Impacts of Post-Combustion pCO2 Capture on Plant Performance –

A Case StudyA Case Study 12th Meeting of the International

Post-Combustion CO Capture Network

Chris van DrielAnindo Dey

Post-Combustion CO2 Capture Network

Anindo DeyDavid Cameron

30 S t b 200930 September 2009

Presentation Overview

• Acknowledgements• Existing Plant Performance• Existing Plant Performance • Modeling Integration and Methodology• Boiler Improvements/Upgradesp pg• Steam Turbine Improvements/Upgrades• Process Implications

C t f R ti St– Cost of Regeneration Steam– Heat Recovery– Flue Gas Water Consumptionue Gas ate Co su pt o

• Risk Assessment• Conclusion

Acknowledgements

This presentation is based on work that Stantec carried out in pconjunction with the SaskPower Clean Coal Team.

Potential performance improvements described herein are only those that have been analyzed using a generic CO capture system and indicative unit performanceanalyzed using a generic CO2 capture system and indicative unit performance.

All design improvements are still under consideration.

Existing Plant Performance Boundary Dam Power StationBoundary Dam Power Station

• Boundary Dam located in Saskatchewan, CanadaB d D C i f Si U it• Boundary Dam Comprises of Six Units

• Current CCS demonstration work focused on Unit 3– Pulverized Coal BoilerPulverized Coal Boiler– 150 MWe Gross Tandem-Compound HIP-LP Steam Turbine

Courtesy of SaskPower

Existing Plant PerformanceBoiler and Turbine PlantBoiler and Turbine Plant

• Steam Generator:P l eri ed Coal Balanced draft Tangentiall fired Unit– Pulverized Coal, Balanced draft, Tangentially fired Unit

– Tubular PA Heater, Rotary SA Heater– Design MCR Rating – 1050 mlb/hr, 1000 ºF/1000 ºF

• Steam Turbine:– GE Tandem-Compound HIP-LP

Six Feedwater Heaters (incl 1 DA)– Six Feedwater Heaters (incl. 1 DA)

HP IP LP

Modeling Integration and MethodologySoftware

• Software Packages - GateCycleTM and ProMax®

G t C l (GE E )

Software

• GateCycle (GE Energy):– Power Island Modeling

• Boiler & Steam Turbine– CO2 Capture

• Flue Gas & Simplified Capture Systems– CO2 CompressionCO2 Compression

• Compressors w/ Simplified Dehydration

• ProMax (BR&E):CO2 C t– CO2 Capture

• Flue Gas & Capture Systems – CO2 Compression

• Compressors w/ Detailed Dehydration

Modeling Integration and Methodology(con’t)(con t)

M t d lli i t• Most modelling is system specific, completed in smaller auxiliary models. Steam Flue Gas

SteamGenerator

y• Overall plant performance

and integration with master model

Turbine System

MasterModel

model.• Both software packages

can interface can through

FG Pre-Treatment

CO2

CO2Capture

gExcel. Comp.

Modeling Integration and MethodologyCO2 Capture System Modelling AssumptionsCO2 Capture System Modelling Assumptions

CO2 Capture Plant Modeling Assumptions:Monoethanolamine 30 Wt% Base Case– Monoethanolamine 30 Wt% - Base Case

– Saturated gas from DCC supplied to absorber– Absorber outlet stream vented to atmosphere– Reflux drum outlet stream to compression plant

• CO2 Compression Unit Modeling Assumptions:CO2 Compression Unit Modeling Assumptions:– Six (6) stages of wet, two (2) stages of dry compression– Dehydration/Dryer Unit– Approx. 2500 psia at pipeline

Boiler Improvements/UpgradesObjectivesObjectives

• Overall objectives:– Increase Steam/Electrical Generation– Minimize Air Heater Leakage

Li it d t iti f it i d• Limited opportunities for capacity increases due to existing structure.Possibility to increase steam conditions• Possibility to increase steam conditions

• Alter air heater arrangement and design –accommodate heat recoveryaccommodate heat recovery

Boiler Improvements/Upgrades(con’t)(con t)

