere. The resultant mixture was aged at 90 C for 72 hours. The Hydrotalcite was separated by high speed centrifugation and washed with de-ionized water. The Hydrotalcite sample was dried at 100 C for 10 hours and then calcined at 400 C and 500 C. The prepared Hydrotalcite were analyzed by using XRD, EDX, FTIR, SEM, BET theory and TGA analysis Mg/Al-NO 3 Hydrotalcite-Co-Precipitation Al(NO 3 ) 3 9H 2 0 (0.01mol) and Mg(NO 3 ). 2 6H 2 O (0.05 mol) were dissolved in de-ionized water (70 ml). A second de-ionized water solution (100 ml) of Na 2 CO 3 (0.1 mol) and NaOH (0.35 mol) was prepared. The first solution was slowly added to the second. The resulting mixture was heated at 65 C under autogeneous pressure (automatic preesure induced in a closed reaction vessel) for 18 h (. After the heating period, the slurry was cooled to room temperature, washed with de-ionized water up to ph 9 and dried at 110 C for 18 h. Hydrotalcite catalyst is activated by calcinations at a rate of 2 ºC/min until 500 C and maintained for 2 h in a flow of air. Later on, samples were cooled in dry nitrogen and stored. Catalyst was characterized using - XRD, EDX, SEM, FTIR, BET theory and TGA analysis.

5 EXPERIMENTAL SETUP A 1000 ml glass cylindrical reactor equipped with a magnetic stirrer, thermometer, reflux condenser and a sample port was used. The reactor was kept in a constant heating mantle with a temperature controller, which was capable of maintaining the temperature within ± 0.3 C. Agitation was provided with a magnetic stirrer, which was set at a constant speed throughout the experiments. Initially, the reactor was filled with 500 g waste cooking palm oil and heated to the required temperature. Figure 3.1 Experimental setup 3.4 EXPERIMENTAL PROCEDURE Biodiesel is processed from waste cooking palm oil by using Acid and Base catalyzed transesterification reaction. The experimental set up is shown in figure 3.1. In this work, Biodiesel was produced from waste cooking palm oil and this can be collected from local restaurants. In fact, WCO contains fried food waste and other food dusts, water molecules and if used this oil may damage total biodiesel process. So, Waste cooking palm oil must

6 71 be heated at 110 C to remove the water molecules and then filtered by using 10µm cloth to separate all food particles and suspended materials. Generally, the FFA value of the WCO is higher than that of fresh oil and the amount of catalyst has an impact of conversion of esters during the Transesterification process and also this biodiesel production is strongly influenced by the FFA content of the waste cooking oil. Owing to its high FFAs, the transesterification of waste cooking palm oil to biodiesel catalyzed directly by both Homogeneous, Heterogeneous catalysts had lower biodiesel conversion. Even using longer reaction time, only lower biodiesel yield can be achieved. In order to remove the FFA in waste cooking palm oil and the biodiesel yield can be increased. So, a two-stage process is followed to convert the biodiesel from waste cooking palm oil. A biodiesel production model is shown in figure 3.2. First stage, an acid-catalyst (sulfuric acid) was used to esterify (pretreatment) with waste cooking oil. For that, a three-neck flask with a water-cooled condenser was filled with 200 ml waste cooking palm oil, 40 ml anhydrous methanol and 4 ml sulfuric acid (H 2 SO 4 ). The mixture was vigorously stirred for 1.5 h at 50 C. After reaction, the mixture was filtered and the unreacted methanol was separated from the liquid phase via distillation. The esterified product was washed three times with sodium chloride solution and then dried using anhydrous sodium sulfate. After the pretreatment, the FFA value of the pretreated oil was lesser than that of freshly used cooking oil. This reaction was described as below: RCOO H + CH OH R'COOCH +H O (3.4) The second stage, a Homogeneous (NaOH, KOH, CH 3 ONa, and CH 3 OK) or Heterogeneous catalyzed (Mg/Al-NO 3 and Mg/Al-SO 4 ) Transesterification reaction was carried out in a reactor:

