A mechanistic model of fuel additive function and performance: Nanoparticle-fuel interactions in future marine fuels

海洋部门支撑着全球80%的贸易，面临着减少燃料排放的压力。其中一个步骤是降低燃料油中的硫含量，IMO MARPOL 2020立法将燃料硫含量限制在0.5%(1)。随着这些法规越来越难以满足，该行业正在转向未来的燃料，这些燃料将使用重燃料油(HFO)或极低硫燃料油(VLSFO)作为与氨、甲烷或氢混合的试点燃料。为了获得更高的燃料和发动机性能，人们正在考虑和设计纳米颗粒添加剂，以与杂质、不可燃产品相互作用，并催化燃烧。目前，该项目的重点是了解纳米颗粒和沥青质之间的相互作用，沥青质是燃料中的一种重组份，容易聚集和沉积。防止沉积物是避免发动机在长时间内性能恶化的关键。利用动态光散射(DLS)研究了沥青质的聚集动力学，探讨了纳米粒子尺寸和表面化学对防止沥青质团簇在燃料中形成的影响。从这一点出发，将使用石英晶体微天平(QCM)和X射线光电子能谱(XPS)等表面技术来确定沉积物的形成过程，以及这些纳米颗粒可能如何影响沉积物的成分和数量。随着这些技术的建立，该项目将开始探索VLSFO/HFO和氨的混合燃料，以确定此类替代燃料的添加如何影响纳米颗粒添加剂的功能和性能。进一步的进展将是使用高温微反应器和纳米颗粒-燃料相互作用的分子模拟来引入更现实的条件，以了解这些纳米颗粒燃料添加剂的作用机理及其对发动机中沉积物形成的影响。

The marine sector supports 80% of global trade and is under pressure to reduce fuel emissions. One such step is to reduce the sulphur content in fuel oils, with the IMO MARPOL 2020 legislation limiting fuel sulphur content to 0.5 % (1). As these regulations get more challenging to meet, the sector is moving towards future fuels which will use heavy fuel oils (HFO) or very low sulphur fuel oils (VLSFO) as a pilot fuel mixed with ammonia, methane or hydrogen. To achieve high fuel and engine performance, nanoparticle additives are being considered and designed to interact with impurities, incombustible products, and to catalyse combustion. Currently the project is focused on understanding the interactions between nanoparticles and asphaltenes, a heavy component of fuel that is prone to aggregation and deposition. The prevention of deposits is crucial for avoiding performance deterioration in the engine over long timescales. Dynamic light scattering (DLS) is used to study the aggregation kinetics of asphaltenes, exploring the effects of nanoparticle size and surface chemistry to prevent asphaltene cluster formation in the fuel. From this insight, surface techniques such as quartz crystal microbalance (QCM) and x-ray photoelectron spectroscopy (XPS) will be used to determine the process of deposit formation and how those nanoparticles may affect deposit composition and amount. With these techniques established the project will begin to explore fuel blends of VLSFO/HFO and ammonia, to determine how the addition of such alternative fuels impact the function and performance of the nanoparticle additives. A further progression will be to introduce more realistic conditions using a high-temperature micro-reactor and molecular modelling of nanoparticle-fuel interactions to understand the mechanism of action of these nanoparticle fuel additives and their effect on deposit formation in the engine.