최근 국제 유가의 상승으로 인한 선박 운용비를 절감하기 위하여 중소형 선박에서도 저질연료유의 사용이 검토되고 있는 추세이다. 이 연구에서는 현재 중소형 선박에서 연료유로 사용중인 경유와 중유MF380을 혼합하여 소형선박에 사용이 가능하도록 제조한 혼합연료유인 MF30 연료유에 대하여 그 물리 화학적 특성을 분석하고 정제처리 및 연료유첨가제 효과에 대해 알아보았다. 연구결과 두 가지 전처리 방식인 원심식청정기와 가열 및 균질 방식(M.C.H)의 효과는 다소 미약하였지만, 유동점과 인화점은 다소 낮아졌다. 연료유첨가제로 인한 개질 효과는 뚜렷이 나타나지 않았다.

최근 선박 연료유는 고점도화 되고 슬러지분이 증가되고 있는 추세이며, 선박에서 발생한 슬러지의 처리 및 보일러 연료유로의 재활용 방안 등에 대해서 많은 연구가 수행되고 있다. 이러한 연구 중 특히 슬러지를 미립화하여 분쇄하기 위한 초음파 유화기는 가장 현실성 있는 재활용 장치로 알려져 있다. 이러한 관점에서, 이 연구는 초음파 유화기 개발에 대한 기초연구로서 슬러지의 유온과 유압이 따른 여과효율을 조사하였다. 실험결과는 보일러 인젝터에 슬러지를 분사할 경우 적절한 온도와 압력을 결정하거나, 또한 초음파 유화기에 의한 실험결과와 비교할 수 있는 자료로 활용될 수 있다. 아울러 유온과 유압의 영향에 따라 분쇄된 슬러지 입자의 여과효율 등을 연구하는데 있어서 기초자료로 활용될 수 있을 것이며, 궁극적으로 선박에서 발생한 슬러지를 자체 처리하여 보일러의 연료유로 사용함으로써 해양유류오염을 방지하는데 기여할 수 있을 것이다.

Transesterfication of vegetable oils and methanol with alkaline catalyst was carried out to produce biodiesel fuel by continuous process. The process consists of two static mixers, one tubular reactor and two coolers and gave 96~99% of methyl ester yield from soybean oil and rapeseed oil. Experimental variables were the molar ratios of methanol to vegetable oil, alkaline catalyst contents, flow rates, mixer element number. The optimum ranges of operating variables were as follows; reaction temperature of 70℃, l:6 of molar ratio of methanol to oil, O.4%(w/w) sodium hydroxide based on oil, static mixer elements number of 24 and 4 min. residence time.

This paper is an experimental study to investigate utility of ultrasonic treatment of fuel oil in diesel engine. Experiment was carrid out to clarify the effect of ultrsonic vibration on the characteristics of maximum pressure, fuel consumption ratio, smoke, BMEP and torque. The result obtained are as follows: 1. In the case of given ultrsonic vibration, the maximum pressure is increased in all experimental conditions. 2. In the case of given ultrsonic vibration, the decrease effect of fuel consumption rate is increased at low rpm. 3. The generation quantity of soots is increased according to load. In the case of given ultrsonic vibration, the decreased quantity of soots does not very according to load. 4. In the case of given ultrsonic vibration, the BMEP and torque are increased at low load.

국산 소형어선용 예연소실식 디젤기관의 연료유를 가열할 경우, 연소특성 및 기관성능에 미치는 영향에 관하여 실험한 결과를 요약하면 다음과 같다. 1) 연료유 분사시작점은 연료유 가열온도의 증가에 따라 늦어지는 경향을 나타냈으며, 특히 저부하 운전시 늦어지는 경향이 현저했다. 2) 연소최고압력점은 연료유 가열온도의 증가에 따라 늦어졌으며, 연소최고압력은 연료유 가열온도 증가에 따라 감소하였으나 부하의 증가에 따라 증가하는 경향을 나타내었다. 3) 연료소비율은 부하의 증가에 따라 감소하였으며, 연료소비율이 가장 작은 연료유의 최적가열온도는 150℃부근임을 나타내고 있다. 4) 그을음농도는 부하와 연료유 가열온도의 증가에 따라 증가하는 경향을 나타냈다.