7 72 TG + 3 CH3OH R COOCH3+ G L (3.5) The reaction procedure was as follows: first, the catalyst was dispersed in methanol then stirring system was connected to it (about 600 rpm). Then, the above pretreated oil was added into the Strriring mixture and heated to 50 C for three hours. After thorough mixing it was kept overnight; two layers were formed. In that, the upper layer consists of biodiesel whereas the lower layer consists of Glycerin and this layer consist of excess methanol, unreacted catalyst and soap. This unreacted methanol was distilled off under a vacuum condition while biodiesel layer was separated with the help of separating system and finally remaining glycerin layer was separated and then distilled to get 98 % purified glycerin. The separated biodiesel was purified with hot water to get ph neutral (Xin Deng et al 2011). These purified methyl ester compositions were analyzed by using Gas Chromatograph, FTIR technique. Now, this biodiesel can be characterized with effect of temperature, catalyst, mole ratio of oil to methanol and reaction time. H 2 SO 4 Methanol Waste cooking oil Esterification Catalyst Methanol Transesterification Figure 3.2 Biodiesel production model

8 CHARACTERIZATION STUDIES In this section, characterization work is done for waste cooking oil, Heterogeneous catalyst and Biodiesel Characterization of Waste Cooking Oil Waste cooking palm oil was characterized by using the below mentioned parameters using various methods. FFA value Fatty acid profile Acid value Iodine value Water content Sulphur content Characterization of Heterogeneous Catalyst The two heterogeneous catalysts were fired in 400 and 500 C temperatures in a Muffle furnace and then used in biodiesel process. In that, 500 C more suitable than 400 C (bettet biodiesel yield) and this catalyst were characterized for using above mentioned techniques for their applicability was given in section and Characterization of Biodiesel Biodiesel was characterized by using the below mentioned parameters using various methods. FFA value Fatty acid profile

9 74 FTIR technique Acid value Viscosity Density Saponification value Water content Iodine value Calorific value Flash and Fire point Biodiesel yield Molecular weight 3.6 INSTRUMENTAL TECHNIQUES The following instruments were used to characterize the waste cooking oil, biodiesel and heterogeneous catalysts Gas Chromatograph Technique (GC-MS) The key analytical method for determining final biodiesel quality in both the ASTM and EN standards is Gas Chromatography-Mass Spectrophotometer. This method is widely applied to determine various key contaminants such as mono-, di- and tri-glycerides and glycerol. The drawback of the GC method is that it is time consuming in terms of sample preparation and analysis, requiring the derivatization of mono-, di-glycerides and glycerol to be analyzed. The samples were analyzed for TG, DG, MG,

10 75 total methyl esters and glycerol content by gas chromatography-mass spectrometry (GC-MS). The composition of the methyl esters was analyzed by GC using a SHIMADZU QP2010 series gas chromatograph system equipped with a split injection system, a flame ionization detector and a GC- MS solution version 2.53 software. The column was a 30.0 m 0.25 mm, and 0.25 m capillary column with helium % purity at 1.50 ml/min as the carrier gas and split ratio of 10:1. Injector and detector temperature were 260 C. Oven temperature started at 70 C for 2 min was increased to 300 C at a rate of 5 C/min and held at this temperature for 5 min. Methyl heptadecanoate was used as the internal standard. Mass Spectrophotometer condition: ion source temp: 200 C, interface temp: 240 C, scan range: m/z, solvent cut time: 5mins, MS start time: 5(min), MS end time: 35 (min), ionization: ei (-70ev), scan speed: 2000, MS library: nist08s, wiley8, fame FTIR Spectrophotometer Techniques Shimadzu was the first company to offer dynamic alignment as a standard feature in an affordable FTIR spectrometer. With state-of-the-art technology, the Shimadzu dynamic alignment system continuously maintains optimal alignment during data acquisition, ensuring consistently reproducible spectra without the need for tedious mechanical adjustments. FTIR-8400S is combined with the Irresolution 32 bit high performance FTIR software to analyze the samples easily and securely. The Dynamic Alignment Advantage: Optimal interferometer alignment is maintained automatically for continuous optimization and exceptional reproducibility. The Signal-to-Noise Advantage: Peak-to-Peak S/N ratio are 20,000:1 or better, guaranteed. The Simplicity Advantage: New FTIR operators will love the quick-start function that prompts the user through every action from setting scan parameters and acquiring the spectrum, to detecting peaks and printing.

