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

© WinGD, June 2016, SCR under pressure – CIMAC Paper 111/2016 / Sandelin and Peitz9

200

250

300

350

400

450

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

400

600

800

1000

1200

1400

1600

220

240

260

280

300

320

340

360

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

19

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

20

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.