Maritime
DisasterPrevention
CenterWorkshop of the Petroleum Association ofJapan
Feb. 22, 2023

Emulsification Properties of VLSFOMaritime Disaster Prevention Center, JapanRESERCH & STUDY OFFICE Seiichi HAMADA 1

Maritime
DisasterPrevention
CenterContents

1. Overview of VLSFO
2. Overview of experiment
3. Changes in water content
4. Changes in viscosity
5. Consideration(Reference) Change of color

IMO restrictions
on the sulfur
content of ship
fuel oil

General marine waters

Ｊａｎｕａｒｙ 1st, 2012

Restricted emissions
marine waters
Ｊａｎｕａｒｙ 1st, 2020

July 1st, 2010

General marine waters: No more than 0.5% sulfur content VLSFO
Restricted emissions marine waters: No more than 0.1% sulfur content ULSFO

ECANear Europe, U.S.A.
and Canada.
Also regulated underdomestic laws of China,Korea, etc.

Courtesy of the JOGMEC website

VLSFOIFO 180

D-1

D-2

E-1

E-2

E-3

Videos showing comparisons of the flow
characteristics of samples (19°C)

How VLSFO is produced
Source: Toshiaki Hayashi (2021) "Production Method andQuality of Low Sulfur Fuel Oil”

1. Made from low sulfur crude from Asia and Africa(roughly 10% of world production)

2. Made by processing and blending residual oilfrom high sulfur crude oil· Low sulfur content achieved usinghydrogenation desulfurization equipment· Heavy oil is cracked into kerosene and diesel
oil components using hydrogenation-cracking
equipment.
Product characteristics (emulsification characteristics)
vary depending on their method of production.

VLSFO viscosity
ＶＬＳＦＯ
ＶＬＳＦＯ(First time)(Second time)IFO 380

IFO180

VLSFO

Temperature (°C）

Viscosity lower thanconventional oil

Viscosity (PaS) log

Viscosity (PaS)

Traditional Fuel oil C(IFO380)
Traditional Fuel Oil C (IFO180)

Results

VLSFO C-1
VLSFO C-2
Line (VLSFO C-1)
Line (VLSFO C-2)

Temperature (°C）
適合油：VLSFO

Varies exponentially withtemperatureDifferences in viscosity
Fuel Oil (IFO-380)

Lower viscosity (1/2 to 1/20)

Viscosity (mPa･s)

Low Sulfur Fuel Oil

Temperature (°C)

2. Overview of experiment
Moussification experiment using
water flow agitation(FY2021 preliminary)Create violent water flow

Moussification compared after performing
water flow agitation under same conditions

Measuring changes in viscosity (FY2021 preliminary)Comparison of changes in viscosity inconventional C fuel oil and regulation-compliant
VLSFO over a 3-hour period

FY2022 Experimenting equipment (1)Lid collects droplets(to measure watercontent)· Settings: 10°C and 25°C
· Agitate for 96 hours· IFO180 and 5 types ofVLSFO· Measure viscosity
Temperature monitored using
thermocouples

Agitated at 1300 rpm

Temperature control (cold and hot water)

Lid for collecting oil and water droplets

Nearly all droplets were collected on the lid.

FY2022 Experimenting equipment (2)Only lower seawater(initial weight: 7.0 kg) iscollected by vacuum

PVC pipe forpreventing oil inflow

Water content is determinedfrom the weight of residual water.

Suctioning residual water

After suction

Residual oil

Almost all residual
water was suctioned.

Some VLSFO samples
contained many water
droplets.

(1% error even if 70 g remains)

FY2022 Experimenting equipment (3)Dark box forblocking out light

Evaluated changes in color in images
taken under fixed conditions.

3. Changes in water content

Results(1) Comparison with flume basin experiment conducted by Petroleum Association of Japan

Elapsed time (h)Temperature: 25°C

Elapsed time (h)Temperature: 10°C

[1] The water content in IFO180 (previously C fuel oil) approximates thechange in water content in C fuel oil in PAJ’s flume basin experiment.
[2] Water content is higher at 25°C

[2] Changes in water content in VLSFO

Elapsed time (h)Temperature: 25°C

Results

Elapsed time (h)Temperature: 10°C

① Water content increases rapidly within 12 hours. The rate ofincrease is faster at 25°C.
② Maximum water content is greater at 25°C.
③ Water content in some products reach higher than in IFO180.

