SCR under pressure - pre-turbocharger NOx abatement · PDF fileCIMAC Congress paper no.: 111,...
Transcript of SCR under pressure - pre-turbocharger NOx abatement · PDF fileCIMAC Congress paper no.: 111,...
CIMAC Congress paper no.: 111, Helsinki 2016, prepared by Sandelin/Peitz
SCR under pressure - pre-turbocharger NOxabatement for marine 2-stroke diesel engines
Emission control areas for sea going vessels
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz2
SOx limits established, NOx limits only in some ECAs
Source: DNV GL
Emission control areas for sea going vessels
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz3
New ECAs are under consideration
Source: http://www.green4sea.com
Emission control for 2-stroke diesel engines
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz4
…a multi-variable equation
Operation profile:
Fuel flexibility:
Fuel availability:
Common approach:
Sailing patternRunning hours (ECA/non-ECA)
Sulphur limitScrubber or low sulphur fuelsNew fuel properties with < 0.1% S fuels
What and where to bunker
Same solution to be used forpropulsion engine and gen sets?
Picture: Langh Tech
NOx control solutions for 2-stroke engines
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz5
Exhaust gas recirculation (EGR)
+ Low space requirement+ Can be designed for fuel flexibility+ Yards choice with respect toinstallation space- Limited suppliers- Common technology with gen sets- By-products
Different NOx control solutions for 2-strokes
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz6
Low pressure SCR is installed down stream turbo.
+ Conventional selective catalyticreduction (SCR) technology+ Equipment common with gen sets+ No space requirement in engine room- Only low sulphur fuels- Requires urea decomposition unit anda heating/regenerating device/strategy
picture: Doosan
Different NOx control solutions for 2-strokes
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz7
High pressure SCR is installed upstream turbo.
+ Fuel flexible. It can be combined withscrubbers.+ Reducing agent system common forgen sets+ Part of the engine- Challenging pressurized piping- Sophisticated temperature control- Multi turbocharging a challenge
High pressure pre-turbo SCR systems
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz8
1999, 2000M/V SpaarneborgM/V SchieborgM/V Slingeborg3x7RTA-52U10’920 kW each
2016«Suezmax tankers»2xW6X7215’080 kW each
2015M/V Papuan Chief5RT-flex58T-D10’000 kW
WinGD’s HP-SCR references available
source: ferrypics.com
Lesson learned: exhaust temperature the most important process parameter forthe operation of the HP-SCR
Exhaust temperatures before and after turbo
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200
250
300
350
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500
1 2 3 4 5
Tem
pera
ture
[°C]
Exhaust pressure before turbine [bar absolute]
Exhaust gas temperaturebefore turbocharger
Exhaust gas temperature afterturbocharger
Source: GTD, W6X72
Variable temperatures before turbo.
Property/Load % 100 75 50 25
Pressure beforeturbine bar 4.3 3.3 2.3 1.4
Temperaturebefore turbine °C 448 379 348 310
Pressure afterturbine bar 1.0 1.0 1.0 1.0
Temperatureafter turbine °C 263 232 243 240
1. Limit due to reducing agent decomposition (min)2. DeNOx catalyst performance limits (min, max)3. Catalyst endurance limit (max)4. Stickiness of soot, lubrication oil residues and unburned hydrocarbons (min)5. Stickiness of ash (min, max)6. Dew point of ammonium sulphate salts (min)7. Deactivation limit due to ammonium sulphate salts (min)
SCR limiting temperatures
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz10
Many factors influence the temperature window for operation
TI
TI
TI
Lee et al 2015
Ammonium sulphates
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz11
1.0 bar
4.3 bar
The bulk dew point can be calculated. It is changing with pressure
Gas
Condensed
Ammonium sulphates
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz12
Pore condensation decreases activity, bulk condensation «fouls» it
Catalyst channel
Catalyst cell opening:typically 3 to 5 mm
Pore size:extent of 10-5 mm
Picture: T. N. White:Duke / WPCA NOx Seminar2005.
Catalyst wall0.5 mm
Ammonium sulphates
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz13
Catalyst activity decreases if the exhaust temperature is too low
Pressure [bar]Pressure [bar]
k = ln(mout/min)/residence time
pcat=2.6 barTrec=345CTcat_in=330CTcat_out=336
Deactivation
Ammonium sulphates
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz14
Catalyst activity restored when temperature is increased
Pressure [bar]Pressure [bar]
k = ln(mout/min)/residence time
pcat=2.6 barTrec=345CTcat_in=330CTcat_out=336
pcat=3.3 barTrec=380CTcat_in=370CTcat_out=373C
Deactivation Reactivation
Ammonium sulphates
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz15
SCR pore condensation/deactivation temperature can be calculated
-12
-11
-10
-9
-8
-7
-6
220 240 260 280 300 320 340 360 380
log
K
Temperature [°C]
in gas form
in condensed form
Tpore= 340 * 14 * ln (Sfuel*p2)Rule of thumb: Tbulk= 310 * 14 * ln (Sfuel*p2)
Operation pointDeactivation
Operation pointReactivation
Summary
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz16
• NOx legislation is in place since January 2016• New ships with two-stoke engines sailing in NECA areas
need to control their NOx emissions according to Tier III• SOx limits are in place at the same time in the NECA
• Good engine temperature management and prediction ofammonium sulphate salt condensation allow successfuloperation of the engine together with HP-SCR:
• With distillate and residual fuels and• At high and low engine loads
• Exhaust gas recirculation, low- and high pressure SCRare potential NOx abatement technologies
• High pressure pre-turbo SCR is fuel flexible and issuitable when burning residual fuels.
NOx abatement for Marine 2-stroke Diesel Engines available
Co-Author: Daniel Peitz of WinGD; Martin Elsener and Oliver Kröcher of the Paul ScherrerInstitute for the good collaboration.
This project has received funding from the European Union’s Horizon 2020 research and innovationprogramme under grant agreement No 634135, HERCULES II.
Thank you!
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz17
Bulk and pore condensation temperature change along the catalyst
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz18
0
200
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1000
1200
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1600
220
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380
0 1 2 3 4 5 6 7 8 9
NH
3[p
pm]
Dew
poin
t[°
C]
Catalyst length
Reducingagentconcentration
Exhaust flow direction
Ammonium sulphates
Emissions regulation by IMO
© WinGD, January 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin, Kristoffer
INTERNAL/EXTERNAL USE
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Table 1 Emission standards, geographic areas and emission limitsthat apply to low speed two stroke engines.
Pollutant Area Rule Geographic area Emission limitNOx NECA Marpol
Annex VITier III
North AmericaUS Caribbean
3.4 g/kWh
SOx SECA MarpolAnnex VI
North SeaBaltic SeaNorth AmericaUS Caribbean
0.1 % Sulphurfuel
SCR under pressure…
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin, Kristoffer
INTERNAL/EXTERNAL USE
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Figure 2 5RT-flex58T two stroke engines test bed results
20.37
16.63
13.2511.95
13.87
4.843.55
2.53 1.882.58
0
5
10
15
20
25
25 50 75 100 E3 weighted
NO
xas
NO
2[g
/kW
h]
Test points [% load]
NOx after engine
NOx after SCR
SCR under pressure…
© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin, Kristoffer21
Figure1 5RT-flex58T two stroke engines.