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Citadel Recap: Understanding and Addressing Today's VLSFO Issues & the Role of Additives to Minimise the Environmental Impact

DMET Club Citadel Live Session with Ritu Chaudhri: A Deep Dive into Maritime Fuel Management, Additive Technology, and Solutions for Industry Challenges

The DMET Club Citadel hosted an in-depth and highly technical session with Ritu Chaudhri from Enmarol, covering critical topics in maritime fuel management, specifically around fuel additives, the handling of VLSFO, and best practices for fuel mixing and storage.


This session, offered comprehensive insights into effective fuel management strategies to optimise vessel efficiency, mitigate costs, and address environmental impacts.


Below is a detailed breakdown of both parts of Ritu’s session, capturing each discussed point for the benefit of maritime professionals seeking solutions to contemporary fuel challenges.



High EU Allowance Costs and the Potential Savings from Fuel Additives

Ritu began with an example of a vessel traveling from Chennai to Rotterdam, making stops in Ghent, and then returning to Chennai. This route, especially considering the current EU allowance price as of August 28, entails significant expenses. She highlighted how these journeys face high costs due to the EU Emissions Trading System (ETS), which puts a premium on carbon emissions within the EU. Here, Ritu emphasised that using a combustion catalyst can help save costs on various fuel types, including MGO, VLSFO, HFO, B30, and B100, by improving fuel efficiency and reducing emissions.


For companies operating within the EU or planning voyages into its ports, incorporating fuel additives like Enmarol’s combustion catalysts can provide notable financial benefits by lowering greenhouse gas emissions.


Combustion Catalysts as an Integral Management Tool

Ritu detailed the multi-dimensional advantages of combustion catalysts in fuel management, labeling them a “management tool” rather than just an additive. By using a combustion catalyst, operators can achieve improved fuel efficiency on board, which directly translates to fuel savings, reduced spare part wear, and minimized maintenance needs. For companies with budget constraints, Ritu recommended these catalysts as an ideal cost-saving measure, especially since they contribute to achieving compliance with the IMO’s Carbon Intensity Indicator (CII).


Combustion catalysts aid in reducing greenhouse gases under the EU’s ETS while also supporting slow steaming strategies, which further help in maintaining the integrity of older vessels.


As the only Nasdaq-listed fuel additive company, Enmarol has a unique position in the market, controlling the entire fuel lifecycle from extraction to final use. This places them in the top tier of fuel additive companies globally, responsible for treating around one-third of the world’s fuel. Notably, Enmarol extends its expertise beyond maritime, with its technology also being applied in aviation.


This robust capability underscores Enmarol’s commitment to solving fuel-related challenges through technology-driven solutions. Beyond the product itself, Enmarol provides a free technical advisory service, supporting clients by addressing fuel issues and offering real-time problem-solving support, which customers see as invaluable in the current complex fuel landscape.


Addressing Fuel Compatibility and Stability: Guidelines and Practical Advice

One of the core concerns in maritime fuel management is ensuring compatibility when blending fuels with different viscosities. Ritu pointed out that, as a rule, the difference in viscosity between two fuels should be under 30 CST to avoid stability issues. In typical operations, companies follow an SOP (Standard Operating Procedure), blending no more than 5–10% with existing tank bottoms.


However, through their tests, Enmarol has found that if using a quality dispersant stabilizer, blends of up to 50–50 are feasible without stability issues. Ritu advised maritime professionals to perform a compatibility or stability test in a laboratory, especially if operational constraints necessitate a higher blend. This testing minimizes the risk of sludge formation and other issues related to fuel instability.


An attendee, Prakash, suggested a prudent approach of conducting compatibility tests using samples of both the new and existing fuels in a controlled environment before mixing, ensuring stability and preventing issues that could arise with incompatible blends.


Clarifying the Lubricity Requirements for VLSFO

A common myth in the industry, Ritu explained, is that Very Low Sulfur Fuel Oil (VLSFO) needs a lubricity improver due to its lower sulfur content. However, she clarified that sulfur itself does not contribute directly to lubricity. Instead, the refining process, specifically hydrotreating, impacts the fuel’s lubricity by altering the molecular structure during the desulfurization process.


She assured participants that VLSFO typically contains enough heavy components to maintain adequate lubricity without additional additives, making lubricity improvers unnecessary for most VLSFO types. This insight can prevent unnecessary additive expenses and ensure that fuel budgets are more effectively allocated.


