• Korean Chemical Engineering Research
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• 제58권3호
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• pp.362-368
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• 2020

합성가스는 화학제품 및 수송연료의 원료로 이용되며, 최근 목질계 바이오매스의 가스화를 통한 합성가스 생산기술에 대한 연구가 다수 진행되었다. 케나프는 높은 생산성과 이산화탄소 흡수율을 가지는 목질계 바이오매스로 이산화탄소 저감을 위한 대체자원으로서 활용 가능성이 높다. 본 연구는 케나프 가스화 실험연구 데이터를 바탕으로 상용 수준의 케나프 가스화 공정을 개발하고, 해당 공정의 타당성 및 실현가능성을 평가하는 연구로서, 케나프 가스화 통합공정 설계, 열교환망 설계, 기술경제성 평가로 구성된다. 개발된 공정으로부터 생산되는 합성가스의 최소판매가격은 1 GJ당 9.55 달러로, 합성가스의 시장가격보다 낮은 것을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제26권3호
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• pp.287-293
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• 2015

The current study has investigated the effects of biodiesel blended with gasoline on the spray characteristics in a Constant Volume Combustion Chamber (CVCC). With the concentration of 5, 10, 15 and 20% by volume, biodiesel was blended with commercial gasoline and performed on the macroscopic visualization test. Pure gasoline and biodiesel were also tested as the reference. The shadowgraph technique was conducted in the constant volume chamber. The spray images were recorded by a high speed video camera with frame speed 10,000 frame per second. Fuel injection was set at 800, 1000 and 1,350 bar with the simulated speed 1,500 and 2,000 rpm. The back pressure was controlled at 20 bar. The spray angle and penetration tip were measured and analyzed by using the image processing. At the high injection pressure, the spray penetration length with the simulated speed 1,500 rpm showed that B100 was lower than GB00-20 whereas the spray penetration length with the simulated speed 2,000 rpm exhibited that GB blends and B100 were insignificantly different. Due to biodiesel concentration, its effects on spray angles were observed throughout injection periods (T1, T2 and T3). At the simulated speed 1,500 rpm, the spray angle of GB blends and B100 presented the same pattern following injection timing. In addition, when the simulated speed increased to 2,000 rpm the different spray angle of all blends disappeared at main injection (T3).

• 한국자동차공학회논문집
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• 제20권5호
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• pp.102-112
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• 2012

The vast stores of biomass available in the worldwide have the potential to displace significant amounts of fuels that are currently derived from petroleum sources. Fast pyrolysis of biomass is one of possible paths by which we can convert biomass to higher value products. The wood pyrolysis oil (WPO), also known as the bio crude oil (BCO), have been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of BCO in a diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the BCO. One of the easiest way to adopt BCO to diesel engine without modifications is emulsification of BCO with diesel and bio diesel. In this study, a diesel engine operated with diesel, bio diesel (BD), BCO/diesel, BCO/bio diesel emulsions was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine fuelled by BCO emulsions were examined. Results showed that stable engine operation was possible with emulsions and engine output power was comparable to diesel and bio diesel operation. However, in case of BCO/diesel emulsion operation, THC & CO emissions were increased due to the increased ignition delay and poor spray atomization and NOx & Soot were decreased due to the water and oxygen in the fuel. Long term validation of adopting BCO in diesel engine is still needed because the oil is acid, with consequent problems of corrosion and clogging especially in the injection system.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.146-153
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• 2011

American NREL (National Renewable Energy Laboratory) reported that BDF20 could reduce PM, CO, SOx, and cancerogenic matters by 13.6%, 9.3%, 17.6%, and 13% respectively, compared to diesel fuel. BDF20 has been being tested on garbage trucks and official vehicles at Seoul City, which is positive on air environment, but negative on combustion by higher viscosity in winter season. This study investigated the combustion characteristics by applying pilot injection for improving the deterioration of combustibility caused by the higher viscosity of the BDF20 with the combustion flames taken by a high-speed camera and the cylinder pressure diagram. A 4-cycle single-cylinder diesel engine was remodeled to a visible 2-cycle engine taking the flame photographs, which has a common-rail injection system. The test was done laboratory temperature at $5{\sim}6^{\circ}C$. The results obtained are summarized as follows, (1) In the case of without pilot injection, the flame propagation speed was slowed and the maximum combustion pressure became lower. The phenomena became further aggravated as the fuel viscosity gets higher. (2) In the case of with pilot injection, early stage of combustion such as rapid ignition timing and flame propagation was activated since intermediate products formed by pilot injection act as a catalyst for combustion of main fuel.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.40-47
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• 2010

