Presence of Chemical Compounds in VLSFO In Malta
Presence of Chemical Compounds in VLSFO in Malta
FINDINGS & INSIGHTS
In the last few weeks CTI-Maritec has tested multiple fuel oil bunker samples from vessels that have taken fuel/bunkered in MALTA and reported operational issues and/or tested to have the presence of high levels of chemical compounds.
Extended Gas Chromatography Mass Spectrometry (GC-MS) testing by ASTM D7845 was conducted for two Very Low Sulphur Fuel Oil (VLSFO) samples, which showed the presence of high concentrations of acetophenone, phenolic compounds (4-cumylphenol, phenol and others), styrene glycol and phenethyl alcohols. Furthermore, testing by Solid Phase Extraction (SPE) GC-MS technique indicated low levels of bisphenol isomers, fatty acids, long chain fatty acids and dehydroabietic acid. All mentioned compounds are non-hydrocarbons. Our GC-MS analysis also indicated the presence of reactive hydrocarbons like DCPD, Dihydro-DCPD, Styrene and Indene.
The common problems encountered, as reported by the vessels, were sludging, filter clogging and in some instances, fuel pump issues associated with phenolic compounds and phenethyl alcohols.
Due to the high levels of these chemical compounds, the fuels do not meet the general requirement and is considered as off-spec fuel as per clause 5 of ISO8217 and MARPOL Annex VI regulation 18 which states:
“The fuels shall be homogeneous blends of hydrocarbons derived from petroleum refining. This shall not preclude the incorporation of small amounts of additives intended to improve some aspects of performance.”
The fuels shall be free from inorganic acids and from used lubricating oils. The fuel should not include any added substance or chemical waste which,
a) jeopardizes the safety of ships or adversely affects the performance of the machinery; or
b) is harmful to personnel; or
c) contributes overall to additional air pollution.”
CTI-Maritec Recommendations:
CTI-Maritec recommends to:
- Closely observe the vessel fuel system/s for signs of filter clogging and purifier sludging and additionally, increase vigilance on the centrifuges to monitor overloading.
- Increase frequency of their de-sludging cycle depending on the accumulated sludge.
- Possibly reduce the Mean Time between bowl cleaning of the purifier and fuel system filters.
- Avoid blending with other fuels, in particular marine diesel and gas oil and also other fuel oil as such mixing may well increase the sediment problem.
Furthermore, at these levels of concentration of chemical compounds present in fuel oil, there is an increased risk of excessive wear to the vessel’s fuel pump plunger and barrel assembly. Therefore, it is advised to monitor the fuel pump index closely to check for deteriorating performance. As a back-up, ensure there are sufficient spare seals and plunger barrel assembly to replace damaged units if necessary.
In addition, as a precaution, it is advised to closely monitor the performance of the engines while using this fuel to detect any deterioration of the fuel injection equipment performance and the sealing effect of the piston rings.
This document, however, does not reflect on the overall quality of fuel being supplied in Malta. If you intend to bunker in this region, please request for a Certificate of Quality prior to loading.
CTI-Maritec can assist you with further information on the quality of bunkers tested in different regions. For further information or assistance please do not hesitate to Contact us.
CTI-Maritec Insights on VLSFO Issues & its Optimal Management
CTI-Maritec Insights on VLSFO Issues & its Optimal Management
Table of Contents
- 1. INTRODUCTION
- 2. CTI-MARITEC DATA EVIDENCE ON MAIN CHALLENGES OBSERVED WITH VLSFO
- 2.1 Comparison of off-spec parameters (Chart-1) and machinery & operational issues for HSFO vs VLSFO (Chart-2) from 2022 till date
- 2.2 Cold Flow Properties Issues, Testing Recommendations & Pour Point vs WAT & WDT
- 3. KEY INSIGHTS ON HANDLING ISSUES ASSOCIATED WITH ONBOARD SYSTEM TEMPERATURE AND STABILITY WITH RECOMMENDATIONS FOR OPTIMAL MANAGEMENT
- 3.1 Onboard System Temperature
- 3.2 Stability
- 3.3 Stability Reserve & P-value testing by SMS 1600 to measure Long Term Stability
- 4. CHEMICAL CONTAMINATION ISSUES & CTI-MARITEC INVESTIGATIVE FINDINGS
- 5. CTI-MARITEC ‘FUEL OPERATIONS MANAGEMENT PACKAGE’ (FOMP)
- 6. SUMMARY & CONCLUSION
Introduction
Since 01 January 2020, the International Maritime Organization (IMO) enforced a 0.50% global sulphur cap in marine fuels for the shipping industry to reduce sulphur oxide (SOx) emissions, which is a significant reduction from the previous limit of sulphur at 3.5%. Therefore, greater use of Very Low Sulphur Fuel Oil (VLSFO) came into play post 2020. However, a comparison between fuel properties of High Sulphur Fuel Oil (HSFO) and VLSFO reveals that VLSFO exhibits greater instability, waxiness, lower density, and viscosity, lower calculated Carbon Aromaticity Index (CCAI), lower vanadium content, higher net specific energy, higher pour point, and higher acid number.
The decreased stability reserve (detected by higher paraffinic and lower aromatic content) of VLSFO also raises concerns about compatibility issues when different fuels are mixed. Even after four years of using VLSFO, the long-term storage of VLSFO still remains a challenge and pain-point for the marine industry.
All present-day complexities of VLSFO arise due to its formulation and the processes used to achieve 0.50% sulphur content. The composition of VLSFO varies widely because it is a blend of several types of refined petroleum products, including distillate oil, residual fuels and additives, among others. VLSFOs are more paraffinic than HSFOs owing to its composition, which consists predominantly of small and medium chain hydrocarbons, including alkanes (paraffins) and cycloalkanes (naphthene), among others.
Furthermore, due to the widely varied compositions of VLSFOs sold in the bunker fuel oil market, the physical and chemical properties and qualities vary greatly, thus exhibiting significantly different chemical behaviours, which can only be accurately determined through focused monitoring/testing. This variability can affect engine performance. The characteristics of VLSFO also demands more attention towards storage and handling practices to prevent issues like stratification or sludge formation, especially during the fuel change over process. VLSFO reduces SOx emissions, however, the emission of other pollutants, such as black carbon remain a concern. Therefore, a careful fuel management process is required to optimally manage VLSFO.
Additionally, the issue of chemical contamination has plagued the bunkering industry for years, and the risk of receiving contaminated bunker fuels is likely to persist due to the complexity of the fuel supply chain.