• Limited opportunities for capacity increases due t i ti t tto existing structure.– Optimization of increased number of tubes spacingnumber of tubes, spacing, and sizing in SH/RH and Econ– Air heater performance

ECAir heater performance

upgrades and new potentialarrangements

SH/RH

PAHg– Potential efficiency improvement of ~ 0.3 – 4.5 Pts SAH

Boiler Improvements/Upgrades(con’t)(con t)

• Possibility to increase steam conditions – Pressure:

• No opportunity to increase existing pressure operation [1800 psig (12.5 MPa)] [ p g ( )]

– Temperature: • Opportunity exists to increase existing temperature

operation from 1000 ºF (538 ºC)operation from 1000 F (538 C) • Potential new operating temperature for main and reheat

steam of 1050 ºF (566 ºC)B il ffi i i l ti l t t h d• Boiler efficiency remains relatively constant, enhanced T-G performance and unit heat rate

Boiler Improvements/Upgrades(con’t)(con t)

• Alter air heater arrangement and design –d t h taccommodate heat recovery

– Air preheating upstream of air heaters delivers increased efficiency potential 0 3 - 1 % Pt increaseincreased efficiency, potential 0.3 - 1 % Pt increase.

80 ºF80 250 ºFPA IN

SA IN

80 ºF

80 ºF

80 - 250 ºF

80 - 250 ºF

Steam Turbine Improvements/UpgradesObjectivesObjectives

• Overall objectives:– Increased Power Generation / Efficiency– Minimize Cycle Impact of Regeneration Steam

E i ti ST G i b ild d b• Existing ST-G requires rebuild and can be re-designed to accommodate new regen extractionPossibility to increase steam conditions >1000ºF• Possibility to increase steam conditions >1000ºF

• Possibility to employ condensate preheating from heat recoveryfrom heat recovery

Steam Turbine Improvements/Upgrades(con’t)(con t)

• Existing ST-G requires rebuild and can be re-d i d t d t t tidesigned to accommodate new regen extraction– Improve stage efficiencies and heat rate over existing

Potential use of uncontrolled extraction to limit losses– Potential use of uncontrolled extraction to limit lossesSTEAM TO PROCESS

EXISTING 1000 ºF / 1000 ºF

HP IP LPPOTENTIAL GROSS OUTPUT INCREASE

OF 3 - 4 %

Steam Turbine Improvements/Upgrades(con’t)(con t)

• Possibility to increase steam conditions >1000ºF– Opportunity exists to operating temperature for main

and reheat steam from 1000 ºF (538 ºC) to 1050 ºF(566 ºC)(566 C)

STEAM TO PROCESS

POTENTIAL 1050 ºF / 1050 ºF

HP IP LPPOTENTIAL GROSS OUTPUT INCREASE

OF 0 5 - 1%OF 0.5 1%

Steam Turbine Improvements/Upgrades(con’t)(con t)

• Possibility to employ condensate preheating f h t (HP & LP)from heat recovery (HP & LP)

HP100% >1% >2% >3%

HP > 5% >1 5% >2 5%50% >.5% >1.5% >2.5%

HP0% BASE >1% >2%

HP IP LP

LP0%

LP50%

LP100%

LP PREHEATHP PREHEAT Potential % Increase in Gross GenerationPotential % Increase in Gross Generation

Process ImplicationsOverviewOverview

• Regeneration Steam• Heat Recovery• Flue Gas Water Consumption• Condenser Off-loading• Booster Fan

Process ImplicationsCost of Regeneration SteamCost of Regeneration Steam

• Regeneration Steam Impacted by:Req ired press re and heat d t at reboiler + line losses– Required pressure and heat duty at reboiler, + line losses

– ‘Cost of Steam’ kWe per lb/hr or MBtu(MWth)

Gross GenerationImpact (kW / MBtu/hr)

Increasing Process Steam

Pressure

Condensate Return Temperature

Process ImplicationsCost of Regeneration Steam (con’t)Cost of Regeneration Steam (con t)

• Regeneration Steam Impacted by:Partial Load Performance Red ced P/T Q alit– Partial Load Performance – Reduced P/T Quality

