Industrial application of multi-catalysts in diesel ... · Industrial application of multi-catalysts in diesel exhaust ... • Ammonia Slip Catalyst (ASC) optional ... • Improved

May 16, 20161

Industrial applicationof multi-catalystsin diesel exhaustclean-up systemsTopsoe PhD ceremony, Moscow 2016Keld Johansen

May 16, 20161

2 May 16, 2016

Outline

• EU and US NOx and PM regulations – and planned Russian regulations• Euro IV and V for SCR catalyst systems and reactions• Euro VI with multi-catalyst systems and reactions• Future EU Stage V off-road regulations• Two different SCR catalysts integrations in DPF: Why?• Passive regeneration with NO2 for V-SCRonDPF• Demonstration of both passive soot regeneration and NOx conversion• Present and future marine regulations• NOx removal with SCR only• Future Marine multi-catalyst system for both PM and NOx removal• Conclusions and future outlook

3 May 16, 2016

-0,24

-0,2

-0,16

-0,12

-0,08

-0,04

0

0,04

0,08

0,12

0,16

-5 -4 -3 -2 -1 0 1 2 3 4 5 6NOx

(g/kWh)

PM (g/kWh)

Tier 3

Euro III

IVV

EU - HD

PM (g/kWh)

EU - Nonroad

NOx(g/kWh)

Stage IIIA

IIIBIV

US - HD

US - Nonroad

4i

US 2004

2007 2010

4VI

Legislation on/off-road

China IVnationwide1/1 2015

China III 1/102014 =EU IIIA

China VBeijing June2012

China IV ?

Russia Class 32008.01

Russia Class 42013.01

Russia Class 52018.01

Russia GostR41 96-20112014.01

≈ Stage III

4 May 16, 2016

Comparison of present on- and off-road regulations inEU/US

EU VI EPA ’10 Stage IV/Tier 4f

NOx [mg/kWh] 400 270 400

PM [mg/kWh] 10 13 25

PN [#/kWh] 6 x 1011 (WHTC)

8 x 1011 (WHSC)

- -

Test cycles WHSC & WHTC FTP &SET

NRTC & NRSC

Introductiondate

31/12/13 1/1/10 01/01/14 (130-560 kW)

01/10/14 (56-130 kW)

5 May 16, 2016

PM (g/kWh)EURO IIIEURO IVEURO VEURO VI

NOx (g/kWh)2,0 3,5 5,00,4 6,0

0,010,03

0,1

0,16

0,2

Simple SCR systems for EURO IV, V, Russia 4, 5, Stage 4EURO IV

• SCR (Selective Catalytic Reduction)• 60-70% NOx conversion required

PM/NOxtrade off

SCR

Urea

SCRNH3 NOx

NO + NO2+ NH3

H2O

N2CO

PM

HCNOxPM CO HC

6 May 16, 2016

PM (g/kWh)EURO IIIEURO IVEURO VEURO VI

NOx (g/kWh)2,0 3,5 5,00,4 6,0

0,010,03

0,1

0,16

0,2

Simple SCR systems for EURO IV, V, Russia 4, 5, Stage 4EURO V

SCR + (ASC)

Source: AVL SAE paper 2001-01-0186Urea

SCRNH3 NOx

NO + NO2+ NH3

H2O

N2

CO

PM

HCNOxPM CO HC ASC

NH3

• 70-85% NOx conversion required• Ammonia Slip Catalyst (ASC) optional

PM/NOxtrade off

7 May 16, 2016

SCR system for Euro IV and V with ASC optionSCR catalysts: V2O5/WO3/TiO2, Fe-beta zeolite, Cu-chabazite

NOx PM HC CO NOx PM HC CO NH3

Urea

SCR ASC

NOx PM HC CO NH3

Out

Oxidations reactionsHC + 1.5O2→ H2O + CO2

Urea/AdBlue: CO(NH2)2 → NH3 + HCNO → 2NH3 + CO2

Standard SCR: 4NH3 + 4NO + O2→ 4N2 + 6H2O,Minor fast SCR: 4NH3 + 2NO + 2NO2→ 4N2 + 6H2OSlow SCR not relevant: 4NH3 + 3NO2→ 3.5N2 + 6H2O

Selective ammonia oxidation4NH3 + 3O2 → 2N2 + 6H2O

Pt/Al2O3, TiO2+ SCR catalyst

8 May 16, 2016

V2O5/WO3/TiO2 catalysts are very sulfur-tolerantEngine tests with 1200 ppm sulfur fuel (Topsoe DNX)

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200 250 300 350 400 450 500

Time (min)

NO

xco

nver

sion

(%)

150

200

250

300

350

400

Tem

pera

ture

(C)

Poisoning 200 C, 6h Regeneration 350 C Retest 200 C Temperature

6h, 200°C

1h, 350°C

30 min, 200°C

NH3 + SO3 + H2O ↔ NH4HSO4!2NH3 + SO3 + H2O ↔ (NH4)2 SO4!

