x (fuel)

tinv.dk

x (fuel)

Exhaust Gas

Scrubber onboard

Ficaria Seaways

(DFDS)

Results from measurements with the Danish

Environmental Agency (represented by COWI

consulting)

Jens Peter Hansen

PhD, Project Manager R&D


Installation of scrubber in 2009

© Alfa Laval Slide 3

www.alfalaval.com


More than 1 year of operation

© Alfa Laval Slide 4

www.alfalaval.com


New glass fiber pipes installed

© Alfa Laval Slide 5

www.alfalaval.com


Environmental benefits

Operation 1. June 2010 – 30. June 2011

• 3801 hours of operation

• Exhaust from combustion of 9513 ton of HFO has been

cleaned

• 422 ton of SO 2 has been removed

• 143 ton more SO 2 than required has been removed

© Alfa Laval Slide 6

www.alfalaval.com


Heavy Fuel Oil analysis

Note:

HFO

High S

© Alfa Laval Slide 7

HFO

Low S

Sulphur g/kg 21.35 9.45

Arsenic (as)

Lead (Pb)

Cadmium (Cd)

Copper (Cu)

Mercury (Hg)

Nickel (Ni)

Vanadium (V)

Zinc (Zn)

mg/kg = g/ton = kg / 1000 ton fuel

mg/kg

mg/kg

mg/kg

mg/kg

mg/kg

mg/kg

mg/kg

mg/kg


SW mode

The energy consumption will

increase by app. 1.4 % due to

an increased engine back

pressure and for running the

water pumps.

x

X (fuel)

© Alfa Laval Slide 8

x

x

www.alfalaval.com


SW mode, water analysis

Sea water 2.2% S 2.2 % S 1.0 % S 1.0 % S

inlet High load Low load High load Low load

Fuel consumption kg/h 3510 1850 3360 1830

Water flow m3 /h 970 1020 1023 1022

pH

7.8

3.7

5.2

5.5

5.8

Suspended solids (SS)

mg/L 14

14

10

15

12

COD

mg/L 44

52

56

48

46

Sulphur (tot-S)

mg/L 865

900

900

890

870

Nitrogen (tot-N)

mg/L 0.12

0.56

0.34 0.36 0.22

Turbidity (on-line analyser) FNU 8

5

3

5

3

Metals

Total hydrocarbons (THC)

µg/L 24 955 407 295 137

Sum, benzene - C35 µg/L N/A 110 140 330 200

PAH, samples /lab (16 USEPA )

- hereof naphthalene

µg/L

µg/L

N/A

N/A

0.96

0.48

Note: µg/L = mg/m 3 = g / 1000 m 3 ≅ g/h = kg / 1000 h

Slide 9

1.1

0.51

1.8

0.52

1.6

0.57

www.alfalaval.com


PAH [ug/L = ppb]

60

50

40

30

20

10

0

SW mode, PAH measurements

© Alfa Laval Slide 10

Onboard sensor

COWI (Eurofins)

Alfa Laval (ASG)

The sensor shows no correlation to

water flow and engine load as

intended in the MEPC guidelines.

The supplier of the sensor cannot

explain the strange measurements

and why they measure about 20

times more PAH than the

accredited laboratories finds in the

water samples.

www.alfalaval.com


Note on PAH

© Alfa Laval Slide 11

No evidence that combustion of low sulphur fuel should generate less amounts of PAH nor less harmful PAH

www.alfalaval.com


SW mode

Exhaust after scrubber

2.2% S

High load

2.2 % S

Low load

© Alfa Laval Slide 12

1.0 % S

High load

1.0 % S

Low load

Fuel consumption kg/h 3510 1850 3360 1830

Water flow m3 /h 970 1020 1023 1022

SO2

ppm, dry 25 21 3 4

CO2

SO2/CO2

%, dry

ppm / %

3.7

6.8

A SO 2/CO 2 ratio on 43 corresponds to 1.0 % fuel-S

A SO 2/CO 2 ratio on 4.3 corresponds to 0.1 % fuel-S

(Documented in MEPC 59)

The scrubber is being modified so it can reduce down to 0.1 % Fuel-S with

high sulfur fuel also.

3.7

5.7

3.3

0.8

3.7

1.0

www.alfalaval.com


SW mode, conclusions

• The exhaust gas sulphur content is below 1.0 % fuel-S equivalent, which is the limit until

2015. The scrubber is being modified to prepare for the 0.1 % S limit after 2015.

• The concentration of soot particles (PM) in the discharge water is so low that the

increase in turbidity is close to zero and therefore significantly below the limits in the

MEPC 59 guidelines.

• The true PAH level in the discharge water is close to zero and therefore significantly

below the limits in the MEPC 59 guidelines. It is not possible to measure the PAH online

as intended in the MEPC guidelines. It is more reliable to take out samples and to have

these analyzed by a certified laboratory at land.