Process Steam Pressure

Process SteamTemperature%

MCR

% MCR

Process Steam Extraction Flow

Process ImplicationsHeat RecoveryHeat Recovery

• Heat Recovery– Flue Gas Coolers

ABSORBERINLET

DCCSO2REMOVAL

FGC

ID FANESPBOILER

A/H OUTLETDCC

– CO2 Capture and CompressionREFLUX

CONDENSER STAGECONDENSER

CWSTRIPPER

COMPRESSIONINLET

STAGEINLET

CWTYPICAL INTERSTAGE COOLER

STAGEOUTLET

Process ImplicationsHeat Recovery (con’t)Heat Recovery (con t)

• Heat Recovery - Sources and SinksTotal Heat Duty (HOT)

Temperature

Total Heat Duty (COLD)

HPCP LPCP SA PA RH

Heat Rejection Required

Process ImplicationsFlue Gas Water ConsumptionFlue Gas Water Consumption

• Water Consumption DCCSO2REMOVAL

DCC

100% Saturation Curve

FGC

Humidity

Curve

y(lb H20 /

lb Dry Gas)

FG INFGD

DCC

FG IN

FG OUTFGC

Temperature

Process ImplicationsOtherOther

• Condenser Off-loading– During process extraction, condenser heat duty is

reduced significantly (~ 25 – 45%)• Booster Fans• Booster Fans

– Required to reuse existing ID fan, maximize use of existing infrastructure.g

Risk AssessmentOverviewOverview

• Prior experience in amine systems

• Bowtie Analysis

• Hazard Identification (HAZID)

• Preliminary Hazard & Operability studies (HAZOP)

• Sensitivity Studies

Risk AssessmentBow-tie AnalysisBow tie Analysis

• Can be applied to assess performance risk of a first-of-its kind technologyits-kind technology

• Bow-tie diagram – Event (or hazards) shown as knot in the middle, threats on the ( )

left; consequences on the right

• Identifies threats and control measures in engineering design for mitigation of threatsdesign for mitigation of threats

• List the control measures for mitigation of potential consequences during commissioning/operational stage

• Assess impact on project capital cost, project schedule and operating costs

Risk AssessmentBow-tie DiagramBow tie Diagram

EVENT

THREAT CONSEQUENCETHREAT CONSEQUENCE

Risk AssessmentBow-tie Diagram - Threat IdentificationBow tie Diagram Threat Identification (Left side of the knot)

• Identify the hazards or the undesirable EVENTS• Suggest Controls to mitigate the hazards or undesirable events• Identify new threats for the suggested controls• Identify new threats for the suggested controls• Suggest Controls for the threats

Risk AssessmentBow-tie Diagram - Consequence IdentificationBow tie Diagram Consequence Identification(Right side of the knot)

• A consequence occurs if the hazard is breached and nohazard is breached and no action is taken to recover from the issue

• Suggest controls to the ggconsequences arising out of the undesirable events or hazardsC b• Consequences can be customized to reflect the need of the exercise

• Develop Risk Matrix for:Develop Risk Matrix for:– People, Assets, Environment,

Unplanned Outage– Construction / Commissioning

Phase– Operational Phase

Conclusion

• With the large heating, cooling, and power demands of a CO2capture and compression system, system integration andcapture and compression system, system integration and optimization is paramount.

• Modelling plant systems facilitates integration, along with identification and qualification of opportunities.identification and qualification of opportunities.

• A combination of boiler and turbine improvements, coupled with heat recovery, have the potential to increase plant efficiency by over 10%. Initial projections placed the net generation at capture at 10010%. Initial projections placed the net generation at capture at 100 MWe, current projections are at 115 – 120 MWe.

• Increased heat recovery can improve cycle efficiency and also reduce water consumptioneduce ate co su pt o

• Increased integration represents increased risks, which require proper threat and consequence identification for mitigation.

Questions

Chris van Driel, P.Eng., M.Sc.E. – Heat and Mass BalanceAnindo Dey, P.Eng., MASc(Engg.), MBA – CO2 Capture and Compression

David Cameron, P.Eng., Senior Principal – Project Executivechris.vandriel / anindo.dey / david.cameron / @stantec.com

30 September 2009