9 May 16, 2016

Multi-catalyst systems for Euro VI, EPA 10 more complexPM removal requires a further DOC and a cDPF upstream

• SCR + (ASC)• EU IV,V/Russia 4+5 China IV+V (on-road)• USA and EU (off road)

• DPF and Zeolite SCR• US10, EU VI and Japan (on road)

• DPF and Vanadium SCR• EU VI, Beijing 6 (on road)

• HEAT and Vanadium SCR• Not presently used in the EU and USA

due to no NO2 for DPF, but revival forEuro VII is possible

10 May 16, 2016

Layout of standard Euro VI, EPA10 multi catalystexhaust systems – flow-optimized constructions

Urea

DOC cDPF SCR

ASC

Source: Scania Source: Volvo Source: MAN

SCR-T

Euro 6 standard exhaust system consists of DOC-cDPF-SCR-ASC

11 May 16, 2016

DOC and cDPF with low PGM for Euro VI systemsFront end of multi-catalyst system. Active/passive sootregen. c:Pt,Pd/Al2O3,SiO2 limited soot solid-solid reactions

DOC reactionsHC + 1.5O2→ H2O+ CO2CO + ½O2→ CO2NO + ½O2 → NO2

cDPF gas-solid reactionsPassive soot regeneration 270ºC-500ºCC + NO2 → CO + NOC + 2NO2 → CO2 + 2NO”CH” + 2.5 NO2 → CO2 + 2.5NO + 0.5H2OPt: NO + ½O2→ NO2 recycleActive NO2 regeneration at 450ºC and max 530ºCActive O2 soot regeneration >550ºCC + O2 → CO2C + ½O2 → CO

DOC cDPF

NOx PM HC CO NOx PM HC CONOx PM HC CO

NO2

Diesel/HC to600/450ºC

Tmax= 700/530ºC/soot load 5g/l

→SCR/ASCNO2/NOx 0.10 - 0.55 for low T

Euro VIengine

Cordierite 300/5 cpsimonolith with PGM

Cordierite cDFP”200/12 cpsiwith PGM

12 May 16, 2016

V-SCR and zSCR catalysts for NOx reduction plus ASCBack end of multi-catalyst system

DOC cDPF V-SCRz-SCR

ASC

Diesel

NOx PM HC CO NOx PM HC CO NH3NOx PM HC CO

NO2

NOx PM HC CO NH3

Urea

Selective NH3 oxidation4NH3 + 3O2 → 2N2 + 6H2O

Urea/AdBlue: CO(NH2)2 → NH3 + HCNO → 2NH3 + CO2Fast SCR: 4NH3 + 2NO + 2NO2→ 4N2 + 6H2OStandard SCR: 4NH3 + 4NO + O2→ 4N2 + 6H2OSlow SCR: 4NH3 + 3NO2→ 3.5N2 + 6H2O

NOx PM HC CO

Out

ASCV-SCR

Euro VI and EPA 2010 complicated PM aftertreatment system with additionalNOx removal reactions

13 May 16, 2016

Soot regeneration on DPF – soot reactionsActive O2-C versus assisted passive NO2-C regeneration

Zouaoui et al: C.R. Chim. 17 (2014)672-680

14 May 16, 2016

DOC and cDPF compositions,reactions and sulfur

Diesel Oxidation Catalyst DOC:Pt,Pd/Al2O3,SiO2,REOx/TiO210 – 30 g PGM/cuftPd/Pt ratio dependent on max temp. i.e.passive vs. active regen.