This study deals with the investigation about the effect of the pilot and split injection strategies on the spray-atomization characteristics of biodiesel fuel derived from a soybean oil. Experimental results were compared with the calculation results obtained from the numerical analysis. Fuel properties of biodiesel according to the variation of the fuel temperature were inserted to the fuel library in the KIVA code. The amount of fuel injection is divided into equal mass for each split and main injection. In this work, the pilot injection strategy can be achieved by the amount of fuel injection shortly before the start of the main injection. A spray tip penetration, radial distance and spray area were measured for the analysis of macroscopic spray characteristics. In addition, the local and overall droplet size distribution were calculated by using KIVA-3V code to study the effect of split and pilot injection on the atomization performance under high ambient pressure. From these studies, the experimental results showed the multiple injection induced the decrease of the spray tip penetration due to the reduction and division of the spray momentum compared to single injection. In the atomization performance, the droplet size increased in the case of the multiple injection a little. Moreover, the SMD slightly increased as the fuel droplets goes through the axial direction. The spray behavior of numerical results were well predicted the experimental multiple spray characteristics of biodiesel fuel.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.140-146
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• 2010

An experimental study was carried out to investigate the emission characteristics for various alternative fuels in a 2.0 liter 4-cylinder turbo-charged diesel engine. The conventional diesel fuel, neat GTL (Gas to Liquid), blends of diesel and biodiesel(BD20), and blends of GTL and biodiesel(G+BD20 and G+BD40) were applied, and their emission characteristics were compared at various steady-state engine operating conditions. A noticeable reduction of exhaust emissions compared to conventional diesel fuel, except for NOx emission, was observed for G+BD40, where there is a maximum 30% averaged reduction for gaseous emissions (THC and CO) and 70% for PM mass concentrations. When comparing PM size distributions for biodiesel blended fuels, the PM number concentration in accumulation mode, where the diameter of PM is greater than 50 nm, decreased due to additional oxygen content in the biodiesel fuel; in nucleation mode, where the diameter of PM is less than 50nm, there was a slight increase or decrease in the PM number concentration depending on the amount of oxygen available in the combustion chamber.

• 한국지반환경공학회 논문집
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• 제17권8호
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• pp.5-15
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• 2016

국내 하수처리장의 증가 및 방류수 수질기준 강화 등에 따라 하수 슬러지의 발생량은 지속적으로 증가하는 추세이다. 기존 하수 슬러지는 소각과 해양배출 등으로 처리하였지만, 대기오염과 해양배출 금지 등에 따라 최근에는 자원화 또는 에너지화 방법 등을 연구하고 있다. 그러나 전반적인 기술의 수준 및 적용기술에 대한 체계적인 분석 등이 부족하여 관련 기술에 대한 향후 분석이 필요한 실정이다. 본 논문은 슬러지 처리기술, 고체연료화 및 바이오가스 증산 활용기술을 대상으로 관련 특허, 논문 동향을 조사하였다. 또한, 국내 외 연구개발 추이를 분야별 5개 국가별(한국, 일본, 중국, 미국, 유럽)로 조사 및 분석하였다. 향후 슬러지의 효과적 처리를 위해 필요한 기술 분야를 제시하였다.

• 한국수소및신에너지학회논문집
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• 제23권4호
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• pp.373-381
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• 2012

To determine the performance characteristics of motorcycle engine using biogas for practical use, the intake system of a 110 cc motorcycle engine is properly modified to operate with biogas as a fuel. Biogas is a potentially renewable fuel for replacing gasoline in future, but it has high percentage of $CO_2$ that could lead to slow the burning rate of biogas-air mixture and cause instability in combustion. Thus, the performance characteristics of biogas-fueled motorcycle engines could be different from those of gasoline motorcycle engines. In this paper, the important parameters of performance characteristics (such as: power output, thermal efficiency, fuel consumption, exhaust emission,${\cdots}$) of biogas-fueled motorcycle engine are studied and estimated with change of engine speed and load. The obtained results when operating with biogas are used to compare with that of gasoline fuel under the same operating conditions. Engine speed in the experimental is changed from 1500 rpm (idle-mode) up to 3500 rpm by a step of 500 rpm. Engine load is changed from zero to maximum load with the help of an exciting voltage device from generator-type dynamometer. The experimental results show that the tested engine operated with richer biogas-air mixture than that of gasoline-air mixture under the same test conditions. Biogas-fueled engine gives a higher fuel consumption and lower thermal efficiency under the same power output. Brake thermal efficiency of biogas engine is found to be about 3% lower than gasoline-fueled motorcycle engine for whole range of speed. Exhaust emission of biogas-fueled motorcycle engine (such as: CO, HC) is found to be lower than the limitation level of the emission standards of Vietnam for motorcycle engines (CO <4.5% HC <1200 ppm).

