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A Study on how to prepare biodiesel on laboratory or small scale. This report also explores the biodiesel viscosity at various temperature taken by using redwood viscometer(device description and calculations included)
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REPORT
on
Study of Biodiesel Viscosity
variation with temperature
PROJECT GUIDE SUBMITTED BY
Dr M K JhaKrittikaSwamee (07101016)
Tushar Sharma (07101052)
INTRODUCTION
With the ever rising fuel demand in our growing world, severe fuel crisis is just round the corner. The fossil fuel resources such as petroleum and coal are being used up at a frenzied pace. The quest for an alternative fuel is inevitable at this stage.
Biofuels have, in recent times, shown promising results in the field of alternative fuels. They are also an efficient method to dispose of waste oils, unusable oil seeds and lower quality of vegetable oils. In advanced nations like America and Europe oil seed such as soya, canola and rapeseeds are being used to produce biodiesel at a large scale. Biodiesel is blended with diesel and used to fuel vehicles in this initial stage. In India, jatropha cultivation is one of the main sources of biodiesel producing seeds. Biodiesel is being used currently to fuel the remaining diesel engines with the Indian Railways (‘Ratanjot’ Plants are established to produce biodiesel for the same.)
Biodiesel can be produced by thetransesterification of a feedstock containing triglyceride with short-chained alcohols (Fukuda et al. 2001; Ma and Hanna, 1999). The alkyl esters of fatty acids produced during this reaction is referred to as biodiesel. In the reaction, glycerinis obtained as abyproduct. Biodiesel has wide applications as alternative fuel for use in unmodified, standard diesel engines. In many of these applications biodiesel can be used alone, or blended with petroleum based diesel. Some of the important benefits derivable from biodiesel are:
renewability of the fuel clean burning in most emission engines, compatibility with current fuel engine systems, lubricity of diesel blends containing biodiesel, and reduction on petroleum dependence for fuel while potentially creating domestic
jobs
As the use of biodiesel becomes more widespread engine manufacturers have expressed concerns over biodiesel viscosity. In particular, they are concerned that biodiesel may exhibit different viscosity temperature characteristics that would result in higher fuel injection pressures and lower engine operating temperatures.
Thus much research is being carriedout to accurately model viscosity variations in biodiesel with temperature. This would help us in assessing its use as a commercial fuel.
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OBJECTIVE
Study of Biodiesel Viscosity variation with temperature both, experimentally and theoretically (with the help of existing mathematical models).
METHODOLOGY
The project work has been divided into four segments
Preparation of Biodiesel Estimation of viscosity of biodiesel experimentally Estimation of biodiesel viscosity by using mathematical models (Yuan’s and
Krisankagura ‘s models ) Analysis of deviations in viscosity’s experimental and theoretical values.
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EXPERIMENTAL WORK
A. Preparation of Biodiesel
Requirements:Chemicals- Vegetable oil, methanol, Potassium hydroxide, waterApparatus- Biodiesel apparatus, consisting of, an assembly of three necked flask, thermometer, reflux condenser with water supply and a motor driven stirrer.
Separating funnel, beaker, funnel, glass rod
Concepts Used:
A base catalyzed methodology was adopted due to several reasons: It can take place at low temperature and pressure. It yields high conversion (98%) with minimal side reactions and reaction time. It is a direct conversion to biodiesel with no intermediate compounds
The oil to methanol molar ratio was taken to be 1:5. The excess alcohol ensures a quick reaction.
The general reaction between oil and methanol to produce biodiesel is depicted below
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Procedure:
The biodiesel samples were prepared in the department laboratory for consistency in reaction parameters, such as temperature, duration of reaction, separation time. The laboratory procedure was as follows:
1. 400 ml of vegetable oil (Sunflower oil, Soy oil, cottonseed oil) was taken and it was heated to 56°C.
2. Calculated amount of Methanol was mixed with KOH (catalyst amount = 1% by weight of oil) and stirred in order to dissolve KOH completely.
3. The mixture of Methanol was added to the hot oil (56°C) with continuous stirring by an agitator driven by a motor.
4. The reaction was continued at constant temperature of
56°C with constant stirring for a period of 1.5 hours. 5. The reaction mixture was now poured into a separating
funnel and allowed to stand for 24 hours in order to effectively separate the biodiesel and glycerol.(as shown in the picture on left)
6. The oil and glycerol are separated.7. The oil is now washed with warm water (40°C) and
allowed to stand for another 24 hours for effective separation and removal of impurities. (picture on right)
8. The biodiesel and water are separated. The sample was stored in dry plastic bottles to avoid contamination.
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Calculations:
The molecular weights were obtained from literature. Catalyst Calculation
1% by weight of Oil The molar ratio of oil to methanol was 1:5
ρOV O
MO
ρMVMMM
=15
Soy Oil Sunflower Oil Cottonseed OilMolecular Weight 874.63 850 848.3
Volume of Methanol (ml)
84.29 86.62 86.8
Weight of Catalyst (gm)
3.67 3.64 3.64
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B. Viscosity Determination
Redwood’s Viscometer was used to determine the kinematic viscosity of oils. It is a standard British-type viscometer in which the viscosity is determined by the time, in seconds, required for a certain quantity of liquid to pass out through the orifice under given conditions; used for determining viscosities of petroleum oils.
