Measuring the Limits of Sulfur Content in Marine Fuel

On January 1st, 2020, MARPOL 2020 became effective and the new measure limits sulfur content in marine fuel. This will cause dramatic changes in the market with a huge demand for low sulfur fuels. PAC has a wide variety of ISO-conforming solutions on offer to support the compliance of IMO 2020 and aid in mitigating the risk of using unreliable marine oils.

Reducing Sulfur Emissions in 2020


Image Credit: BP MARPOL 2020 and Beyond

The International Marine Organization's (IMO) regulations are used on ships operating outside designated emission control areas to limit the sulfur content in fuel oil. According to the International Convention for the Prevention of Pollution from ships (also known as the MARPOL Convention), a reduction in the limit has been observed from 3.50% m/m to 0.50% m/m worldwide. The most affected by this will be vessel owners, ports and contract labs.

Available Fuel Options

Known as a light distillate fuel, marine gas oil (MGO) is currently used by several shipping vessels in Emission Control Areas (ECAs) while sailing or berthing close to specific coastal regions in Europe, North America, and Asia. The ships can already use this type of fuel without significant modifications because they have previous experience using MGO and this is the solution with the least barriers to implementation.

Although it is the easiest and most feasible option, there is no doubt that challenges will present themselves when transitioning to using marine gas oil as the primary fuel and operational problems are to be anticipated. For instance, vessels using MGO have the potential to experience cold flow problems in frigid waters, which can result in an increase in clogged fuel lines and disruptions to operations or even loss of propulsion.

Alternative fuel options are:

  • HSFO: High Sulphur Fuel Oil. This is used on ships fitted with scrubbers, are high in cost, and require a long installation time.
  • VLSFO: Very Low Sulphur Fuel Oil. It has a maximum sulfur content of 0.50% mass.
  • LNG: Liquified natural gas. This requires a unique vessel, engine design, and crew.

Parameters to Measure

Using MGO as an alternative and blending bunkers from different suppliers can lead to fuel instability and incompatibility. These are some characteristics that require monitoring to remain compliant.

Sulfur Content

IMO 2020 has its focus on sulfur reduction. While most sulfur streams are already low, testing and confirming may be needed to reach compliance.


ISO 8217:2017 needs MGO to operate at a minimum of 2 mm2 /s at 40º C. Due to engine rooms being hotter than 40º C, a fuel that is close to meeting specifications can rapidly become out of specification when heated to higher temperatures. Shippers require a technology that will let them know at what temperature the fuel will get to 2 mm2 /s.

Flash Point

In comparison to road diesels, MGO has a higher minimum flash point limit (–60 ºC), so it is thought to be safer and follows the minimum flashpoint limit specified in SOLAS and MARPOL Annex VI.

Pour Point

This is a standard cold flow specification for marine fuel oil. Due to MGO being rarely heated during storage or even during use, it is vulnerable to a build-up of wax in cold weather. Due to this, ISO 8217 was modified to comprise cloud point and CFPP requirements, in addition to pour point measurement.

Cloud Point/CFPP

When exposed to cold weather, MGO can clog fuel lines and filters. Cloud point and CFPP offer an increased proactive measure of potential cold-flow issues, which delivers extra time to take preventative action.


The density value delivers a guarantee that the fuel being utilized reflects the right weight-to-volume ratio and associated energy density.


To address global environmental and decarbonization initiatives, renewable FAME in concentrations no higher than 7% is allowed in MGO. Monitoring of FAME is required because of issues with sealing, dirt, water, and microbial issues when the concentrations have increased too much.

Carbon Residue

The amount of carbon residue gives estimations of the tendency of MGO to form deposits, which, in turn, can affect the performance of the engine.

PAC Solutions

Phase MFA 70Xi

Viscosity: 40 °C (mm2/s)
Density: 15 °C (kg/m3)
Pour Point in Winter and Summer
Cloud Point in Winter and Summer


Phase Technology's MFA-70Xi is the solitary analyzer that is specially designed to test four extremely important properties of marine fuel: viscosity (at 40 ºC), density, cloud point, and pour point. This all occurs in 20 minutes or less and is simple and easy to use. The MFA-70Xi completes all four tests with the single push of a button.

A sample is automatically loaded, with no need for a pipette and an optional 48-position autosampler offers improved throughput and enhanced automation if wanted. The MFA-70Xi is 100% self-cleaning and no solvent is needed. MFA-70Xi was developed to meet the increasing requirements of the marine fuel industry as they test MGO distillate fuels. This includes DMX, DMA, DMZ, and DMB (also known as DFA, DFZ, DFB).



OptiFPP is a cold filter plugging point analyzer and it accurately and reliably measures CFPP at ultra-low temperatures (as low as -70 ºC) to control cold flow.

OptiFlash SS


OptiFlash SS requires only samples at low-volume and offers accurate flash point determination. Several traditional flashpoint testers use a huge amount of fuel sample, whereas OptiFlash SS uses a small amount of sample (2 mL in comparison to a typical > 50 mL in traditional test methods), which lessens fuel exposure to the user and makes fuel handling and disposal easier. The instrument is designed to lessen the risk of an incorrectly set flash point and has an optional built-in fire extinguisher.



With the advantage of automatically determining the carbon residue, MCRT160 gives results that are comparable to the Conradson Test D189, a more time-consuming and operator-intensive device.



MultiTek is the complete solution to determine total sulfur content and combines advanced UV Fluorescence and Chemiluminescence to guarantee fuel compliance to IMO 2020.



OptiFuel is a robust FTIR-based fuel analyzer that determines FAME content. It offers a very quick analysis to measure sulfur in just two minutes.

WAT 70Xi


Measurements of compatibility of different waxing profiles are taken in 20 to 40 minutes even with the most opaque samples and with a precision of 1 ºC.

What is PAC?

PAC is the number one producer of advanced analytical instruments for gas chromatography, elemental analysis, physical properties, and fuel composition. The business portfolio comprises the world's most respected brands of lab and process analyzers. For example, AC Analytical Controls, Advanced Sensors, Alcor, Antek, Cambridge Viscosity, Herzog, ISL, PetroSpec and Phase Technology.

PAC complies with ISO 9001-2015 and 17025-2017 standards, which reiterates the business's commitment to quality and customer support. PAC is a diversified technology company and a unit of Roper Technologies. It is also a constituent of S&P 500, Fortune 1000, and Russell 1000 indices.

PAC is committed to delivering the best local customer service worldwide with 14 office locations and a network of more than 50 distributors. Field services are offered for preventative maintenance, calibration, installation, and emergency site visits.

Service programs aid customers to guarantee the best quality and repeatability, in addition to complying with standards and regulatory requirements. PAC has Service Repair Centers situated around the world, and they are all ISO-9001 accredited.

This information has been sourced, reviewed and adapted from materials provided by PAC L.P.

For more information on this source, please visit PAC L.P.


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