Post Combustion CO2 Capture Scale Up Study

Prachi Singh and Mike HainesInternational Greenhouse Gas R&D programmeg

6th International Conference on Clean Coal Technologies (CCT 2013)12-16th May 2013

Thessaloniki GreeceThessaloniki, Greece

Email: PRACHI.SINGH@IEAGHG.ORG

Challenges for Post Combustion Capture (PCC) •High energy requirement

•High capture costs

NH•Uncertainties of the environmental impactsNH3 CO2environmental impacts

•Challenge related to the scale up

Air Heater

BoilerElectrostatic

Flue Gas StackSelected Catalyst Carbon

Precipitator (ESP)

Flue Gas Desulphurization (FGD)

StackyReactor (SCR)

Dioxide Capture

Source: Mitsubishi Heavy Industries

Post Combustion CO2 Capture Scale-up• This study define different technical challenges related to

conventional scale-up and full scale operational requirements for PC capture technologies

• Focus of this study:

Technical & Operational Performance

Technical challenges Sensitivity to

several variablesOperational risks gaps several variables

are evaluated

• Suggested PCC Scale-up Strategy for future development

Thi d d k b Bl k & V h USA• This study was undertaken by Black & Veatch, USA

PCC Scale-up Study• Technical challenges associated with PCC full scale design for

p y

o Supercritical Pulverized Coal (SCPC) 900MWo Natural Gas Fired Combined Cycle (NGCC) 800MW

• Basis of the Studyo With 90% CO2 captureo Selective Catalytic Reduction (SCR) for both SCPC and

NGCC power plants with 80-84% NOx removal efficiencyo Particulates were removed by Pulse Jet Fabric Filter

(PJFF) for SCPC with 90% removal efficiencyo Wet Flue Gas Desulphurisation (WFGD) with Limestone

Forced Oxidation (LSFO) for SCPC with SO2 removal efficiency of 97 5% & additional SO2 polishing scrubberefficiency of 97.5% & additional SO2 polishing scrubber

Major equipment for SCPC with COCO2 capture

12 mole%CO25 mole% O2

CO2 Capture Unit CO2 Compression and Dehydration

900MW SCPC Power plant

•1 Absorber, 28m height•1 Absorber, 28m height

5 mole% O2

••1 SCPC steam generator

•1 Steam turbine

1 Absorber, 28m height

•2 Stripper columns, 23m height

•2 Three stage CO2compression train

2 CO D h d ti•1 Steam turbine generator

•1 SCR

•8 Reboilers

•4 Stripper overhead coolers

•2 CO2 Dehydration unit

•1 Fabric filter

•4 Flue gas fans

coolers

•3 Heat exchangers

•4 Amine pumps•1 Primary FGD

•1 Polishing FGD

2 C d

p p

•5 Lean amine coolers

•5 Side draw coolers

•

•2 Condensers

•1 Cooling tower•1

•2 Water wash pumps

•1 Water wash coolers

Major equipment for NGCC with COCO2 capture

4 mole% CO212 mole% O2

CO2 Capture Unit CO2 Compression and Dehydration

800MW NGCC Power plant

2 G Cl G•1 Absorber, 28m height•1 Absorber, 28m height

•2 G-Class Gas turbine generators

•2 HRSG (w/SCR)

, g

•1 Stripper column, 23m height

•2 Three stage CO2compression train

CO( )

•1 Steam turbine generator

•4 Reboilers

•2 Stripper overhead coolers

•2 CO2 Dehydration unit

•1 Condenser

•1 Cooling tower

3 Q h l

coolers

•2 Heat exchangers

•4 Amine pumps•3 Quench cooler heat exchanger

•2 Quench cooler

p p

•1 Lean amine coolers

•1 Side draw coolers

•

pumps

•2 Flue gas fans •2

•2 Water wash pumps

•2 Water wash coolers

Impact on Electricity OutputUNIT SCPC SCPC with

CO2

NGCC NGCC withCO22 2

Net Plant Thermal efficiency % 40.4 28.3 58.0 49.6CO2 Capture % No 90 No 90

Steam Turbine Generators MW 900 1 756 6 280 4 223 7Steam Turbine Generators MW 900.1 756.6 280.4 223.7Gas Turbine Generators (total)

