Effects of hybrid nanoparticle additives in n-butanol/waste plastic oil/diesel blends on combustion, particulate and gaseous emissions from diesel engine evaluated with entropy-weighted PROMETHEE II and TOPSIS: Environmental and health risks of plastic waste

In recent years, the International Maritime Organization (IMO), Europe, and the United States and other countries have set up different emission control areas (ECA) for ship exhaust pollutants to enforce more stringent pollutant emission regulations. In order to meet the current IMO Tier III emission regulations, an after-treatment device must be installed in the exhaust system of the ship power plant to reduce the ship NOx emissions. At present, selective catalytic reduction technology (SCR) is one of the main technical routes to resolve excess NOx emissions of marine diesel engines, and is the only NOx emission reduction technology recognized by the IMO that can be used for various ship engines. Compared with the conventional low-pressure SCR system, the high-pressure SCR system can be applied to low-speed marine diesel engines that burn inferior fuels, but its working conditions are relatively harsh, and it can be susceptible to operational problems such as sulfuric acid corrosion, salt blockage, and switching delay during the actual ship tests and ship applications. Therefore, it is necessary to improve the design method and matching strategy of the high-pressure SCR system to achieve a more efficient and reliable operation. This article summarizes the technical characteristics and application problems of marine diesel engine SCR systems in detail, tracks the development trend of the catalytic reaction mechanism, engine tuning, and control strategy under high sulfur exhaust gas conditions. Results showed that low temperature is an important reason for the formation of ammonium nitrate, ammonium sulfate, and other deposits. Additionally, the formed deposits will directly affect the working performance of the SCR systems. The development of SCR technology for marine low-speed engines should be the compromise solution under the requirements of high sulfur fuel, high thermal efficiency, and low pollution emissions. Under the dual restrictions of high sulfur fuel and low exhaust temperature, the low-speed diesel engine SCR systems will inevitably sacrifice part of the engine economy to obtain higher denitrification efficiency and operational reliability.

https://www.mdpi.com/2073-4433/13/5/731/pdf?version=1651488262

Application and Development of Selective Catalytic Reduction Technology for Marine Low-Speed Diesel Engine: Trade-Off among High Sulfur Fuel, High Thermal Efficiency, and Low Pollution Emission

Effect of low CeO2 nanoparticles dosage in biodiesel-blends on combustion parameters and toxic pollutants from common-rail diesel engine

This study aimed to investigate the effect of biodiesel and CeO2 nanoparticles (NPs) blends on organic carbon (OC) and elemental carbon (EC), organic compounds, size distribution, gaseous emissions and combustion reactivity from CRDI diesel engine at the steady-state mode. To ensure that gaseous pollutants do not depend on a filter device, the research engine was allowed to operate without a diesel particulate filter. The nano-additive of 20 ppm was included in various biodiesel blends through the ultrasonication process. Experimental results revealed that the addition of biodiesel in CeO2 NPs blends significantly improved the in-cylinder pressure and heat released rate (HRR) of the engine. As for the B15C20 fuel, significant reductions in CO and HC emissions were observed by 32.16% and 45.59%, respectively with a rise in NOx by 5.97% compared to B0. It was also found that the B0 and B0C20 fuels generate more particles within a diameter size range over 50 nm compared to B10C20 and B15C20 that generate particles of diameter ranging from ∼10 nm to 37 nm. EC-soot was slightly higher compared to OC for all test fuels, which could be explained by the catalytic effect of metals on soot oxidation as a result of low amount of total PM2.5 mass presence. The toxic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and n-alkanes turned out to be more less when the ratio of biodiesel increases in CeO2 NPs. This might reduce the effect of cancer and direct eye irritants that cause an allergic response in humans and animals. 

The effect of biodiesel and CeO2 nanoparticles blends on CRDI diesel engine: A special focus on combustion, particle number, PM2.5 species, organic compound and gaseous emissions

Ibrahim Yahuza

Papers

Influence of waste oil-biodiesel on toxic pollutants from marine engine coupled with emission reduction measures at various loads