Innovative Exhaust Gas Aftertreatment: NOx Storage Catalysts for
2010 Diesel Emission Reduction Consortium Experimental Studies of Exhaust Chemistry and...
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Transcript of 2010 Diesel Emission Reduction Consortium Experimental Studies of Exhaust Chemistry and...
2010 Diesel Emission Reduction Consortium
Experimental Studies of Exhaust Chemistry and Aftertreatment
Professor Thatcher RootDepartment of Chemical and Biochemical Engineering
September 21, 2004
2010 Diesel Emission Reduction Consortium
DPF, LNT, DPNF Agenda
Investigate the link between surface chemistry and macroscopic trap behavior. – Chemical reactions to reaction engineering– Reaction parameters and model validation
Effects of engine operation via soot chemistry– Elemental vs. organic carbon with engine load– Trapping efficiency, reactivity during regeneration
Trap diagnostics – T, P, sensors for O2, NOx, …
Track soot and NOx accumulation
– Link to surface chemistry– Eventual goal: control of cyclical operation
2010 Diesel Emission Reduction Consortium
Diesel Particulate Matter
Semi-Volatile Condensed Aerosol
(VOC+sulfate+H2O+ trace metal
compounds)
Elemental Carbon Agglomerate
Adsorbed Semi-Volatile
Compounds(VOC+sulfate+
H2O + trace metal compounds)
0.1 m
2010 Diesel Emission Reduction Consortium
EC, OM, Sulfates (SO4) in PM2.5
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00
50
100
150
200
250
300
350
400
450
EC
/PM
2.5,
OM
/PM
2.5
Equivalence Ratio,
Mode 5 [100%]Mode 6 [75%]
Mode 7 [50%]Mode 4 [25%]
Spe
cific
Par
ticul
ate
Che
mic
al C
ompo
sitio
n [m
g/ih
p-hr
]
Equivalence Ratio,
Engine Speed:1200 rpm Elemental Carbon Organic Mass Sulfates
0.0 0.2 0.4 0.6 0.8 1.00.0
0.2
0.4
0.6
0.8
1.0
OM/PM2.5
EC/PM2.5
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00
50
100
150
200
250
300
350
400
450
Equivalence Ratio,
EC
/PM
2.5,
OM
/PM
2.5
Mode 1 [100%]
Mode 2 [75%]
Mode 3 [50%]
Spe
cific
Par
ticul
ate
Che
mic
al C
ompo
sitio
n [m
g/ih
p-hr
]Equivalence Ratio,
Engine Speed:1800 rpm Elemental Carbon Organic Mass Sulfates
0.0 0.2 0.4 0.6 0.8 1.00.0
0.2
0.4
0.6
0.8
1.0
OM/PM2.5
EC/PM2.5
1200 rpm 1800 rpm
Specific EC, OM, and sulfates shift significantly with the change in the engine load.
2010 Diesel Emission Reduction Consortium
Chemical Characterization of Diesel Exhaust
EXHAUST
SECONDARY DILUTION TUNNEL
RESIDENCETIMECHAMBER
PRIMARY DILUTION TUNNEL
PRIMARY DILUENTS
FLOW ORIFICE
REGULATOR
FILTER
BUILDING AIR
TO
RE
AC
TO REAC
TO REAC
TO REAC
T
T
142 MM FILTER HOLDER
FLOW ORIFICES
EXHAUST
VACUUMPUMP
47 MMFILTER HOLDER
EXHAUST FLOW ORIFICE
VACUUM PUMP
T, P
T, P_VAC
T, P_ABS
P_VAC
P_VAC
INCLINED MANOMETER
AIHH CYCLONE
Augmented sampling system Sulfate ions Trace metals EC/OC PM Con.
Organics Semi-volatile organics
Size dist. - number - mass - volume
Real-time PM - concentration - total mass - mass rate
Trace metals Sulfate ionsMass
Mass EC/OC
Organic compounds
Semi-volatileorganiccompounds
2010 Diesel Emission Reduction Consortium
Engine Layout
Pre
ssur
e T
rans
duce
rF
eed
Gas
Air Compressor
Fro
m F
uel
T
ank
pum
p
2010 Diesel Emission Reduction Consortium
Fuel Burning System for Filter Regeneration
MV 1
MV 2
MV 3
MV 4
EV
LV ZFG
Control Unit
MixingChamber
Pressurereducer
Diesel Fuel Tank
Compressed Air Tank
Burner / Filter Unit
TB
PG
TvF TnF
PLD+
V1530Diagnosis
M
4
6
8
10
12
14
16
18
20
800 1000 1200 1400 1600 1800
30 35
4045
50 60
70
11 l DI/TCI Diesel Engine with cooled EGR (EURO 4)
BM
EP
(b
ar)
Engine speed (rpm)
2
25
Power in kWComplete burner system for retrofit applications. OEM applications might use an air pump instead of compressed air.
