ABSTRACT

The use of residual fuel as the main fuel in the shipping industry since the 1960s has presented a concern due to the emissions of harmful particulate matter (PM), sulfur oxides (SOx), nitrogen oxides (NOx), and carbon dioxide (CO2). Therefore, there is a push for alternative fuels that can meet the

emission standards and regulations set by the IMO (International Maritime Organization) as well as meet the market demands for energy-efficient and lower-cost fuels within the shipping industry. Fuel oils blended with biodiesel are one of the alternative fuels that can be used with or without a small modification to the engine and associated infrastructure to reduce CO2, HC (hydrocarbon), PM, and SOx emissions. This has created a great interest in using these fuels as one of the blend stocks nowadays for GHG (Greenhouse gas) reduction.

A small number of publications on blending biodiesels with residual fuels exist in the industry. Neither specification standards nor test methods are available for these blended fuels. Currently, when biodiesel blended fuel oils are supplied, they are generally checked against the existing ISO 8217 grades & specification limits. This is an area that needs to be addressed and needs a specific set of protocols for these Biodiesel fuel oil blends to be successfully used by the maritime industry.

There has been a lot of interest from shipping companies and suppliers to supply and use these blended fuels since 2020. Several shipping companies have made agreements with suppliers to use these blended fuel oils on their ships on an experimental basis. There are three major potential issues related to blending biodiesel with residual fuels/VLSFOs which need to be studied and addressed in detail: Compatibility and stability properties of the blend, oxidation stability (storage stability properties), and acidity. This study will discuss the characteristics of the biodiesel blended with residual fuels in terms of properties such as density & viscosity, thermal and storage stability, and acidity.

In addition, the ignition-combustion quality and cold flow properties of these blends are analyzed and discussed in detail.