• 오리마을
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• 통권92호
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• pp.50-59
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• 2011

2008년 급등하였던 국제곡물 가격은 209년 들어 하락하여 2010년 상반기까지 안정세를 보였으나, 기상악화로 인한 구소련 지역의 밀 생산 감소로 러시아가 수출 금지 조치를 취하면서 2010년 7월부터 밀 가격 급등을 시작으로 현재까지 강세를 보이고 있다. 옥수수 국제 가격 상승은 사료비 상승의 주된 요인으로 작용하여 축산 농가의 수익성을 악화시키고, 밀과 대두 국제 가격 상승은 이를 원료로 하는 가공품 가격 상승으로 이어져 소비자들의 부담으로 연계된다. 따라서 본고에서는 2008년의 애그플레이션 경험을 토대로 최근의 국제곡물 가격상승 원인과 2011년 상반기 국내 물가에 미치는 영향을 분석하고, 시사점을 제시하였다. 최근의 국제곡물 가격 상승은 생산 감소, 수요 증가, 곡물 선물 투기 증가에서 기인하고 있다. 2010/11년도 세계 곡물 생산량은 전 세계적인 이상기후로 전년보다 2% 감소하고, 소비량은 2.4% 증가하여 곡물 기말재고율은 전년대비 3.1%p 하락할 것으로 예상된다. 향후 바이오연료 소비는 지속적으로 증가할 전망이며, 이에 따른 세계 곡물 수요 증가는 불가피해 보인다. 곡물 수급이 전년보다 좋지 않은 상황에서 곡물 선물에 대한 투기가 증가하고, 중국과 인도의 육류 소비 증가에 따른 곡물 소비 증가도 국제곡물 가격 상승의 주된 원인으로 작용하고 잇다. 2010년 하반기 국제곡물 가격을 적용하면, 2011년 상반기 국내 물가 상승은 불가피한 것으로 나타났다. 2011년 상반기 국제곡물 가격을 적용하면, 2011년 상반기 국내 물가 상승은 불가피한 것으로 나타났다. 2011년 상반기 배합사료는 2010년 6월 시세보다 11.5%, 제분 부문은 31.3%, 유지 및 식용유는 6.6%, 제당 부문은 30.0%의 물가 상승요인이 있는 것으로 나타났다. 한편 전분 및 당류는 전년 6월대비 10.9%의 물가 상승요인이 있을 것으로 예상된다. 이와 같이 밀, 옥수수, 대두의 대부분을 수입에 의존하는 우리나라는 국제곡물 가격이 상승할 경우 국내물가 상승이 불가피한 실정이며, 국내 생산을 늘린다 하더라도 수요량을 충족하기에는 한계가 있다. 따라서 국제곡물 수급 및 가격을 상시 모니터링하여 향후 국제곡물 가격을 전망하는 관측시스템 개발을 통해 조기경보를 주고, 이에 따른 매뉴얼을 만들어 대응해야 할 것이다. 한편, 정부 차원에서는 세계 곡물 생산량 감소와 수요 증가로 곡물 공급에 차질이 생길 경우 수입선 다변화 등의 빠른 정책적 대응을 위해 주요 곡물 생산국과의 네트워킹을 강화시킬 필요가 있다.

• Tribology and Lubricants
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• 제32권6호
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• pp.183-188
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• 2016

Engine oil plays an important role in the mechanical lubrication and cooling of a vehicle engine. Recently, engine development has focused on the adoption of gasoline direct injection (GDI) and turbocharging methodology to achieve high-power and high-speed performance. However, oil dilution is a problem for GDI engines. Oil dilution occurs owing to high-pressure fuel injection into the combustion chamber when the engine is cold. The chemical components of engine oil are currently developed to accommodate gasoline fuel; however, bio-alcohol mixtures have become a recent trend in fuel development. Bio-alcohol fuels are alternatives to fossil fuels that can reduce vehicle emissions levels and greenhouse gas pollution. Therefore, the chemical components of engine oil should be improved to accommodate bio-alcohol fuels. This study employs a 2.0 L turbo-gas direct injection (T-GDI) engine in an experiment that dilutes oil with fuel. The experiment utilizes a variety of fuels, including sub-octane gasoline fuel (E0) and a bio-alcohol fuel mixture (Ethanol E3~E7). The results show that the lowest amount of oil dilution occurs when using E3 fuel. Analyzing the diluted engine oil by measuring density and moisture with respect to kinematic viscosity shows that the lowest values of these parameters occur when testing E3 fuel. The reason is confirmed to influence the vapor pressure of the low concentration bio-alcohol-fuel mixture.