Connect with us


VPS: Why do VLSFOs still require quality considerations?

VLSFO play an important role, comprising 55% of marine fuel samples; while no official ISO8217 specs exist, VLFSOs demand careful management due to unique properties.




Untitled design 16

Steve Bee, Group Commercial & Business Development Director of marine fuels testing company VPS, on Thursday (18 August) shared that in the pursuit of greener shipping, the shipping industry should not overlook the importance of quality fuel management for traditional fossil fuels. 

Very Low Sulphur Fuels (VLSFO) play an important role, comprising 55% of marine fuel samples. While no official ISO8217 specs exist, VLFSOs demand careful management due to unique properties:

As the world of shipping quite rightly focuses on reducing its carbon footprint and endeavours to comply with a host of decarbonisation legislation, it may be easy to forget that traditional fossil fuels are still the main energy source for the majority of the global fleet. As such, the fuel management of fossil fuels and their quality, continues to be an important factor in protecting vessels, their crew and the environment.

As the most widely used fossil fuel, Very Low Sulphur Fuels (VLSFOs) require more focus than others, in terms of their fuel management. VLSFOs currently account for 55% of all marine fuel samples received by VPS for fuel quality testing. There are still no official standard specifications within ISO8217 for VLSFOs.

As such, most VLSFOs are tested against the RMG380 specifications, knowing that the viscosities of VLSFOs in particular, are very much lower than 380cSt. Currently, 68% of all VLSFOs tested have a viscosity between 20cSt-180cSt. This can have a significant impact on the transfer and injection temperatures onboard a vessel, requiring much less heating of the fuel to achieve the optimum injection viscosity. It would be beneficial to see the introduction of a minimum viscosity specification limit for VLSFOs, as well as a current maximum viscosity limit within ISO8217?

Currently 3.8% of all VLSFOs tested have at least one off-specification parameter. This compares favourably with the off-specification rates for HSFO fuels at 11.4% and MGO fuels at 16.9%. However, the VLSFO off-specifications are potentially more concerning than some of those associated with HSFO and MGO. Sulphur, water, cold-flow properties and cat-fines are the most frequent of VLSFO off-specification parameters.

Screenshot 2023 08 21 at 1.47.56 PM

Sulphur off-specification is the most common of all VLSFO off-specifications, with over 30% of all off-specifications being attributed to this one parameter. However, recent test results have shown that sulphur off-specification is certainly better today than it was back in 2021, with only 1.6% of VLSFOs tested being >0.50% Sulphur compared to 2.4% >0.50% in 2021.

Also, it would appear that so far this year, suppliers are producing more fuel in the 0.41%-0.46% Sulphur range, than the 0.47%-0.50% range, than over the past two years, which means that there is less chance of the VLSFOs falling outside of the 95%-confidence interval, or being off-specification.

Screenshot 2023 08 21 at 1.48.04 PM

Due to the higher level of paraffinic content of VLSFOs over HSFO fuels, it is more likely to see wax precipitation occur with VLSFOs, when subjected to colder temperatures.

The formation of wax crystals during storage and consumption is a potential major source of operational problems with VLSFOs. Therefore, it is vitally important to test for wax appearance (WAT) and wax disappearance temperatures (WDT), as the pour point of the fuel is not a reliable indicator of potential cold-flow issues.

During 2019, VPS developed a proprietary test to be able to measure both WAT and WDT in VLSFOs, which many of our customers have become reliant upon to safeguard their vessels from wax precipitation and it’s potentially damaging consequences.

Current global averages show VLSFO Pour Point is 16°C, whilst the average WAT is 38°C, and the average WDT is 48°C. These figures illustrate why using +10°C above the pour point as an indicator of the cold-flow properties of VLSFO blends is simply insufficient, as well as inappropriate as a risk mitigation measure.

When WAT and WDT results are high, vessels need to consider raising the temperatures of their onboard separators, as well as the temperatures within storage, settling and service tanks.

However, VLSFOs with a short shelf life and high WAT may not be suitable for storing, as heating such fuel accelerates the ageing process and increases the likelihood of fuel sludging.

VLSFOs with low viscosity but high WAT & WDT, need to be heated to ensure a stable flow and to prevent wax formation. Such fuels will likely need to be cooled before entering the main engine, due to their low viscosity. This could present operational issues such as wax formation when the fuel temperature drops below the WAT.

Screenshot 2023 08 21 at 1.48.12 PM

Stability issues relating to VLSFOs have been a concern since their introduction in 2019. To this day we still witness spikes in Total Sediment Potential (TSP) across the world.

