Determination of Kinematic Viscosity of Different types of Biodiesel at Low Temperatures

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Friday, Dec ember 17, 2 021

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Determination of Kinematic Viscosity of Different types of Biodiesel at Low Temperatures

DARBAZ ABDULLA

Mechanical Engineering Department

Near East University

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PURPOSE

 determine experimentally the kinematic viscosity and cold flow properties (cloud point and pour point) of five different ratio of biodiesel fuel (from 20

⁰

C down to -10

⁰

C).

 determine the effect of both temperature and composition on the

biodiesel properties.

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Friday, Decem ber 17, 2021

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OUTLINE

 Introduction

 Theory and Methods

 _Viscosity

• Capillary Viscometers

• Biodiesel Samples

• Experimental Set-ups

• Methodology

 Cold Flow Properties (Cloud Point and Pour Point)

• Cloud Point and Pour point Set-up

• Methodology

 Results and Discussions

 Reliability of the Results

 Kinematic Viscosity

 Cloud Point (CP) and Pour Point (PP)

 Conclusions

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INTRODUCTION

 The world will need 50% more energy in 2030 than today.

 The transportation energy use is expected to increase by 1.8% per year from 2005 to 2035.

 The rising prices day after day of crude oil.

 It is expected that about 12.7 billion metric tons of carbon dioxide (CO

₂

) will be released to the atmosphere from 2007 to 2035.

 The possibility depletion of fossil fuel in the future.

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INTRODUCTION (Contd.)

 Biodiesel possesses some advantages over petroleum diesel, such as:

• Reducing global warming gas emissions, (HC), (CO) and other air toxics.

 Biodiesel faces some problems such as:

• The main problems are high viscosity, cold flow properties and high cost.

 Biodiesel (FAME)

 Biodiesel is derived from vegetable oils and animal fats.

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INTRODUCTION (Contd.)

 Viscosity affects the performance of fuel injection system.

 High viscosity causes to form larger droplets upon injection, poorer atomization, poor combustion and increasing emission.

 Biodiesel viscosity must be in the range of 1.9-6.0 mm

²

/s (ASTM D6751) and 3.5-5.0 mm

²

/s (EN 14214) at 40

⁰

C .

 Viscosity

 What is the effect of high viscosity?

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INTRODUCTION (Contd.)

 Recently, more than 95% of the world biodiesel is produced from edible oils.

 Used oil can be a good source for the production of biodiesel to reduce the using of edible oil because feedstock alone represents 75% of the overall biodiesel production cost.

Oil feedstocks 75% Chemical feedstock 12%

Depreciation 7% Direct labour 3%

Energy 2% General overhead 1%

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THEORY AND METHODS

 Viscosity: When a liquid flows, there is a resistance to flow, which is mainly, depends on the interaction forces of molecules.

Viscosity is a measure of this resistance to flow.

 Cloud point is defined as the temperature of the fuel at which the first cloud of wax can be observed when it is cooled.

 pour point is the lowest temperature at which the fuel can still flow.

 Definitions

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THEORY AND METHODS (Contd.)

 There are two types of viscosity: Dynamic viscosity and Kinematic viscosity.

 Dynamic viscosity is the tangential force per unit area required to move one layer against another layer at unit velocity.

Shear stress = μ (strain rate)

 Viscosity

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 Kinematic viscosity is like dynamic viscosity but no force involved.

 Kinematic viscosity is dynamic viscosity over density.

Kinematic viscosity is expressed as m²/s or stoke (St).

where 1St = 10^-4m²/s

THEORY AND METHODS (Contd.)

 What factors affecting viscosity?

 Temperature

 Composition

 Pressure

 Kinematic viscosity

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THEORY AND METHODS (Contd.)

 Viscosity is measured by a device, called viscometer.

 The most common viscometer is the glass capillary viscometer.

 Viscometer

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THEORY AND METHODS (Contd.)

 Theory of Capillary Viscometers

From the continuity equation

By using Navier Stoke’s equation for steady flow

while

(The velocity is parabolic)

Consider fully developed laminar flow.

,

(hydrostatic pressure)

,

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THEORY AND METHODS (Contd.)

 Biodiesel samples (specimens)

1. 100 % UFOME (Used Frying Oil Methyl Ester) 2. 100 % UCOME (Used Canola Oil Methyl Ester) 3. 50 % UFOME + 50 % UCOME

4. 75 % UFOME + 25 % UCOME 5. 25 % UFOME + 75 % UCOME

100% UFOME 100% UCOME 50% UFOME + 50% UCOME

75% UFOME + 25% UCOME

25% UFOME + 75% UCOME

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THEORY AND METHODS (Contd.)