11 76 The IR solution Advantage: Powerful IR solution software offers a myriad of standard data processing functions of the management of User group; protection by user name/password, Prerecording, and Electric Signature supports the FDA 21 CFR Part 11. The Validation Advantage: The software validates instrument performance to ensure compliance based on Japanese/European Pharmacopoeia and ASTM. The instrument and data reliability are ensured by GLP/GMP and FDA 21 CFR Part 11 compliance. IR solution agent software is needed to fully comply with FDA 21 CFR Part 11 regulation Interpretation of Infrared Spectra The interpretation of infrared spectra involves the correlation of absorption bands in the spectrum of an unknown compound with the known absorption frequencies for types of bonds. Table 3.1 will help users become more familiar with the process. Significant for the identification of the source of an absorption band are intensity (weak, medium or strong), shape (broad or sharp) and position (cm -1 ) in the spectrum. Characteristic examples are provided in the table below to assist the user to become familiar with the intensity and shape absorption bands for representative absorptions.

12 77 Table 3.1 Characteristic Infrared Absorption Frequencies Bond Compound Type Frequency range (cm -1 ) C-H Alkenes CH 3 umbrella Deformation (s) stretch (v) scissoring and bending 1380(m-w) - Doublet - isopropyl, t-butyl Bond Compound Type Frequency range (cm -1 ) Alkenes Alkynes (m) stretch (s) bend (s) stretch (b) bend C=C Alkenes (m, w)) stretch C C Alkynes (w, sh) stretch C-O C=O O-H N-H Alcohols, Ethers,, Esters and Carboxylic acids Aldehydes, Ketones, Esters, Carboxylic acids, Monomeric - Alcohols, Phenols Hydrogen-bonded- Alcohols, Phenols Carboxylic acids Amines (s) stretch (s) stretch (s, b) stretch (b) stretch (b) stretch (m) stretch (m) bend C-N Amines (m) stretch C N Nitriles (v) stretch NO 2 Nitro Compounds (s) asymmetrical stretch (s) symmetrical stretch SO4 2- Sulphate 1115(s)/610(w) Organic sulphate 1378 V-Variable, M-Medium, S-Strong, Br-broad, W-Week

13 XRD Techniques X-ray powder diffraction (XRD) is a rapid analytical technique primarily used for phase identification of a crystalline material and can provide information on unit cell dimensions. The analyzed material is finely ground, homogenized and average bulk composition is determined. Raw Data Origin: XRD measurement (*.XRDML), Scan Axis: Gonio, Start Position ( 2 ): , End Position ( 2 : , Step Size ( 2 ):0.0200, Scan Step Time (s):1.0000, Scan Type Continuous Offset ( 2 : , Divergence Slit Type: Fixed, Divergence Slit Size ( ): , Specimen Length (mm):10.00, Receiving Slit Size (mm):0.1000, Measurement Temperature ( C): 25.00, Anode Material:Cu, K-Alpha1 (Å): , K-Alpha2 (Å): , K-Beta (Å): , K-A2 / K-A1 Ratio ,Generator Settings 30mA, 45kV, Goniometer Radius mm, Dist. Focus-Diverg. Slit (mm):100.00, Incident Beam Monochromator No, Spinning No TGA Techniques Thermo gravimetric Analysis (TGA) measures weight changes in a material as a function of temperature (or time) under a controlled atmosphere. Its principal uses include measurement of a material's thermal stability and composition. Thermo gravimetric Analysis instruments are routinely used in all phases of research, quality control and production operations. TA Instruments offers the Discovery TGA, Q500, Q50, and simultaneous DSC / TGA (Q600) to meet the various needs of the researcher, quality control analyst and academic instructor. It consists of the following components. Thermo balance: The Q600 features a highly reliable horizontal dual-balance mechanism that supports precise TGA and DSC measurements. It delivers superiority in weight signal measurements (sensitivity, accuracy and precision) over what is available from single beam devices, since the dual

