Estimation of Fuel Higher Heating Value (HHV) Using Proximate Analysis

Presentation by: Dr. Saqib Nasir

Senior Scientific Officer, Coal Technology Section,

Pakistan Council of Scientific & Industrial Research Laboratories,

Lahore – 54600, Pakistan

Webpage: http://pk.linkedin.com./pub/dr-nasir-saqib

Venue: 5th Pakistan Oil & Gas Forum 2013,

Marriot Hotel, Islamabad

May 30, 2013

Presentation Agenda: Fuels & Combustion

Introduction

Type of fuels

HHV Correlations and Evaluation

Correlations based on proximate analysis

Introduction

• Solar energy is converted to chemical energy through photo-synthesis in plants

• Energy produced by burning wood or fossil fuels

• Fossil fuels: coal, oil and natural gas

The Formation of Fuels

Wood n(C6H10O5)

Peat n(C8H10O5)

Lignite n(C35H16O4)

Sub-bituminous n(C49H19O4)

Chemical Models for Real Fuels

Type of Fuels

Solid Fuels Coal classification • Anthracite: hard and geologically the

oldest

• Bituminous

• Lignite: soft coal and the youngest

• Further classification: semi- anthracite, semi-bituminous, and sub-bituminous

Type of Fuels

Solid Fuels

Physical properties • Heating or calorific value (GCV)

• Moisture content

• Volatile matter

• Ash

Chemical properties • Chemical constituents: carbon, hydrogen,

oxygen, sulphur

Type of Fuels

Solid Fuels (Physical properties)

Heating or Calorific Value • The typical GVCs for various coals are:

Parameter Lignite (Dry

Basis)

Pakistani Coal

Indonesian Coal

South African Coal

GCV (kCal/kg)

4,500 4,793 5,500 6,000

Type of Fuels

Solid Fuels (Physical properties) Moisture content • % of moisture in fuel (0.5 – 10 %)

• Reduces heating value of fuel

• Weight loss from heated and then cooled powdered raw coal

Volatile matter • Methane, hydrocarbons, hydrogen, CO, other

• Typically 25-35 %

• Easy ignition with high volatile matter

• Weight loss from heated then cooled crushed coal

Type of Fuels

Solid Fuels (Physical properties) Ash • Impurity that will not burn (5-40 %)

• Important for design of furnace

• Ash = residue after combustion

Fixed carbon • Fixed carbon = 100 – (moisture + volatile matter + ash)

• Carbon + hydrogen, oxygen, sulphur, nitrogen residues

• Heat generator during combustion

Type of Fuels

Solid Fuels (Physical properties) Ash • Impurity that will not burn (5-40 %)

• Important for design of furnace

• Ash = residue after combustion

Fixed carbon • Fixed carbon = 100 – (moisture + volatile matter + ash)

• Carbon + hydrogen, oxygen, sulphur, nitrogen residues

• Heat generator during combustion

Type of Fuels

Solid Fuels (Physical properties) Proximate analysis of coal • Determines only fixed carbon, volatile matter,

moisture and ash

• Useful to find out heating value (GCV)

• Simple analysis equipment

Ultimate analysis of coal • Determines all coal component elements: carbon,

hydrogen, oxygen, sulphur, other

• Useful for furnace design (e.g flame temperature, flue duct design)

• Laboratory analysis

Type of Fuels

Solid Fuels (Physical properties)

Proximate analysis Typical proximate analysis of various coals (%)

Parameters (%) Pakistani Coal

Indonesian Coal

South African Coal

Moisture 5.00 9.43 8.50

Ash 36.10 13.99 17.00

Volatiles 27.20 29.79 23.28

Fixed Carbon 31.70 46.79 51.22

Type of Fuels

Solid Fuels (Chemical Properties) Ultimate analysis

Typical ultimate analysis of coal (%)

Parameters Pakistani Coal Indonesian Coal % Moisture % Mineral Matter

5.00 41.08

9.43 15.40

% Carbon % Hydrogn % Nitrogen % Sulphur % Oxygen

44.8 4.10 1.08 3.82 46.2

58.96 4.16 1.02 0.56 11.88

GCV (kcal/kg) 4,793 5,500 *Parr Formula: % MM = 1.08 × ash + 0.55 × sulphur

Practical fuels are complex mixtures of compounds. Some useful for generation of heat & some are useless. Some are threat to environment. Proximate Analysis & Ultimate Analysis. Proximate analysis - to determine the moisture, ash, volatiles matter and fixed carbon

Generation of Fuel Model

The Energy content -- CFRI Formulae -- Low Moisture Coal(M < 2% ) -- CV (Kcal/kg) = 71.7 FC + 75.6 (VM-0.1 A) - 60 M High Moisture Coal(M > 2%) -- CV(kcal.kg) = 85.6 {100 - (1.1A+M)} - 60 M Where, M, A, FC and VM denote moister, ash , fixed carbon and Volatile mater (all in percent), respectively.

