High Efficiency SCR for New Technology Diesel Engines

Jerry Liu Executive Scientist / Director – Research & Development Cummins Emission Solutions

Outline Introduction Evolution of Engine & Aftertreatment Technologies – New Technology Diesel Engines Current Status – Typical Aftertreatment Architecture Challenges Approaches to High Efficiency NOx Reduction Summary

Australia

•ADR80 / EPA07 – 2011

•EPA10 - 2015

Tougher Emission Standards

North America

•EPA07 – 2007

•EPA10 – 2010 •Tier 4B – 2014 •EPA13 – 2013

•T4F - 2014

Mexico

•Euro4 - 2008 •EPA07 - 2015 •Euro5 – 2015

Latin America

•Euro4 (Chile/Colombia) •Euro5 (Brazil) – 2012

•EPA07 –2013

Middle East

(Israel)

•EPA07 - 2008 •Euro5 – 2009 •EPA10 - 2010 •Euro6 – 2014

Western Europe

•Euro5 – 2009 •Euro6 - 2013

•Stage 3b – 2011

Russia

•Euro4 – 2011 •Euro5 - 2014

China

•NS4 / Euro4 – 2013 •NS5 / Euro5 - 2016

India

•BS4 / Euro4 – 2010

•BS4/5 / Euro4/5 – 2014/5

Japan

•EPA07 – 2008 •EPA10 – 2010 •Step 4i - 2011

CO2

Diesel Particulate Filter

Selective Catalytic Reduction

Cooled Exhaust Gas Recirculation

Electronic Fuel Systems

1990 2000 2010 2020

Turbocharged / Aftercooled / 4Valve / 4 Stroke

Evolution of Engine & AT Technologies

Ultra-Low Sulfur Fuel

Diesel Particulate Filter

(Wall, CARB Chairman Seminar, 2012)

NTDE: Less PM/NOx & Very Different Chemical Composition

(Kittelson, J. Aero. Sci., 1998)

(Liu et al., Aerosol Sci. & Tech., 2009)

(ACES, Air & Waste Manag. Asso., 2011) (Liu et al., Atmos & Environ, 2010)

(Wall, CARB Chairman Seminar, 2012)

Surface Transportation Fuel Use

Diesel engines are involved directly in ~40% of all

surface transportation fuel consumption.

Total U.S. Surface Transportation Diesel + Gasoline Fuel Use

= 12.68 MBPD (Million Barrels Per Day) (Trans. Energy Data Book, Edition 31, 2012)

2007 HD Engine Energy Balance

(Ekerle, DEER, 2007)

Why High Efficiency SCR?

6/19/2013

EPA Tier 4 Final - QSM12 w/o EGR (Off Highway)

Fuel Efficiency and GHG emission standards beginning in 2014 (10-20% improvement by MY 2018) SCR only (no EGR) systems becoming an option

80%82%84%86%88%90%92%94%96%98%

100%

1 2 3 4 5 6

Syst

em C

onv.

Eff.

Req

uire

men

t [%

]

Engine Out NOX [g/bhp-hr]

US EPA 2010 Tier 4 final

Passive NOX adsorber

Cold start catalyst

0

20

40

60

80

100

0 100 200 300 400 500 600

[%]

Exhaust Temp [°C]

Challenges & Opportunities

Heat retention/generation/close coupling DEF dosing possibleSCR deNOx [%]S

Dutycycle time below T, [%]

Low-T SCR formulations

Low-T NH3 delivery (L), (G)

Decomposition, mixing

Sensors & controls

Improved catalyst durability

Temperature stability

Approaches to High Efficiency NOx Reduction

Integrated systems approach Technology trends – Catalysts – Doser / reductant / delivery – Advanced packaging,

decomposition / mixing / uniformity – Architecture – Thermal management: heat

retention / generation – Sensors and controls – Etc.