DOC reactions

HC + 1.5O2 → H2O + CO2

CO + ½O2→ CO2

NO + ½O2→ NO2

Fuel S > 50 ppm a problem as the reaction SO2+ ½O2→ SO3 outperforms NO + ½O2→ NO2 andstops passive soot regeneration

Catalyzed Diesel Particulate FiltercDPF: Pt,Pd/CeO2,ZrO2,Al2O3,REOx:3 - 5 g PGM/cuft (40 - 50 g/cuftused previously)NO2 recycle on Pt –DPF is claimed for enhancedsoot combustion but doubtful with ash (!). Butimportant for SCR reactions

Passive soot regeneration 270ºC-500ºC

C + NO2 → CO + NO

C + 2NO2 → CO2 + 2NO

”CH” + 2.5 NO2 → CO2 + 2.5NO + ½H2O

Pt: NO + ½O2→ NO2 recycle for deSoot and SCR

For HC and CO clean up during regeneration

Active O2 soot regeneration takes over above550ºC

C + O2→ CO2 ,C + ½O2→ CO

NO2 formation catalysts for passive soot regen. and for SCR

15 May 16, 2016

Catalyzed diesel particulate filter and NO2 recycleNO + ½O2→ NO2 recycle for deSoot and SCR

Source: MECA

Source Sappok DEER 2012

Source: AeriNOx modified

Catalyst layer

Soot particle

NONO2 NOx

CO2 H2O

NONO2

NOxCO2

H2O

Substrate (ceramic or metallic)

CO

NO + ½O2 → NO2

NO + NO2 C + NO2 → CO + NODirty exhaust

HCNOx

16 May 16, 2016

Comparison of different Euro VI vs. solutions

• Lowest operating costs• 4% improvement @ Adblue 50% of

diesel

DOCDOC CDPFCDPF SCRSCR ASCASC

• Scania’s 410 hp engine is mostefficient

• Lowest fuel consumption and CO2

Source: Verkehrsrundschau und Trucker - Green Truck 2014

17 May 16, 2016

Comparison of on- and off-road regulationsWith new foreseen off-road EU Stage V ≈ 2020

EU VI Stage V Stage IV/Tier 4fNOx [mg/kWh] 400 400? 400

PM [mg/kWh] 10 15? 25

PN [#/kWh] 6 x 1011 (WHTC)8 x 1011 (WHSC)

1 x 1012 ?(NRTC) (NRSC)

-

N2O (GHG) [ppm] 10? ?

Test cycles WHSC & WHTC NRTC & NRSC NRTC & NRSC

Introduction date 31/12/13 2020?all classes?

01/01/1401/10/14

18 May 16, 2016

Why SCR integration in DPF?

Integration of DPF with SCR – advantages:• Lower volume• Improved heat transfer for both deNOx and deSoot• Improved transport of gas components to catalyst surface• Earlier urea injection after cold start• Improved cold start NOx reduction performance for system• Low exhaust temperature from coming future fuel-efficient engines• Lower weight• Lower cost?

Typical Euro 6 system, that works but ..

DOCDOC cDPFcDPF SCRSCR ASCASC

Urea

19 May 16, 2016

Why SCR integration in DPF?

Integration of DPF with SCR – advantages:• Lower volume• Improved heat transfer for both deNOx and deSoot• Improved transport of gas components to catalyst surface• Earlier urea injection after cold start• Improved cold start NOx reduction performance for system• Low exhaust temperature from coming future fuel-efficient engines• Lower weight• Lower cost?

Typical Euro 6 system

DOCDOC cDPFcDPF SCRSCR ASCASC

Urea

20 May 16, 2016

Two potential SCR filter integrationsAdvantages and challenges

Catalyst type: Cu-zSCRonDPFExample: Cu-SSZ-13 zeolite, Cu-SAPO-34 zeolite type

Filter material: High porosity SiC, cordierite, mullite

Soot combustion process: Active above 550ºC

Passive soot regeneration? minor importance

Max SCR/DPF temperature: ≈ 800ºC

Pros: High NOx conversion for 200 -300ºC

Cons: Sulfur poisoning, fuel consumption for active regeneration

Application: Passenger cars, tractors, mobile cranes

21 May 16, 2016

Two potential SCR filter integrations

Catalyst type: V-SCRonDPFExample: V2O5/WO3/TiO2

Filter material: High-porosity cordierite

Soot combustion process: Assisted passive

Passive soot regeneration: Only allowedmechanism

Max SCR/DPF temperature: ≈ 600ºC

Pros: V-SCR has long time durability record asSCR in many applications

Low cost

High sulfur resistance

Cons: NOx conversion in low-temperature cycle,max temperature

Application: Stage V off-road: Crushers,dumpers, tractors

Advantages and challenges → V-SCRonDPF for this off–roadstudy

22 May 16, 2016

V-SCR integrated filter for off-road – configurationpossibilities with assisted NO2 passive regeneration!

