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Using CFD for Gasifier Components design

Shaoping Shi

Engineering Technical Leader

GE Energy

NETL 2011 Workshop on Multiphase Flow Science, Aug. 16-18, Pittsburgh, PA

©2011 GE ENERGY (USA) LLC AND/OR ITS AFFILIATES. All rights reserved. The information herein contained is GE's Gasification Confidential Technical Information and belongs to the General Electric Company, GE Energy (USA) LLC

and/or their affiliates, which have provided it solely for an express restricted private use. All persons, firms, or corporations who receive such information shall be deemed by their act of receiving the same to have agreed to

make no duplication or other disclosure or use whatsoever of any or all such information except as expressly

authorized in writing by the General Electric Company, GE energy (USA) LLC and/or their affiliates.

GRC Team (Greg Laskowski, etc.)

© 2011 General Electric Company. All Rights Reserved. This material may not be copied or distributed in whole or in part, without prior permission of the copyright owner.

Agenda

• Introduction: GE Energy & GE’s Gasification

• Examples on how GE is using CFD for designing gasifier components with multiphase flow science and Challenges we are facing

• Conclusion

A typical GE quench gasifier


• Drilling/production for … land, offshore, subsea

• LNG and pipelines

• Refining/petrochemical

• Industrial power gen

• Complete lifecycle services

Oil & Gas

GE Energy

Energy Services

• Thermal

• Renewables

• Nuclear

• Water treatment

• Process chemicals

Power & Water

• Contractual agreements

• Smart Grid

• Field services

• Parts and repairs

• Optimization technologies

• Plant management


GE Power & Water… power generation platforms

• Gas turbines

– Heavy duty (40–500MW)

– Aeroderivatives

(18-100MW)

– Combined cycle systems

• Gasification

– IGCC

– Gasification Licensing

Thermal

• ABWR & ESBWR

• Adv nuclear fuel

• CANDU fuel & services

• Reactor & field services

• Performance services

• Nuclear isotopes

Nuclear

• Wind

– Land based

– Offshore

• Solar

– Grid connected

– Stand alone

• Jenbacher

– Gas engines 0.3-3MW

– Fueled with waste gas

Renewables

• Steam turbines


Experience • Six decades of experience: 145 gasifiers operating worldwide

• First oil gasification plant in 1961

• First coal gasification plant in 1978

• First pet coke gasification plant in 1984

• 30 gas turbines operating on syngas … > 1 million operating hours

• IGCC leader… >3 GW with GE Energy technologies

• 40 projects globally that separate CO2

GE Gasification & IGCC Technology

Simple system configuration

• Proven Slurry system design

• Generate high H2/CO ratio

• Provides a size advantage for downstream systems



Gasifier Modeling (Design Methods)

Objective • Development & validation of robust, accurate &

practical gasifier design method (DM)

• Quantify model predictive capability.

Business Impact

• Enable design comparisons of new gasifier concepts .

• Meet future customer needs.

Model development approach

• Sub-model searching, evaluation, and development

• Sub-model verification/validation

• Lab test/Data collection to provide data for sub-model inputs or validation



Task Focal Schematic

Sub-model Integration into overall model

Sub-model and overall gasifier model Verification & Validation

Gasifier Modeling Overall Approach

Cells: 28 k Cells: 116 k Cells: 464 kCells: 23 k Cells: 94 k Cells: 370 kCells: 28 k Cells: 116 k Cells: 464 kCells: 23 k Cells: 94 k Cells: 370 k

Verification & Validation

Bench scale

Pilot scale

Kinetics model Flow-thermal model

Inputs, Thermo-physical

properties Char-slag flow

FLUENT Solver

Geometry/Mesh

Spray model

Lab - Plant scale

Sensitivity studies



Accomplishments Accomplishments

Developed a series of gasifier model versions corresponding to new features or lesson learned

Established & documented the best practices for model setup, execution & convergence criterions

Quantification of grid error

Quantification of plant BC sensitivity

Validation spanning bench scale to plant scale

Gasifier performance CTQ’s Relative Error

(Model / Plant data) Uncertainty of Plant

Data

Carbon conversion at exit 1% 2.25%

Syngas temperature at thermocouple <1 % 90 F

% Carbon in “total slag”* at gasifier exit (dry basis) 10%

Plant data available after lock-hopper

Syngas composition at scrubber overhead, dry basis

Plant data accuracy ± 1%

MOLE

CO2 5%

CO 5%

H2 5%

Static

temp., F

Not to scale

Example #1: Validation with a commercial plant:



Gasifier Modeling Challenges Model

• Char particle reaction kinetics need to cover wider feed stock

• Particle radiation model

• Radiation, turbulence, reaction interaction

• High pressure atomization

Data for validation High temperature measurement inside gasifier

Flame detecting

In-situ syngas composition measurement

Uncertainty of measurement

Public opinion • Difficult acceptance of CFD based analysis because the

lack of fully understanding of all the physics.

• Negative effect of some careless CFD work.

Sensitivity studies

Numerical error quantification

Sensitivity studies


Sensitivity studies


Engineering design requires quantitative information

Quench Design Method Development

Objective: Develop validated design methods to predict Quench/Scrubber

performance and optimize design and control

Ga

sifi

er

Qu

en

ch

Syngas With Possible

Entrained Water

Hot Syngas + Slag/Fines

Draft Tube

Dip Tube

Baffle

QUENCH CHAMBER

Using validated QG design methods to meet customer’s requests

• High throughput • Low cost • Stable operation

• Feasible to build • Satisfied transportation limit

Not to Scale


Approach and Challenges

Needs: at high pressure and high temperature • Droplet generation model; Liquid vaporization model • Droplet-solid particle interaction and droplet-droplet interaction model

Primary entrainment Secondary entrainment

0

10

20

30

40

50

60

70

80

90

100

0

50

100

150

200

250

300

350

400

450

500

700 750 800 850 900 950 1000

Scru

bber

Liqu

id Le

vel (

%)

Flow

Rat

es (m

3/h)

Time Mark

Flow Rates Condensate Water (top)

Condensate Water (bottom)

HP Grey Water

Scrubber Blowdown

Quench Flow

Scrubber level

Plant Data

Not to Scale

Approach:

• Optimize design of quench

internals.

• Test with lab scale rig

• Model developed based on physics

• Model validated on test rig and

commercial plant.


Conclusions

• Per advanced physics models combining with CFD, detailed insights can be discovered

• Validation and uncertainty quantification are critical

• Provide new tools for developing new technologies to meet customer’s needs.

• Yet, there are gaps: Physics models Measurement/Data collection

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