1. Energy and Exergy analysis of a dual fuelled diesel
engine run on biogas
ICAER, 2013
Indian Institute of Technology Bombay,
Mumbai-400076, India
Bhaskor Jyoti Bora
PhD Student
12/11/2013
Department of Mechanical Engineering
Indian Institute of Technology Guwahati,
Guwahati-781039, India
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2. Outline of Presentation
 Introduction
 Literature Review
 Problem Identification
 Experimental set-up
Thermodynamic Analysis
 Results and Discussion
 Conclusion
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3. Introduction
Energy sources
Non-renewable
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Renewable
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4. Wood
Pellets
Briquettes
Biomass Energy
Producer gas
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Alcohol
Bio gas
Bio-diesel
Bio-oil
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5. Biogas
Methane
Content
(Vol.-%)
50-75
Carbon dioxide
25-45
Water vapor
2 (20°C) -7 (40°C)
Oxygen
<2
Nitrogen
<2
Facts:
Ammonia
<1




Hydrogen
<1
Hydrogen
Sulphide
<1




Compound
environmentally friendly, clean, cheap gaseous fuel
mainly mixture of methane and Carbon dioxide
anaerobic digestion of biomass
calorific value vary from 19 to 25 MJ/m 3
Avogadro identified methane in marsh gases in 1821
17% of vehicle Fuel in UK
Germany is the Europe’s biggest producer of biogas
3% of North America’s Electricity
Applications




Cooking
Lighting
Automobile
Power production
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Biogas powered train, Sweden
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6. IC Engines and Biogas
 Octane rating=130
 Extremely suitable for engines with high CR
Biogas
 Derating of Power [Walsh et al. (1989), Bari (1996),Henham and Makkar
(2002),Bedoya (2012)]
 Rough engine operation for methane < 23% [Jawurek et al. (1987)]
 Engine performance deterioration [Huang and Crookes (1998)]
SI Engine
 Drop in Efficiency [Sahoo (2011), Yoon (2011)]
 CO emission is higher[Sahoo (2011)]
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CI engine
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7. Reasons for Low efficiency in CI engine
Diesel




Every Fuel has certain chemical composition
Based on chemical composition , operating parameters vary
Diesel engine settings is standardized for diesel fuel
Diesel engine settings need to be standardized for Biogas fuel
Operating parameters
 Compression ratio
 Injection Timing
 Injection Pressure
 Inlet manifold Design
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Biogas
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8. Dual Fuel Diesel Engine
 Dual Fuel diesel engine is a diesel engine, fitted with an additional device called
“Gas mixer”
 Dual Fuel engine requires some amount of diesel for ignition of the gas fuel
 The gaseous fuel is called primary fuel as the engine runs mainly on it
 Diesel is called pilot fuel which acts as the ignition medium for gaseous fuel
Advantages
Disadvantages






