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Development of a Bunker Norm for Ships

8. Proposal for a New Bunker Norm

The actual purpose of and the wish to introduce a new bunker norm were described already at the beginning of this report.

Bunker diesel standards exist for the purchase of bunker oil – with ISO 8217 and CIMAC being the best known and in most widespread use. It should be noted that specifying a fuel reference only to a standard provides no guarantee that a quality oil will be received – even following an oil analysis which confirms that the oil is consistent with, e.g., the ISO standard or CIMAC. The reason for this absurd situation is that the ISO standard does not cover all relevant quality parameters. Among the relevant quality parameters are: low calorific value, stability, sodium content, lead content, calcium content, phosphorous content, zinc content, ignition index-CCAI, waste lubricants, and solvents.

The Steering Group for the establishment of this norm has found that the fuel oil quality for Danish ships and Danish waters can be braced up with regard to the sulphur content. The Steering Group has not deemed it appropriate to include the above additional relevant quality parameters, but the Environmental Protection Agency seems to think it might be a good idea.

The Steering Group does not find IMO’s future requirement (that the sulphur percentage must not exceed 4.5%) sufficiently restrictive – in view of the fact that the average sulphur content worldwide is about 2.6 to 3.0%.

Shipowners are generally inclined to have the sulphur content in the fuel oil reduced – in order to improve the operating conditions and their public image - and also in relation to IMO’s high sulphur content. Also, being exposed to environmentally differentiated harbour dues is a great nuisance for the shipping companies’ operations.

It is the Steering Group’s view that a maximum sulphur limit of 1.5% is acceptable by the industry.

When specifying a fuel oil for a ship it is extremely important that the quality requirements for the fuel oil for the individual ship and its machinery match the engine manufacturer’s specifications. In many cases it is a good idea to choose an oil with a quality better than that prescribed by the engine manufacturer.

In the light of CIMAC’s recommendations for oils diagrams were drawn up, as a first proposal, for distillated fuels and residual fuels for diesel engines. CIMAC’s fuel oil summary of residual oils includes thirteen main groups, and initially it was deemed most appropriate to reduce the number of classes to two, so as to simplify the summary. For the two classes the viscosity has been determined at 500C. The distillate category has also been divided into two classes.

First Proposal

Danish Bunker Norm, DBN - 1998 for distillate fuel DBN

Class
1

DBN

Class
2

 

Test method

Characteristic Dim Limit
Residual inclusion none some trace allowed
Density at 150C kg/m3 max 890.0 920.0 ISO 3675 or 12185
Kinematic viscosity at 400C cSt max 6.0 14.0 ISO 3104
Kinematic viscosity at 400C cSt min 1.4 2.5 ISO 3104
Flash point deg.C min (43)* 60 60.0 ISO 2719
Pour point winter deg.C max -6.0 `0 ISO 3016
Pour point summer deg.C max `0 6.0 ISO 3016
Cloud point deg.C max -16.0 ISO 3015
Carbon residue Ramsbottom on 10% res. % (m/m) max 0.2 ISO 10370
Carbon residue, microcarbon % (m/m) max 3.0 ISO 10370
Ashes % (m/m) max 0.01 0.03 ISO 6245
Sediment, % % (m/m) max 0.07 ISO 3735
Total existent sediment % (m/m) max 0.10 ISO 10307-1
Water %(V/V) max 0.3 ISO 3733
Sulphur % (m/m) max 0.2 ISO 8754
Vanadium mg/kg max 100.0 ISO 14597
Aluminium + Silicon mg/kg max 25.0 ISO 10478
Cetane number min 40.0 35.0 ISO 5165
Visual inspection clear may be black

(43)* the flash point must be equal to or higher than 600C.

Danish Bunker Norm, DBN - 1998 for residual fuels DBN

Class
3

DBN

Class
4

 

Test
method

Characteristic Dim Limit
Density at 150C kg/cub.m max 991.0 1,010.0 ISO 3675 or 12185
Kinematic viscosity at 500C cSt max 180.0 700.0 ISO 3104
Kinematic viscosity at 500C cSt min 22.0 380.0 ISO 3104
Flash point deg.C min 60.0 60.0 ISO 2719
Pour point deg.C max 10.0 30.0 ISO 3016
Carbon Residue % (m/m) max 20.0 22.0 ISO 10370
Ashes % (m/m) max 0.2 0.2 ISO 6245
Total sediment after aging % (m/m) max 0.1 0.1 ISO 10307
Water %(V/V) max 0.5 0.5 ISO 3733
Sulfur % (m/m) max 1.5 1.5 ISO 8754
Vanadium mg/kg max 500.0 600.0 ISO 14597
Aluminium + Silicon mg/kg max 60.0 60.0 ISO 10478
Approximate equivalent viscosities for information only:
Kinematic viscosity cSt at 1000C 6 10 15 25 35 45 55
Kinematic viscosity cSt at 500C 22 40 80 180 380 500 700
Sec. Redwood I at 1000F 165 300 600 1500 3500 5000 7000

For practical purposes the diagrams were intended to be used in the following manner when purchasing bunkers for the relevant machinery:

  • Determining a type of fuel oil according to the manufacturer’s directions, and drawing up a specification with the parameters shown in the diagram (Characteristics). The reference could be the User’s Manual or after direct contact with the manufacturer and, not to forget, the shipping company’s own experience and operating policy.

