Fuel Quality

Singapore: Maritec releases whitepaper reviewing VLSFO bunker fuel

Study reviews fuel stability, fuel stability reserve, and the corresponding analysis techniques of Very Low Sulphur Fuel Oils given that fuel stability is the primary concern with this fuel type, says Maritec.

Published

1 year ago

October 2, 2023

Admin

Bunker fuel testing and marine surveying business Maritec Pte Ltd (Maritec) on Friday (29 September) published a whitepaper on reviewing fuel stability, fuel stability reserve, and the corresponding analysis techniques of Very Low Sulphur Fuel Oils (VLSFOs).

The following are excerpts from the ‘Analysis Methods for Measuring Stability, Stability Reserve & Compatibility of Residual Marine Fuels’:

Introduction

Since 1 January 2020, the International Maritime Organization (IMO) has enforced a 0.50% global sulphur cap for the shipping industry to reduce sulphur oxide emissions. A comparison of pre-IMO 2020 fuels and post-IMO 2020 fuels reveals that the latter exhibit greater instability, waxiness, lower density & viscosity, lower micro carbon residue (MCR), lower calculated carbon aromaticity index (CCAI), lower vanadium content, higher net specific energy, higher pour point, and higher acid number. The decreased stability reserve (higher paraffinic and lower aromatic content) of post-IMO 2020 fuels also raises concerns about compatibility issues when different fuels are mixed.

To address these challenges, Maritec lab is equipped with the necessary equipment and testing methods to assess the cleanliness, stability, stability reserve, compatibility, and cold flow properties of post-IMO fuels. Given that fuel stability is the primary concern with Very Low Sulphur Fuel Oils (VLSFOs), this article focuses on reviewing fuel stability, fuel stability reserve, and the corresponding analysis techniques.

Blending of Very Low Sulphur Fuel Oil (VLSFO, IMO 2020 Compliant Fuel)

IMO global sulphur cap of 0.5%S has changed the primary blending target from viscosity and density to sulphur. Marine fuels post-IMO 2020 has seen a wide variability of fuel formulations and characteristics.

Typically, very low sulphur fuel oils can be blended using three categories of blend stocks (1):

Blending of Very Low Sulphur Fuel Oil (VLSFO, IMO 2020 Compliant Fuel)

Typically, very low sulphur fuel oils can be blended using three categories of blend stocks (1):

Based on the available blend stocks, very low sulphur fuel oils can generally be blended into four major types/groups:

Fuel characteristics evolution and potential quality issues due to 0.5%S Limit

Post-IMO 2020 fuels (VLSFOs) exhibit lower density, lower viscosity, lower MCR (Micro Carbon Residue), lower CCAI (Calculated Carbon Aromaticity Index), lower vanadium content, higher net specific energy, higher pour point, and higher acid number compared to pre-IMO 2020 fuels

It is also noted that VLSFOs generally have better ignition and combustion properties, which contribute to efficient fuel utilization and combustion processes.

However, there is a rise in cold flow property issues within paraffinic-grade very low sulphur fuel oils (VLSFOs), characterized by higher pour points, can potentially introduce concerns regarding cold flow problems, particularly wax formation.

An increase in fuel stability issues is also observed which arises from two factors. Firstly, the use of hydrotreated blend stocks reduces the stability reserve of the fuel due to lower aromaticity and asphaltene solubility. Secondly, when low sulphur aromatic and paraffinic blend stocks are mixed, fuel instability may occur if the blend lacks adequate aromatic content to dissolve the asphaltenes present. Additionally, an increase in fuel compatibility issues can occur when aromatic and paraffinic-grade VLSFOs are co-mingled, leading to incompatibility and potential flocculation of asphaltenes if the blend lacks sufficient aromatics.

Conclusion

The factors that influence stability of residual fuels are fuel formulation (an internal factor, fuel blend itself – on whether the fuel has sufficient aromaticity or contains any appreciable amount on non-hydrocarbons especially non-hydrocarbons containing hydroxyl group such as alkylresorcianols/alkyl-1,3-benzenediols and others) and the external factors such as thermal & mechanical stress and storage time/duration.