 Cannot operate without pilot fuel
 Lower engine output
 Higher CO emission
Reduces diesel consumption
Flexibility of operation in diesel or dual mode
Localization of fuel
Use of carbon neutral fuel
variations in fuel source
Reduction of exhaust emissions: NOX ,CO2 and
particulates
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9. Thermodynamic Analysis
Energy Analysis
Exergy Analysis
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10. Energy Analysis
 Fuel energy supplied
 Shaft power
 Heat taken away by
cooling water
 Heat taken away by
exhaust gases
 Unaccounted heat loss
due to radiation
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Exergy Analysis
 Fuel Availability
 Shaft availability
 Cooling water availability
 Exhaust gas availability
 Availability destroyed
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11. Objectives
Energy and Exergy Analysis of a Dual Fuelled Diesel Engine Run on Biogas
PARAMETER UNDER STUDY
COMPRESSION RATIO
PRIMARY FUEL
BIOGAS
PILOT FUEL
DIESEL
ANALYSIS
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ENERGY
EXERGY
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12. Original Set-up
Parameter
Engine type
General details
Rated output
Bore and stroke
Capacity
Compression ratio
Injection timing
Dynamometer
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Specifications
Research engine test setup
1 Cylinder, 4 stroke, VCR, water cooled diesel engine
3.5 kW at 1500 rpm
87.5 mm×110 mm
661cc
17.5 (Range 12–18)
23oBTDC (range 0–35oBTDC)
Eddy current type, 0–12 kg, 185mm radius
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13. Modified set up
Venturi gas mixer
Fuel control mechanism
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Experimental set-up
Y-connector
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14. Fuel Properties
Properties
Diesel
Biogas
Chemical Composition
C12H26
59%CH4,41% CO2 (volume)
Density(kg/m3)
840
1.2
Lower calorific value (MJ/kg)
42
17.8
Cetane number
45-55
-
Auto-ignition Temperature (K)
553
1087 [6]
Stoichiometric air fuel ratio
14.92
10 [6]
Experimental Matrix
Mode
Fuel used
Load(%)
Diesel
Fuel: 100% Diesel
Compression
timing
ratio
20, 40, 60,
Dual
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Injection
Primary Fuel: Biogas 80, 100, 110
17.5
23oBTDC
18, 17.5, 17, 16
Pilot Fuel: Diesel
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15. Results and Discussion
Diesel,CR=17.5
Biogas,CR=18
Biogas,CR=17.5
Biogas,CR=17
Biogas,CR=16
30
20
Fuel Energy (kW)
Brake Thermal Effiency
(%)
40
10
0
0
20
40
60
80
Engine Load (%)
100
120
Diesel,17.5
Biogas,CR=18
Biogas,CR=17.5
Biogas,CR=17
Biogas,CR=16
0
Fig. 2 Variation of Brake thermal efficiency with load
20
40
60
80
Engine Load(%)
100
120
Fig. 3 Variation of fuel energy with load
80
650
Diesel,CR=17.5
Biogas,CR=18
Biogas,CR=17.5
Biogas,CR=17
Biogas,CR=16
600
550
Pilot Fuel
Replacement(%)
Exhaust Gas Temperature
(K)
35
30
25
20
15
10
5
0
500
450
70
60
Biogas,CR=18
Biogas,CR=17.5
Biogas,CR=17
Biogas,CR=16
50
40
30
400
0
20
40
60
80
Engine Load(%)
100
120
0
20
40
60
80
Engine Load (%)
100
120
Fig. 4 Variation of exhaust gas temperature with load Fig. 5 Variation of pilot fuel substitution with load
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16. 20
Biogas,CR=18
Biogas,CR=17.5
Biogas,CR=17
Biogas,CR=16
2.5
BSEC (kJ/s/kw)
Biogas Flow Rate(m3/hr)
3
2
1.5
1
0
20
40
60
80
Engine Load(%)
100
10
5
120
0
50
45
40
35
30
25
20
15
10
30
Diesel,CR=17.5
Biogas,CR=18
Biogas,CR=17.5
Biogas,CR=17
Biogas,CR=16
20
40
60
80
Engine Load(%)
100
120
Fig. 7 Variation of fuel BSEC with load
Fuel Exergy (kW)
Exergetic Efficiency (%)
15
0
Fig. 6 Variation of biogas flow rate with load
Biogas,CR=18
Biogas,CR=17.5
Biogas,CR=17
Biogas,CR=16
Diesel,17.5
25
20
15
10
5
0
20
40
60
80
Engine Load (%)
100
120
Fig. 8 Variation of fuel exergetic efficiency with load
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BSEC,CR=18
BSEC,CR=17.5
BSEC, CR= 17
BSEC,CR=16
0
20
40
60
80
Engine Load (%)
100
120
Fig. 9 Variation of fuel exergy with load
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17. Fig. 10 Effect of compression ratio on energy distribution
Fig .11 Effect of compression ratio on exergy distribution
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18. Conclusion
The maximum brake thermal efficiency for dual fuel mode are found to be 22.56%,
21.34%, 19.94% and 18.63% at CR 18, 17.5, 17 and 16 respectively at 80% load as
compared to 31.78% for diesel mode at 100% load.
The maximum exergetic efficiency for dual fuel mode are found were found to be
27.91%, 24.33%, 22.81% and 19.01% at CR 18, 17.5, 17 and 16 respectively at 80%
load as compared to 38.87% for diesel mode at 100% load.
The maximum substitution of diesel that is obtained in dual fuel mode for CRs 18,
17.5, 17 and 16 are 73.33%, 73.80%, 73.18% and 71% respectively at 110% load.
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19. Main Findings of This Research Work
 Standardization of Operating Parameters for Biogas Run Diesel Engine is a
must for attainment for higher efficiency
 Higher Compression Ratio results in Higher efficiency
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