Scrubber Wash Water Monitoring Challenges

and Solutions for PAH

Presented to:

EGCSA

25FEBRUARY2016

Gary Bartman

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Onboard Testing Requirements

Monitoring and Calculating PAH levels

Samples and Data Collected

White paper with suggested changes to IMO

available MEPC.184(59)

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PAH as Phenanthrene Equivalents “UV” “Fluorescence” Closed loop vs Open loop Type Certification Metrology Bilge water discharge model? “Bilge Alarm” Onboard Validation Sampling Protocol Measurement Methods - lab Onboard measurements vs lab results Monitor vs Analyzer

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GENERAL:

pH and Turbidity sensors must meet international standards.

However, standards for on-line PAH monitors (standardized

metrology test protocol) do not exist.

PAH and Turbidity sensors are known to report flat line (non-

responsive) due to fouling and other issues.

Wash water instrument performance monitoring seems to be

ignored after start up due to lack of operator confidence or fear.

Currently, there are no prescribed procedures to validate wash

water monitors onboard (onboard demonstration of compliance),

especially for PAH sensors. (It is required by IMO.107(49) for Bilge

Alarm)

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Take Away’s

SPECIFIC TO CLOSED LOOP DISCHARGES:

MEPC. 184(59) Guidelines do not specifically address

wash water discharge during closed loop operation.

Water volumes discharged during closed loop operation

push the flow rate in t/MWh to that of a small scrubber /

engine combination.

Color correction (light absorption) may be required for

closed loop discharges.

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Stack gas pollutants are now in the water phase

Monitoring is required to prevent pollution

(upsets).

Still many unknowns on the water monitoring side

in the eyes of IMO and the world. Therefore,

monitoring to gather data for future rules review.

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Flow Rate (t/MWh) Discharge Concentration Limit (PAHPHE,

μg/L)

0-1 2250

2.5 900

5 450

11.25 200

22.5 100

45 50

90 25 10

Background on Regulations

Guidelines require that the PAH content of scrubber waste water be monitored by

fluorescence for water flow rates ≥ 2.5 tonnes/megawatt-hour (t/MWh). The

maximum allowed concentration limit depends upon the water flow rate as shown in

Table 1.

PAH Discharge Limits for Differing Water Flow Rates

The PAH concentration must be reported in units of phenanthrene equivalents

(PAHPHE). A PAHPhe is the fluorescence emitted by 1 μg/L of phenanthrene. A

waste water sample has a PAHPhe concentration of 1 μg/L when it has a

fluorescence response that is equal to the fluorescence response of 1 μg/L of

phenanthrene

Fluorescence

UV Absorption (Suggested)

Why Phenanthrene?

What is a “Phenanthrene Equivalent”?

How do we measure it?

How do we report it?

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0

5

10

15

20

25

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1 2 3 4 5 6

Con

centr

ati

on (PPB)

5 ppm HFO Samples from Various Locations

Phenanthrene Total PAHs

Definition: A Phenanthrene equivalent is the fluorescence emitted by 1 μg/L of Phenanthrene. The PAH concentration of a wash water sample can be expressed as the μg/L of Phenanthrene that emits fluorescence equal to the total emitted by all the PAHs.

Wash water sample has a fluorescence equal to 5 μg/L of phenanthrene. PAHPhe = 5 μg/L

Total PAH

Fluorometer

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This is important

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Fluorescence is a simple field proven method for measuring light emitted from hydrocarbons that have aromatic content. The “A” in PAH stands for Aromatic. Yes, PAH’s fluoresce.

Note that there may also be non-PAH chemicals that fluoresce and may cause interference.

The secret to success is in the elimination of most of the interference while maintaining sensitivity to Phenanthrene equivalents.

The fluorescence monitor should demonstrate correlation to a prescribed standard laboratory method.