Water droplets included in water content

Water droplets

Does not stick

Sticks[1] Not only emulsification, but also water droplets in oil[2] Easily separated, already separated[3] Reduces viscosity.
[4] Non-absorbent, and oil does not stick easily to smooth surfaces.

(3) Water content and asphaltene

Elapsed time (h)Temperature: 25°C

Results

Elapsed time (h)Temperature: 10°C

Asphaltene content ishigh in sample D-2.
Currently analyzing waxcontent.

4. Changes in viscosity

Elapsed time (h)Temperature: 25°C

Results

Elapsed time (h)Temperature: 10°C

[1] Emulsified VLSFO has a lower viscosity than IFO 180.
[2] Viscosity is higher at a temperature of 10°C, exceeding 20,000 mPa-S.
[3] 20,000 mPa-S or lower at a temperature of 25°C or lower

25°C Emulsion

VLSFO

IFO 180

D-1

D-2

E-1

E-2

E-3

10°C Emulsion

VLSFO

IFO 180

D-1

D-2

E-1

E-2

E-3

Videos showing flowability ofemulsified oil(flowability at 19°C)

25°C Emulsion

10°C Emulsion

5. Considerations - From the perspective oil removal(Reference) Skimmer recovery efficiency

Maritime Disaster Prevention Center, oil removal course textbook

Skimmer recovery efficiency is high at 2000-3000 cSt.
24

（Reference） Applicable viscosity of skimmer

Textbook of Marine Oil Spill Control Course, MDPC
25
Applicable viscosity of skimmers are up to about 20,000 cSt.

(1) Changes in VLSFO viscosity and skimmer feasibility

Elapsed time (h)Temperature: 25°C

Elapsed time (h)Temperature: 10°C

· Summer (water temperature 25°C): Viscosities are expected to be20,000 cSt or lower.
Skimmers are expected to be feasible even after 4 days, depending on theskimmer model.
· Winter (water temperature 10°C): While viscosities 20,000 cSt or lower are
expected on the first day after spillage, oils exceeding 20,000 cSt have been
observed after the second day, which may make it difficult to use skimmers.

26

(Reference) Effectiveness of oil treatment agents“Effectiveness declines at viscosities greater than
2,000 cSt”
“No effects observed once viscosity reaches 5,000 to
10,000 cSt”
Maritime Disaster Prevention Center, oil removal course textbook
Oil treatment agent added to emulsified VLSFO(Comparison)

Dispersion
effect: Yes(agitated for 96 hours ) (using Center’s test kit)

No dispersion effect from treatment agent
27

(2) Changes in VLSFO viscosity and treatment agent effectiveness

Elapsed time (h)Temperature: 25°C

Elapsed time (h)Temperature: 10°C

· Summer: Effective for some oil types in some cases until after 3 days. After thefourth day, the viscosities of all experimental oil types were at levels that wouldrender agents ineffective.
· Winter: May be effective for some oil types up to 24 hours. After 36 hours, theviscosities of all experimental oil types were at levels that would render agents
ineffective.

28

(2) Changes in VLSFO viscosity and treatment agent effectiveness

Limit of skimmers

Limit of oil treatment
agentsElapsed time (h)Temperature: 25°C

Elapsed time (h)Both oil treatment
agents and skimmers
are effective.

Temperature: 10°C

•In both summer and winter, oil treatment agents are
expected to provide high efficacy in the roughly 1 to 4
hour window after a VLSFO spill (2,000 cSt or lower).
* Based on correlations with results from PAJ’s flume basin test, wave
conditions are assumed to be between "wave height 10-50 cm" and"wave height less than 10 cm."
29

(Reference) Change of color

Red hues become more pronounced.
Values converted to gray scale are highly correlated.

30

Summary
Low sulfur C fuel oil (VLSFO) ...
· Has lower viscosity than conventional C fuel oil.
· Viscosity and emulsion characteristics vary depending on the product.
(The following statements assume wave conditions with wave heights ofseveral tens of centimeters)· When subjected to emulsion action for 4 days:
10,000 to 20,000 mPaS in summer / 15,000 to 25,000 mPaS in winter.
Roughly the viscosity of ointments· In winter (10°C), using skimmers may become difficult in some cases
after the second day (viscosity reaches 20,000 cSt or higher).
· Both in summer (25°C) and winter (10°C), oil treatment agents are
effective until about 1 to 4 hours after the spill (2,000 cSt or lower).
· Oil treatment agents are expected to become ineffective after 4 days insummer and 36 hours in winter (viscosity reaches 10,000 cSt or higher).