• Journal of Biosystems Engineering
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• 제38권4호
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• pp.306-311
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• 2013

Purpose: With the ever-rising energy prices, thermal energy heavily consuming facilities of the agricultural sector such as commercialized greenhouses and large-scale Rice Processing Complexes (RPCs) need to cut down their energy cost if they must run profitable businesses continually. One possible way to reduce their energy cost is to utilize combustible agricultural by-products or low-price oil instead of light oil as the fuel for their boiler systems. This study aims to analyze the heavy oil combustion characteristics of a newly developed hot water boiler system that can use both rice husk and heavy oil as its fuel convertibly. Methods: Heavy oil combustion experiments were conducted in this study employing four fuel feed rates (7.6, 8.5, 9.5, 11.4 $l/h$) at a combustion furnace vacuum pressure of 500 Pa and with four combustion furnace vacuum pressures (375, 500, 625, 750 Pa) at fuel feed rates of 9.5 and 11.4 $l/h$. Temperatures at five locations inside the combustion furnace and 20 additional locations throughout the whole hot water boiler system were measured to ascertain the combustion characteristics of the heavy oil. From the temperature measurement data, the thermal efficiency of the system was calculated. Flue gas smoke density and concentrations of air-polluting components in the flue gas were also measured by a gas analyzer. Results: As the fuel feed rate or combustion furnace vacuum pressure increased, the average temperature in the combustion furnace decreased but the thermal efficiency of the system showed no distinctive change. On the other hand, the thermal efficiency of the system was inversely proportionally to the vacuum level in the furnace. For all experimental conditions, the thermal efficiency remained in the range of 80.1-89.6%. The CO concentration in the flue gas was negligibly low. The NO and $SO_2$ concentration as well as the smoke density met the legal requirements. Conclusions: Considering the combustion temperature characteristics, thermal efficiency, and flue gas composition, the optimal combustion condition of the system seemed to be either the fuel feed rate of 9.5 $l/h$ with a combustion furnace vacuum pressure of 375 Pa or a fuel feed rate of 11.4 $l/h$ with a furnace vacuum pressure between 500 Pa and 625 Pa.

• 한국항해항만학회지
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• 제46권4호
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• pp.297-302
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• 2022

탄산칼슘과 염산 수용액에 폴리프로필렌 섬유를 침지시켜 표면에 염화칼슘 결정을 생성시킴으로써 발열 흡착포를 제작하였다. 발열 흡착포를 유출 기름으로 인해 유막이 형성된 해수면에 적용하면 염화칼슘 결정이 주변의 수분을 흡수하여 이온화되면서 용해열을 방출한다. 염화칼슘의 용해열을 유동점 이하의 저온에서 응고된 저유황 중질유를 액화시켜 흡유 가능한 상태로 전환시킨다. 발열 흡착포의 제작을 위해 폴리프로필렌 표면에 염화칼슘 결정을 생성시키기 위한 탄산칼슘과 염산의 최적 몰농도는 각각 0.25 M과 0.5 M이다. 저유황 중질유 발열 흡착포의 흡유능은 해수 온도에 따라 다르지만, 우리나라 인근 해역의 동절기 평균 수온인 10℃에서 4.5-7.08 g/g으로 매우 우수하였다. 염화칼슘 발열 흡착포를 사용하면 동절기 선박사고로 인하여 해양에 유출된 저유황 중질유를 효과적으로 흡유하여 제거할 수 있다.

• 수산해양기술연구
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• 제24권1호
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• pp.36-43
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• 1988

Boilers and diesel engines have many problems because their exhaust particles, i.e., soot have lots of bad influence on environment. And it's spray and flame have fundamentally axial symmetric shape. To investigate the relationship between fuel concentration distribution of spray and soot concentration distribution as well as temperature distribution of flame, we made a axial symmetric two phase spray-flame and analyzed the structure of is. The measuring method is the principle of the light extinction method for the spray-flame and onion peeling model is applied to analyze the radial distribution of fuel and soot concentration. The temperature of flame is measured by ø 0.4mm Pt-Pt.RH 3% thermocouple. The oils for the experiments are diesel oil and 10% water emulsified diesel oil. It was found that the soot concentration becomes higher as it comes near to the center of flame, and the fuel concentration does, too. And the soot concentration level of diesel oil is generally higher than that of the 10% water emulsified fuel. The maximum flame temperature of diesel oil is 1,17$0^{\circ}C$, however, 10% water emulsified diesel oil is 1,27$0^{\circ}C$.