Best Practices for Long-Term Storage of VLSFO

For vessels primarily running on LNG, which only use VLSFO as a backup or in gas-stripping situations, long-term storage is a common practice. Ritu shared that to maintain VLSFO stability over several months, it’s recommended to increase the additive dosage to a 1:10 ratio, rather than the standard 1:15, for prolonged storage periods. After six months, the fuel should be redosed, and she recommended tank-to-tank circulation to ensure even distribution. In cases where this isn’t feasible, the vessel’s motion should naturally mix the fuel over a few days, though circulation remains the best option.


Chemical Contaminants in Fuel: Addressing Xylene and Other Volatile Compounds

Several participants voiced concerns about chemical contaminants like xylene, which have caused machinery damage in certain cases. Ritu noted that xylene, along with similar chemicals like styrene and phenol, lacks specific safety limits due to limited testing. In her experience, levels below 20-40 ppm generally do not cause damage, but this can vary widely depending on fuel sources and contaminants. In cases where fuel contamination occurs, Ritu recommended dilution as an effective way to reduce risk if debunkering isn’t an option, although ensuring the lowest possible contamination from the start is always preferable.


Managing VLSFO Heating to Prevent Fuel Aging and Oxidation

Another common problem is the overheating of VLSFO in storage, which can result in oxidation and peroxide formation. This process, which is not immediately visible due to VLSFO’s dark color, can cause severe acid corrosion when the fuel is burned. Ritu stressed the importance of managing fuel temperature correctly.


Overheating leads to the formation of peroxides, resulting in acid corrosion, while underheating risks fuel waxing. She advised operators to understand the Wax Appearance Temperature (WAT) of their fuels, as WAT values typically fall outside of ISO 8217 specifications and must be requested separately.


Cylinder Oil Compatibility for Dual-Fuel Engines

For dual-fuel engines that alternate between LNG and VLSFO, Ritu addressed the challenges of using appropriate cylinder oils. LNG’s negligible sulfur content requires low-BN (Base Number) oils, while VLSFO demands higher BN levels. Some operators alternate between BN 40 and BN 70 oils based on fuel use.


However, Ritu pointed out that using combustion catalysts can improve combustion quality and reduce deposits, allowing operators to rely on BN 40 oils even with dual-fuel engines. This approach minimizes dependency on more expensive Category 2 oils and streamlines operations.


Calcium Deposits in LNG-Driven Vessels

For LNG-powered vessels that occasionally switch to VLSFO, high-BN oils can lead to calcium deposits due to LNG’s low sulfur content. Ritu explained that calcium, usually present to counteract sulfur’s acidic effects, accumulates when there’s little sulfur for it to react with, causing deposits. Proper fuel management and careful planning when switching between LNG and VLSFO can prevent such issues and optimize performance.


Recommendations for Redosing and Storage in LNG Vessels

For LNG vessels storing VLSFO for prolonged periods, Ritu suggested dosing at a 1:10 ratio and redosing every six months to maintain fuel stability. She also recommended using tank-to-tank transfer for optimal mixing and avoiding issues with uneven additive distribution.


Importance of Compatibility Testing During Bunkering

A participant shared an example from Shell’s practices, where compatibility testing kits are provided to test various mix ratios between old and new bunker fuels before storage. This step, especially for major operators, is critical to prevent fuel quality and stability issues. Ritu supported this approach as a necessary precaution, especially in cases where companies are mixing fuels from different sources or qualities.


Long-Term Solutions for Fuel Management with Combustion Catalysts

In her concluding points, Ritu emphasized that using combustion catalysts addresses core combustion issues, reducing reliance on high-cost additives and enabling vessels to achieve stable, efficient combustion with standard BN 40 oils, even in complex operating conditions. This practice not only saves costs but also enhances operational reliability and consistency.


Final Thoughts and Acknowledgments

In closing, Ritu expressed her gratitude to the DMET Club community for allowing her to share insights on Enmarol’s technology and its practical applications for the maritime industry. She underscored the importance of fuel additives as tools for sustainable, efficient operations, offering long-term benefits and environmental compliance. Attendees, including both onshore and seafaring professionals, voiced their appreciation for Ritu’s expert guidance and practical advice on managing VLSFO and other marine fuels.

The session concluded with mutual thanks, recognizing the informative nature of the presentation and the importance of ongoing discussions in the fuel management sector. Ritu reiterated Enmarol’s commitment to providing technical support and advisory services to clients, underscoring that every challenge offers an opportunity to refine and enhance fuel management practices.


This Citadel Live Session was not only a technical discourse but also a bridge for maritime professionals to understand and adapt to modern fuel challenges with actionable insights and reliable solutions. The shared knowledge in this session is a testament to the value of collaboration in advancing fuel management, ensuring the sustainability and efficiency of maritime operations for years to come.

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