(No method is prescribed under MEPC.184(59))

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Phenanthrene measured here

Turbidity measured here

Green Laser in Clean Water

Green Laser in Rhodamine Water Mixture

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Reflections

Fluorescence at a longer wavelength

We believe it requires an analyzer / monitor calibrated

with Phenanthrene or equal water soluble surrogate in

order to report Phenanthrene equivalents.

Because fluorescence is a measurement of light, the

fluorometer calibrated with Phenanthrene will typically

report higher than actual PAH. But it must correlate to

standard lab methods.

Scrubber wash water contains unburned HFO which is a

complex combination of many PAH’s all of which

fluoresce.

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“We are not confident in water monitoring

systems.”

“Not certain they are making a measurement!”

“Does Flat Line mean no change or that the

patient has expired?” - No way to validate

performance onboard.

“We have no way to keep them clean.”

“Suppliers do not understand the requirements!”

“Surveyors are starting to pay attention to wash

water monitoring equipment!”

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Measurement can be challenging due to

concentration water soluble chemicals developed

during recycle.

UV (Absorption) is not viable for this kind of water.

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0

50

100

150

200

250

300

350

400

Ph

enanth

rene E

qu

ivale

nts

(p

pb

, PA

Hp

he)

Date & Time

TD-5100ECA - Open Loop Monitoring

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0

10

20

30

40

50

60

70

80

90

100

Ph

enanth

rene E

qu

ivale

nts

(p

pb

, PA

Hp

he)

Date & Time

TD-5100ECA Open Loop Monitoring

Currently installed monitoring systems have become

suspect by both the scrubber manufacturers and the

certifying agencies even though they passed overall

system certification.

Current off the shelf systems that we have observed are

under reporting PAH (should be over reporting).

Users have no way to validate PAH or Turbidity

performance onboard.

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E09 Operating System w/

Communication and Alarms

Internal data logger

3 Levels of Security

Injection Port for Onboard

Validation of PAH and Turbidity

and Onboard Calibration with

Simple Standards

Ultrasonic Cleaning

Waste Collection Bottle

Corrosion Resistant Materials

Marinized – Ready for DNV GL

Type Certification (in process)

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Type certification is not currently required unless by the customer.

Current type certification does not address metrology (making the measurement).

Within reason, sensor companies can write their own test protocol for certification – no uniform metrology protocols, long term testing requirements, yet.

We expect type certifications to be required at some point but much needs to be done to create a proper test protocol.

We expect uniform metrology protocols to be developed

Closed Loop operational monitoring needs to be addressed.

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Confirmation of Compliance “This is to confirm that the undernoted product has been

tested in accordance with the requirements of

MEPC.184(59) in respect of washwater monitoring.”

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MEPC. 184(59) Guideline is not specific to wash water discharge

during closed loop operation of scrubbers.

We believe that monitoring for PAH in closed loop discharge

operation is not yet viable.

pH and Turbidity sensors must meet international test standards but

no existing standards for on-line PAH monitors (standardized

metrology test protocol).

Currently no prescribed procedures to validate wash water monitors

onboard (onboard demonstration of compliance). True especially

for PAH sensors.

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Water monitoring systems (especially PAH and Turbidity) are known

to be flat line, non-responsive due to fouling and other issues.

Sensor maintenance is vital and my differ from ship to ship

Wash water instrument performance monitoring may be ignored

after start if operators have no confidence in them.

Regarding Sustainability – Communication of test results – be

certain to have proper sample gathering and third party results to

recognized and acceptable standards.

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PAH as Phenanthrene Equivalents “UV” “Fluorescence” Closed loop vs Open loop Type Certification Metrology Bilge water discharge model? “Bilge Alarm” Onboard Validation Sampling Protocol Measurement Methods Onboard measurements vs lab results Monitor vs Analyzer

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Gary Bartman:

Gbartman@oilinwatermonitors.com

+559 253-1414 x 335

www.oilinwatermonitors.com

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