Urea

DOC V-SCR/DPF V-SCR ASC

NOx PM HC CO NOx PM HC CO NH3NOx PM HC CO

NO2

NOx PM HC CO NH3

Fast SCR reaction4NH3 + 2NO + 2NO2 → 4N2+ 6H2O

Passive soot regeneration below 500ºCC + NO2 → CO + NOC + 2NO2 → CO2 + 2NO

NO2 formation needed

Late post injection Tmax=550ºC

Important NO –NO2equilibrium

23 May 16, 2016

Passive and active soot oxidation, SCR reactions on V-SCRonDPF - the competing reactions

Passive soot reactions on SCRonDPF 275 – 500ºC:

C + NO2 → CO + NO ΔH0298K = -53 kJ mol-1

C + 2NO2 → CO2+ 2NO ΔH0298K = -279 kJ mol-1

“CH” + 2.5NO2 → CO2 + 2.5NO + 0.5H2O ΔH0298K = -784 kJ mol-1

Active soot reactions on SCRonDPF above 500ºC

C + O2→ CO2 ΔH0298K = -394 kJ mol-1

C + ½O2→ CO ΔH0298K = -110 kJ mol-1

Below 500ºC the “active” oxygen reactions and temperature runaway are avoided

SCR reactions:

(NH2)2 CO + H2O → 2NH3 + CO2 Above 180ºC

Standard SCR: 4NH3 + 4NO + O2→ 4N2 + 6H2O Important 300 - 500ºC

Fast SCR: 4NH3 + 2NO + 2NO2→ 4N2 + 6H2O Important 180 - 300ºC

Slow SCR: 4NH3 + 3NO2→ 3.5N2 + 6H2O Unwanted?

Competing SCR and soot reactions on SCRonDPF for 275 - 500ºC

24 May 16, 2016

DOC characteristic after de-greeningHigh NO2/NOx ratio very important. Optimal?

Reactions• NO + 0.5O2 → NO2

• CO + 0.5O2 → CO2

• ”CH” + 1.5O2 → CO2 + H2O

Still fairly high NO2 ratios afterdegreaning @ 600ºC for 5hr

A NO2/NOx ratio of ≈ 0.4-0.7 wanted

DOC from a EU VI silencer Ø12”x L6” (11.1 l) with 20 g PGM/cuft

25 May 16, 2016

After-treatment system layout for NRTC for Stage IV

• DOC: Ø12”x (11.1 l) L6” 20 g PGM/cuft

• V-SCRonDPF: Ø12” x L12” (22.2 l) NGK cordierite 300 cpsi 102 g/l V-SCR

• Flow-through SCR: Topsoe DNXR-805 12.7” x L7” (14.5 l) 260 cpsi

• ASC: Topsoe DNXS-312 Ø12.7” x L4” (8.3 l) 260 cpsi

DOC V-SCR/DPF V-SCR ASC

Diesel

NOx PM HC CO NOx PM HC CO NH3NOx PM HC CO

NO2

NOx PM HC CO NH3

Urea

→out

NOx PM HC CO

NO2

26 May 16, 2016

200 400 600 800 1000 12000

0.05

0.1

0.15

0.2

Time [s]

NO

x[g

/kW

h]

200 400 600 800 1000 12000

20

40

Time [s]

NH

3[p

pm] 6 ppm mean NH3

NRTC results, SAE 2016-01-0915

• Engine out emissionsapproximately 7.6 g/kWh

• Close to 97% conversion with0.23 g/kWh NOx

• Peak slip nearly 60 ppm, notethis was with fixed ANR = 1.2

Below Stages IV and V NOx limit 0.4 g /kWh!

27 May 16, 2016

200 400 600 800 1000 1200

2

4

6

8

10

12

14

Time [s]

Pre

ssur

eD

rop

[kP

a]

NRTC results

• 8 cycles

• Small variations in backpressure at the start of thecycle, no discernible trend !

• No change to filter weight !

