modeling-based evaluation of gasification processes for

TU Bergakademie Freiberg I Institute of Energy Process Engineering and Chemical Engineering Reiche Zeche I 09596 Freiberg I Tel. +49(0)3731/39 4511 I Fax +49(0)3731/39 4555

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Department of Energy Process Engineering and Chemical Engineering

Modeling-based Evaluation of Gasification Processes for High-Ash Coals

Martin Gräbner, Bernd Meyer

5th International Freiberg Conference on IGCC & XtL Technologies

May 21-24 2012 – Leipzig, Germany (Paper 11-1)

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Outline

1. Trends in coal gasification development

2. Approach of this study

3. Results

• The influence of ash content

• Exergetic analysis

4. Conclusion

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1 – Trends in coal gasification development

Sasol or Lurgi/AL dry ash

BGL (Enviro-therm)

Entrained-Flow Processes

Fixed-Bed Processes

Available Gasification Technologies

Accroding to Gräbner, M. et al. Energy Strategy Reviews, 2012 (submitted).

U-Gas(GTI)

HTW (Uhde)

Fluidized-Bed Processes

TRIG (KBR)

Shell

GE Energy

(Texaco)

Siemens (GSP)

Prenflo (Uhde)

OMB (ECUST)

Clean Coal Gasifier

(Choren)

Mitsu-bishi

(MHI)

HT-L Tsinghua 2-stage-oxygen

TPRI 2-stage-

coal

Phillips 66 (E-Gas)

MCSG (NRI)

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Phillips 66 – E-STR Entrained slagging transport reactor

Prenflo – full water quench

[14]

Shell – partial water quench

Siemens – radiant coolerLurgi/AL – Mark+

PWR – compact gasifier

New concepts for traditional technologies New concepts

etc.

GE – posimetric feeding system

[1] de Graf, J. D.: Shell Coal Gasification Technology, EindhovenUniv. of Tech., NL, 23.9.2008[2] PRENFLO Broshure 2nd Edition, Uhde GmbH, Gelsenkirchen27.8.2009[3] Amick, P: ConocoPhillips Technology Solutions: GasificationUpdate, GTC Annual Conference, 2004[4] Zuiker, J.R.: Building on History…the Next Generation ofTechnology, GTC Annual Conference, 2009[5] Weiss, M-M.: A new HP version of Lurgi´s FBDBTM gasifier isbringing more value to clients, GTC Annual Conference, 2011[6] Morehead, H.: Siemens IGCC and Gasification Update. GTCAnnual Conference, 2010.[7] A. Darby. Status of the Pratt & Whitney Rocketdyne/DOEAdvanced Single Stage Gasifier Development Program. GTC AnnualConference, 2005.

[2]

[1]

[3] [4]

[5] [6]

[7]

INCI – internal circulating gasifier

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Reduction of capital costs

Adaptation to low- grade feedstock

Increase in efficiency

Increase in single unit capacity

Integration of dry feed solid pumps

Inclusion of syngas cooler in

portfolio

Increase in single-pass carbon

conversion

Migration from slurry to dry feeding

or slurry drying

Inclusion of full water quench in

portfolio

Increase in gasification

pressure

New concepts

Lurgi FBDB

P66 Prenflo

Shell

INCI P66

P66

GE

HTW

Siemens

PWR GE

GE Siemens Overview on technology development drivers

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2 – Approach of this study

Coal (Pitt#8/SAf)

H2O

O2

Gasifiers

Coal H2O

O2 Ternary Gasification

Diagram

Results of generic modeling

Results of adiabatic equilibrium calculations (30 bar)

Temparture & carbon conversion

Syngas yield & H2/CO ratio

Cold gas efficiency & dry CH4 yield

Selectivity of CO/C & CH4/C

Location of gasifiers, maxima, operation domains and assessment of potential Gräbner, M.; Meyer, B.: Introduction of a ternary diagram for comprehensive evaluation of gasification processes for ash-rich coal, Fuel (in press), 2012

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Unified boundary conditions for gasifier modeling

Technology Verification data Shell Rich et al. [9] Siemens Babcock [10] GE McDaniel [11] Phillips 66 Woods et al. [12] HTW Bellin et al. [13]

[8] Miller, B.G. and Tillman, D.A. Combustion Engineering Issues for Solid Fuel Systems, Academic Press, 2008.[9] Rich, J.W. et al. WMPI - Waste Coal to Clean Liquid Fuels. Gasification Technologies Conference, 2003.[10] Deutsche Babcock. Kombikraftwerk mit GSP-Flugstromvergasung. Deutsche Babcock Werke AG Brochure, 1992.[11] McDaniel, J. Polk Power Station 250 MW IGCC. Compact Course Gasification, TU Bergakademie Freiberg, November 2008.[12] Woods, M.C. et al. Cost and Performance Baseline for Fossil Energy Plants, Volume 1, DOE/NETL-2007/1281, National Energy Technology Laboratory, 2007.[13] Bellin, A. et al. Kohlevergasung im Hochtemperatur-Winkler-Vergaser. Technical Report FK 03E1092C, Rheinbraun AG, 1988.

Coal (abbreviation) South Africa Pittsburgh #8

Coal rank (ASTM [8]) HV C Bit. HV A Bit.

