Exhaust Gas Cleaning Systems(Scrubber / SCR)

Dual Fuel Engines

Agenda

• Legislation Sulfur Limits

• Scrubber Systems

• Legislation NOx

• SCR System

Legislation Sulphur Limit Requirements

0,0%

0,5%

1,0%

1,5%

2,0%

2,5%

3,0%

3,5%

4,0%

4,5%

5,0%

2005 2010 2015 2020 2025year

Sulp

hur C

onte

nt in

fuel

in %

globalSOx-ECAEU portsUSA 200nmCalifornia

actual legislationIn SOx-Emission-Control-Areas (SECAs)

• 1,50 % (15.000 ppm) vor dem 1. 7. 2010

• 1,00 % (10.000 ppm) ab 1. 7. 2010

• 0,10 % (1.000 ppm) ab 2015

• Alternative Verfahren (z. B. Scrubber) sind zulässig

Actions to reduce SOx emissionPrimary Action

• Fuel Conversion

• Fuel Switching

Secondary Action

• Exhaust Gas Cleaning Systems (Scrubber)

The IMO and EPA both recognize Exhaust Gas Cleaning Systems (EGCS) as acceptable alternative to low sulfur fuels.

Different Scrubber Systems

Wet Scrubber

• Open loop• Closed loop• Hybrid system

Dry Scrubber

Open Loop Scrubber (wet system)

WaterMonitoring

Control Cabinet

WaterMonitoring

Wat

er T

reat

men

t

De-aeration

Sludge Tank

Exhaust Gas

Scru

bbed

Exha

ust G

as

Pump Control

Water / Exhaust Gas Monitoring

Venting

Alkalinity / NOx emission in the Baltic Sea

http://www.helcom.fi/BSAP_assessment/ifs/archive/ifs2007/en_GB/ship_emissions/_print/ 09.02.2011

Alkalinity

Pros & Cons open loop systemAdvantages of the Open Loop System

• The process requires no hazardous chemicals, seawateris the only scrubbing agent.

• The system has fewer components than other wet systems.

Disadvantages of the Open Loop System

• Operation in brackish or fresh water or in high water temperaturescan inhibit scrubbing of SOx.

• The discharge of effluent with acid pH may be restricted in someregions, therefore it may require a switchover to low sulphur fuel or analternative scrubbing system.

Closed Loop Scrubber (wet system)

Control CabinetExhaust G

as

Scru

bbed

Exha

ust G

as

Pump Control

Water / Exhaust GasMonitoring

Tank

NaOH

Water Treatment

Sludge Tank

Holding Tank(Optional)

Fresh Water

Pump(Optional)

Pros & Cons closed loop systemAdvantages of the Closed Loop System

• The system can operate in all regions regardless ofseawater alkalinity or temperature.

• Effluent can be stored on board until a possibility ofdischarging in the next harbour can be used.

Disadvantages of the Closed Loop System

• The system has more components than an open loop system.• The system requires a constant supply of sodium hydroxide

solution, a hazardous substance requiring special handling,care and cost. In addition, the use of caustic soda chemicalsincrease the effort to gain regulatory approval.

Hybrid Scrubber (wet system)

Control Cabinet

Exhaust Gas

Scru

bbed

Exha

ust G

as

Pump Control

Water / Exhaust GasMonitoring

Tank

NaOH

Water Treatment

Sludge Tank

Fresh Water

Pump(Optional)

Open Loop

Close Loop

Pros & Cons hybrid system

Advantages of the Hybrid System

• The system can operate in all regions regardless ofseawater alkalinity or temperature.

Disadvantages of the Hybrid System

• The system requires the most components of any wet option.• Highest price of wet systems.

Dry System

Flow Chart.jpg Granulate

Pros & Cons dry systemAdvantages of the dry system include the following:

• The system does not produce any liquid effluent for overboard discharge.• The system can reduce NOx emissions.• Temperature stays constant• Possibility to install a SCR after the Scrubber• Possibility to use more residual heat

Disadvantages of the dry system include the following:

• The ship must have suitable storage and handling arrangements toaccommodate the dry bulk reactants and products, as well as a reliablesupply of materials.

• Increased costs from use of calcium hydroxide for SOx abatement.• Size and weight of the scrubber.