Potential Low-T SCR Formulations Current zeolite and V-based SCR formulations can achieve high (> 80%) NOx conversion at temperatures as low as 170°C

Cu-zeolite SCR catalysts are less sensitive to NO2:NOx ratio at low-T

Novel SCR catalysts are required to achieve high NOx conversion at lower temperatures

Mn-Fe/ZSM5 has shown promise in recent results [1] Sulfation results reveal that formation of MnSO4 is likely in the presence of SO2

6/19/2013

(Y.J. Kim et al., Appl. Catal. B 126, 2012)

6/19/2013

Low Temperature NH3 Delivery

(Koebel et al., Catalysis Today, 59(3), 2000) Courtesy: Amminex Emissions Technology A/S.

DEF evaporation and urea thermolysis reach thermodynamic/physicochemical limitations at <200°C

Gas phase NH3 delivery advantages include: Reduces mixing length, enables close coupling Eliminates DEF deposit risk Reduces exhaust temperature requirements

DEF droplet

(32.5%wt. urea, 67.5%wt water) Water vaporization (100 degC)

NH2-CO-NH2 (aq.) --> NH2-CO-NH2 (s) + 6.9 H2O(g)

Urea Particle

Melting & Thermolysis (starting at 133 deg C)

NH2-CO-NH2 (s) - -> NH2-CO-NH2 (l) --> NH3 (g)+ HNCO(g)

Hydrolysis – surface / gas-phase reaction

NH3(g), HNCO(g)

NH3(g), HNCO(g),

CO2(g), H2O(g) ……

6/19/2013

Improvement to urea decomposition due to increase in available length shows a diminishing trend

(Munnannur & Liu, SAE 2010-01-0889)

Optimization of spray shape based on performance and spaceclaim requirements

Uniformity of Ammonia to NOX ratio (ANR UI) critical for high efficiency Static mixers and flow distribution devices that are well-matched with injector location and injected spray characteristics are necessary

Baseline

Baseline with mixer

50

60

70

80

90

100

0.5 0.6 0.7 0.8 0.9 1

NO

x Con

vers

ion

Effic

ienc

y

ANR UI

avg

Aavg

ANR

ANRANRUI

21

Decomposition & Mixing

Dioxin/Furan Reduction from CES Cu-Z SCR Systems

Concentration % Reduction Detection LimitEngine Out DOC+DPF+SCR Engine Out DOC+DPF+SCR

Compound pg/dscm pg/bhp·hr pg/dscm pg/bhp·hr pg/dscm pg/bhp·hr pg/dscm pg/bhp·hr2,3,7,8-TCDD ND ND ND ND - 0.19 0.75 0.11 0.45

1,2,3,7,8-PeCDD ND ND ND ND - 0.45 1.74 0.20 0.791,2,3,4,7,8-HxCDD ND ND ND ND - 0.38 1.46 0.16 0.631,2,3,6,7,8-HxCDD ND ND ND ND - 0.38 1.48 0.16 0.641,2,3,7,8,9-HxCDD ND ND ND ND - 0.40 1.54 0.19 0.75

1,2,3,4,6,7,8-HpCDD 0.69 2.68 0.29 1.14 57% 0.66 2.56 0.17 0.68OCDD 3.06 11.92 1.44 5.74 52% - - - -

2,3,7,8-TCDF 0.76 2.95 0.25 1.01 66% - - - -1,2,3,7,8-PeCDF ND ND ND ND - 0.60 2.31 0.12 0.492,3,4,7,8-PeCDF ND ND ND ND - 0.54 2.11 0.12 0.47

1,2,3,4,7,8-HxCDF ND ND 0.09 0.37 - 0.35 1.38 0.10 0.391,2,3,6,7,8-HxCDF ND ND ND ND - 0.34 1.35 0.10 0.382,3,4,6,7,8-HxCDF ND ND ND ND - 0.35 1.36 0.09 0.371,2,3,7,8,9-HxCDF ND ND ND ND - 0.18 0.71 0.12 0.47

1,2,3,4,6,7,8-HpCDF ND ND 0.10 0.40 - 0.53 2.03 0.10 0.401,2,3,4,7,8,9-HpCDF ND ND ND ND - 0.17 0.66 0.11 0.44

OCDF ND ND ND ND - 1.14 4.39 0.39 1.55Total TCDD 0.98 3.78 0.38 1.50 60% - - -

Total PeCDD 0.29 1.13 ND ND - 0.38 1.50 0.20 0.79Total HxCDD 0.64 2.49 0.20 0.78 69% 0.52 2.02 0.19 0.78Total HpCDD 1.15 4.46 0.56 2.23 50% - - - -