• Tribology and Lubricants
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• 제21권4호
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• pp.159-164
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• 2005

An experimental study was conducted to evaluate characteristic variation of diluted engine oils in which contains diesel fuels and its tribological effects on engine components. In this study, diluted engine oils with $10\%,\;15\%,\;and\;20\%$ of initial fuel content rate have been used for measuring the viscosity reduction rate, blow-by gas increment rate, main gallery pressure reduction rate, and fuel content rate in engine oils. These parameters are strongly related to the tribological characteristics of key engine components. The kinematic viscosity of engine oils in which is contained by diesel fuels from $10\%\;to\;20\%$ in oils is decreasing to approximately $54\%$ of initial diluted fuel-oil volume ratios. The experimental results show that the distillated engine oil decrease the viscosity of engine oil and its oil film stiffness, and increase the wear rate of rubbing parts of engine components. Thus we recommend that the containing volume rate of fuels in engine oils should be restricted to $3\~4\%$ for a sophisticated Diesel engine and $5\~7\%$ for a standard one.

• 한국분무공학회지
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• 제5권1호
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• pp.5-12
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• 2000

The beneficial aspects of applying emulsion fuels to combustion systems may be due to the changes of fuel properties which lead to the enhanced atomization characteristics. The spray characteristics of water/oil emulsified fuel injected from the pressure-swirl(simplex) atomizer using for oil burner were investigated. Four different water contents from 10 to 40 % by volume at 10% increment were prepared by mixing with the different contents of surfactants. Total amount of surfactant used was varied from 1 to 3 % by volume. This study demonstrates the influence of water and surfactant contents of emulsified fuel, injection pressure on the spray characteristics, i.e. Sauter mean diameter(SMD) and spray angle. The drop size distribution of the emulsified fuel spray was measured with a Malvem particle sizer. In order to measure the spray angle, the digital image processing was employed by capturing multiple images of the spray with 3-CCD digital video camera. It was evident that the addition of water and surfactant changes fuel properties which are the key parameters influencing the atomization of the spray. The increase in surfactant content results in the decrease of SMD and the increase in spray angle. The droplets decease with increase in injection pressure, but the influence of injection pressure in this experimental condition was less important than expected. The more viscous fuel with the increase of water content exhibits the larger droplets in the centerline of the spray, and the less viscous fuel in the outer edges of the spray. The increase in axial position from the nozzle causes the spray angle to decrease. The spray angle decreases with increase in water content. This is due to increase in viscosity with increase in water content.

• Journal of Advanced Marine Engineering and Technology
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• 제32권7호
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• pp.1080-1088
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• 2008

This paper addresses some concerns faced by the shipping industry nowadays. Initially, the environmental issues were resolved and stricter regulations are now being implemented with regards to the exhaust gas, specifically nitrogen oxides (NOx) and sulfur oxides (SOx), emitted from ships. Secondly, with the increasing and unstable cost of fuel oils in the world market, it has become almost a necessity to explore on a new alternative fuel. Hence, this study was conducted. An experiment was carried-out on a fishing survey vessel with the main engine (M/E) and generator engine (G/E) operated on expensive marine gas oil (MGO). During the experiment, two pre-refinery systems were installed and different fuel oil samples were employed for the M/E and the G/E. Furthermore, the NOx emission and soot concentration were monitored and verified. The results confirmed the compatibility of some fuel oil types to the engines and meeting the emission standards. MDO, MF15 and Bunker A can be used in place of MGO for the engines(M/E, G/E).

