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Innospec highlights important overview on handling fuel instability issue of VLSFO

Majority of VLSFO components come from low cost distillate and low sulphur petrochemical streams which can be readily separated to form distillate sludge.




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Colorado-based global specialty chemicals company Innospec has published an article on handling fuel instability of very low sulphur fuel oil (VLSFO) in their February technical bulletin :

Problems associated with VLSFO

  • Polished liners, Piston ring failure
  • Instability / compatibility
  • Fuel injector / pump damage
  • Low combustion efficiency
  • Post combustion fouling (Turbochargers, EGE, EGR, SCR, scrubbers/wash water)
  • Short storage lifespan
  • Reduced service intervals (purifiers)

What is Fuel instability and why is it more important than ever?

HSFO instability meant Asphaltenes dropped-out of solution causing filter blocking, tank fouling, poor combustion and increased purifier cleaning/servicing frequency. VLSFO still contains Asphaltenes from residual streams; however, it is a different animal. The majority of VLSFO components come from low cost distillate and low sulphur petrochemical streams which can be highly volatile, these can separate readily to form distillate sludge such as sticky gums, hard sediments or even polymers in storage/handling tanks, filters, pipework, purifiers and mechanical contact surfaces.

It has been shown that after-burn and dumb-bell ignition (both early and late ignition) are a high risk due to the incompatible mixture of light (paraffinic) and heavy (Asphaltenes) fractions used to achieve lower costs and 0.5% Sulphur found in VLSFO. Using the best methods for component mapping and stability monitoring we have proven the blend of two dissimilar components pose a significant risk of instability through rapid chemi-cal ageing, this makes storage/handling unpredictable with some of the effects being unavoidable on-board. 

Distillate sludge blocks filters and purifiers just as residual sludge does, only this can happen rapidly for a variety of reasons including prolonged storage (>1 month), heating or co-mingling. Unfortunately, it can also happen due to an inherent instability, which leads to chemical changes in the fuel once on-board.

The true risk of distillate sludge is to ships engines. Paraffinic gums are highly adhesive and stick to contact surfaces such as injectors and fuel pumps. Once established they allow hardinorganics such as metals/cat fines to become imbedded within, creating an abrasive surface that wear down fine tolerances, or create blockages. The quick onset of injector nozzle blockage leading to poor spray pattern and ignition efficiency which will lead to greater instance of liner impingement, after- burn and post combustion fouling (soot, ash, T/C deposits).

What does this mean for combustion?

Asphaltenes have always existed within Marine Fuels, they have a high calorific value and burn readily if effectively dispersed within the fuel; if stabilised the Asphaltenes are dispersed and protected by naturally occurring resins, which keep them small enough to find sufficient oxygen and burn during combustion. By contract, VLSFO can be an overly refined product containing low cost distillate streams that strip-away protective resins causing the Asphaltenes to agglomerate to form huge complex structures, which drop out of solution. Those that are not removed during filtration or purification or develop afterward are injected into the combustion chamber but are too large to burn effectively. This is when we see ‘black’ residual deposits on liners and pistons from unburnt fuel.

The same is true of distillate sludge, only that we have seen that these tend to effect engine components far more than Asphaltenes. Once injector efficiency is reduced through nozzle blockage, early ignition or contact surface wear, this leads to poor spray pattern and further compounds poor combustion efficiency.

How do we keep ships sailing?

Fuel handling practices will need to change to face the new challenges; unfortunately, each fuel bunkering will vary significantly from region to region or even within the same port. VLSFO is still a residual fuel that requires heating due to high pour points, variable viscosity and waxy distillate components. Unfortunately heating VLSFO can lead to the rapid onset of aging, which brings us instability. There are cases where fuel has polymerised within four hours of leaving the storage tank and entering the fuel handling system (with purifier temperatures as low as 60°C!). These chemical reactions cannot be avoided even when good on-board practices are followed.

Innospec were approached by Industry to develop OctamarTM HF-10 PLUS; our expertise in the Marine, Automotive, Aviation and Refinery business uniquely places us in a position to maximise the operability of fuels. 

OctamarTM HF-10 PLUS contains our famous Asphaltenes dispersant/stabiliser which has been used in over 3000 vessels world-wide to clean-up and maintain fuel tank cleanliness, and our unique distillate stabiliser/detergent and dispersant, which targets problem elements in the low quality distillate streams, preventing them from propagating into sludge or adhering to machinery contact surfaces.

This means clean tanks, filters, purifier, engines and better combustion. Our formulas have been a must-have in automotive/industrial diesels and long-term storage units for decades and we are pleased to bring it to the marine sector in these trying times.

OctamarTM HF-10 Plus chemically targets problem elements within the fuel, cleaning up Asphaltenes, distillate gums and sediments, and prevents the onset of polymerisation and oxidation.

Would you like to know more?

To find out more details please contact our technical team in your region and visit our website:

For Europe, Middle East and Africa mail [email protected]

For Asia Pacific mail [email protected]

For America mail [email protected]

Related: Innospec launches Octamar™ series of additives for new blends of IMO 2020 bunker fuels

Photo credit: Innospec
Published: 17 February, 2020


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Singapore: EMA, MPA shortlist two consortia for ammonia power generation and bunkering

Chosen consortia are Keppel’s Infrastructure Division and Sembcorp-SLNG, and the bunkering players in these consortia are Itochu Corporation, NYK Line and Sumitomo Corporation.





RESIZED bunker tanker singapore

The Energy Market Authority (EMA) and the Maritime and Port Authority of Singapore (MPA) on Thursday (25 July) said they have shortlisted two consortia that will proceed to the next round of evaluations of proposals to provide a low- or zero-carbon ammonia solution on Jurong Island for power generation and bunkering. 

