The use of cashew nut shell liquid (CNSL) as a very low sulfur fuel oil (VLSFO) blendstock has gained attention in recent years due to its potential to reduce emissions and mitigate climate change. CNSL, a by-product of cashew nut processing, is rich in phenolic compounds and has been explored as a biofuel source. However, its suitability as a VLSFO blendstock has raised concerns among shipowners, operators, and regulators.
Proponents of CNSL argue that it can help reduce sulfur emissions, as it contains only 0.2-0.5% sulfur, significantly lower than the 0.5% limit set by the International Maritime Organization (IMO) for VLSFO. Additionally, CNSL has a high calorific value, making it a potential substitute for fossil fuels. Some manufacturers have already started producing CNSL-based blends, claiming they meet the IMO’s VLSFO standards.
However, several concerns have been raised regarding the use of CNSL as a VLSFO blendstock. One major issue is the potential for lubricity problems, as CNSL can affect the viscosity and lubricity of the fuel. This could lead to increased wear and tear on engines, potentially resulting in costly repairs and downtime. Furthermore, CNSL’s high phenolic content may also cause issues with fuel stability, potentially leading to sludge formation and filter clogging.
Another concern is the potential for CNSL to contaminate fuel systems and harm engines. The phenolic compounds in CNSL can react with other fuel components, leading to the formation of potentially harmful substances. Some experts warn that using CNSL-based blends could lead to increased maintenance costs, engine damage, and even premature engine failure.
Regulatory bodies, such as the International Council on Clean Transportation (ICCT), have also expressed concerns about the use of CNSL as a VLSFO blendstock. The ICCT argues that CNSL’s chemical composition and potential to contaminate fuel systems make it unsuitable for use in marine fuels.
In conclusion, while CNSL may offer some benefits as a biofuel source, its use as a VLSFO blendstock is not without concerns. The potential for lubricity problems, fuel instability, and contamination raises significant questions about its suitability for use in marine fuels. As the shipping industry continues to explore alternative fuels to reduce emissions, it is essential to carefully evaluate the risks and benefits of CNSL and ensure that any blends used meet strict safety and environmental standards. Further research and testing are needed to fully understand the implications of using CNSL as a VLSFO blendstock and to mitigate any potential risks.