The data collated in this article indicates that most of the unstable fuels or marginally stable fuels that cause sludging and filter clogging issues were mostly due to fuel formulation (an internal factor) - either high or borderline high total sediment due to the presence of chemical contaminants, fuels containing appreciable amount of non-hydrocarbons that contain hydroxyl group such as alkylresorcianols/alkyl-1,3-benzenediols, phenolic compounds and others.

Our past historical data indicated that there are also instances that fuels are detected with certain concentration of alkylresorcinols, phenolic compounds and slightly reactive hydrocarbons however the vessels are able to consume the fuels without any operational issues. It is recommended that when a fuel is detected with the presence of alkylresorcinols, phenolic compounds and slightly reactive hydrocarbons, it is important that fuel stability reserve for the fuel shall also be evaluated, if the fuel is identified to contain alkylresorcinols, phenolic compounds & slightly reactive hydrocarbons and the fuel is also unstable or marginally stable, the vessel is recommended practice the aforementioned preventive measures to prevent, reduce and solve the potential sludging and filter clogging issues.

Moving Forward

In the near future when biofuels is widely adopted as drop-in marine fuel to achieve the regulatory requirements on reduction of carbon/GHG emission, due to the diversity of the liquid cutter stocks derived from biomass, marine fuel stability and marine fuel stability reserve will become critical test parameters.

Note: The full version of the ‘Analysis Methods for Measuring Stability, Stability Reserve & Compatibility of Residual Marine Fuels’ whitepaper can be viewed here.

Photo credit: Maritec Pte Ltd
Published: 2 October, 2023

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Bunker Fuel Quality

MPA responds to warning on CNSL biofuel bunker blends found at Singapore

Following an alert by CTI-Maritec , MPA says it has yet to receive reports of vessels experiencing operational problems related to fuel bunkered in Singapore.

Published

4 months ago

November 25, 2024

Admin

Maritime and Port Authority of Singapore on Monday (25 November) said to date, it has not received reports of vessels experiencing operational problems related to fuel bunkered in Singapore.

This comes following bunker fuel testing and marine surveying business Maritec Pte Ltd (CTI-Maritec) issuing a bunker flash stating testing of Very Low Sulphur Fuel Oil (VLSFO) samples from ships in the Singapore and Rotterdam area which reported operational problems, indicated it was blended with Cashew Nutshell Liquid (CNSL).

“All bunker fuels supplied in the Port of Singapore must meet the ISO 8217 standards,” MPA said.

“The Maritime and Port Authority of Singapore (MPA), in consultation with relevant industry experts, has also developed a provisional national standard on specifications of marine biofuel (WA 2:2022) to supplement the international standards.”

MPA added an enhanced set of testing parameters was implemented on 1 June 2024, in addition to the existing quality assurance measures, to test the quality of fuels upstream before they are supplied as bunker fuel in Singapore.

CTI-Maritec said in the recent-past few months several ships in the Singapore and Rotterdam area reported operational problems including fuel sludging, injector failure, filter clogging, system deposits and corrosion of turbocharger nozzle rings.

In light of the reported problems, CTI-Maritec swiftly carried out extended Gas Chromatography Mass Spectrometry (GC-MS) testing for Very Low Sulphur Fuel Oil (VLSFO) samples from these said vessels.

GC-MS testing by Solid Phase Extraction (SPE) method showed the presence of high concentrations (>10000 PPM) of cardol, cardanol, anacardic acid and other alkyl resorcinols. All mentioned compounds, which are substituted long chain phenols, indicated the fuel was blended with Cashew Nutshell Liquid (CNSL) from undeclared source materials or production processes.

CTI-Maritec recommended that shipowners should not use 100% CNSL as a marine fuel or use CNSL as a blending component in marine fuel, which is contrary to the guidance by IMO on best practices for suppliers on the quality of fuel oil delivered to ships.

Photo credit: Manifold Times
Published: 25 November, 2024

Bunker Fuel Quality

CTI-Maritec warns of CNSL biofuel bunker blends found at Singapore, Rotterdam

Testing of VLSFO samples from vessels in Singapore and Rotterdam encountering operational problems indicated it was blended with CNSL from undeclared source materials or production processes.

