The shift in direction of biofuels in 2024 has introduced new dynamics to gas high quality and efficiency. The discharge of the up to date ISO 8217:2024 specification now consists of testing necessities for biofuel blends, reflecting the rising adoption of those fuels.
The Viswa Group issued its 2024 report on World Gasoline Traits, highlighting key traits in general gas high quality, off-specification parameters throughout totally different areas, and the operational points comparable to air purifier sludging, gas pump seizure, and so on. affecting vessel efficiency.
Gasoline Sort Distribution in 2024
This part offers an summary of the distribution of varied gas sorts, together with VLSFO, HSFO, LSMGO, HSMGO, ULSD, ULSFO, and biofuels. Determine 1 illustrates the gas sort distribution. A rise within the adoption of biofuels was noticed in 2023 and 2024. Biofuels might help shipowners preserve or enhance their vessel’s CII ranking. As “drop-in” fuels, they can be utilized in standard ship engines with out requiring modifications, making them a sensible choice for attaining near-term GHG emissions reductions with out important investments in new ships or expensive vessel modifications.
FIG 1 | Gasoline sort distribution in 2024
Traits of VLSFO vs. HFO vs. Bio-residual Fuels
Desk 1 exhibits the minimal, common, and most values of the ISO 8217 parameters for VLSFOs, HSFOs and Bio-residual fuels in 2024 (off-spec samples not thought-about). This collected knowledge exhibits that 2024 VLSFOs have decrease viscosity, decrease density, decrease MCR, decrease CCAI & larger calorific worth compared to the HSFO.
TABLE 1 | VLSFO, HSFO and Bio-residual traits in 2024 (off-spec samples not thought-about)
Vital factors to notice
Total, the standard of bio-residual fuels is just like the VLSFOs, with decrease common viscosity and decrease web warmth of combustion (roughly 3.4% decrease calorific worth). A lot of the examined biofuels had been B20-B35 samples.
Common density, viscosity and MCR of VLSFOs are decrease than HSFOs which exhibits that they’re extra paraffinic in nature.
Internet calorific worth of VLSFOs is larger than HSFOs, which is as a result of relative larger carbon content material of VLSFOs compared to HSFOs.
Distribution of VLSFO traits by area – 2024
Density & Viscosity
FIG 2 | Density (Kg/m3) distribution of VLSFOs in 2024
FIG 3 | Viscosity (cSt at 50C) distribution of VLSFOs in 2024
Stability properties
One of many most important challenges with VLSFOs is the soundness of those fuels. They’re comprised of a various vary of mixing shares various from extremely paraffinic to extremely fragrant. When mixing two fuels, one paraffinic and one fragrant, that are secure by themselves, the ensuing combination would possibly turn out to be unstable. Due to this fact, the end result can be extreme sludging due to asphaltene deposition. Determine 4 exhibits the distribution of the sediment content material of VLSFOs from totally different areas. Gasoline stability knowledge from totally different areas, expressed via Complete Sediment Potential (TSP) exhibits that fuels from Houston, ARA, and New York have the very best variety of samples with off-spec sediment values. As well as, Hong Kong had the very best variety of samples with sediment content material within the borderline secure vary (0.06-0.1%).
FIG 4 | Distribution of the sediment content material of VLSFOs from totally different areas
Catfine (Al & Si content material)
Catfines (Al and Si compounds) are onerous abrasive particles that stay in gas oil as a by-product ensuing from the catalytic cracking know-how or fluid catalytic cracking (FCC) used within the intensive refining and mixing course of to cut back the sulfur content material. The typical catfine content material of all of the areas are beneath the restrict of 60 ppm as per ISO8217 specification. Houston and Singapore have the very best common catfine content material.
FIG 5 | Catfine distribution in numerous areas and main ports
VLSFO traits in 2024
Off spec parameters
In 2024, 4.3% of the VLSFO samples examined by Viswa had been discovered to be out of the ISO 8217 specification. Desk 2 exhibits the share of VLSFOs that didn’t adjust to ISO 8217 parameters throughout totally different areas. The first off-spec parameter in Africa, and Asia was sulfur content material. In North America and Europe, sediment content material was the principle challenge, whereas in Oceania, off-spec water content material samples had been the very best. In South America, the very best proportion of off-spec parameters was associated to acid quantity.