 Experimental Set-up (Kinematic viscosity)

 Cooling Bath System

Ubbelohde

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THEORY AND METHODS (Contd.)

 Ubbelohde viscometer

1 Capillary tube 2 Venting tube 3 Filling tube 4 Reservoir

6 Dome-shaped top part 7 Capillary

8 Measuring sphere M₁Upper timing mark M₂Lower timing mark

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THEORY AND METHODS (Contd.)

 Methodology

1. The viscometer is cleaned with ( H

₂

O

₂

) and HCl, then with Acetone.

2. Set the liquid bath to required temperature

3. transfer required amount of sample (15ml) into the viscometer 4. Place the viscometer in the holder then to cooling bath

5. It is left for a long enough time to get the same temperature of the bath.

6. Apply suction to capillary tube (1) and closing venting tube (2) by a finger.

Then suction is disconnected.

7. The time interval (efflux time t) is measured.

8. Kinematic viscosity is calculated by:

9. Without changing the sample, the steps 6 to 8 were repeated four or more

than four times for each degree of temperature from 20

⁰

C down to pour

point by stepwise of 5

⁰

C.

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THEORY AND METHODS (Contd.)

 Calculation of kinematic viscosity

Capillary Ic constant (K) = 0.02799 (mm²/s)/s Flow time (averaged) t = 372.75 s

Kinetic energy correction (HC) y for 372.75 = 0.01 s

Kinematic viscosity = 0.02799*(372.75-0.01) =10.4329926 mm²/s

In the same manner, test all the samples.

Times

(T ⁰C @ 20) Sec. Ave. Time (sec.)

Ave. Time (±1%)

Capillary Constant (K)

(mm²/sec²)

Kinetic Energy Correction

(y) (sec.)

Kinematic Viscosity (mm²/sec)

Time 1 373.1

372.75 ^376.4775 0.02799 0.01 10.4329926

Time 2 372.2

Time 3 374.1

369.0225

Time 4 371.6

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 Cloud Point and Pour Point Set-up THEORY AND METHODS (Contd.)

 Cloud point and pour point apparatus.

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THEORY AND METHODS (Contd.)

 The cloud point and pour point were determined as per ASTM D2500 and ASTM D97 respectively.

 Methodology (CP and PP)

1. Cooling alcohol down to -25

⁰

C. 2. Transfer required sample into the test jar, put it into the aluminum cylinder inside the stainless steel cooling bath.

3. Inspected at stepwise of 1

⁰

C until a cloud of crystal is appeared.

4. Same sample is heated to 9

⁰

C above the expected pour point then one more time immersed it into the cylinder.

5. Inspected at stepwise 1

⁰

C until it was totally ceased to flow then the

degree before ceased degree is recorded as a pour point.

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RESULTS AND DISCUSSIONS

 Reliability of the Results

 The measurements were taken after long enough time.

 The actual time measurement was performed with a stopwatch by observing the exact starting and ending time of flowing.

 Repeating accuracy is the most important point.

Biodiesel type Measured kinematic

viscosity (mm²/s) Average Kinematic

viscosity (mm²/s) Absolute error in (%)

50%UCOME+ 9.6058881

9.63737685

0.327806754

50%UFOME 9.6562701 0.195657845

9.6310791 0.065389869

9.6562701 0.195657845

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RESULTS AND DISCUSSIONS

 Kinematic Viscosity

Temperature (⁰C)

Kinematic viscosity (mm²/s)

100%UCOME 75%UCOME +

25%UFOME

50%UCOME +

50%UFOME

25%UCOME +

75%UFOME

100%UFOME

20 7.35171345 10.43299260 9.63737685 9.63737685 7.41539070 15 8.61224310 12.31532010 11.47282110 11.42663760 8.71160760 10 9.78852285 14.51953260 13.42092510 13.42792260 nd^a

8 10.41479910 15.55726185 14.35159260 nd^a -

5 11.83459185 17.57044260 nd^a - -

2 13.14382410 20.28419105 - - -

0 14.03040735 nd^a - - -

-3 15.59015010 - - - -

-5 18.28278810 - - - -

-7 21.51664030 - - - -

-8 23.86299105 - - - -

-10 nd^a - - - -

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RESULTS AND DISCUSSIONS

 Kinematic Viscosity

0 10 20 30 40 50 60

6 8 10 12 14 16 18 20 22 24 26

100%UCOME

75%UCOME+25%UFOME 50%UCOME+50%UFOME 25%UCOME+75%UFOME 100%UFOME

Temperature (0C)

Kinematic viscosity (mm2/s)

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RESULTS AND DISCUSSIONS

 Kinematic Viscosity

 The effect of temperature on the kinematic viscosity of liquid is described by means of the Arrenhius equation.