• A discharge pH down to 3.0 must be expected. It is however not easy to measure in

practice, that the discharge water is diluted to pH 6.5 four meters from the ships hull as

supposed in the MEPC guidelines.

• Only the sulfur in the heavy full oil is converted to harmless sulfate. Heavy metals etc.

are emitted either with the exhaust gas or the discharge water. The release of heavy

metals etc. from the scrubber and piping material itself is insignificant (else it would have

been corroded).

© Alfa Laval Slide 13

www.alfalaval.com


FW mode tests

© Alfa Laval

A test with circulating water and without any cleaning of this water

was carried out on request from our EPA in order to better

measure how soot, sulphur and metals build up in the water. In

SW mode, it is more difficult to measure this because of the large

flow of SW.

THIS IS NOT NORMAL OPERATION!!!

www.alfalaval.com


FW mode

The energy consumption will increase

by app. 3.4 % due an increased engine

back pressure, for running the water

pumps (including cooling water), and x

for producing the NaOH.

x (fuel)

x (fuel)

x

x

x

X = Sample or measurement positions

© Alfa Laval Slide 15

x

X (fuel)

x

x

x

www.alfalaval.com


FW mode, NaOH consumption

120

80

40

0

NaOH 100 % [kg/ton fuel]

NaOH 45 % [kg/ton fuel]

NaOH 45 % [L/ton fuel]

Cost [€/ton fuel]

0 1 2 3 4

Fuel‐S [% (w/w)]

© Alfa Laval Slide 16

www.alfalaval.com


FW mode, NaOH production

http://www.olinchloralkali.com/Library/Literature/OverviewOfProcess.aspx


Diaphragm Cell

Approximately 71% of electrolytically produced Caustic Soda in North America is produced by this process.

This process utilizes asbestos, or alternate substitutes to asbestos, to separate the co-products Caustic

Soda and Chlorine. The production of 50% Caustic Soda occurs primarily outside of the electrolytic

cell. The diaphragm cell produces a very weak 'cell liquor,' which contains 12-14%, by weight, NaOH and roughly

the same concentration NaCl salt. The 'cell liquor' is subsequently evaporated in a three or four 'effect'

evaporation process to a final nominal concentration of 50% NaOH by weight (49-52% range). The excess salt is

precipitated and filtered through the evaporation process for subsequent reuse/recycle. This process produces

the lowest quality electrochemical Caustic Soda solutions.

The quality considerations with respect to the diaphragm cell produced Caustic solutions include relatively high

salt, chlorates, carbonates, and sulfates. Salt, as NaCl, concentrations are typically 1.0%, with maximums

ranging from 1.1 to 1.3 weight %, depending on producer. Sodium Chlorates are typically 0.15 weight %, with a

maximum of 0.3 weight %. Sodium Carbonates are typically 0.1 weight %, with a maximum of 0.2 weight %.

Sodium Sulfates are typically 0.01 weight %, with a maximum of 0.02 weight %.

The diaphragm cell produced Caustic Soda is often referred to as Diaphragm Cell Grade. It is also called

Commercial Grade, Technical Grade, and occasionally Technical Diaphragm or other similar combinations.

An additional 'grade' of Caustic Soda produced by the diaphragm cell process is the Purified Grade. The

production of Purified Grade involves the further evaporation of the 50% Diaphragm Grade Caustic Soda solution

to reduce the salt concentration. The higher Caustic Soda concentration forces precipitation of the salts, which

are soluble in Caustic Soda solutions in an inverse relationship. The higher concentration solution is then rediluted

to the 50% concentration that is commercially available as Purified Grade Caustic Soda.

Common uses include process and wastewater neutralization, textiles production, soaps and detergents and

aluminum production. These uses and applications generally will refer to the Caustic Soda as any of the various

grades previously addressed, dependent on supplier's terminology.

Total equivalent energy, on a DC basis, needed to produce Caustic Soda via the diaphragm

cell process is approximately 5000 kWh per metric ton.

© Alfa Laval

NaOH production 5000 kWh/ton

= 18000 kJ/kg

Energy in HFO 41000 KJ/kg HFO

HFO sulphur content 2.2 % (w/w)

mol NaOH

Molar ratio 1.75 /mol S

NaOH required 0.048 kg/kg HFO

NaOH energy 866 kJ/kg HFO

% of energy in HFO 2.1 %

www.alfalaval.com


FW mode

Exhaust after scrubber

2.2% S 1.0 % S

High load High load

Fuel consumption kg/h 3500 3500

SO2

ppm, dry 16 4

CO2

%, dry 4.3 4.4

SO2/CO2

ppm / % 3.6 0.8

A SO 2/CO 2 ratio on 43 corresponds to a fuel sulfur content 1.0 %

A SO 2/CO 2 ratio on 4.3 corresponds to a fuel sulfur content 0.1 %

(Documented in MEPC 59)

© Alfa Laval Slide 18

www.alfalaval.com


FW mode, sludge

Substance/parameter Unit Wash water from scrubber

© Alfa Laval Slide 19

Wash water from scrubber

FW-mode, HFO 2.2 % S

FW-mode, HFO 1.0 % S

T = 0 T = 120 T = 120 T = 0 T = 120 T = 120

centrif.

centrif.

