Emitec SCR

High efficiency SCR system for most effective NOx reductionand best fuel economy for on- and off-road applications

Dr. Ulrich Pfahl, Emitec Inc.Detroit, June 20th, 2012

Agenda

Exhaust Emission Legislation & Strategies SCR System Layout & Development Requirements of Urea Dosing System Air Assisted / Airless Conclusion

Exhaust Emission Legislations & Technologies Example : Commerical Vehicle - ETC

Engine Technology Euro VI

P

M

[

m

g

/

k

W

h

]

NOx [g/kWh]1

60

30

42 6

EU V EU IV

EU VI

0 3

F

u

e

l

C

o

n

s

u

m

p

t

i

o

n

High Efficient SCR: > 95%

Engine Technology Euro IV

Agenda


SCR System Layout & Development

Euro IV : > 70% NOx efficiency

Euro V : > 85% NOx efficiency

Euro VI : > 95% NOx efficiency DPF/SCR

S

L

I

P

Hyd.

DOC

SCRS

L

I

P

DOC

SCR SilencerSilencer

SilencerSilencer

SilencerSilencer

SCR Processes

{(NH2)2CO 7H2O}fl {(NH2)2CO}fl + 7 H2O water evaporation

{(NH2)2CO}fl HNCO + NH3 thermolysis of urea

HNCO + H2O CO2 + NH3 hydrolysis of isocyanic acid

NH3 Formation

4 NO + O2 + 4 NH3 4 N2 + 6 H2O standard reaction with NO

2 NO2 + 2 NO + 4 NH3 4 N2 + 6 H2O fast reaction with NO+NO2

NOX Reduction

0102030405060708090

100

0 100 200 300 400

Temperature [C]

N

O

x

C

o

n

v

e

r

s

i

o

n

R

a

t

e

[

%

]

NO2 / NO50%

NO2 / NO0%

SCR Processes

{(NH2)2CO 7H2O}fl {(NH2)2CO}fl + 7 H2O water evaporation

{(NH2)2CO}fl HNCO + NH3 thermolysis of urea

HNCO + H2O CO2 + NH3 hydrolysis of isocyanic acid

NH3 Formation

Develop System according to Critical SCR Processes : Good evaporation of DEF optimized amount of DEF injected per time per unit

targeted area , in order to minimize the temperature loss in the system Optimum hydrolysis of isocyanic acid Preference for Hydrolysis Catalyst Good uniformity of NH3 Optimized Mixing Tube Design

Adblue Droplet Hitting the Target Surface Evaporation

Agenda


Key Considerations of Urea Dosing System Design

Air Assisted / Airless Mass Per Droplet Size

Air assisted SCR System: Measured Droplet Size - and Droplet Mass Distribution at 20 l/min Airflow

Droplet Size Distribution

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60

R

e

l

a

t

i

v

e

D

i

s

t

r

i

b

u

t

i

o

n

D

e

n

s

i

t

y

Droplet Size in Microns0

20

40

60

80

100

0 10 20 30 40 50 60

C

u

m

u

l

a

t

i

v

e

M

a

s

s

%

Droplet Size in Microns

Droplet Mass Distribution

5 m

70 m

30 m

< 5 mm

1110 mm

6100 mm

Evaporation distance requ. at 200 kg/h exhaust mass flow @ 430 C Technical University Munich, tube- 55 mm



Temperature Layout Exhaust Gas Temperature ( injector

location, insulation), Injection Strategy

New Conditions for HD Truck Catalyst Systems;Exhaust Gas Temp. EU V / US 2010 (EU VI); 13mode steady state

0

100

200

300

400

500

600

0 200 400 600 800 1000 1200 1400 1600 1800

T

e

m

p

.

u

p

s

t

r

e

a

m

S

C

R

C

a

t

[

C

]

Time [s]

Oxi-Catalyst

UreaDosing

SCR

EU VI / US 2010 Engine

EU V Engine

Temperature Profile of a Commercial Vehicle with and withoutElectrically Heated Catalyst (EHC): City Driving Cycle

150

175

200

225

250

275

300

0 250 500 750 1000 1250 1500 1750 2000t [sec]

T

e

m

p

e

r

a

t

u

r

e

[

C

]

0

500

1000

1500

2000

2500

3000

E

x

h

a

u

s

t

M

a

s

s

F

l

o

w

[

k

g

/

h

]

Exhaust Temperature EHC Not ActiveEhxaust Temperature EHC ActiveExhaust Mass Flow

Benefit in Temperature with

EHC




location, insulation), Injection Strategy Mixing Pipe Design - Tasks

Avoid Deposit formation Good Uniformity Creation of NH3

Calculated NOx-Reduction and NH3 Slip as Function of NH3-Uniformity and DEF-Dosing Rate

0

10

20

30

40

50

60

0.88 0.9 0.92 0.94 0.96 0.98 170

75

80

85

90

95

100

0.88 0.9 0.92 0.94 0.96 0.98 1

NH3- Slip [ppm]

NH3-Uniformity

NOx-Reduction [%]