 In the case of vegetable oils, the equation can be written as the Andrade equation:

 This is the most common equation that is empirically used to

determine the relationship between viscosity and temperature.

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RESULTS AND DISCUSSIONS

 Kinematic Viscosity

0.0025 0.0027 0.0029 0.0031 0.0033 0.0035 0.0037 0.0039 1

2 3 4 5 6 7 8 9 10 f(x) = 0 11 R² = 0

Temperature 1/T (Kelvin)

ln of kinematic viscosity

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RESULTS AND DISCUSSIONS

 Kinematic Viscosity

 The relationship between the viscosity of the samples and their

percentage composition.

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RESULTS AND DISCUSSIONS

 Also, it can be found the empirical coefficients for the

kinematic viscosity and composition relationship by using forth order of polynomial regression

 Kinematic Viscosity

Where υ is kinematic viscosity and x any required percentage of UFOME in the mixture.

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RESULTS AND DISCUSSIONS

 Kinematic Viscosity

Temperature

(⁰C) A B C D E R²

20 -8.00E-07 2.00E-04 -0.0125 0.3400 7.3517 1 15 -9.00E-07 2.00E-04 -0.0144 0.3983 8.6122 1

10 - 7.00E-05 -0.0102 0.3983 9.7885 1

8 - - -0.0051 0.3327 10.415 1

5 - - - 0.2294 11.835 1

2 - - - 0.2856 13.144 1

0 - - - - 14.030 1

-3 - - - - 15.590 1

-5 - - - - 18.283 1

-7 - - - - 21.517 1

-8 - - - - 23.863 1

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RESULTS AND DISCUSSIONS

 Cloud Point (CP) and Pour Point (PP)

0 25 50 75 100

-15 -10 -5 0 5 10 15 20

Cloud point

Composition of UFOME with UCOME (%)

Temperature (0C)

100%UFOM E

100%UCOM E

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RESULTS AND DISCUSSIONS

 Cloud Point (CP) and Pour Point (PP)

 The measurements of cloud point and pour point have been

correlated as function of percentage composition by second order polynomial equations.

0 25 50 75 100

245 250 255 260 265 270 275 280 285 290 295

f(x) = − 0 x² + 0.35 x + 263.16 R² = 0.99

f(x) = − 0 x² + 0.29 x + 272.27 R² = 0.99

Cloud point

Polynomial (Cloud point) Pour point

Polynomial (Pour point)

Volume composition (%)

Temperature (K)

100%UFOME 100%UCOME

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RESULTS AND DISCUSSIONS

 Cloud Point (CP) and Pour Point (PP)

 From the regression coefficient, it was observed that:

The polynomial equation is better fitted than a linear equation.

 The proposed equations for calculating both CP and PP are:

 where x is the percentage of biodiesel.

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Biodiesel samples UFOME (%) Measured pour point

(K) Calculated pour point

(K) Absolute error in (%)

100% UCOME 0 262.65 263.20 0.2094

75% UCOME + 25%

UFOME 25 272.15 270.97 0.4336

50% UCOME + 50%

UFOME 50 276.65 276.99 0.1229

25% UCOME + 75%

UFOME 75 280.85 281.26 0.1460

100% UFOME 100 284.45 283.78 0.2355

Biodiesel samples UFOME (%) Measured cloud point

(K) Calculated cloud point

(K) Absolute error in (%)

100% UCOME 0 272.15 272.33 0.0661

75% UCOME + 25%

UFOME 25 278.85 278.80 0.0188

50% UCOME + 50%

UFOME 50 284.65 284.02 0.2231

25% UCOME + 75%

UFOME 75 287.15 287.98 0.2899

100% UFOME 100 290.95 290.70 0.0859

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RESULTS AND DISCUSSIONS

 Cloud Point (CP) and Pour Point (PP)

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Conclusions

Ubbelohde viscometer was used to determine kinematic viscosity per ASTM D445-07.

Also the cloud point and pour point were tested

per ASTM D2500-09 and ASTM D97-05 respectively.

Concluded these:

 The kinematic viscosity of the samples is a little high.

 The highest kinematic viscosity is in (75%UCOME+ 25%UFOME).

 The viscosity of the biodiesels increase logarithmically with decrease in temperature, experimentally as predicted by Andrade equation.

 Cloud point always occurs a few degree of temperature above the pour point.

 The cloud point and pour point of 100%UCOME increases by increasing the

percentage of UFOME.

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Determination of Kinematic Viscosity of Different types of Biodiesel at Low Temperatures