Commercial Use of Proximate Analysis

• Combustion: rapid oxidation of a fuel

• Complete combustion: total oxidation of fuel (adequate supply of oxygen needed)

• Air: 20.9 % oxygen, 79 % nitrogen and other

• Nitrogen: (a) reduces the combustion efficiency (b) forms NOx at high temperatures

• Carbon forms (a) CO2 (b) CO resulting in less heat production

Principles of Combustion

• Control the 3 Ts to optimize combustion:

• Water vapor is a by-product of burning fuel that contains hydrogen and this robs heat from the flue gases

1T) Temperature

2T) Turbulence

3T) Time

Principles of Combustion

Oxygen is the key to combustion

Principles of Combustion

Stochiometric air needed for combustion of furnace oil

Theoretical CO2 content in the flue gases

Actual CO2 content and % excess air

Constituents of flue gas with excess air

Theoretical CO2 and O2 in dry flue gas by volume

Stochiometric calculation of air required

Blending of coal • Used with excessive coal fines

• Blending of lumped coal with coal containing fines

• Limits fines in coal being fired to < 25 %

• Ensures more uniform coal supply

Preparation of Solid Fuels

Higher Heating Value (HHV) Correlations

Correlation Reference Correlation (HHV, MJ/kg)

Jimennez and Gonzalez [1] HHV = -10.81408 + 0.3133 (VM + FC)

Current authors HHV = -0.03 A - 0.11 M+ 0.33 VM + 0.35 FC

Demirbas [2] HHV = 0.196*FC + 14.119

Cordero et. al. [3] HHV = 0.3543× FC + 0.1708 × VM

Parikh et. al. [4] HHV = 0.3536 FC + 0.1559 VM -0.0078 A

S. No. Description Proximate Analysis

Higher Heating Value (MJ/kg)

Experimental Predicted TM VM Ash FC 1. Pe 5.73 34.6 31.6 28.0 20.38 21.54 (+ 5.38) 2. Pt 7.93 33.4 33.4 25.2 18.31 19.98 (+ 5.00) 3. Ep 8.32 42.7 19.0 30.0 23.77 24.23 (+ 1.89) 4. Ec 3.93 35.6 25.9 34.6 22.35 24.18 (+ 7.56) 5. Er 4.63 30.4 42.7 22.2 18.32 18.58 (+ 1.39) 6. Qi 3.24 24.5 54.3 17.9 14.56 15.63 (+ 6.84) 7. Ow 4.83 32.2 37.9 25.1 19.82 20.00 (+ 0.90) 8. Ot 2.21 16.2 72.2 11.3 11.76 11.24 (-4.42) 9. Om 4.58 10.2 24.7 60.4 22.66 24.74 (+ 8.24)

10. Sh 6.17 11.5 5.46 76.7 29.71 30.12 (+ 1.36) 11. CC1 3.70 27.6 6.40 62.3 28.88 30.69 (+ 5.89) 12. CC2 2.60 32.6 28.6 36.1 23.75 23.96 (+ 0.87) 13. CC3 4.85 37.0 12.1 46.0 28.23 28.13 (- 0.35) 14. CC4 5.00 27.2 36.1 31.7 20.07 20.60 (+ 2.57) 15. CC5 11.9 44.6 30.2 13.3 20.73 18.97 (- 4.96) 16. CC6 2.10 62.1 20.8 15.0 26.72 26.13 (- 2.20) 17. CC7 3.30 35.7 34.5 26.5 20.02 21.72 (+ 7.82) 18. CC8 2.60 32.4 41.7 23.3 20.83 19.81 (- 4.89) 19. CC9 4.60 30.8 30.2 34.4 20.38 22.60 (+ 7.83) 20. CC10 5.70 28.7 36.1 29.5 21.18 20.25 (- 4.39) 21. CC11 4.60 37.3 14.6 42.1 24.57 26.97 (+ 8.89) 22. CC12 4.90 34.6 18.6 39.2 21.40 23.19 (+ 7.71) 23. CC13 2.40 24.6 16.1 56.9 27.00 28.25 (+ 4.42) 24. CC14 3.70 27.7 19.4 49.2 19.55 19.93 (- 1.90) 25. CC15 6.90 31.2 17.9 44.0 23.14 25.47 (+ 9.14) **Parenthesis, the deviation from the experimental value (in %)

Proximate Analysis of Pakistan Coal (Punjab Coalfield)

**Parenthesis, the deviation from the experimental value (in %)

Higher Heating Value (HHV) Correlations Evaluation

S. ID.

Higher Heating Value (MJ/kg)

Experimental Correlation Predicted HHV

Jimennez and Gonzalez

Current authors Demirbas Cordero et. al.