국산 소형어선용 예연소실식 디이젤기관에 혼합연료유(정유+중유)를 사용할 경우 혼합연료유의 성질, 연소특성 및 기관성능에 관하여 실험한 결과를 요약하면 다음과 같다. 1) 혼합연료유의 혼합비율(중량비율)이 증가함에 따라 비중은 선형적으로 증가하였고, 점도-온도 곡선은 Walther-ASTM 식과 일치하였으며, 착화성지수인 CCAI의 값은 기울기 1.0에 가까운 직선으로 증가하였다. 2) 동일운전조건에서 착화지연은 CCAI의 값이 810(혼합비율 60%)까지는 미소하게 증가하였으나, 그 이상의 값에서는 현저하게 증가하였다. 따라서, 혼합연료유의 착화성을 나타내는 CCAI의 값은 810 이상에서 적용하는 것이 타당하다. 3) 연소최고압력은 혼합비율 40%까지 증가하다가 감소하였으며, 그을음농도는 60%부터 현저하게 증가하였으므로, 본 실험에서 무그을음 연료비절감의 안전운전 혼합비율은 50%가 적당하다

(1) 디이젤기관용 대체연료로서 혼합유가 디이젤유의 연료에 대한 특성을 검토하였다. (2) 혼합유로서 디이젤기관을 운전할 경우 배기가스량은 디이젤유보다 평균 8% 정도 많음을 나타내었다. (3) 혼합유로서 디이젤기관을 운전할 경우 디이젤유에 비하여 연료소비량이 약 3% 정도 증가하였다. (4) 정미열효율에 있어서는 디이젤유와 혼합유는 거의 비슷한 상태를 나타내었다.

Waste heavy oil sludge is considered oil waste that can be utilized as a renewable energy source. Although it has high calorific values, it should be treated as a designated waste. During the recycling process of construction and demolition wastes or the trimming process of woods, a lot of sawdust is produced. In this study, the feasibility of BOF (biomass and waste heavy oil sludge fuel) as a source of renewable energy was estimated. To investigate its combustion characteristics, a lab scale batch type combustion reactor was used, and temperature fluctuation and the flue gas composition were measured for various experimental conditions. The results could be summarized as follows: The solid fuel pellets manufactured from waste heavy oil sludge and sawdust had C 50.21 ~ 54.77%, H 10.25 ~ 12.66%, O 25.84 ~ 34.83%, N 1.01 ~ 1.04%, S 1.03 ~ 1.07%. Their lower heating values ranged from 4,780 kg/kcal to 5,530 kg/kcal. The density of the solid fuel pellets was increased from 0.63 g/cm3 to 0.85 g/cm3 with increasing the mixing ratio of waste heavy oil sludge. The maximum CO2 concentration in the flue gas was increased with increasing waste heavy oil sludge content in BOF. SO2 concentration in the flue gas was showed a tendency such as the highest CO2 concentration in the flue gas. With increasing waste heavy oil sludge content in BOF, the combustion time became rather shorter although the increase of the CO2 concentration in the flue gas was delayed. Because the carbon conversion rate showed small difference with increasing the mixing ratio of waste heavy oil sludge in BOF, BOF with the mixing ratio of waste heavy oil sludge of 30% was effective for combustion. With increasing the mixing ratio of waste heavy oil sludge in BOF, activation energy and the amount of total CO emissions were increased, while activation energy was decreased with increasing the air/fuel ratio. Therefore, the optimal air/fuel ratio for the combustion of BOF was 1.5.

Waste heavy oil sludge is considered oil waste that can be utilized as a renewable energy source. In this study, an attempt has been made to convert the mixtures of waste heavy oil sludge and sawdust into solid biomass fuels. The solid fuel pellets from waste heavy oil sludge and sawdust could be manufactured only with a press type pelletizer. The mixing ratios of waste heavy oil sludge and sawdust capable of manufacturing a solid fuel pellet were 30 : 70, 40 : 60 and 50 : 50. Ultimate analysis result revealed that these mixtures had C 50.21 ~ 54.77%, H 10.25 ~ 12.66%, O 25.84 ~ 34.83%, N 1.01 ~ 1.04%, S 1.03 ~ 1.07%. With increasing the mixing ratio of waste heavy oil sludge, the carbon and hydrogen content in solid fuel pellets were increased, while the oxygen content was decreased. But the nitrogen and sulfur content in solid fuel pellets did not show much difference. Their lower heating values ranged from 4,780 kg/kcal to 5,530 kg/kcal. The density of the solid fuel pellets was increased from 0.63 g/cm3 to 0.85 g/cm3 with increasing the mixing ratio of waste heavy oil sludge and the collapse of the solid fuel pellets occurred at a moisture content of 21%. As the mixing ratio of waste heavy oil sludge in the solid fuel pellets was increased, the reaction of thermal cracking became faster. It was also observed that the solid fuel pellets were thermally decomposed in two steps and their DTG curves were simpler with increasing the mixing ratio of waste heavy oil sludge. The activation energy and the pre-exponential factor of the solid fuel pellets ranged from 18.90 kcal/mol to 21.36 kcal/mol and from 201 l/sec to 8,793 l/sec, respectively. They were increased with increasing the mixing ratio of waste heavy oil sludge.