TABLE 2 | Proportion of off-spec parameters throughout totally different areas
Gasoline traits in 2024
Off spec parameters
Off spec parameters
VLSFO traits in 2024
Operational points
The primary operational challenge associated to VLSFOs in 2024 was instability. Almost 60% of the issue instances reported to Viswa had been Air purifier choking/ Air purifier choking & Filter choking, due to the instability points. There have been instances the place the VLSFO met the ISO8217 specification restrict for the sediment content material (TSP & TSA) on the time of bunkering after which turned unstable inside a matter of weeks. This constitutes the shelf lifetime of the VLSFO.
FIG 8 | VLSFOs downside in 2024
VLSFO operational points in 2024
Sludging points
60% of downside instances reported to us in 2024 had been associated to air purifier sludging and filter choking. VLSFO sludging points was not solely associated to the samples with excessive sediment content material on day 1 of testing but in addition associated to the samples by which the sediment content material on day 1 was inside the specification of ISO8217 (0.1%). After two to 4 weeks of storage or utilization of the gas the pattern turned unstable and sediment elevated to larger than 0.1%. Complete sediment potential or Complete sediment accelerated are usually not a assure for long run stability properties of VLSFOs. Fig 9 exhibits 9 samples with low sediment content material on day 1 of testing which turned unstable after a couple of weeks of utilization and storage of the fuels and resulted in to the air purifier choking and sludging points.
Desk 3 highlights the traits of a number of unstable fuels that led to sludging points. An fascinating statement is that normally, sediment content material, TSP, and TSA are elevated when sludging happens. In roughly 20% of the instances, the distinction between the TSP and TSA values is notable, with the TSP being 0.1% larger than the TSA. Moreover, the vast majority of these sludging issues are related to low-viscosity VLSFOs, with viscosities beneath 100 cSt.
Gasoline pump points
Based mostly on our downside gas knowledge in 2023 and 2024, there was a notable enhance in gas pump issues, marking an increase in comparison with 2022. This pattern is probably going attributed to using new advanced mixing streams with larger concentrations of chemical contaminants within the manufacturing of Very Low Sulphur Gasoline Oil (VLSFO).
In 2024, gas pump downside instances concerned gas pump corrosion, sticking and seizure, stress drops, and diminished Pmax ranges. Moreover, some incidents reported air purifier clogging and elevated exhaust fuel temperatures.
The three main cluster of instances had been related to fuels bunkered within the following areas:
1. US Gulf Coast ports2. ARA (Amsterdam-Rotterdam-Antwerp) region3. Malta ports
Drawback fuels from US Gulf Coast
In 2024, we acquired reviews of gas pump-related points from 9 vessels that had bunkered in Houston, Bolivar Roads, Barbours Reduce, and New Orleans. The contaminated fuels had been related to gas pump malfunctions, corrosion and, in some instances, air purifier sludging and filter choking. For all 9 samples, the ISO 8217 parameters had been inside acceptable limits. Nonetheless, GCMS evaluation revealed the presence of unusual chemical compounds, together with 2-Ethylhexanol, Tetrachloroethylene, FAME, and free fatty acids.
Whereas these compounds might in a roundabout way trigger operational points, their presence at some elevated ranges serves as an indicator of contaminated VLSFO bunkers originating from US Gulf ports. Please additionally notice that solely in VLSFOs, the presence of those fingerprint compounds have been related to issues. We examined some HSFOs and ULSFOs with the identical fingerprint chemical compounds and the vessel was in a position to make use of the fuels with none downside. We’re nonetheless investigating the basis trigger of those issues.
Drawback fuels ARA
In 2024, we encountered gas contamination points throughout 11 bunkers provided inside the ARA areas, which included 2 fuels from Antwerp, 8 from Rotterdam, and 1 from Amsterdam. These fuels all offered with operational challenges, comparable to extreme put on, gas pump points, air purifier sludging, and filter choking. The affected fuels consisted of 8 VLSFOs and three HSFOs.