Screenshot 2023 08 21 at 1.48.23 PM

Some VLSFO blends appear stable on bunkering but become unstable over time (within a week or two). Heating the fuel in the tanks (to maintain suitable storage and transfer) and purifiers (to achieve efficient purification) deteriorates the fuel’s stability and fastens the ageing process. 

VLSFOs that are incompatible can cause separator sludging and clogging of filters. As such, numerous vessels have witnessed incompatibility issues when the vessels change from MGO to VLSFO or (vice versa). 

VLSFOs with high WAT/WDT and high cat-fines create a need to operate separators at higher temperatures, at shorter discharge intervals. When this is practice is undertaken, wax starts to form, affecting purifier operation as well as clogging the fuel system’s filters. 

Finally, regarding stability, VLSFOs with high WAT/WDT, that also have chemical contamination, followed by low viscosity, will unlikely to be handled on-board of vessels. In such cases, the only solution is to de-bunker the fuel. 

Between Feb-July 2023, VPS detected contamination in VLSFO fuels in Houston. This contamination saw the presence of two specific isomers of Dicyclopentadiene (DCPD) at concentrations between 1,000ppm-40,000ppm. 

The specific isomers were: 

  • Di-hydro dicyclopentadiene Chemical CAS Number: 4488-57-7 
  • Tetra-hydro dicyclopentadiene Chemical CAS Number: 6004-38-2 

DCPD’s are unsaturated chemical compounds which can polymerise and oxidise under certain conditions. When DCPD polymerises, the fuel begins to exhibit a level of stickiness and becomes more viscous, making it difficult for moving components, eg fuel pump plungers & fuel injector spindles to move freely. These effects cause damage to the fuel injection system. Over a period of time excessive sludge formation is likely to be experienced. 

This specific case saw 12 vessels which bunkered the fuel in Houston suffer major operational issues and damages to auxiliary engines & fuel delivery systems, from fuel supplied by 4 suppliers. The type of problems witnessed were fuel leakage in the ICU (Injection Control Unit) units and fuel pumps not being able to develop the required fuel pressure.

Screenshot 2023 08 21 at 1.48.32 PM

In order to mitigate the risks associated with chemical contamination of VLSFOs, VPS recommend their GCMS-HS Chemical Screening service with each VLSFO bunkering. This service is a pre-burn, rapid, low-cost test, which can identify the presence of volatile chemicals within VLSFOs such as styrene, DCPD and chlorinated hydrocarbons, to name but a few and provide an elevated level of protection to the vessel. 

To summarise, VLSFOs as the most widely used marine fuel powering today’s global fleet, can potentially create numerous operational and compliance issues, due to their varying quality. In order to mitigate the potential risks caused by, poor cold-flow parameters, fuel stability, chemical contamination, low viscosity and sulphur non-compliance, effective fuel management and testing can certainly help reduce and even eliminate such risks.

Related: VPS identifies new bunker fuel contamination at Houston
Related: FOBAS: Possible bunker fuel contamination in Houston and US Gulf area
Related: Viswa Group gives update on bunker fuel issues in Houston
Related: FuelTrust analysis finds fuel content discrepancies in 39% of global bunker deliveries
Related: VPS: Houston contaminated VLSFO bunker fuel was also supplied in Singapore
Related: BREAKING: Vessels supplied in Singapore yet to report engine issues due to contaminated bunkers, following Houston VLSFO case


Photo credit: VPS
Published: 21 August, 2023

Continue Reading


Singapore: EPS orders ammonia, LNG dual-fuel vessels from China

EPS signed one contract for a series of ammonia dual-fuel bulk carriers with CSSC Beihai Shipbuilding and another for a series of LNG dual-fuel oil tankers with CSSC Guangzhou Shipbuilding International.






Singapore-based Eastern Pacific Shipping (EPS) on Wednesday (28 February) said it signed two new contract orders in a signing ceremony in Shanghai, one for a series of ammonia dual-fuel bulk carriers with CSSC Beihai Shipbuilding and another for a series of LNG dual-fuel oil tankers with CSSC Guangzhou Shipbuilding International. 

The contracts signed cover four 210,000 dwt ammonia dual-fuel bulk carriers and two 111,000 dwt LNG dual-fuel LR2 oil tankers, expanding our fleet of green vessels on water. 

“These are pivotal for EPS, testament to our continued commitment towards the decarbonisation of shipping,” EPS said in a social media post.

Manifold Times recently reported EPS signing a contract for its first ever wind-assisted propulsion system, partnering with bound4blue to install three 22-metre eSAILs® onboard the Pacific Sentinel

The turnkey ‘suction sail’ technology, which drags air across an aerodynamic surface to generate exceptional propulsive efficiency, will be fitted later this year, helping the 183-metre, 50,000 DWT oil and chemical tanker reduce overall energy consumption by approximately 10%, depending on vessel routing.