Waste oil sludge was generated from waste oil purification process, oil bunker, or the ocean plant. Although it has high calorific values, it should be treated as a designated waste. During the recycling process of construction and demolition wastes or the trimming process of woods, a lot of sawdust is produced. In this study, the feasibility of BOF (biomass and waste oil sludge Fuel) as a source of renewable energy was estimated. To estimate combustion characteristics, a lab scale batch type combustion reactor was used and temperature fluctuation and the flue gas composition were measured for various experimental conditions. The results could be summarized as follows: the maximum CO2 concentration in the flue gas was increased with increasing waste oil sludge content in BOF. SO2 concentration in the flue gas was showed a tendency such as the highest CO2 concentration in the flue gas. With increasing waste oil sludge content in BOF, the combustion time was rather shorter although the increase of the CO2 concentration in the flue gas was delayed. Because the carbon conversion rate showed small difference with increasing the mixing ratio of waste oil sludge in BOF, BOF with the mixing ratio of waste oil sludge of 40% was effective for combustion. With decreasing the air/fuel ratio and the mixing ratio of waste oil sludge in BOF, activation energy and frequency factor were increased. The optimal air/fuel ratio for the combustion of BOF was 1.5.

The large amount of waste oil sludge was generated from waste oil purification process, oil bunker, or the ocean plant. Although it has high calorific values, it should be treated as a designated waste. During the recycling process of construction and demolition wastes or the trimming process of woods, a lot of sawdust is produced. In this study, the feasibility of BOF (biomass and waste oil sludge fuel) as a renewable energy source was estimated. For manufacturing a BOF, a press type pelletizing was better than an extruder type and also 40 ~ 60% of mixing ratio in waste oil sludge was appropriate to produce a pellet. The pellet was 13 mm in diameter and 20 mm in length. There was no fixed carbon in waste oil sludge, and its carbon content and higher heating value were 63.90% and 9,110 kcal/kg, respectively. With an increse of mixing ratio of sawdust, the carbon content and heating value of the BOF were dropped, but fixed carbon content was increased. The heating value of BOF was in the range of 6,400 ~ 7,970 kcal/kg at the mixing ratio of 40 ~ 60% in waste oil sludge. It means that the BOF can be classified as the 1stgrade solid fuel. In TGA experiment carried out at heating rate of 10oC/min and under nitrogen atmosphere, thermal decomposition of sawdust was occurred in two steps, but waste oil sludge was destructed in one step. The initiated cracking temperature of sawdust and waste oil sludge was 300 and 280oC in respective and after 450oC the thermal decomposition process of sawdust was slowly progressed by 800oC in contrast to waste oil sludge. Thermal decomposition of waste oil sludge was finished around 600oC. It can be considered that this difference is due to the fixed carbon content. Thermal decomposition pattern for the pellet of mixing ratio over 50% in waste oil sludge was similar to that for waste oil sludge and thermal cracking was occurred between 300 and 350oC. As the mixing ratio of waste oil sludge in the pellet increased, the reaction of thermal cracking became fast.

For container shipping company, fuel oil prise is a considerable expense. Since 2008, fuel oil prises have risen dramatically. An increasing fuel oil price in container shipping, in the short term, is only partially compensated through surcharges and may affect earnings negatively. This study discusses the impact of an increasing fuel oil price and capital costs for vessels on the Asia-Europe trade of 'H' Shipping Company. According to the result of 'H' carrier's operation in 2008, there were no cost differences between 8 and 9 vessels operations in case of fuel oil price with USD 169/tons while adopting USD 31,818 as a fixed cost. We can expect that the fuel oil price will not go lower than USD 200/Ton on the basis of current high oil price phenomenon. When the fuel oil price is over USD 200/ton, 9 vessel operation is more economic than 8 vessel operation even if the fixed cost is over USD 35,000.