Dry Scrubber

3,6 MW engine power

Caterpillar Motoren Rostock CMR

24 MW dry scrubber

Marine application

MS Timbus

Comparison of different scrubber systems

Vessel Type: Cargo ShipOperating Aera: ECA Zone Engine Type: MaK 8 M 25 / 2320 kWFuel Oil: Heavy Fuel Oil (S = 2,7%)Exhaust gas flow rate: 15.776 kg/hExhaust gas temperature: 325°CSpecific fuel consumption: 181 g/kWhOperating time: 240 h at 85% engine load

ComparisonComparison of: Dry System (C) Wet System (H) Wet System (A) Engine: MaK 8M25C / 2.320 kW dimension: Height H: 8800 mm 7020 mm 4400 mm

Width W: 4680 mm 3300 mm 2900 mm

Length L: 3100 mm Ø 1750 mm Ø 1500 mm

weight:

dry: 42 t 4,32 t 4 t

running: 55 t 5,82 t closed loop: operation on 10 hours residence tank: 12 t pumps: 7 t multi-cyclone: 1 t NaOH tank: 2 m³ ~ 2,5 t Holding tank: 10 m³ ~ 12 t Sludge tank: 1 m³ ~ 1,5 t piping, etc. ~ 42 – 45 t

5 t closed loop: estimated water buffer tank: 5 t pumps: ~ 7 t urea tank: ~ 7 t storage tank: ~ 5 t water cleaning system: ~ 5 t piping etc. ~ 30 - 35 t

pumps non In total 6 2 wash water supply (one stand by) 2 wash water return (one stand by) 2 reaction water pump (one stand by)

In total 9: SW/FW: 4 pieces High Pressure Pumps: 3 pieces NaOH: 1 Other: 1

material Steel SS / Super Duplex SS SS / Super Duplex SS tank included De-aeration, multi-cyclone, sludge

Optional: flocculent dosing, tank, skimming tank, etc.

Urea, storage, buffer, water cleaning system, etc.

system dry wet / hybrid wet / hybrid

bypass existing existing existing

operating area world wide world wide world wide

energy consumption Low, 20kW several minutes per hour + exhaust gas fan

High (~ 70 kW) at 3,5% S 100 % engine load, add. Cooling water pumps

High (~ 24 kW SW mode / ~ 14 FW mode) Additionally: cooling water pump

ComparisonComparison of: Dry System (C) Wet System (H) Wet System (A)

serviceability Good Good Good

service requirements Low Low Low

service availability Good Good Good

safety ++ + Caustic, violent reaction with water

additives Lime stone consumption (Ca(OH)2), discharge of gypsum, existing logistics

No, only seawater in hybrid mode. SW Mode: discharge of sulphate in the sea FW Mode: caustic soda consumption, need of a discharge water storage tank Global caustic soda suppliers: AGC, Akzo, BASF, …

consumption 30 kg/h per MW at 3% S to 0,1% S %S (HFO) x 29 l/h per ton HFO %S (HFO) x 29 l/h per ton HFO

back pressure 10 – 12 mbar 10 mbarmax 10 mbarmax

disposal sea / harbour Sea / harbour sea / harbour

PM 80 – 90 % reduced up to 80 % reduced up to 80 % reduced

environment pollution No, gypsum for industry Sulphate into the sea Sulphate in open loop into the sea advantages SCR installation after the Scrubber if

needed (retrofit). Robust, low maintenance, low energy consumption. SCR service interval longer (PM will be reduced from the scrubber)

Possibility to change between open and closed loop. Open loop the majority of time and closed loop while sailing in certain areas.

Possibility to change between open and closed loop.

Control & monitoring Complete control system Connection for fan Temperature control Pressure control Level control Heating control Exhaust gas monitoring unit for CO2, SOx, NOx, According to resolution MEPC 184 (59) scheme B, Using continuous monitoring SOx, CO2, and NOx emission.

Standard control system.

Gas analyser: SO2, CO2 and optional NOx Water analyser: PH, PAH, Turbidity The gas analyser do have a probe, particle filter, heated hoze an a gas conditioner cabinet. This analysers are needed to control the exhaust gas cleaning system and monitoring the system to fulfil the requirements of regulations. The pumps are automatically selected based on above mentioned parameters and controlled by the PLC.