MW - - 529.5 529.5

Total Gross Output MW 900 1 756 6 809 9 753 2Total Gross Output MW 900.1 756.6 809.9 753.2Auxiliary Electric Load

Power Block MW 35.5 35.1 19.6 22.1Flue Gas Fans MW 17 2 44 0 N/A 26 1Flue Gas Fans MW 17.2 44.0 N/A 26.1

Air Quality Systems MW 5.8 8.5 - -CO2 Capture MW N/A 5.2 N/A 3.6

CO2 Compression MW N/A 75 0 N/A 25 5CO2 Compression MW N/A 75.0 N/A 25.5Total Auxiliary Electric Load MW 58.5 167.8 19.6 77.3Net Plant Output MW 841.6 588.8 790.3 675.9Energy Penalty % N/A -30 0 N/A -14 5Energy Penalty % N/A -30.0 N/A -14.5CO2 for Transport t/h N/A 629 N/A 250CO2 to Atmosphere t/h 702 73 276 28

Impact on Utility Consumption d W t G tiand Waste Generation

UNIT SCPC SCPC withCO

NGCC NGCC withCOCO2 CO2

PLANT UTILITY CONSUMPTIONMakeup Water

3 4 400 6 400Cooling Tower m3/h 9,600 12,500 4,400 6,400Cycle Makeup m3/h 25.9 26.1 7.7 8.1

Advanced Amine Solvent(1) kg/h N/A 283 N/A 210gCO2 Dehydration Adsorbent(2) kg/h N/A 16 N/A 7PLANT WASTE PRODUCTIONWastewaterWastewater

Cooling Tower Blowdown m3/h 1,900 2,300 880 1,300CO2 Capture Wastewater(3) m3/h N/A (Note 3) N/A (Note 3)

Amine Waste kg/h N/A 146 N/A 108Amine Waste kg/h N/A 146 N/A 108Notes:1. Amine degradation includes degradation from oxygen and sulfur, but excludes NOx.2. Bed replacement every 3 to 5 years.3. Minimal wastewater discharge. Water condensed from flue gas and CO2 streams are used

for cooling tower makeup.

Some Key Results (1): Technical Assessments

Steam system, Turbine, Condenser

Technical Assessments

• SCPC case steam is extracted from the cross-over piping and de-superheated to saturationand de superheated to saturation

• NGCC case a quarter of the steam is from HRSG and the LP turbine

• Minor modifications to steam turbine design and HRSG• Opportunity optimization of steam extraction point and

condensate returncondensate return

High gas turbine back pressure required to lower g g p qfootprint and complexity

Plant stiffening is required for boiler ductwork and fluePlant stiffening is required for boiler, ductwork and flue gas equipment

Some Key Results (2):

S C f S

Technical Assessments

Size and Construction of Absorber and Stripper unit

Si l t l t b b ith lti l ll l• Single rectangular concrete absorber with multiple parallel sections with random packing of 17.8 m x 17.8 m x 28 m

• More precision required for correct internal dimensions• More precision required for correct internal dimensions and feeds for the absorber

• The size of strippers for SCPC and NGCC cases wasThe size of strippers for SCPC and NGCC cases was 2x7.2 m and 1x 7.0 m columns and approx. 23m height respectively.

• Main challenge for stripper is its transportation due the large size; but this issue is very site specific

Some Key Results (3):T h i l A tTechnical Assessments

Flue gas bypassg yp

• Required during start-up, shutdown and other upset conditionsconditions

• Cost to construct and maintain a flue gas bypass system• Pressure loss in absorber column• Transition of operation in and out of bypass• Proper coordination of flue gas and boiler draft pressure

d i t iti hduring transition phase

Fl f iFlue gas fan size

• 4 axial ID fans for SCPC and 2 axial ID NGCC cases• No technical challenges; Higher flow fans will reduce cost

Some Key Results (4):Technical Assessments

Nitrosamine Emissions & RegulationsEmission Issues Nitrosamine Emissions & RegulationsEmission Issues

• IEAGHG study 2012/07 on Gaseous emission was focused yon amine emissions

• Sustainable way of amine waste disposal; IEAGHG will• Sustainable way of amine waste disposal; IEAGHG will commission study on Reclaimer waste disposal