Constant filter weight, soot load and pressure drop

28 May 16, 2016

Marine multi-catalyst filter systemsSCR is not a new technology. Four ships with SCR 1989

4 Ships, MAN 6S50MC, 8MW

Haldor Topsoe SCR installed from 1989

92% NOx reduction, (IMO 2016 compliant)

NOx out: 1.8 g/kWh

Operating part time on MDO

3 vessels still in operation with the original catalyst!Scan of brochure from 1992

29 May 16, 2016

Marine SOx and NOx regulations, but no PMregulations scheduledMain Engine – PM (global GHG potential), NOx and SOxAuxiliary engine – PM (unhealthy soot/metals), NOx and SOx emissions in cities

Or with scrubber < 6g SO2/kWh or 4.3 SO2 [ppm]/CO2 [%v/v]

30 May 16, 2016

Emission-controlled areas

DNV/Watlow

31 May 16, 2016

V-SCR DeNOx 4-stroke diagram for HFO andMDO/MGO

Urea Solution Storage

Tank

Engine

Load %Load %

FIC IP

AIC SP

AT

NOx

Pump

SCRReactor

Cleaned Gas

Engine Exhaust

Press. air

Standard SCR: 4NH3 + 4NO + O2→ 4N2 + 6H2O FastSCR: 4NH3 + 2NO + 2NO2→ 4N2 + 6H2O

NH3 + SO3 + H2O ↔ NH4HSO4!2NH3 + SO3 + H2O ↔ (NH4)2 SO4!

32 May 16, 2016

Topsoe V-SCR DeNOx system for HFO and MDO/MGOProcess feature, 2-stroke system. Heat avoiding NH4HSO4

Standard SCR: 4NH3 + 4NO + O2→ 4N2 + 6H2OFast SCR: 4NH3 + 2NO + 2NO2→ 4N2 + 6H2O

NH3 + SO3 + H2O ↔ NH4HSO4!

2NH3 + SO3 + H2O ↔ (NH4)2 SO4!

33 May 16, 2016

HFO DPF challenges: Solution-stable V2O5-based sootoxidation catalyst on a silicon carbide filter

HFO diesel particulate filter challenges• Sulfur content in fuel up to 3.5% and no NO2

• Ash content in HFO up to 0.2%

• Filter pressure drop max 25–60 mBar

Solution• SiC filter substrate coated with

Pd/V2O5-based solid contact catalyst

• Soot combustion• V2O5 + C → V2O4 + CO• V2O4 + ½O2 → V2O5

• HC (PAH) conversion and CO conversion

• Ash removed by reverse pulse flow

• Sulfur-tolerant with low SO2 oxidation

• Patent EPO 040144586

Neeft et al App. Catal. B 12 (1997) 21-31

(Patented)

34 May 16, 2016

Queen Victoria cruise ship soot removal summary

Δp max 40 mBar

Johansen Catalysis Today 258 (2015) 2-10

Soot removal 80 – 92% <1 mg/m3

required

35 May 16, 2016

Particulate removal process with BMC-101 catalystintegrated in SiC filter with passive soot regeneration

NH3/Urea

Pd,V2O5/DPF V-SCR

SO2 NOx PM HC CO SO2 NOx PM HC COSO2 NOx PM HC COTemperature-managedpassive regeneration is crucial:350ºC < T < 430ºCLow load of soot/ash

SOx scrubber

SO2 NOx PM HC CO

Diesel with Fe,V,Ni,Cu,Na,Co,Zn,Al,SiReverse pulse flow

Sea water

Out

To sea water w Na2SO4, CaSO4Low turbidity < 25NTU (nephlometric units)PAHphe < 50 μg/LHeavy metals low”

Heavy metalsulphates + C

36 May 16, 2016

Conclusions and future outlook for multi-catalystdiesel exhaust systems – on/off-road

1. Euro IV and Euro V NOx regulations for truck exhaust system requirefew SCR catalyst bricks

2. Euro VI and EPA10 regulations for both PM and NOx reduction require amulti-catalysts system that performs many aligned reactions

3. Fuel sulfur level important for system layout4. Limited space and improved thermal management make V-SCR

integrated in DPF very interesting in future off-road exhaust systems5. NOx conversion and passive NO2-soot regeneration proven feasible for

V-SCRonDPF and NO2 optimized DOC. Off-roadNRTC – NOx regulationlimit 0.4 g NOx/kWh passed for a multi-catalyst system

6. V-SCRonDPF seems to be a solution for future off-road regulations

37 May 16, 2016

Conclusions and future outlook for multi catalystdiesel exhaust systems - marine

7. Marine IMO NOx regulation is now started in North America and isexpected in near future in European ECA areas

8. Single-brick V-SCR catalyst proven feasible for 4-stroke and 2 strokeengines

9. Marine IMO PM regulation is not yet decided. HFO sulfur and metalcontent makes the PM removal process difficult, but a catalytic processsolution has been invented

10. Marine multi-catalyst systems with both PM and NOx removal incombination with SOx scrubber are now on demonstration ships.

38 May 16, 2016

Thank you for your attention

Questions?