Drawing-up the said specification was only a once-off job and could be amended, of course, if operating experience should so dictate. The specification could also be expanded with additional parameters, such as with the other relevant quality parameters as mentioned earlier in this section.

The first proposal could not find acceptance with the Steering Group, however – especially because the maximum value for sulphur had been set at 0.2% for distillate fuels, Class 1. The argumentation was that such an oil was not readily available on the marine market.

In contrast, agreement could be reached as to the use of CIMAC’s recommendations for oil classifications as well as parameters, except with changes in the sulphur percentages for various categories of fuel oil. The advantage of using CIMAC’s list in combination with the ISO 8217 standard is that these two are already well known and adopted by the maritime industry as well as by the bunker oil trade. Besides, most user’s manuals for engines refer to these two norms.

Regarding the Council’s directive relating to the sulphur content of certain liquid fuels, a new proposal has been received from the Commission; the proposal suggests 0.2% sulphur for all distillates that meet the viscosity and density requirements contained in the ISO 8217 standard, Table 1.

A proposal for a new bunker norm for distillate fuels and residual fuels is shown in the following two diagrams.

The diagram for distillate fuels include the groups: CIMAC DX and CIMAC DA, which are designated marine gas oils (MGO), and the groups: CIMAC DB and CIMAC DC, which are designated marine diesel oils.

The diagram for residual fuels includes 13 different types.

Proposal for a New Bunker Norm

Sulphur-Controlled (SC) Fuel Specification for Domestic Waters and the Baltic Sea
Requirements (1998) for distillate fuels for diesel engines as delivered

Designation: CIMAC
DX SC
CIMAC
DA SC
CIMAC
DB SC
CIMAC
DC SC
Related to ISO 8217 (87) F- DMX DMA DMB DMC
Characteristic Dim. Limit
Residual inclusion none none some trace allowed
Density at 150C kg/m3 max - 890 900 920
Kinematic viscosity at 400C cSt max 5.5 6 11 14
cSt min 1.4 1.5 2.5
Flash point Deg.C min 43 60 60 60
Pour point winter Deg.C max - -6 0 0
Pour point summer Deg.C max - 0 6 6
Cloud point Deg.C max -16
Carbon residue
Ramsbottom on 10% res. % m/m max 0.2 0.2
Microcarbon % m/m max 0.25 3
Ashes % m/m max 0.01 0.01 0.01 0.03
Sediment by extraction % m/m max - - 0.02 -
Total sediment % m/m max - - - 0.05
Water %V/V max - - 0.3 0.3
Cetane number min 45 40 35 35
Visual inspection clear clear may be black
Sulphur % m/m max 0.2 0.2 0.2 0.2
Vanadium mg/kg max 100
Aluminium + Silicon mg/kg max 25

Test method for sulphur: ISO 8754

Tabel 8.1
Sulphur-Controlled (SC) Fuel Specification for Domestic Waters and the Baltic Sea
Requirements (1998) for residual fuels for diesel engines as delivered

The most significant change in the new bunker norm as compared to earlier norms is the determination of a sulphur content not exceeding 1.5% for residual fuels, and that the maximum content for distillates is 0.2%.

The situation in Denmark – as regards smaller diesel engines, such as in the so-called "Island Ferries" – is thus that they are designed to run on gas oil, and that when bunkering they will receive a gas oil with a sulphur content of 0.2% or less. The reason for this is that the market for marine gas oil is relatively small, and the oil companies therefore supply a gas oil which is actually intended for diesel motorcars and has a maximum sulphur content of 0.2%.

In this connection it might be mentioned that the International Chamber of Shipping (ICS) takes a very favourable view of a possible reduction of the sulphur content in fuel oils globally – and finds IMO’s maximum limit for sulphur (4.5%) very high. This high value may seem absurd, considering that it has also been proved that only an infinitesimal part (less than 0.02%) of all fuel samples in 1996 contained a higher level of sulphur. – The attitude of ICS is quite clear and can be expressed as follows: "Shipowners do not want, nor do they need, sulphur in fuel".

Control

When requirements are made as to the properties of a bunker oil, particularly as to the content of sulphur, obviously there must be some sort of control. The following paragraphs contain some proposals for control:

  • The bunker supplier must provide documentation showing that the bunker specification is fulfilled, including the requirements as to sulphur content. The ship must be in possession of these details regarding the oil delivered. The information might appropriately be indicated on the "Bunker Delivery Note". This Delivery Note must be kept on board for three years after the oil was delivered, as documentation for the authorities.
  • Ships using separate fuel oils in order to comply with the rules in the low-emission area must be granted a suitable operating time to flush the fuel oil system with an oil containing a maximum of 1.5% of sulphur.
  • The ship must keep records showing in detail the volume of low-sulphur oil in each tank, specifying the date, time and position when changing to another type of oil.
  • Control of compliance with the above could be carried out, for example, by the Danish Maritime Authority or the Danish Environmental Protection Agency. (For foreign ships it is conceivable that the control could be carried out in connection with the so-called Port State Control).

The authorities must:

  • establish and maintain a register of local bunker suppliers;
  • require local bunker suppliers to deliver a "Bunker Delivery Note" to the ship;
  • require local bunker suppliers to file a copy of the "Bunker Delivery Note".
  • A proposal for a Bunker Delivery Note is shown on the next page.

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