Moisture wt% 6.0 2.4

Proximate analysis (dry basis)

Ash wt% 25.0 10.2

Volatiles wt% 23.0 36.1

Fixed carbon wt% 52.0 53.7

Ultimate analysis (dry & ash free basis)

Carbon wt% 80.0 83.3

Hydrogen wt% 4.0 5.7

Oxygen wt% 13.0 8.3

Nitrogen wt% 2.0 1.4

Sulphur wt% 1.0 1.3

Calorific Value (dry basis)

Lower Heating Value MJ/kg 21.9 31.5

Exergy reference environment:

T0 = 25°C, p0 = 1013.25 hPa Water is in the liquid state. Dry atmosphere: 78.1 vol% N2,

21.0 vol% O2 and 0.9 vol% Ar Chemical exergies of substances

containing C, S and N are in inhibitedequilibrium with the environment in theiroxidized state (CO2, SO2, NO).

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Unified boundary conditions for gasifier modeling Parameter Value Comment / Reference

Pressure 30 bar Suitable for IGCC and several syntheses

Temperature 1550/1450 °C > 100 K above ash fluid temperature for slagging systems

Thermal capacity 500 MW Coal input on LHV basis

Coal/N2 temperature 25 °C N2: 99.96 %vol purity, +3 bar above reactor

Coal/transport gas 350 kg/m³(eff.) Higman and van der Burgt [14], Schingnitz [15]

Solids in slurry 65 %wt Hornick and McDaniel [16]

Slurry temperature 120 °C Valenti [17]

O2 purity 95 %vol Residual: 3 %vol Ar, 2 %vol N2

O2 temperature 240 °C +3 bar above reactor

Moderator steam 37 bar / 246 °C Saturated

Quench water 37 bar / 175 °C Preheating for high raw gas moisture

IP steam 37 bar / 246 °C No superheating

HP steam 140 bar / 377 °C von Morstein et al. [18]

[14] Higman, C. and van der Burgt, M. Gasification. Elsevier Science, New York, 2003.[15] Schingnitz, M. G SP-Verfahren, In: Die Veredlung und Umwandlung von Kohle, Technologien und Projekte 1970 bis 2000 in Deutschland, 537–552. DGMK, 2008.[16] Hornick, M.J. and McDaniel, J. TECO Polk Power Station IGCC Project - Final Report. Technical Report DE-FC-21-91Mc27363, Tampa Electric Company, Polk Power Station, 2002.[17] Valenti, M. Bringing coal into the 21st century. Mechanical Engineering, 117(2), 1995.[18] von Morstein, O. et al. Verbessertes IGCC-Kraftwerk ohne und mit CO2-Abtrennung, Endbericht COORIVA. Technischer Bericht AP2001, FK 0327700A, 2009.

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3 – Results: Understanding the influence of ash content

Cold gas efficiency (CGE)

Operation area, whereCGE > 80%, becomessmaller and shifts belowash fluid temperature withincreasing ash content

Single-stage slagginggasifiers cannot beadapted!

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Cold gas efficiency (CGE)

Slurry gasifiers are not suitable for high ash contents,dry-feed slagging system lose approx. 6 %-pts. in CGE

Except for Siemens and Shell (only gas cooling is changed), all new concept show improvements

Fluidized-bed processes are most independent from ash content

INCI concept optimal for ash contents between 15 and 35 wt%(wf)

Standard systems New concepts


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Syngas yield (SGY)

Operation area whereSGY > 2 m3/kg becomessmaller and shiftssignificantly below ash fluidtemperature withincreasing ash content

Again single-stage slagginggasifiers cannot beadapted!


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Syngas yield (SGY)

High SGY up to 25 wt%(wf) ash for dry-fed entrained-flow gasifiers

Significant improvements in the new concepts of GE and INCI

E-STR concept improves with increasing ash content

Traditional fluidized-bed processes (HTW) operate on a lower level

INCI concept optimal for ash contents >40 wt%(wf)


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3 – Results: Exergetic analysis

Exergy losses in gas cooling (in standard designs)

Siemens P66

GE-R Shell

GE-RC

Siemens: -37.7% thermo-mechanical (tm.) exergy lossdue to full water quench

P66: chemical qunech allowspart of the tm. exergy to beconverted to chemical exergy

GE-R: in fouling-safe radiantcooler-only design 32.5% tm.exergy recovery by steamgeneration

Shell: the cold gas quenchcauses an tm. exergy loss of-7.2%

GE-RC: 51.6% of tm. exergy canbe recovered employingradiant and convective syngascooling (e.g. Polk IGCC)

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Understanding the influence of ash content – Syngas Yield (SGY)

3 – Results: Exergetic analysis

All new concept except the full water quench design from Shell lead to improved overallexergetic efficiency of the systems

Improvements become more significant with increasing ash content of the coal

INCI concept has the highest potential for high-ash coals

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4 – Conclusion

Processing of high-ash coals (esp. fines): Development of high-conversion fluid-bed gasifiers is recommended

INCI concept shows:

Advantages in terms of cold gas efficiency at ash contents of 15-35 wt%(wf) and syngas yield at >40 wt%(wf)

The highest exergetic efficiency of all concepts

highest potential for high-ash coals

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End of Presentation

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