14 79 beam design virtually eliminates beam growth and buoyancy contributions to the underlying signal. It also uniquely permits independent TGA measurements on two samples simultaneously. Temperature Control and Measurement: A matched platinum / Platinum-Rhodium thermocouple pair within the ceramic beams provides direct sample, reference and differential temperature measurements from ambient to 1500ºC. This results in the best available sensitivity in detection of thermal events. Curie point or pure metal standards can be used for single or multi-point temperature calibration. Calibration of the DSC signal with sapphire standards results in a differential heat flow (DSC) signal that is intrinsically superior to that from single beam devices. Furnace: The Q600 features a rugged, reliable, horizontal furnace encased in a perforated stainless steel enclosure. The design ensures accurate and precise delivery of programmed and isothermal operation over the full temperature range from ambient to 1500ºC. The design also provides for operator ease-of-use due to its automatic furnace opening / closing, easy sample loading and rapid postexperiment furnace cool-down. Purge Gas System: A horizontal purge gas system with digital mass flow control and integral gas switching capability provides for precise metering of purge gas to the sample and reference pans. The design produces better baselines, prevents back diffusion, and efficiently removes decomposition products from the sample area. A separate gas inlet tube efficiently delivers reactive gas to the sample. The Q600 exhaust gas port can be readily connected to a MS or FTIR for component identification purposes. High Resolution SDT: If separation of closely related weight losses is required, the Q600 offers an automated version of Stepwise Isothermal (SWI), the classical technique for improved TGA resolution. The stepwise isothermal approach consists of heating at a constant rate until a weight change begins (as determined by an operator-chosen rate or

15 80 amount of weight loss) and then holding isothermally until the weight change is complete. This sequence of heating and isothermal steps is repeated for each weight change encountered. The result is optimum weight loss resolution. Temperature Calibration and Weight Loss Verification: TA Instruments offer the widest range of ICTAC certified and NIST traceable Curie point reference materials that provide SDT apparatus temperature calibration over the range from 150 to 1,120 C. TA Instruments also offer certified Mass Loss Reference Materials for validation of SDT instrument performance. Q600 Sample Pans: Platinum pans (40 and 110 L) and ceramic cups (40 and 90 L) are available for use with the Q600. The platinum cups are recommended for operation to 1000 C, and for their general inertness and ease of cleaning. The ceramic cups are advised for operation to 1,500 C, and or samples that react with platinum EDX Techniques Energy-dispersive X-ray spectroscopy (EDS, EDX, or XEDS) is an analytical technique used for the elemental analysis or chemical characterization of a sample. It relies on the investigation of an interaction of some source of X-ray excitation and a sample. Its characterization capabilities are due in large part to the fundamental principle that each element has a unique atomic structure allowing unique set of peaks on its X-ray spectrum. Thermo Electron Corporation has improved its X-ray microanalysis system, NORAN System SIX, enabling superior productivity gains in high throughput microstructure characterization laboratories. NORAN System SIX is now powered by the innovative new Direct-to-Phase software to perform energy dispersive spectroscopy (EDS) analyses concurrently with sample acquisitions, thus enabling scientists to make better informed decisions across a range of industries including mining, minerals, geophysics, metal production, semiconductor and microelectronics, ceramics, art and