• Journal of Advanced Marine Engineering and Technology
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• 제33권3호
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• pp.373-377
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• 2009

It is well known that SOx and NOx concentration has a considerable influence on the $N_2O$ emission of the greenhouse gas properties. The quantity of SOx generated during combustion, on fuel specific basis, is directly related to the sulfur content of the fuel oil. However, restricting the fuel oil sulfur content is only a partial response to limiting the overall quantity of SOx emissions, as there remains no over control on the fuel oil consumption other than the commercial pressure which have always directed the attention. This study was carried out as a new basic experiment method of emission control, manly targeted to the vessel. In the experiment, where the scrubbing was achieved through spray tower with high alkaline water made from the electrolysis of seawater, the combined action was to neutralize the exhaust gases (SOx, PM, CO etc.), dilute it, and wash it out. The results showed that SOx reduction of around 95 percent or over could be achieved when using in the high alkaline water, and also leaded to a reduction in the stability of the each pollutant components including the PM (Particulate Matter). The results suggest that the seawater electrolysis method has a very effective reduction of emissions without heavy cost, or catalysts particularly on board.

• 동력기계공학회지
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• 제18권5호
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• pp.156-163
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• 2014

Diesel engine is most suitable one for biodiesel fuel because the compression-ignition diesel engine has desirable fuel consumption due to higher thermal efficiency and in addition, the improvement of the fuel consumption also leads to a reduction of $CO_2$ emission and then it does not need to have spark-ignition system, which means that there is less charge on the technic and complexity. In this study, the spray behavior characteristics of the vegetable palm oil were analyzed by using a common-rail injection system of commercial diesel engine and the results were compared with those obtained for the diesel fuel. The injection pressures and blend ratios of palm oil and diesel(BD3, BD5, BD20, BD30, BD50, and BD100) were the main parameters. The experiments were conducted for different injection pressures: 500bar, 1000bar, 1500bar, and 1600bar by setting injection duration to $500{\mu}s$. Consequently, it was found that there is no significant difference in the macro characteristics of the spray behavior(spray penetration and spray angle) in response to change in the blend ratio of palm oil and diesel at a fixed injection pressure. In particular, all experiments showed the spray angle about $12^{\circ}{\sim}13^{\circ}$.

• 동력기계공학회지
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• 제22권1호
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• pp.72-78
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• 2018

With growing concerns over air pollutions attributed to shipping activities, the international maritime organization has enacted a series of stringent regulations. In particular, MARPOL Annex IV Reg. 16 requires sulfur contents from exhaust gases of marine engines to be progressively reduced. To comply with this regulation, three feasible options have been introduced: using LNG as a marine fuel, using heavy fuel oil with the scrubber system, and using the marine gas oil (a type of low sulfur fuel oil). For the objectives of this paper, the holistic environmental impacts pertinent to these options were investigated and compared in ways that the flows of energy and emission were tracked and quantified through the life cycle of the ship. Research findings obtained from a case study with a large bulk carrier showed that the use of the scrubber system to purify heavy fuel oil would produce relatively fewer amounts of emissions attributing to global warming than other two options. On the other than, the use of LNG would be the way to operate the ship in a cleaner way in terms of reducing the acidification, eutrophication, and photochemical effects. Throughout the analysis, the excellence of life cycle assessment was proven to shift the environmental impact of marine systems from the short-term view to the long-term one.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.36-38
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• 2011

As the increase of the fuel oil price, the demand for saving of the ship running cost is growing. To meet the needs of the shipowners, the method for low load operation has been developed by engine licenser. As one of low load operation, the turbocharger cut-out system can be utilized flexibly both full and part load operation. It can be possible to optimize fuel consumption at both full and part load operation. Tests by engine licenser with 12K98MC engine have proven that the fuel oil consumption can be reduced approximately 5%. In this paper we will study the application of main engine turbocharger cut-out system onboard a vessel. One of four turbochargers with MAN Diesel & Turbo 12K98MC-C and 12K98ME-C engine is cut out with swing gate valve. The fuel oil consumption is measured during sea trial and engine shop test.