Power draw of the burner to heat exhaust to 650 C depends on the load point. 2% instantaneous fuel penalty is typical
Zeuna Staerker, AVL International Commercial Powertrain Conference, Budapest, 10/01
Alternative: regeneration in external furnace for comparison with complete regeneration
2010 Diesel Emission Reduction Consortium
DPF, LNT, DPNF Agenda
Investigate the link between surface chemistry and macroscopic trap behavior. – Chemical reactions to reaction engineering– Reaction parameters and model validation
Effects of engine operation via soot chemistry– Elemental vs. organic carbon with engine load– Trapping efficiency, reactivity during regeneration
Trap diagnostics – T, P, sensors for O2, NOx, …
Track soot and NOx accumulation
– Link to surface chemistry– Eventual goal: control of cyclical operation
2010 Diesel Emission Reduction Consortium
Chemistry in a Four-Way Catalyst
The principle of combination diesel particulate/NOx reduction system.
PM is oxidized in both lean and rich conditions.
Periodic rich pulse causes PM to oxidize
Toyota SAE 2002-01-0957
2010 Diesel Emission Reduction Consortium
Trapped soot on inlet wall surface Cell Plugs
Exhaust(Soot, CO, HC)Enter
Exhaust (CO2, H2O)Out
Ceramic HoneycombWall with SupportedCatalyst
Plugged-monolith Wall-flow Filter
Place a catalyst in front of or within filter to oxidize NO to NO2
2010 Diesel Emission Reduction Consortium
Mechanism for NOx Storage, Part I
Adsorption, desorption, and reaction over Pt sites
Rate parameters from Olsson et al.
PtNOPtOPtNOPt
NOPtPt NO
NOPtPt NO
O2PtPt 2O
2r
r
2r
r
2(g)
r
r
(g)
r
r
2(g)
8
7
6
5
4
3
2
1
RRhh
AlAl22OO33
NONO + + ½OO22
Ba(NOBa(NO33))22
BaCOBaCO33
NONO22
COCO22
Pt
Rh
2010 Diesel Emission Reduction Consortium
Mechanism for NOx Storage, Part II
NOx storage on Barium sites
Rate parameters from Olsson et al.
RRhh
AlAl22OO33
NONO + + ½OO22
Ba(NOBa(NO33))22
BaCOBaCO33
NONO22
COCO22
Pt
Rh
PtNOBaNOSNOPt
O2SO2S
NOBaNOSNO
NOSOSNO
NOOSNOS
NOSSNO
23r
r
312
2(g)1r
r
1
23r
r
312(g)
31r
r
12(g)
1r
r
21
21r
r
12
20
19
18
17
16
15
14
13
12
11
10
9
2010 Diesel Emission Reduction Consortium
Regeneration With Hydrocarbon
Reduction of NOx with propene
Rate parameters from Olsson et al.
AlAl22OO33
CO + HC + HCO + HC + H22
PPtt
BaCOBaCO33
RRhhBa(NOBa(NO33))22
NN22 + + COO22
NOxNOx COCOO2
2(g)22(g)2r
22
(g)22(g)2(g)r
222
22r
r
22
21r
r
12(g)
(g)22(g)31(g)r
223
(g)22(g)1(g)r
221
(g)22(g)r
63
63r
6(g)3
2(g)(g)22(g)r
2
(g)22(g)r
2
2r
63
63r
r
6(g)3
1.5NOHCOS3PtNO3PtCHS
OHCOS3Pt3NONO3PtCHS
CHSPtSCHPt
COSSCO
OHCONO3SPt3NOCHPtNO3Ba
OHCO3SPt3NOCHPtNO3S
O3H3CO9PtO8PtHCOPt
HCOPtOPtHC
1.5NOHCO4PtNO3PtCHPt
OHCO4PtO3PtCHPt
CH3Pt2PtHCPt
HCPtPtHC
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21