Pl i ibilit b i b f th h l• Plume visibility may be an issue because of the much lower release temperature

• Addition of a superheater to the vent stream can be an option

Secondary IssuesyIncrease in cooling waterg

• The cooling requirements approx. 20% higher for SCPC & approx 40% higher for NGCC caseapprox. 40% higher for NGCC case

• Cooling system design is very site specific and economics depends on the price of available waterdepe ds o t e p ce o a a ab e ate

Flue Gas DesulphurizationFlue Gas Desulphurization

• Wet flue gas desulfurization (WFGD) and a polishing scrubber system were usedscrubber system were used

• Integration of primary and polishing FGD stages into a single SO2 absorber system will reduce the footprint ofsingle SO2 absorber system will reduce the footprint of the flue gas cleaning.

Other Points

CO Compression issues are mainly related to theCO2 Compression issues are mainly related to the availability of the plant and its start-up requirements

Solid adsorbents technology is found to be suitable for CO2 drying requirement 2 y g q

Large size required for Heat Exchangers required g q g qand multiple units will be needed

Integration of CO2 capture process controls with the main power plant distributed control system

Size BreakpointspNo significant size breakpoints; Main issues identified are

• Single absorber may no longer be• Single absorber may no longer be

as follows:

• Single absorber may no longer be reasonable

• Second stripper would be required

• Single absorber may no longer be reasonable

• Second stripper would be requiredAbove

Power Plant Second stripper would be required for a NGCC plant

• Third stripper required for a SCPC

Second stripper would be required for a NGCC plant

• Third stripper required for a SCPC

Power Plant size 1000-1200MW pp q

plantpp q

plant

• Size is limited to around 75,000kW• Size is limited to around 75,000kWCO2compressors

Future EvaluationProcess Units• Evaluation of the design change in gas turbine with an

increased exhaust pressure up to 18kPa (g) for NGCC• Evaluation of the cost, safety and permit issues for CO2

stack discharge for extended period of time for large scale t b ti CO t tpost combustion CO2 capture system

• Evaluation and optimization of the integrated primary and polishing FGD stages into single SO absorber systempolishing FGD stages into single SO2 absorber system

• Investigate effect of rectangular shape absorber on its hydrodynamicshydrodynamics

• Evaluation of the CO2 capture plant control system integration to the main power plant DCS systemg p p y

Future EvaluationProcess Issues

• Evaluation for amine emission reduction & amine waste disposalp

• Operational requirement during startup and shutting down of highly integrated power plant with CO2 capture

• Evaluation of the operation flexibility for large scale CO2post combustion capture plant application in power plants

PCC Development Strategyp gy

Equipment design

Environmental

q p g-Construction and transport of equipmentEnvironmental

Issues-Solvent emissions li it

-Heat integration-Heat exchanger optimization

Solvent Development

limits-Solvent co-product emissions

p-Modified equipment designsImproved controlsp

-Absorption rate-Sensible heat

and exposure limits-Flue gas buoyancy and

-Improved controls

requirementy y

dispersal studies

ConclusionsBarrier Technical

BreakthroughComplexity of Development Cost

Steam Generation + + +Steam Extraction + + +Flue gas bypass + + +

ss U

nit

Flue gas bypass + + +Cooling + + +ID Fans + + +

Proc

es Absorber + + +Heat exchanger + ++ +Stripper + ++ +CO2 Compression + + +CO2 Drying + + +CO2 Drying + + +

cess

ues

Amine Emission + + +Capture plant Startup & Shutdown + + +

Proc Issu Retrofit + + +

Advanced Control System + + +

Recommendations

Amine emission issue and disposal of amine based waste

Cycling, part-load, intermittent operation, start-up, shut-down operation issues

CO2 large scale venting or depressurizing HP pipeline issues related to safety and permitsp p y p

Evaluation of mid and peak merit market operation, following a specific weekly demand curvefollowing a specific weekly demand curve

Identifying the capacity limits and ramping capabilities of de t y g t e capac ty ts a d a p g capab t es oequipment like the stripper and reboiler

REFERENCEREFERENCE

• IEAGHG Report No.: 2013-05

• For any questions:P hi Si hPrachi Singhprachi.singh@ieaghg.org