Related: Singapore: EPS orders its first wind-assisted propulsion system for tanker


Photo credit: Eastern Pacific Shipping
Published: 1 March 2024

Continue Reading

LNG Bunkering

Malaysia: Port of Tanjung Pelepas completes first LNG bunkering operation

Landmark event involved the CMA CGM Monaco, a 14,024 TEUs containership operated by French shipping giant CMA CGM.






Port of Tanjung Pelepas Sdn Bhd (PTP), a joint venture between MMC Group and APM Terminals, on Wednesday (28 February) announced a significant milestone with the successful completion of its first Liquefied Natural Gas (LNG) bunkering operation. 

The landmark event involved the CMA CGM Monaco, a 14,024 TEUs (Twenty-foot Equivalent Units) capacity containership operated by French shipping giant, CMA CGM.

Tan Sri Che Khalib Mohamad Noh, Chairman of PTP in a statement remarked this latest milestone demonstrates PTP’s commitment to continuously enhance its competitive advantages in an increasingly competitive global market.

“The successful completion of our first LNG bunkering operation also underscores our unwavering commitment to sustainability and environmental leadership. We are proud to partner with Petronas Trading Corporation Sendirian Berhad (PETCO) and CMA CGM on this initiative and showcase PTP’s capabilities as a leading facilitator of clean and efficient maritime operations.”

“This milestone paves the way for further growth in LNG bunkering at PTP, contributing significantly to the decarbonisation of the maritime industry.”

Commenting on this achievement, Mark Hardiman, Chief Executive Officer of PTP stated this latest milestone further highlights PTP’s position as the largest transshipment hub terminal in Malaysia.

“In preparation for the LNG bunkering operation, PTP worked closely since March 2022 with PETCO and CMA CGM, as well as with various other related government agencies to organise table-top exercises (TTX) and workshops, before carrying out the deployment exercise.”

“The success of the bunkering operation is a result of the seamless collaboration and preparations involving rigorous safety procedures through in-depth operational and risk assessments, modelling, and validation. We thank PETCO, CMA CGM all other involved parties for their joint efforts in operationalising the bunkering capability and we welcome partners to work with us to accelerate maritime decarbonisation,” said Hardiman.

Port of Tanjung Pelepas (PTP) is Malaysia’s largest transshipment hub with the capacity to handle 13 million TEUs annually. The port delivers reliable, efficient, and advanced services to major shipping lines and box operators, providing shippers in Malaysia and abroad with extensive connectivity to the global market. PTP is currently ranked 15th among the world top container ports.


Photo credit: Port of Tanjung Pelepas
Published: 1 March 2024

Continue Reading

Alternative Fuels

Wallenius Wilhelmsen to order four additional methanol DF PCTCs

Newbuilds will also be ammonia-ready and able to be converted as soon as ammonia becomes available in a safe and secure way.





Wallenius Wilhelmsen PCTC order

Roll-on/roll-off (Ro-Ro) shipping company Wallenius Wilhelmsen on Tuesday (27 February) declared options to build four additional next-generation Shaper Class pure car and truck carrier (PCTC) vessels.

The 9,300 CEU methanol dual fuel vessels can utilise alternative fuel sources, such as methanol, upon delivery. They will also be ammonia-ready and able to be converted as soon as ammonia becomes available in a safe and secure way.

“Together with our customers we are committed to further shaping our industry and accelerating towards net zero. These new vessels are a vital part of that journey,” says Xavier Leroi, EVP & COO Shipping Services.

This latest commitment brings the total number of Shaper Class vessels currently on order with Jinling Shipyard (Jiangsu) to eight. Wallenius Wilhelmsen also retains further options.

The first of the Shaper Class vessels already ordered are expected to be delivered in the second half of 2026. The four additional vessels under the declared options will be delivered between May and November 2027.


Photo credit: Wallenius Wilhelmsen
Published: 1 March 2024

Continue Reading
  • EMF banner 400x330 slogan
  • RE 05 Lighthouse GIF
  • v4Helmsman Gif Banner 01
  • SBF2
  • Consort advertisement v2
  • Aderco advert 400x330 1


  • HL 2022 adv v1
  • Triton Bunkering advertisement v2
  • 102Meth Logo GIF copy
  • Singfar advertisement final

  • Uni Fuels logo advertisement white background
  • E Marine logo
  • Energe Logo
  • Innospec logo v6
  • Cathay Marine Fuel Oil Trading logo
  • CNC Logo Rev Manifold Times
  • intrasea
  • MFA logo v2
  • Central Star logo
  • pro liquid
  • Advert Shipping Manifold resized1
  • Headway Manifold
  • VPS 2021 advertisement
  • 400x330 v2 copy