NH3-Uniformity

Alpha = 1.00

NOx Reduction @ selected US EPA 13mode / ESC load points

DEF Injector Initial Layout

0102030405060708090

100

B50 A50 A25 B100 B25 C100 C25

N

O

x

E

f

f

i

c

i

e

n

c

y

,

%

ESC Load Point

DEF Injector New Layout

0102030405060708090

100

B50 A50 A25 B100 B25 C100 C25

N

O

x

E

f

f

i

c

i

e

n

c

y

,

%

ESC Load Point

High Load Points

NOx Efficiency with Optimized Airless Dosing Layout & StrategySummary of Sweep Test

86

88

90

92

94

96

98

100

0.85 0.9 0.95 1 1.05

N

O

x

E

f

f

i

c

i

e

n

c

y

Alpha (-)

Test conditions: constant speed / torque

constant temperature and massflow and exhaust gas condition

exhaust gas 714 kg/h, T = 420 C, NO x = 543 ppm; NO2/NOx = 0,27theoretical DEF demand for (alpha = 1) = 1100 ml / h

setup with Fe-Zeolithe catalyst [242 x (110 + 110)] 10,1 ltr

alpha = 0,87 1.04

NH3-distribution Example

Engine parameters With H-Cat Without H-CatNH3 HNCO NH3 HNCO

A 25 Load Point:Exh Gas Temp: 310 CExh Gas Massf.: 850 kg/h

54,7 32,5 17,3 17,9

Average Concentration

Hydrolysis Cat ( H-Cat) gives significant Advantage for NH3 formation

6th ICPC, Graz, 25. - 26.04.2011

Catalyst System Validation of Mixing Pipe - Deposits6th ICPC, Graz, 25. - 26.04.2011

Design w/o Hydrolysis-Catafter 10 h Load point A 25

Design with Hydrolysis-Catafter 10 h Load point A 25

Hydr.-Cat outletHydr.-Cat Inlet

Liebherr SCR Production System

watercooledinjector

hydrolysiscatalyst

SCR catalyst

LS Technology

6th ICPC, Graz, 25. - 26.04.2011




location, insulation), Injection Strategy Mixing Pipe Design - Tasks

Avoid Deposit formation Good Uniformity Creation of NH3

SCR Catalyst Structure Conversion Efficiency Ammonia Slip

Influence of Cell Structure on NOx Conversion Efficiency

0

10

20

30

40

50

60

70

80

90

100

200 250 300 350

Temperature [C]

N

O

x

C

o

n

v

e

r

s

i

o

n

E

f

f

i

c

i

e

n

c

y

[

%

]

200cpsi Standard200/400cpsi LS

+ 4 %

+ 14%

2

0

0

c

p

s

i

2

0

0

/

4

0

0

L

S

0

20

40

60

80

100

120

Std LS

W

M

[

%

]

0

20

40

60

80

100

120

140

160

Std LS

[

%

]

Washcoat Mass Transfer

100

80

60

40

0

20

ConcentrationTracer gas [%]

Position A Position H

18 [mm]

Flow

Radial Mixing after a substrate length of 18 mm LSPETracer Gas injected into a single Channel; 200kg/h; 300C

LS/PE-Foil

79

88

0

10

20

30

40

50

60

70

80

90

100

Ceramic System Metallic System

N

O

x

C

o

n

v

e

r

s

i

o

n

E

f

f

i

c

i

e

n

c

y

,

%

Comparison of Ceramic and Metallic Systems:NOx-Emission Reduction in ETC

7. FAD-Konferenz , November 2009

79

88

97

0

10

20

30

40

50

60

70

80

90

100

Ceramic System Metallic System Metallic System, DEF increased 20%

N

O

x

C

o

n

v

e

r

s

i

o

n

E

f

f

i

c

i

e

n

c

y

,

%

Comparison of Ceramic and Metallic Systems:NOx-Emission Reduction in ETC

7. FAD-Konferenz , November 2009

Euro VI Development

020

40

60

80

100

120

140

160

180

200

N

H

3

-

S

l

i

p

,

[

p

p

m

]

(

M

a

x

.

V

a

l

u

e

)

0

5

10

15

20

25

30

35

40

45

50

N

H

3

-

S

l

i

p

,

[

p

p

m

]

(

A

v

e

r

a

g

e

V

a

l

u

e

)Maximum ValueAverage Value

Ceramic-SCRWith NH3-Slip

Catalyst

Metallic-SCRwithout NH3-Slip

Catalyst

Metallic-SCRwithout NH3-Slip

CatalystDEF incr. 20%

Metallic-SCRwith NH3-Slip

CatalystDEF increased 20%

Comparison of Ceramic and Metallic Systems : NH3 Slip in ETC7. FAD-Konferenz , November 2009

Agenda


High Efficient SCR System Development

LS

LS/PE

LS

SCR

S

L

I

P

EHCHydr. Silencer

DOC

LS

Emicat

Mixer

PM Metalit

SilencerSilencer

Vertraulich / ConfidentialCopying of this document and giving it to others is strictly forbidden without express authority of Emitec!

Airless Urea Injection

Emitec NoNOx SCR Platforms

Airless Urea Injection

Digital Dosing Pump Urea Injection

Air-Assisted Urea Injection

Capacity 60 l/hup to 1000 l/h

Capacity 7,5 l/h

Capacity 2 l/hand 8 l/h

Capacity 2 l/hand 8 l/h

Thank You

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