Parikh et. al

Pe 20.38 28.02 (+27.2) 21.54 (+5.38) 19.60 (-3.82) 15.83 (-22.3) 14.94 (-26.6) Pt 18.31 24.85 (+26.3) 19.98 (+5.00) 19.05 (+3.88) 14.63 (-20.0) 13.76 (-24.8) Ep 23.77 32.56 (+26.9) 24.23 (+1.89) 19.99 (-15.9) 17.91 (-24.6) 17.00 (-28.4) Ec 22.35 34.93 (+36.0) 24.18 (+7.56) 20.90 (-6.48) 12.41 (-44.4) 17.45 (-21.9) Er 18.32 20.91 (+12.4) 18.58 (+1.39) 18.47 (+0.81) 13.05 (-28.7) 12.17 (-33.5) Qi 14.56 14.76 (+1.35) 15.63 (+6.84) 19.03 (+23.5) 10.52 (27.7) 9.66 (-33.6) Ow 19.82 24.37 (+18.6) 20.00 (+0.90) 19.03 (-3.98) 14.38 (-27.4) 13.50 (-31.8)Ot 11.76 5.56 (-52.7) 11.24 (-4.42) 16.33 (+28.0) 6.66 (-43.3) 5.96 (-49.3) Om 22.66 52.78 (+57.0) 24.74 (+8.24) 25.95 (+12.7) 23.12 (+1.98) 22.53 (-0.57) Sh 29.71 69.48 (+57.2) 30.12 (+1.36) 29.15 (-1.88) 29.11 (-2.01) 28.59 (-3.76) CC1 28.88 60.13 (+52.0) 30.69 (+5.89) 26.32 (-8.86) 26.76 (-7.34) 26.05 (-9.79) CC2 23.75 35.49 (+33.0) 23.96 (+0.87) 21.19 (-10.8) 18.34 (-22.7) 17.49 (-26.3) CC3 28.23 35.49 (+20.4) 28.13 (-0.35) 23.13 (-18.0) 22.60 (-19.9) 21.77 (-22.8) CC4 20.07 29.40 (+31.7) 20.60 (+2.57) 20.33 (-1.27) 15.35 (-23.5) 19.80 (-1.34) CC5 20.73 16.45 (-20.6) 18.97 (-4.96) 16.72 (-19.3) 12.32 (-40.6) 11.37 (-45.11) CC6 26.72 23.64 (-11.5) 26.13 (-2.20) 17.05 (-36.1) 15.91 (-40.4) 14.76 (-44.7) CC7 20.02 26.57 (+24.6) 21.72 (+7.82) 19.31 (-3.54) 15.47 (-22.7) 13.57 (-32.2) CC8 20.83 23.31 (+12.5) 19.81 (-4.89) 18.68 (-10.3) 13.78 (-33.8) 12.88 (-38.2) CC9 20.38 33.23 (+38.7) 22.60 (+7.83) 20.86 (-2.30) 17.43 (-14.4) 16.60 (-18.5) CC10 21.18 27.67 (+23.4) 20.25 (-4.39) 19.90 (-6.04) 21.24 (+0.28) 14.51 (-31.5) CC11 24.57 42.97 (+42.8) 26.97 (+8.89) 22.37 (-8.95) 21.27 (-13.4) 20.43 (-16.8) CC12 21.40 39.22 (+45.4) 23.19 (+7.71) 21.80 (+1.83) 19.78 (-7.57) 18.96 (-11.4) CC13 27.00 53.79 (+49.8) 28.25 (+4.42) 25.27 (-6.40) 24.34 (-9.85) 23.62 (-12.5) CC14 19.55 47.06 (+58.4) 19.93 (-1.90) 23.76 (+17.7) 22.14 (+11.7) 21.38 (+8.55) CC15 23.14 42.96 (+46.1) 25.47 (+9.14) 22.74 (-1.72) 20.90 (-9.68) 20.12 (-13.0)

Disclaimer and References

• This PowerPoint training session was prepared as part of the project “Coal Quality Evaluation and Beneficiation Project” sponsored by Coastal Saba Power Limited, Pakistan. Full references are included in the textbook chapter that is available on http://pk.linkedin.com./pub/dr-nasir-saqib

[1] Jimennez L, Gonzales F. Study of the physical and chemical properties of lignocelluloses' residues with a view of the production of fuels. Fuel 1991;70:947-50.

[2] Demirbas A. Calculation of higher heating value of biomass fuels. Fuel 1997;76:431-4

[3] Cordedo T, Marquez F, Rodriguez-Mirasol J, Rodriguez JJ. Predicting heating values of lignocellulosic and carbonaceous materials from proximate analysis. Fuel 2001;80:1567-71

[4] Parikh J, Channiwala SA, Ghosal GK. A correlation for calculating HHV from proximate analysis of solid fuels. Fuel 2005;84:484-94

Fuels & Combustion

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