16 81 archeology, forensics and nanotechnology. Combined with a newly introduced 30 mm 2 silicon drift detector, NORAN System SIX operates at ten times the efficiency of traditional X-ray microanalysis systems. Thermos NORAN System SIX compresses data acquisition to intelligent reporting in just one single step. Critical decisions are made by the micro analyzer itself throughout the acquisition, analysis and data interpretation process. The Direct-to-Phase software enables the system to terminate based on statistically and compositionally significant feedback. Alternatively, the analyst can visually observe the development of data and then decide when sufficient information is available for proper data interpretation. Traditionally, X-ray microanalysis combines spectral data with imaging capabilities to create spatial maps of each element in the sample. However, materials typically do not exist in simple elemental states; they are often made up of compounds in spatially unique phases. Leveraging the wealth of information collected in a spectral imaging dataset, where a complete EDS spectrum is recorded at every x-y point in the image, NORAN System SIX characterizes samples in terms of phases, not just elemental concentrations, enabling new compositionally unique features to be identified and mapped during the analysis SEM Techniques The new Hitachi S-3400N Variable Pressure SEM has been developed by improving the design of the S-3000N VP SEM which has been well accepted in the world market. It allows the study of wet, oily and/or nonconductive samples without metal coating or other complicated specimen preparation techniques. New hardware and software functions have been developed after listening to the user s requests for better imaging, larger sample sizes, analytical capabilities and higher throughput and easy to use. Better electron optics, larger specimen chamber, faster, cleaner evacuation

17 82 system and fully automated software are just a few of the new features of the S-3400N. Due to a newly designed TMP evacuation system, no cooling water is necessary. It takes less than 100 seconds to exchange a specimen and 6 minutes to reach ready status from a cold start. It requires only 2.0kVA for the power supply. The S-3400N will be a new world standard in the middle class Variable Pressure SEM. Built on the success of the S-3000 series instruments, the S-3400N offers advances in automation including full filament saturation and no touch objective aperture alignment. A new analytical chamber provides a total of ten ports with three high take off angle ports for EDS, Full Focusing WDS, PBS, EBSD and XRF. A BSE detector allows TV rate scanning and high resolution imaging. Hitachi s quad variable gun bias and SE accelerator plate ensures high currents for low voltage applications now approaching Field Emission performance. 3.7 OPTIMIZATION PARAMETERS The following parameters are used to optimize the biodiesel production from waste cooking palm oil with addition of homogeneous and heterogeneous catalysts. Effect of FFA of the waste cooking oil Effect of the various alcohol Effect of molar ratio of alcohol to oil Effect of temperature Effect of various catalysts Effect of reaction time

18 KINETIC MODELS Reaction Condition Experiments were designed to determine the reaction rate constants and activation energies for the temperature of 50, 55, 60 and 65 C. This temperature dependence was carried out using 4:1 molar ratio of alcohol to oil and also to identify the hypothesis of the process. A certain amount of catalyst was dissolved in methanol to prepare methoxide and then it was added into waste cooking palm oil reactor and the samples were collected for kinetic study. Based on the temperature ranges for every temperature collected from the three samples with respect to 20 min intervals, a total of 12 samples were collected with respect to time intervals. All experiments were carried out at atmospheric pressure level Rate Constant This kinetic model is used to predict whether the reaction is a second order or other order and to find out the rate constant as well as activation energy of the reaction. The second-order reaction rate for TG in equation (3.6) would be as follows: d(tg) / dt = k TG [TG] 2 (3.6) Integration of Equation (3.6) yields: -k TG.t =1/ [TG] - 1/ [TG O] (3.7) Similarly: - DG O k.t =1/[DG] -1/ [DG ] (3.8) - MG O k.t =1/ [MG] - 1/ [MG ] (3.9)

19 Activation Energy Arrhenius equation is used to determine the activation energy from a plot of the rate constant (k) vs. the reciprocal of absolute temperature (T), according to the equation (3.10): log 10 k = (-Ea / 2.303R) / T + C (3.10) Where, E a is the energy of activation, R is the Gas constant, k is rate constant and C is a constant. 3.9 DATA EVALUATIONS FFA value of Waste Cooking Palm Oil It is the number of mg of KOH required to neutralize the FFA in 1 gm of oil and Free Fatty Acids (FFA) is the result of the breakdown of oil or biodiesel fatty acid concentration. FFA measured in mg KOH/gm. Procedure 5 gm of oil with 60 ml of methanol then heat it up to 50 o C. Add few drops of phenolphthalein indicator then titrate against 0.1 N KOH and appearance of pale pink color. FFA V N 28.2 / W (3.11) Where, V = Volume of the KOH used (ml), N = Normality of the KOH used (N), W= Weight of the oil taken (gm).

