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Effects on of blended biodiesel and heavy oil on engine combustion and black carbon emissions of a low-speed two-stroke engine

100%

Wei C. , Jiang G. , Wu G. , Zhou Y. , Liu Y.

Polish Maritime Research

2024

tom nr 1

94--101

The effects of heavy fuel oil and biodiesel blends on engine combustion and emissions were studied in a marine twostroke diesel engine. The engine was operated under propeller conditions using five different fuels with biodiesel blends of 10% (B10), 30% (B30), 50% (B50), and sulphur contents of 0.467% low sulphur fuel oil (LSFO) and 2.9% high sulphur fuel oil (HSFO). Tests have shown that using a biodiesel blend increases the engine fuel consumption due to its lower calorific value. Heavy fuel oil has a high Polycyclic aromatic hydrocarbons (PAH) content, which leads to higher exhaust temperatures due to severe afterburning in the engine. A comparison of engine soot emissions under different fuel conditions was carried out, and it was found that the oxygen content in biodiesel promoted the oxidation of soot particles during the combustion process, which reduced the soot emissions of biodiesel. Compared to HSFO, B10, B30, B50 and LSFO, the soot emission concentrations were reduced by 50.2%, 56.4%, 61% and 37.4%, respectively. In our experiments, the soot particles in the engine exhaust were sampled with a thermal float probe. Using Raman spectroscopy analysis, it was found that as the biodiesel ratio increased, the degree of carbonisation of the soot particles in the exhaust became less than that in the oxygenation process, resulting in a decrease in the degree of graphitisation.

Prediction of the amount of waste cold from liquefied natural gas (LNG) regasification for gas-fuelled low-speed main engines

86%

Korlak P. K.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2021

tom nr 68 (140)

69--79

Existing and future regulations on ship energy efficiency and methods for their improvement are presented in this work. The design and operational features of gas-fuelled low-speed main engines, liquefied natural gas (LNG) regasification conditions, and amount of waste cold are compared. Using a simple linear regression model based on the least squares method, formulae were developed to predict the amount of waste cold as a function of the brake power of gas-fuelled low-speed main engines operating under ISO ambient conditions in Tier III-compliant mode. A sufficiently accurate prediction of the waste cold amount at the initial design stage is feasible due to the formulae developed as part of this work

Improving the efficiency of a gas-fueled ship power plant using a Waste Heat Recovery metal hydride system

86%

Cherednichenko O. , Tkach M. , Timoshevskiy B. , Havrysh V. , Dotsenko S.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

2019

tom nr 59 (131)

9--15

Due to environmental, energy, and operating cost constraints, the number of liquefied natural gas (LNG)–powered ships is increasing. To avoid decreasing the thermal efficiency of two-stroke, low-speed diesel engines, high-pressure gas injection is used. The specific energy consumption of a gas fuel compressor is around 0.35 kWh/kg, which has a negative impact on the efficiency of ship power plants. To reduce the primary energy consumption of a gas fuel supply system, waste heat recovery (WHR) technologies may be used. This study investigated whether WHR metal hydride technology was suitable for improving the efficiency of low-grade heat waste in marine diesel engines. The key factors of this technology were revealed, and the design scheme was described. Working fluids were also analyzed, and a mathematical model of a WHR metal hydride plant was developed, and the results were represented. The calculations showed that the above technology could increase the operating power of a propulsion plant by 5.7–6.2%. The results demonstrate the possibility of applying WHR metal hydride equipment for gas fuel compressor drives in LNG-powered ships. The novelty of this study lies in the investigation of metal hydride technology for application in the waste heat recovery systems of LNG-powered ships.