M.Sc. Andreas Geißler, M.Sc. Markus Steibel, M.Sc. Federico Botteghi,

Prof. Hartmut Spliethoff

Institute for Energy Systems

Technical University of Munich

8th International Freiberg Conference on IGCC & Xtl Technologies

Experimental Investigation of the

Entrained Flow Gasification of a

Bituminous Coal and a Lignite

2

1 Motivation and Aim of this Work

3 Experimental Equipment and Experiment Matrix

5 Conclusion and Future Aspect

• Pressurized High Temperature Entrained Flow Reactor (PiTER)

Agenda

4 Results

• High Pressure Thermogravimetric Analyzer (PTGA)

2 Experimental Procedure

3

1 Motivation and Aim of this Work

Motivation

• Entrained flow gasification for high conversion rates

• Fuel properties (e.g. coal rank) and gasification conditions influence conversion

behavior

• Detailed knowledge of occurring phenomena during gasification important for

design and performance of efficient gasifiers

Experimental data for coals of different rank at conditions comparable to

industrial gasifiers necessary for understanding the conversion process and

designing gasifiers

CO2

CxHy

CO

H2O

Soot

H2

Tars Ash

Reaction gas

Fuel

CO2

H2O

O2

CO H2

Synthesis gas

Pyrolysis Gasification

Aim of this work

• Experimental investigation of entrained flow gasification for two fuels at high

temperatures (up to 1600 °C) and high pressures (up to 2.0 MPa)

• Comparison of devolatilization and gasification behavior (overall conversion)

• Focus on char properties (reactivity and surface area) of the collected samples

Comparison of char surface area at different pyrolysis conditions

Comparison of intrinsic kinetic data of representative char samples

determined in thermogravimetric analyzers (Regime I)

Determine and compare the behavior of the fuels in regard to thermal

annealing

4

TGA: Intrinsic

Parameters

Entrained Flow

Conditions

Obtain insights of the gasification behavior of

two fuels at condition comparable to industrial

scale gasifiers

1 Motivation and Aim of this Work

5

2 Experimental Procedure

Char Sample

Lab Analysis

• Proximate and Ultimate Analysis

• Surface Area Measurement

Thermogravimetric Analyzers

• Char gasification kinetics

• Obtain intrinsic kinetic data for different

gasification agents

Pressurized Entrained Flow Reactor

Devolatilization and Gasification Experiments

FuelAsh

ContentMoisture

Volatile

ContentCarbon Hydrogen Nitrogen Sulfur

wt% (dry) wt% (ar) wt% (dry) wt% (dry) wt% (dry) wt% (dry) wt% (dry)

Bit. Coal 8.44 4.35 38.46 68.14 4.82 1.37 0.64

Lignite 5.77 10.07 52.90 63.43 4.77 0.62 0.75

6

Fuel Feeding

Gas inlet

QuenchSampling probe

Technical Data

Gasification AgentsAr, N2, O2, CO2,

H2O

Max. Temperature 1800 °C

Max. Pressure 5.0 MPaReaction

tube

Ga

s P

reh

ea

tin

gR

ea

ctio

n z

on

e

3 Experimental Equipment

Pressurized High Temperature Entrained Flow Reactor (PiTER)

Evaluation: Ash-Tracer-Method

𝑋𝑂𝑣𝑒𝑟𝑎𝑙𝑙 =𝑚0,𝑑𝑎𝑓 −𝑚 𝑑𝑎𝑓

𝑚0,𝑑𝑎𝑓=

1 −𝑥0,𝐴𝑠ℎ𝑥 𝐴𝑠ℎ

1 − 𝑥0,𝐴𝑠ℎ

7

3 Experimental Equipment

Thermogravimetric Analyzer

Technical Data

Gasification AgentsAr, N2, O2, H2,

CO2, H2O, CO

Max. Temperature 1000 °C

Max. Pressure 5.0 MPa

Gas

inlet

Heating

Element

Sample

Beam Balance

Up to 100 % vol. of gasification agent

concentration

𝑟𝑜𝑏𝑠 = −1

𝑚𝑡

𝑑𝑚𝑡

𝑑𝑡

𝑋 𝑡 =𝑚0 − 𝑚𝑡

𝑚0

8

3 Experiment Matrix

PiTER:

• Pyrolysis experiment: Gas residence time between 0.4–2.4 s in N2

• Gasification experiments:

Constant O/C-Ratio of 1

CO2-Gasification: Constant partial pressure of 0.2 MPa

Thermogravimetric Analyzers:

• PTGA:

Lignite and Bit. Coal char from PiTER experiments at similar conditions

Investigated temperatures determined by heating rate experiments

• ATGA (atmospheric):

Pyrolysis chars: 5% O2; constant temperature: 375 °C Lignite, 425 °C Bit. Coal

Reactivities in relation to reactivity of reference char (according to DIN 51720)

9

4 Results

Pyrolysis Experiments at Different Pressures and Temperatures

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3

Ove

rall

Co

nve

rsio

n [

-]

Residence Time [s]

Bit. Coal - Pyrolysis

1200 °C; 0.5 MPa

1200 °C; 1.0 MPa

1200 °C; 2.0 MPa

1400 °C; 0.5 Mpa

• Higher volatile content of lignite

• Bit. Coal: Release of volatiles completed for every investigated residence time

• Lignite: Influence of temperature and residence time detectable

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3

Ove

rall

Co

nve

rsio

n [

-]

Residence Time [s]

Lignite - Pyrolysis

1200 °C; 1.0 Mpa

1200 °C; 2.0 Mpa

1400 °C; 0.5 Mpa

1400 °C; 1.0 Mpa

1400 °C; 2.0 Mpa

1600 °C; 0.5 Mpa

10

4 Results

Pyrolysis Experiments at Different Pressures and Temperatures

0

50

100

150

200

250

300

350

400

450

500

0 1 2 3

Spe

cifi

c su

rfac

e a

rea

[m2/g

]

Residence Time [s]

Bit. Coal - Surface area

1200 °C; 0.5 MPa

1200 °C; 1.0 MPa

1200 °C; 2.0 MPa

1400 °C; 0.5 MPa

• Surface areas decrease with increasing residence time

• Bit. Coal: Higher temperature leads to a lower surface area

• Lignite: Chars more sensititve to reaction conditions

0

50

100

150

200

250

300

350

400

450

500

0 1 2 3

Spe

cifi

c su

rfac

e a

rea

[m2 /

g]

Residence Time [s]

Lignite - Surface area

1200 °C; 1.0 MPa

1200 °C; 2.0 MPa

1400 °C; 0.5 MPa

1400 °C; 1.0 MPa

1400 °C; 2.0 MPa

1600 °C; 0.5 MPa

11

4 Results

O2-Gasification at Different Temperatures:

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3

Ove

rall

Co

nve

rsio

n [

-]

Residence Time [s]

Lignite - O2-Gasification

1000 °C; 0.5 MPa

1400 °C; 0.5 MPa

1600 °C; 0.5 MPa

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3

Ove

rall

Co

nve

rsio

n [

-]

Residence Time [s]

Bit. Coal - O2-Gasification

1200 °C; 0.5 MPa

1400 °C; 0.5 MPa

1600 °C; 0.5 MPa

• Temperature and residence time influence detectable

• Bit. Coal: Overall conversion of 80% reached

• Lignite: Overall conversion of 95% reached

12

4 Results

CO2-Gasification at Different Pressures and Temperatures:

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3

Ove

rall

Co

nve

rsio

n [

-]

Residence Time [s]

Lignite - CO2-Gasification

1000 °C; 0.5 Mpa

1000 °C; 1.0 MPa

1000 °C; 2.0 MPa

1400 °C; 0.5 Mpa

1400 °C; 1.0 MPa

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3

Ove

rall

Co

nve

rsio

n [

-]

Residence Time [s]

Bit. Coal - CO2-Gasification

1200 °C; 0.5 MPa

1400 °C; 0.5 MPa

• Temperature and residence time influence detectable

• Bit. Coal: Temperature of 1200 °C too low for the CO2-Gasification

• Lignite: More reactive than Bit. Coal

13

4 Results

• Determine intrinsic kinetic data

• Modeling with Arrhenius- and Power-Law Approach

• Heating rate experiment for determining temperatures for isothermal experiments:

• Reactivity of Lignite significantly higher than for Bit. Coal

• Reactivity towards H2O-gasification for both fuels higher than to CO2-gasification

HPTGA: Char from PiTER-Experiments (2.0 MPa, 1200 °C, 2.5 s)

𝑟𝑜𝑏𝑠𝑒𝑟𝑣𝑒𝑑 𝑋, 𝑇, 𝑝𝑖 = 𝑆 𝑋 ∙ 𝑟𝑖𝑛𝑡 𝑇 ∙ 𝑝𝑖𝑛 = 𝑆 𝑋 ∙ 𝑘0 exp −

𝐸𝐴

𝑅∙𝑇∙ 𝑝𝑖

𝑛

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 200 400 600 800 1000 1200

r ose

rved

(g/g

/min

)

Temperature [°C]

Heating rate experiment CO2

KOL

TBK

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 200 400 600 800 1000

r ose

rve

d(g

/g/m

in)

Temperature [°C]

Heating rate experiment H2O

KOL

TBK

14

4 Results

HPTGA: Char from PiTER-Experiments (2.0 MPa, 1200 °C, 2.5 s)

FuelActivation Energy [kJ/mol] Reaction order [-]

CO2 H2O CO2 H2O

Bit. Coal 205 212 0.70 0.43

Lignite 187 166 0.47 0.24

• Reaction order: Bit. Coal more sensitive to partial pressure of gasification agent

• Activation energy: Less temperature dependency of the reaction with lignite

00.10.20.30.40.50.60.70.80.9

1

0 100 200 300 400 500

Car

bo

n C

on

vers

ion

[-]

Residence time [min]

Lignite: CO2-Gasification (675 °C, 2.0 MPa)

0.5 MPa

1.0 MPa

2.0 MPa

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 100 200 300 400 500 600

Car

bo

n c

on

vers

ion

[-]

Residence time [min]

Bit. Coal: CO2-Gasification (800 °C, 2.0 MPa)

0.5 MPa

1.0 MPa

2.0 MPa

15

4 Results

ATGA: Thermal Annealing of Different Pyrolysis Chars

0

20

40

60

80

100

120

140

160

0 1 2 3

r in

trin

sic/

r Ref

,intr

insi

c

Residence time

Lignite - Annealing

1000 °C; 2.0 MPa

1200 °C; 1.0 MPa

1400 °C; 0.5 MPa

1400 °C; 1.0 MPa

1400 °C; 2.0 MPa

1600 °C; 0.5 MPa

• Reactivity reduced with increasing temperature and residence time during pyrolysis

• Lignite much more sensitive to temperature and residence time influence

• No pressure influence detectable

0

1

2

3

4

5

6

0 1 2 3

r in

trin

sic/

r Ref

,intr

insi

c

Residence time

Bit. Coal - Annealing

1200 °C; 0.5 MPa

1200 °C; 1.0 MPa

1200 °C; 2.0 MPa

1400 °C; 0.5 MPa

Reactivites of char samples is reduced by thermal annealing:

16

5 Conclusion and Future Aspects

Future Aspects

• Transfer intrinsic kinetic data with effectiveness-factor approach to entrained flow

conditions (Regime II and III)

• Use data for model validation

• Test further coals (other ranks such as anthracite) or biomass

• Create databank with kinetic data and further parameters relevant for gasification

• Data of experiments at high temperature and pressure are presented

• Pyrolysis behavior and surface area development shows higher sensitivity to

operation parameters for the lignite than for the bituminous coal

• Higher reactivity of lignite → Higher conversion of the lignite at equal conditions

Obtained data can be used for designing large scale applications

according to the fuel rank

Conclusion

17

Thank you for your Attention!

M.Sc. Andreas Geißler

andreas.geissler@tum.de

+49 (0) 89 287 16263

Institute for Energy Systems

Technical University of Munich

This work is part of a project supported by the German Federal Ministry of Economics and Technology and

industrial partners (AirLiquide, RWE, EnBW, Vattenfall and Siemens Fuel Gasification) under the

Contract Number: 0327773A.