Published

4 months ago

November 22, 2024

Admin

Bunker fuel testing and marine surveying business Maritec Pte Ltd (CTI-Maritec) on Thursday (21 November) issued an alert regarding testing of VLSFO samples from ships in the Singapore and Rotterdam area which reported operational problems indicated it was blended with Cashew Nutshell Liquid (CNSL):

Findings & Insights:

In the recent-past few months several ships in the Singapore and Rotterdam area reported operational problems including fuel sludging, injector failure, filter clogging, system deposits and corrosion of turbocharger nozzle rings.

In light of the reported problems, CTI-Maritec swiftly carried out extended Gas Chromatography Mass Spectrometry (GC-MS) testing for Very Low Sulphur Fuel Oil (VLSFO) samples from these said vessels.

CNSL is a non-FAME BioFuel, which is a naturally occurring byproduct of the cashew nut industry and acts as a low-cost alternative renewable fuel. It’s a substituted phenol, which is highly reactive and less stable owing to its high iodine value. The application of CNSL is known in the production of plastic, resin, adhesives, laminates, and surface coatings. CNSL has high acid values and is therefore highly corrosive as well. High Potassium found in CNSL blend fuels cause serious post-combustion deposits and corrosion of turbocharger nozzle rings.

The latest version of ISO:8217 specifies the accepted BioFuels such as FAME based biofuels, Hydrotreated Vegetable Oil (HVO), defined by the specifications of EN 14214, ASTM D6751 and EN 15940 respectively.

These fuels are now established and acknowledged by equipment manufacturers (OEM), Classification Societies (Class) and flag Administrations as ‘drop-in’ fuels. There is no specification available for CNSL from any authorised body like above.

CTI-Maritec Recommendations:

CTI-Maritec recommends that shipowners should not use 100% CNSL as a marine fuel or use CNSL as a blending component in marine fuel, which is contrary to the guidance by IMO on best practices for suppliers on the quality of fuel oil delivered to ships.

MEPC.1 /Circ. 875/Add.1 section ‘5’ – where it states that:

5.3 Blend components should be tried and tested so that their typical properties and suitability for bunker production and how they combine with other components is well understood…… and

5.4 Where there are any uncertainties as to the nature and quality of blend component, any issue should be identified and resolved before its use in the production of bunkers.

Furthermore, CTI-Maritec recommends not using unestablished bioproducts in marine diesel engines. Blending these substances in a marine fuel might meet specifications as per ISO:8217 tables 1 and 2 parameter limits but may not fulfil general requirements of compliance as per Clause 5 of ISO:8217.

Photo credit: Louis Reed from Unsplash
Published: 21 November, 2024

Methanol

ISO publishes international standard for methanol as a marine fuel

As the convenor of ISO/TC28/SC4/WG18, Monique Vermeire, announced the publication, which covers general requirements and specifications for methanol being used as a marine fuel.

Published

4 months ago

November 21, 2024

Admin

The International Organization for Standardization (ISO) has recently published the first edition of the international standard for methanol as marine fuel, ISO 6583:2024.

As the convenor of ISO/TC28/SC4/WG18, Monique Vermeire, announced the publication, which covers general requirements and specifications for methanol being used as a marine fuel.

“While methanol is being globally traded based on the International Methanol Producers and Consumers Association (IMPCA) reference specifications, there was no international standard specifically for methanol used as marine fuel,” Vermeire, who is also a Fuels Specialist at Chevron, said in a social media post.

Vermeire added the ISO 6583:2024 addresses this gap by setting the requirements and limits for three methanol grades for marine: MMA, MMB and MMC – marine methanol grades A, B and C.

“We used the IMPCA specifications as a starting point, with some properties less critical for marine and other fuel related aspects not covered,” she said.

“Grade MMC allows for wider tolerances in certain characteristics compared to MMB, while MMA includes additional requirements for lubricity and cleanliness.”

According to the sample of the standard, the document defines the general requirements and specifications for methanol from all forms of production at the point of custody transfer, prior to any onboard required treatment, for use as fuel in marine diesel engines, fuel cells and other marine applications.

The specifications in this document can also be applied to methanol used as fuel in land-based applications of the same or similar type as those used for marine purposes.

Note: The ISO 6583:2024 standard can be purchased here or from any national standardisation organisation.

Photo credit: Louis Reed from Unsplash
Published: 21 November, 2024