ConsumptionWet scrubber

NaOH consumption

% S (HFO) x 29 l/h per ton HFO(50 % NaOH solution)2,7 % S x 29 l/h x 86t HFO(240h at 85%) ~ 6,5 t NaOH

Fresh water

closed loop: 76 m³/hopen loop: 150 m³/h

Sludge

1 t HFO ~ 6,3 kg PM dry ~ 10 kg PM sludge86 t HFO (240h at 85%) ~ 860 kg sludge (at 85% particle filtration + sulphate)

Dry scrubber

Lime consumption

27 kg/h MW at 2,7 % S - reduce to - 0,1 % S27 kg (CaOH) x 2,32 MW x 0,85 load x 240 h ~ 12778 kg (CaOH)

Example data

Engine power: 2320 kWLoad factor: 85 %Fuel consumption: 181 g/kWhRunning hours: 240 hHFO: 2,7% S

Challenges to integrate a scrubber system

• Weight and stability

• Water handling system

• Machinery and exhaust pipe arrangements

• Exhaust back pressure

• Electric power

• Failure modes

We would like to support you

Necessary Information

• Shipping routes• Operating time and load• Operating time in ECA• Operating time in ports (or special EC Areas)• Acceptance of additives like NaOH (caustic soda) or

Ca(OH)2 (lime hydrate)• X-sectional drawing• Ambient conditions

NOx reduction

SCR

8M43C

Selective Catalytic Reaction

Legislation NOx

IMO, NOx-Kurve

0,0

2,0

4,0

6,0

8,0

10,0

12,0

14,0

16,0

18,0

0 250 500 750 1000 1250 1500Drehzahl in 1/min

NO

x in

g/k

Wh

Tier I, ab 2000Tier II, ab 2011Tier III, ab 2016

2,6 2,3

10,59,0

MaK Engine Range

SCR system overview

SCR – The Chemistry of NOx reduction

• Step 1: Hydrolysis of Urea

Urea Solution (CO (NH2)2 + H2O ) Ammonia (NH3) + CO2

• Step 2: Reduction of NOx

Ammonia (NH3) + NOx +O2 N2 + H20

SCR

Catalyst

Elevated

temperature

SCR – Urea Consumption and Cost Calculation

• Necessary NOx Reduction (IMO II → IMO III) – appr. 8 g/kWh

• Urea Consumption (40% solution) → 12.00 l/MWh

• Urea Cost (300 $/t) → 0,27 €/kg → 3,65 €/MWh

• TExhaust = f (TInletAir, Operating Point)• Exhaust gas mass flow• Engine out emissions• Allowed backpressure• Fuel (HFO, MDO, MGO, ULSF)

• Sulfur Content• Catalyst poisons

• Lube oil • Ash content• catalyst poisons

Important values for future aftertreatment layouts

SCR - System

SCR- technology for HFO Operation

250

275

300

325

350

375

0,0 0,5 1,0 1,5 2,0 2,5 3,0

Sulphur Content in Fuel in %

Exha

ust G

as T

empe

ratu

re b

efor

e SC

R in

°c

SCR Fouling

No Problems

Critical / important components

Technical Options (After Treatment view)Post Turbo SCR for SSC engines

- MDO / MGO (LSF) Solution -

61 2 3 4 5

Coo

ler

Urea

SCR Module

61 2 3 4 5

Coo

ler

UreaUrea

SCR ModuleSCR Module

Post Turbo SCR for SSC engines - HFO Solution with DryScrubber -

61 2 3 4 5

Coo

ler

UreaUrea

SCR ModuleSCR ModuleDryScrubberDryScrubber

Post Turbo SCR for SSC engines - HFO Solution with WetScrubber -

61 2 3 4 5

Coo

ler

UreaUrea

SCR ModuleSCR Module WetScrubber

WetScrubber

Advantage Disadvantageonly low sulfur fuel <

0,1%-S in ECA possible

lower temperature limit for catalyst operation, when

running with low sulfur fuel

higher durability and lifetime of catalyst

smaller catalyst possible

No Sox abatement technologies necessary

small plant size compared to scrubber systems

Advantage Disadvantage

High sulfur fuel >0,1%-S in ECA allowed

lower temperature limit for catalyst operation, when running with dry

scrubberhigher durability and lifetime of catalyst

smaller catalyst possible

SOx abatement technolgie necessaryDry Scrubber large

and Heavy

Advantage Disadvantage

High sulfur fuel >0,1%-S in ECA allowed

Sulfur content might be restriced to 1% to to

catalyst poisinghigh temperature limit since SCR has to be

arranged infront of the scrubbing unit

low durability and lifetime of catalyst

large size of catalyst due to short individual lifetime necessarySOx abatement

technolgie necessaryAll negative points of a wet scrubbing system

THANK YOU

For more information, please contact

Steen Kjærhus LarsenAccount Manager MaK ServiceTel:+45 36 88 01 46Mobile: +45 40 16 01 46 Steen.k.larsen@pon-cat.com