20 Acid number of Biodiesel It is commonly used to describe the FFA content of finished biodiesel and is the amount of KOH in mg needed to react with the acid with a given amount of oil in grams. The Acid Number is one of the ASTM tests for finished biodiesel. The maximum value for finished biodiesel is 0.50 mg KOH/gm. Procedure Take 5 gm of oil sample and then dissolve it in 50 ml of methanol, then heat it up to 50 o C. Titrate the mixture using 0.1 N KOH solution phenolphthalein indicator with appearance of pale pink color. AN (V B) N 56.1 / W (3.12) Where, V = Volume of the KOH used (ml), B = Blank titration (ml), N = Normality of the KOH used (N), W = Weight of the oil taken (gm) Relationship between AN and FFA% we can Solve Both Equations for Common Values Now, combining the equations (3.11) and (3.12) and gives twice of free fatty acid into acid number. AN / 56.1 FFA% / 28.2 Or AN= 1.99FFA% (3.13)

21 Kinematic viscosity Viscosity is defined as the resistance to shear or flow; it is highly dependent on temperature and it describes the behavior of a liquid in motion near a solid boundary like the walls of a pipe. The presence of strong or weak interactions at the molecular level can greatly affect the way the molecules of an oil or fat slide pass each other, therefore, affecting their resistance to flow. The kinematic viscosity test calls for a glass capillary viscometer with a calibration constant (c) given in mm 2 /s. The kinematic viscosity determination requires the measurement of the time (t) the fluid takes to go from point A to point B inside the viscometer. The kinematic viscosity ( ) is calculated by means of the following equation: = c t (3.14) Density Relative density is the density of the component compared to the density of water. Relative density is a measure of weight per unit volume. The relative density of biodiesel is needed to make mass to volume conversions, calculate flow and viscosity properties, and is used to judge the homogeneity of biodiesel tanks. = m/v (3.15) Where, is the density (kg/m 3 ), m is the mass (kg), and V is the volume (ml) Saponification value The Saponification value (mg KOH/gm) is defined as the amount of potassium hydroxide (KOH) in milligrams required to saponify one gram of fat or oil under the conditions specified. Based on the length of the fatty

22 87 acids present in the triacylglycerol molecule, the weight of the triacylglycerol molecule changes which in turn affects the amount of KOH required to saponify the molecule. Hence, Saponification value is a measure of the average molecular weight or the chain length of the fatty acids present. As most of the mass of a triglyceride is in the three fatty acids, it allows for comparison of the average fatty acid chain length. Procedure The difference between the blank (B) and the test reading (T) gives the number of milliliters of KOH required to saponify 1g fat. 1ml (0.5 N HCl) = mg KOH (B-T) = S SV = (B-T) 28.05/ Wt. of fat (1g) (3.15) B = Blank titration and T = Test titration Water Content Water in the sample can promote microbial growth, lead to tank corrosion, participate in the formation of emulsions, as well as cause hydrolysis or hydrolytic oxidation. Sediment can reduce the ow of oil from the tank to the combustion chamber. D 2709 (water and sediment) in D 6751 prescribes the use of a centrifuge whereas ISO in EN represents a coulometric Karl-Fischer titration to determine water content Iodine Value The iodine value (iodine adsorption value or iodine number or iodine index) in chemistry is the mass of iodine in grams that is consumed by 100 grams of a chemical substance. Iodine numbers are often used to

23 88 determine the amount of unsaturation in fatty acids. This unsaturation is in the form of double bonds, which react with iodine compounds. The higher the iodine number, the more C=C bonds are present in the fat. Procedure Pipette out 10 ml of fat sample dissolved in chloroform to an iodination flask labeled as TEST". Add 20 ml of Iodine Monochloride reagent in to the flask. Mix the contents in the flask thoroughly. Then the flask is allowed to stand for half hour incubation in dark. Set up a blank titration in another iodination flask by adding 10ml Chloroform to the flask. Add to the blank titration, 20 ml of Iodine Monochloride reagent and mix the contents in the flask thoroughly. Incubate the blank titration in dark for 30 minutes. Mean while, take out the TEST from incubation after 30 minutes and add 10 ml of potassium iodide solution into the flask. Rinse the stopper and the sides of the flask using 50 ml distilled water. Titrate the TEST against standardized sodium thiosulphate solution until a pale straw colour is observed. Add about 1 ml starch indicator into the contents in the flask, a purple colour is observed. Continue the titration until the color of the solution in the flask turns colourless.