Whereas the ISO 8217 parameters of the fuels had been inside regular specs, GCMS evaluation recognized elevated ranges of a number of contaminants within the affected samples. Of specific concern, 4 of the problematic instances had Cardanol concentrations exceeding 10,000 ppm. This compound, which has additionally been detected in fuels provided inside the ARA area in 2023, is indicative of the presence of cashew nut shell liquid within the gas.
Moreover, the remaining 7 problematic samples exhibited excessive concentrations of phenolic compounds, together with Resorcinol, 2-Methylresorcinol, 5-Methylresorcinol, 2,5-Dimethylresorcinol, C2 Phenols, C3 Phenols, and others. Some samples additionally contained ketonic compounds. You will need to spotlight that the presence of phenolic compounds, significantly in substantial portions, can result in elevated sludging, which can trigger gas pump seizure as a result of sticky nature of the sludge generated by these compounds.
Drawback fuels Malta
From July to September 2024, 4 downside samples reported to us had been associated to gas pump points and a few instances of sludging. These samples had been provided by totally different suppliers. Of the 4 VLSFO samples, three exhibited gas pump seizures, whereas one skilled extreme sludge accumulation in purifiers.
The ISO 8217 parameters for these fuels had been inside the regular limits. Nonetheless, the whole acid quantity (TAN) for these fuels was larger than the typical for Malta, though nonetheless inside the ISO 8217 specification restrict of two.5 mg KOH/g. Moreover, the whole sediment potential in two of the samples was elevated, at 0.07%.
GCMS evaluation of those downside samples recognized the presence of phenolic compounds (e.g., 2-Methylphenol, 2-Ethylphenol, C3 Phenols) in concentrations starting from 1,000 to 2,000 ppm, alcohol-based compounds (e.g., 1-Phenylethanol, 2-Phenylethanol, 1-Phenoxy-2- propanol, 2 Phenoxy-1-propanol) between 2,000 and 4,000 ppm, and free fatty acids starting from 362 to 530 ppm. Moreover, unknown oxygenated compounds had been detected, together with fragrant acids comparable to benzoic acid.
Additional testing revealed that the oxygen content material of those problematic samples ranged from 0.7% to 1%, which is larger than the typical for VLSFOs (usually beneath 0.5%). These findings, mixed with the GCMS outcomes, recommend the presence of oxygenated compounds within the samples. Our knowledge signifies that oxygenated compounds, comparable to ethers or ketones,are susceptible to oxidation, resulting in gum formation, which may end up in sludging and gas pump seizures, significantly at elevated temperatures.
HSFO-MGO traits in 2024
Operational points
Bio-Gasoline traits in 2024
Biofuel operational points
In 2024, we acquired reviews of points from three vessels utilizing biofuel blends. Two of the samples (Bio-residual 1 & Bio-distillate 1) met ISO 8217:2017 specs, however the examined FAME content material didn’t match the designated gas grades.
The third pattern (bio-distillate 2) confirmed an acid variety of 20 mg KOH/g and a FAME content material of solely 4%. Investigative GCMS evaluation on Bio-distillate 2 recognized contamination with excessive ranges of free fatty acids. Copper corrosion take a look at on this pattern confirmed a ranking 1a.
A metal corrosion test1 was performed in accordance with ASTM D665. The rod was discovered to be absolutely rusted, seemingly resulting from oxidation and corrosion processes. This final result is predicted, because the acid variety of the pattern is significantly excessive and comprises considerably excessive focus of free fatty acids.
Because of this, one of many vital assessments for biofuel blends is testing the FAME content material of fuels. Testing FAME content material is essential to make sure it complies with the desired gas grade. In case of utilization of recent sorts of biofuels with Non-FAME feedstock, please guarantee detailed testing and trials earlier than the utilization onboard the vessel.
1 The metal corrosion take a look at, performed as per ASTM D665, doesn’t absolutely replicate vessel situations for fuels and has been used solely for investigative functions.
Supply: The Viswa Group