The device consists of a small holding vessel surrounded by a trough. The trough is fitted with a heating coil to raise the temperature of surrounding fluid (water).
The bottom of the vessel consists of an orifice. The orifice can be covered with a movable ball.
Biodiesel sample was kept in the vessel and water in the trough was heated gradually from temperatures ranging from room temperature to 100°C at an interval of 5 °C. 50 ml of oil sample was allowed to fall into the collecting beaker and time is noted by a stopwatch.
To obtain viscosity at temperatures below the room temperature the accessory agitator was removed from the trough and it was filled with ice cubes. The viscosity was hence noted for temperatures of 0°C, 5°C, 10°C and 15°C.
The time of falling of biodiesel is in the terms of Redwood’s seconds. This was converted to regular units by the following relation
η = 0.260t – 0.0188t
t- Time (in Redwood’s seconds)η- Kinematic Viscosity (in cS)
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Viscosity Readings:
Soy Oil
Temperature(°C) Time (seconds) Viscosity (CentiStoke)
0 228.75 59.475 174 45.2310 159 41.3315 144.75 37.6320 109.75 28.5325 97.75 25.4230 89.75 23.3335 87 22.6240 76 19.7545 73.75 19.1750 67.5 17.5455 73 18.9760 68.25 17.7465 71 18.4570 65.25 16.9675 64.75 16.8380 60.5 15.7385 59 15.3390 54.25 14.10495 58.75 15.27100 60.75 15.79
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1 2 3 4 5 6 7 8 9 1011121314151617181920210
10
20
30
40
50
60
70
Kinematic Viscosity v/s Temperature
Viscosity (cS)
Sunflower Oil
Temperature(°C) Time (seconds) Viscosity (CentiStoke)
0 - -5 - -10 - -15 - -20 240 62.425 200 51.99930 176 45.7635 171.25 44.5240 167.75 43.6145 156.75 40.7550 145 37.755 133.25 34.6560 119 30.9465 124 32.2470 118.25 30.7575 113.75 29.5880 111 28.8685 99.5 25.8790 89.75 23.33595 99.75 25.94100 90 23.40
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5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 100
Temperature (°C)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 170
10
20
30
40
50
60
70
Kinematic Viscosity v/s Temperature
Viscosity
C. AnalysisThe analysis ofbiodiesel viscosities at various temperatures will be carried out with the help of following mathematical models: Yuan’s model Krisankagura ‘s model
The theoretical values of viscosity will be determined using these models which require the gas chromatography analysis of the biodiesel to determine the composition of the biodiesel or pure fatty acids methyl esters (FAMEs).
We intend to study the deviation of theoretical values of viscosity, as obtained from the mathematical models based on the information of their FAME composition, from experimental values of viscosity of biodiesel. This analysis can be used to determine which model predicts the viscosity of biodiesel most accurately and can thus be used as tool to the design of biofuels or biofuel blends with viscosities that comply with legal specifications.
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5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 100
Temperature (°C)
REFERENCES
Yuan,W.; Hansen, A. C.; Zhang, Q. “Predicting the temperaturedependent viscosity of biodiesel fuels”; Fuel 2009, 88, 1120.
Samuel V. D. Freitas, Maria Jorge Pratas, Roberta Ceriani, Alvaro S. Lima,and Jo~ ao A. P. Coutinho “Evaluation of Predictive Models for the Viscosity of Biodiesel”; Energy Fuels 2011, 352-358
KanitKrisnangkuraa, TawatchaiYimsuwanb, RatanachaiPairintraa “An empirical approach in predicting biodiesel viscosity at various temperatures”;
http://www.tis-gdv.de/tis_e/ware/oele/senf/senf.htm http://hypertextbook.com/facts/2000/IngaDorfman.shtml http://www.csgnetwork.com/specificgravliqtable.html http://gurgaon.dronacharya.info/apsdept/Downloads/Labmanuals/Chemistry/
ExperimentsDetail_Chemistry.pdf http://www.contractorsunlimited.co.uk/toolbox/viscosity.shtml http://www.carbibles.com/viscosity.html http://www.svlele.com/biodiesel_in_india.htm http://www.biodiesel.org/pdf_files/fuelfactsheets/prod_quality.pdf http://www.answers.com/topic/redwood-viscometer
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