Total TCDF 4.10 15.93 1.67 6.68 58% - - - -Total PeCDF 0.55 2.14 0.17 0.67 69% 0.40 1.58 0.09 0.36Total HxCDF 0.37 1.42 0.15 0.59 59% 0.26 1.02 0.08 0.34Total HpCDF 0.44 1.71 0.16 0.62 64% 0.24 0.93 0.09 0.37

TEQ (ND=0 WHO 1998) 0.08 0.31 0.03 0.12 61%TEQ (ND=DL/2 WHO 1998) 0.66 2.56 0.26 1.05 59%

TEQ (ND=DL WHO 1998) 1.27 4.94 0.50 1.98 60%TEQ (ND=DL WHO 2005) 1.15 4.47 0.47 1.88 58%

(Liu, Wall, Barge, Environ Sci. & Technol., 2011)

Vanadium-SCR Characterization Flow

RTC

ThermocoupleValve

SecondaryMicro-Diluter

Pump

Pump

Engine

TO-9A Sampling Train

See Figure 2b

(a)

0.1%

1.0%

10.0%

100.0%

Chapman (670°C)

Chapman (750°C)

Core-Reactor (700°C)

Engine (700°C)

Norm

alize

d Van

adium

Emi

ssion

s

(Liu & Ottinger, SAE Trans. 2012-01-0887)

SCR System ALD

(AVL-FIRE)

Hand Calculations/ Excel-based tools:

CFD Modeling with DEF decomposition model

CFD Modeling with single component DEF surrogate:

Spray Characterization data : A&TT Spray lab / Suppliers

16

System Performance Modeling

Core reactor data : A&TT Reactor lab/ R&T Cat Tech

CFD modeling of decomposition and catalytic reactions

CMI/ Supplier kinetic models: R&T SPA

Performance data : CES Performance

System Perf. Modeling incorporating ANR non-

uniformity

(AVL-FIRE, FLUENT+ In-house model )

(AVL-BOOST + In-house PDF based method)

Component level analysis

System level analysis

(FLUENT)

Performance data : CESPerformance

Core reactorr data :A&TT Reactor lab/ R&T Cat Tech

SprayCharacterizationnnnnnnnnnnn data :A&TT Spray lab / SuSuSSSSSSSSSSSSSSSSSSSSSS ppliers

1616161616161616161616161616161616161616161616

CMI/ Supplier kinetic models: R&T SPA

Non-Standard, Rules & Tools / Research

projects

Correlation Between UI and SCR DeNOx Efficiency

Measured Ammonia-NOx -Ratio Distribution for ISB 2010 EI – B50

Correlation between measured and predicted ANR UI for different configurations at different

operating points Correlation between measured and

predicted ANR UIs and De-NOx efficiency

70

85

100

0.8 0.9 1De

-NO

x Effi

cien

cy (%

)UI

UI- CFD (liq + vapr)UI- Test

UI data at B50

0.5

0.75

1

0.5 0.75 1

UI -

Pred

icte

d

UI - Measured

ANR UI+11%-11%perfect correlation

Predicted

Establish DEF mixing uniformity measures that can be used for CFD analysis based evaluation of SCR performance

Methods and Tools for DEF Deposit Mitigation

(Munnannur et al., SAE 2012-01-1287)

(Liu et al., US Patent 8240137, 2012)

(Nishioka et al., SAE 2006-01-0644) (Schaber et al., Thermochimica Acta, 2004)

Transition to Clean “New Technology” Diesel: Advanced Component Technologies and System Integration

Clean Diesel

Air Handling

Controls

Combustion

Fuel Systems Exhaust Aftertreatment

Ultra Low Sulfur Fuel

19

Acknowledgement

Dr. Achuth Munnannur – Simulations Nathan Ottinger – Catalysts Dr. Yuanzhou Xi – Kinetics Nik Schmidt – Dosing / Spray Dr. Don Stanton – Product Architecture Mike Robinson – Emissions Development

Thank you! Questions?