24 89 The disappearance of the blue colour is recorded as the end point of the titration. Similarly, the procedure is repeated for the flask labeled Blank'. Record the endpoint values of the blank titration. Calculate the iodine number using the equation below: Volume of Sodium thiosulphate used = (Blank - Test) ml Iodine No.of fat Equipment Wt.of Iodine Volume of Na 2S2O3 used Normally Na 2S2O = Weight of fatsampleused for analysis (g) (3.16) Calorific Value The Bomb Calorimeter is a classic device used to determine the heating or calorific value of solid and liquid fuel samples at constant volume. Basically, this device burns a fuel sample and transfers the heat into a known mass of water. From the weight of the fuel sample and temperature rise of the water, the calorific value can be calculated. The calorific value obtained in a bomb calorimeter test represents the gross heat of combustion per unit mass of fuel sample. This is the heat produced when the sample burns, plus the heat given up when the newly formed water vapor condenses and cools to the temperature of the bomb. Determinination of calorific value is important parameters why because of fuels are one of the biggest commodities in the world. The bomb calorimeter study is used to find out the gross calorific values of different types of liquid fuel like petrol, diesel, and biodiesel. Calorific value is an important parameter in Biodiesel production and this can be calculated by using the given formulae. CVs = T W-(CV T +CV W )/M (3.17)

25 90 T - Final rise in temperature ( C) E - Energy equivalent of Calorimeter (cal/ C) CV T - Calorific value of Thread (CV=21Cal) CV W - Calorific value of ignition wire (CV=9.32Cal) M - Mass of standard benzoic acid (gm) Flash and Fire Point Flash point The flash point is the lowest temperature at which fuel emits enough vapors to ignite. Biodiesel has a high flash point; usually more than 150 C, while conventional diesel fuel has a flash point of C. If methanol, with its flash point of 12 C, is present in the biodiesel, the flash point can be lowered considerably. To ensure that the methanol has been adequately stripped from the biodiesel, the Pensky-Martens closed cup flash point test was adopted Fire point The fire point of a fuel is the temperature at which it will continue to burn for at least 5 seconds after ignition by an open flame. At the flash point, at lower temperature, a substance will ignite briefly, but vapor might not be produced at a rate to sustain the fire. Most tables of material properties will only list material flash points, but in general the fire points can be assumed to be about 10 C higher than the flash points. However, this is no substitute for testing if the fire point is critical from safety point of view.

26 91 Procedure The flash fire points were measured with a Pensky-Martens closed cup tester. The apparatus and method consist of the controlled heating of the biodiesel in a closed cup, introducing an ignition source and observing if the heated biodiesel flashes. The temperature at which the biodiesel flashes is recorded as the flash point. For biodiesel, a flash point below 93 C is considered to be out of specification. If the biodiesel has not flashed at 160 C, the test is finished and the result is reported as more than160 C Biodiesel Yield Calculation Biodiesel yield, (%) Total actual weight Total theoretical of methylesters x 100 weight of methylesters (3.18) Molecular Weight of the Oil Waste cooking palm oil is not a pure compound. It is a triglyceride that is composed of a mixture of fatty acids: mainly Palmitic acid, oleic acid and Linoleic acid (also Myristic acid and Stearic acid). It has a Saponification value of The Saponification value can be used to estimate the molecular weight of the oil (Milligrams of KOH to saponify 1 gram of oil/fat). The Saponification value of waste cooking palm oil is 195mgKOH/gm. RCOOCH 2CH OCOR ' CH2OCOR" 3KOH ROH R'OH R"OH (3.19) KOOCH 2CH OCOK CH2OCOK 195mgKOH = 0.195/56= mole /3 = molepalmoil 1g/MW = mole MW estimate = 833gm/mol.