Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Thermoneutral Point Analysis of Lignite Coal DryGasification

Chaitanya Gupta1 Varsha Choudhary1 Dr. Ganesh R Kale2

1Department of Chemical EngineeringIIT Bombay

2Chemical Engineering and Process Development divisionNational Chemical Laboratory

International Conference on Advances in Energy Research, 2013

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Outline

1 IntroductionDefinitionMotivationObjective

2 Schematic

3 Key Parameters

4 Data Simulation

5 Observations and FiguresFeed ConditionSyngas variationTNP AnalysisEnergy Optimization

6 Conclusion

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Definition

Definitions

Coal gasification → Process in which coal reacts with anoxidizer at high temperature to produce a fuel-rich product.

1 Oxidizers can be → H2O, CO2 and air.

2 CO2 involvment in oxidizer → Dry gasification

3 O2 involvement in oxidizer → Autothermal gasification

Thermonutral Point → Temperature at which reactionenthalpy becomes zero.

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Motivation

Why are we doing this process ?

CO2 emission → A major reason for climate change.

Utilizing CO2 in dry gasification of lignite coal to make fuelrich product

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Objective

Problem Formulation

Find optimum operating conditions of lignite coal drygasification with respect to

1 Change in pressure

2 Temperature

3 Feed compositions

Solution approach→ Thermodynamic analysis of the process

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Process Flow Diagram

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Key Parameters

Fuel → Lignite coal (C 73%, O 20%, H 5%, S 1%, N 1%)

Operating temperature range → 500− 1200 ◦C

Pressures → 1, 15, 30 bar

CCCR (Feed CO2 to carbon in coal ratio) → 1, 2, 3

OCCR (Feed O2 to carbon in coal ratio) → 0, 0.1, 0.2, 0.3

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Data Simulation

HSC Chemistry Package (Version 5.1)

1 Used for thermodynamic equilibrium study

2 Uses Gibbs free energy minimization algorithm to find theequilibrium compositions of species in a chemical reaction.

Input species → Coal composition, CO2(g), air(g)

Output species → H2(g), CH4(g), CO2(g), CO(g), NH3(g),H2S(g), H2O(g), H2O(l), C(s), S(s)

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Feed Condition

Feed Condition

S.no. Notation Composition

1. A1 OCCR=0, CCCR=1

2. A2 OCCR=0, CCCR=2

3. A3 OCCR=0, CCCR=3

4. B1 OCCR=0.1, CCCR=1

5. B2 OCCR=0.1, CCCR=2

6. B3 OCCR=0.1, CCCR=3

7. C1 OCCR=0.2, CCCR=1

8. C2 OCCR=0.2, CCCR=2

9. C3 OCCR=0.2, CCCR=3

10. D1 OCCR=0.3, CCCR=1

11. D2 OCCR=0.3, CCCR=2

12. D3 OCCR=0.3, CCCR=3

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Syngas variation

Syngas variation with Temperature, Pressure andComposition

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Syngas variation

Syngas variation with Temperature at Pressure = 1 bar

0.00

0.50

1.00

1.50

2.00

2.50

500 600 700 800 900 1000 1100 1200

Syng

as (m

oles

)

Temperature (0C)

A1

A2

A3

B1

B2

B3

C1

C2

C3

D1

D2

D3

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

TNP Analysis

TNP Calculation

-200

-150

-100

-50

0

50

100

150

500 600 700 800 900 1000

Reac

tion

Ent

halp

y

Temperature (0C)

A1

A2

A3

B1

B2

B3

C1

C2

C3

D1

D2

D3

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

TNP Analysis

TNP variation with Pressure

500.00

600.00

700.00

800.00

900.00

1000.00

0.00 5.00 10.00 15.00 20.00 25.00 30.00

TNPs

Pressure(bar)

A1

A2

A3

B1

B2

B3

C1

C2

C3

C1

C2

A1

C3

B3 A2

A3

B2

B1

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

TNP Analysis

Syngas moles variation at TNP

0.60

0.80

1.00

1.20

1.40

1.60

1.80

2.00

550.00 600.00 650.00 700.00 750.00 800.00 850.00 900.00 950.00

Mo

les

of

Syn

gas

pro

du

ced

at

TN

P

Temperature (0C)

P=1

P=15

P=30

A1

A2

A3

B1

B2

B3

C1

C2

C3

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

TNP Analysis

Syngas ratio variation at TNP

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

550.00 600.00 650.00 700.00 750.00 800.00 850.00 900.00 950.00

Syn

gas

rati

o a

t T

NP

Temperature(0C)

P=1

P=15

P=30

A1

A2

A3

B1

B2

B3

C1

C2

C3

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

TNP Analysis

Product compositions at TNP for Pressure = 1 bar

A1

A2

A3 B1 B2 B3 C1 C2 C3

TNP (0C)

640

595

568 677 628 602 703 652 625

CO(g)

0.5758

0.6084

0.6088 0.9958 1.0278 1.0523 1.4617 1.4709 1.5016

CO2(g)

0.7404

1.6977

2.6824 0.6505 1.6065 2.5789 0.5336 1.4987 2.4673

N2(g)

0.0061

0.0061

0.0059 0.3821 0.3819 0.3820 0.7583 0.7583 0.7583

C

0.6748

0.6872

0.7035 0.3479 0.3607 0.3646 0.0000 0.0265 0.0276

H2(g)

0.2389

0.1909

0.1636 0.2856 0.2314 0.2022 0.3198 0.2610 0.2299

H2O(g)

0.1488

0.2016

0.2318 0.1086 0.1645 0.1952 0.0766 0.1371 0.1691

CH4(g)

0.009

0.0067

0.0053 0.0058 0.0050 0.0042 0.0047 0.0039 0.0034

H2S(g)

0.0051

0.0051

0.0051 0.0051 0.0051 0.0051 0.0051 0.0051 0.0051

Syngas 0.8147 0.7994 0.7724 1.2814 1.2592 1.2545 1.7815 1.7319 1.7315

Syngas ratio 0.4149 0.3138 0.2687 0.2868 0.2251 0.1922 0.2188 0.1774 0.1531

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

TNP Analysis

H2O/CO Vs Temperature

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

500 600 700 800 900 1000 1100 1200

H2O/CO

Temperature

A1

A2

A3

B1

B2

B3

C1

C2

C3

D1

D2

D3

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Energy Optimization

Energy Optimization

Composition

Enthalpy of

Preheating

(KJ)

Extra steam

amount

(Moles)

Enthalpy for

extra steam

(KJ)

Total enthalpy of

Preheating (KJ)

Total enthalpy /

mole of syngas

(KJ/mole)

B1 61.2561 0.9868 66.9054 128.1615 100.0168

B2 84.1462 0.9661 63.3385 147.4848 117.1258

B3 106.7602 0.9623 62.3394 169.0995 134.7944

C1 74.0139 1.5313 105.4509 179.4648 100.7381

C2 97.1531 1.4809 98.9095 196.0626 113.2067

C3 120.359 1.4827 97.2947 217.6537 125.7024

Introduction Schematic Key Parameters Data Simulation Observations and Figures Conclusion

Results

Syngas yield decreases with increase in pressure.

C1 (OCCR 0.2, CCCR 1) is optimum composition for coalgasification from every aspect.

Applicability

1 Low syngas ratio can be used for petrochemicals manufacture.

2 High syngas yield can be used in SOFC.

Thank you