The two consortia were selected from a total of six that were earlier shortlisted in 2023 to participate in a restricted Request for Proposal (RFP), following an Expression of Interest (EOI) called in 2022. The bids were assessed based on the technical, safety and commercial aspects of their proposals. 

The two consortium leads are Keppel’s Infrastructure Division and Sembcorp-SLNG, and the bunkering players in these consortia are Itochu Corporation, Nippon Yusen Kabushiki Kaisha (NYK Line) and Sumitomo Corporation. The two consortia will proceed to conduct engineering, safety and emergency response studies for the proposed Project.

At the next phase, we will select one of the two bidders as the lead developer of the project. The lead developer will develop the end-to-end ammonia solution comprising (i) generating 55 to 65 MW of electricity from imported low- or zero-carbon ammonia via direct combustion in a Combined Cycle Gas Turbine; and (ii) facilitating ammonia bunkering at a capacity of at least 0.1 million tons per annum (MTPA), starting with shore-to-ship bunkering followed by ship-to-ship bunkering. 

Given the nascency of the technology and global supply chains, the Government will work closely with the appointed lead developer to implement the Project. We aim to announce the lead developer by Q1 2025.

The project is part of Singapore’s National Hydrogen Strategy launched in 2022, which outlines Singapore’s approach to develop low-carbon hydrogen as a major decarbonisation pathway as part of the nation’s commitment to achieve net zero emissions by 2050.

A key thrust of this strategy is to experiment with the use of advanced hydrogen technologies that are on the cusp of commercial readiness. Ammonia is currently one of the most technologically-ready hydrogen carriers with an established international supply chain for industrial use.

“If successful, the project will position Singapore as one of the first countries in the world to deploy a direct ammonia combustion power plant and support the development of ammonia bunkering for international shipping, EMA and MPA said.

“This will help to unlock the potential of low-carbon ammonia as a low-carbon fuel.”


Photo credit: Manifold Times
Published: 25 July 2024

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LNG Bunkering

China: River-sea LNG bunkering vessel named and delivered in Shanghai

The 14,000 cubic metre ship, “Huaihe Nengyuan Qihang”, was independently developed, designed and built by Hudong-Zhonghua Shipbuilding (Group) for Huaihe Energy Holding Group.





China: River-sea LNG bunkering vessel named and delivered in Shanghai

China’s river-to-sea LNG bunkering vessel, which was built locally, was named and delivered in Shanghai on Monday (19 July), according to the Shanghai Association of Shipbuilding Industry (SASIC). 

The 14,000 cubic metre (cbm) ship, Huaihe Nengyuan Qihang, was independently developed, designed and built by Hudong-Zhonghua Shipbuilding (Group) Co., Ltd for Huaihe Energy Holding Group as part of China’s "Gasification of the Yangtze River” project.

The ship is capable of travelling through the Nanjing Yangtze River Bridge all year round and has been dubbed a “Customised Yangtze River” LNG refuelling and transportation ship.

The ship is equipped with the B-type LNG containment system independently developed by Hudong-Zhonghua and authorised by a national patent.

According to SASIC, this was the first time such a system has been applied to a domestic LNG  refuelling and transportation ship, marking a major breakthrough in the B-type LNG containment system developed by China with independent intellectual property rights.

Related: China’s first river-sea LNG bunkering ship completes inaugural bunkering operation

Disclaimer: The above article published by Manifold Times was sourced from China’s domestic market through a local correspondent. While considerable efforts have been taken to verify its accuracy through a professional translator and processed from sources believed to be reliable, no warranty is made regarding the accuracy, completeness and reliability of any information.


Photo credit: Shanghai Shipbuilding Industry Association
Published: 25 July 2024

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Singapore-flagged tanker “Hafnia Nile” to be moved to safe location for cargo transfer

“Hafnia Nile” and the Sao Tome and Principe-flagged “Ceres I” collided and caught fire about 55km northeast of Pedra Branca on 19 July.





Singapore-flagged tanker “Hafnia Nile” to be moved to safe location for cargo transfer

Shipowner Hafnia, the operator of Singapore-flagged tanker Hafnia Nile, is in discussion with The Maritime and Port Authority of Singapore (MPA) on a safe location to transfer the ship’s cargo, MPA said on Wednesday (24 July). 

They are also discussing towage plans for repairs to be approved by MPA.

Hafnia Nile and the Sao Tome and Principe-flagged Ceres I collided and caught fire about 55km northeast of Pedra Branca on 19 July.

“An additional tug with deep-sea towing capacity has arrived on site on 23 July 2024, joining four other tugs equipped with oil response and firefighting capabilities,” MPA said. 

In a meeting with MPA on 23 July, Hafnia informed MPA of light oil sheens near Hafnia Nile

“As part of the towage plan, Hafnia will arrange for repairs, containment and clean-up of the assessed localised seepage,” it added.

Reuters reported Hafnia stating that an initial assessment by a team of specialists conducting inspections of damaged areas of the tanker, showed Hafnia Nile's engine room had suffered damage from the fire.

Hafnia also reportedly said a salvage team has boarded the vessel and transferred equipment from one of the attending tugs on site to contain and stop any localised seepage.

Manifold Times previously reported Ceres 1 allegedly leaving the site of the collision as of 20 July and turned off its Automatic Identification System (AIS) but was believed to be in Malaysian waters.

The Malaysian Maritime Enforcement Agency (MMEA) was able to locate Ceres 1 some 28 nautical miles northeast of Pulau Tioman.

Related: “Ceres 1” goes dark after collision with Singapore-flagged tanker, located by MMEA
Related: MPA: Fire breaks out on two ships near Pedra Branca, search and rescue underway


Photo credit: Malaysian Maritime Enforcement Agency
Published: 25 July 2024

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