Fuel consumption

General and inorganics

kg/h 0 3520 3520 0 3490 3490

pH

Suspended solids (SS)

COD

Sulphur (tot-S)

-

mg/L

mg/L

mg/L

5.9

91

450

1800

6.5

350

1000

6400

Nitrogen (tot-N)

mg/L 24 120 120 25 55 86

Metals

Total hydrocarbons

µg/L 6898 22561 18394 5093 8497 7961

Sum, benzene - C35 µg/L 500 4500 11000 5400 29000 21000

PAH (16 USEPA)

µg/L 9.2 16 3.8 16 30 24

- hereof naphthalene

µg/L

0.71

THIS IS NOT NORMAL OPERATION!!!

0.71

-

25

440

9000

0.32

6.2

85

300

1500

0.75

7.0

220

800

4500

0.82

-

39

490

4800

0.49

www.alfalaval.com


FW mode, sludge

pH

Dry weight (dw)

Loss on ignition

Sulphur

Unit Sludge

(HFO, 2.2 % S)

-

7.1

%

11

% of dw

51

mg/kg dw 79000

© Alfa Laval Slide 20

Sludge

(HFO, 1.0 % S)

7.2

11

59

52000

Metals mg/kg dw 18823 11848

Organics

THC, sum benzene-C35

PAH (16 USEPA)

PCB (7 congeners)

PCDD/PCDF (I-TEQ)

mg/kg dw

mg/kg dw

mg/kg dw

ng/kg dw

111000

230


FW mode, conclusions

• The exhaust gas sulphur content is below 0.1 % fuel-S equivalents (limit after 2015)

• Suspended solid, sulphur and other components accumulates in the circulating water as

expected.

• The PAH level in the water is - even after 120 minutes - very low. Most of the PAH is

associated with the sludge collected in the centrifuge

• The sludge mainly consist of unburned carbon, sulphate but also vanadium, nickel and

copper originating from the fuel oil. The sludge must be delivered to adequate port

reception facilities together with the ships normal sludge.

© Alfa Laval Slide 21

www.alfalaval.com


Particle Measurements

Force Technology, Danish Technological Institute, and Copenhagen

University were onboard for making detailed particle measurements

before and after the scrubber (SW mode).

Operating on high sulfur (2.3 % S) and low sulphur (1.0 % S) fuel were

compared.

Equipment used:

- Scanning Mobility Particle Sizer (SMPS)

- Electrical Low Pressure Impactor (ELPI)

- Handheld Condensation Particle Counter (CPC)

- Scanning Electron Microscopy (SEM)

- Energy dispersive X-ray spectroscopy (EDX)

The results will be fully published - see www.NAKIM.dk

Measurements are very difficult to generalize because the particle

emission greatly depends on actual fuel oil, lube oil, engine load,

turbocharger, scrubber operation, air humidity, etc. The engine,

turbocharger and exhaust boiler is never stable – soot builds up and

blows off.

© Alfa Laval

www.alfalaval.com


Legislators and Industry need to

co-operate in order to work

around the “holes”

© Alfa Laval Slide 23

The main goal must be to reduce the number

of premature deaths, asthma diseases, etc.

due to sulfur emissions with as little

environmental (side) impact as possible and

at an affordable price.

The MEPC guidelines must be slightly

modified to work around the following two

“holes”:

1. No reliable sensor is available to measure

that our actual discharge PAH is below

limits.

2. No practical methods are available to

measure that our discharge pH is below

6.5, four meters from the ships discharge

point.

www.alfalaval.com


1135 days to 2015….

It is now time to get some scrubbers installed in order to:

• Reduce the risk for lack of low sulfur fuel oil in 2015 / 2020 and hence significant price increases

• Prepare our organization and production for the 2015 need

• Avoid that we are going to fit all ships with scrubbers in Dec 2014

• Get more data and experiences for further technical development and legislative changes

• Finance further R&D

Investments can only continue, provided that

• The MEPC guidelines are modified slightly with respect to pH and PAH

• IMO member states and other authorities acknowledge and approve scrubbers as an equivalent to

low sulfur fuel

Alfa Laval is prepared to contribute to further improvements of the technology and legislation. Especially,

• The insensitive to improve PM removal from the exhaust and subsequently from the discharge water

should be improved in the legislation

However, we can still save many human lives by installing scrubbers tomorrow. Future corrections to the

technology should not stop this work

© Alfa Laval Slide 24

www.alfalaval.com

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