• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.248.1-248.1
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• 2010

수송용 바이오연료로써 바이오디젤의 보급 활성화에 따른 원료인 식물성 기름의 가격 상승 및 수급 불안정성 문제를 해결하고자 그동안 활용되지 않았던 폐유지를 바이오디젤 생산 원료로 사용하여 바이오디젤 생산 단가를 낮추고 원료의 수급 안정성도 확보하려는 시도가 이루어지고 있다. 폐유지의 경우 대부분 유리지방산 함량이 높아 염기 촉매를 적용하는 방법으로는 비누의 생성으로 전환이 힘들며 산 촉매를 적용하여 유리지방산을 에스테르화하는 공정을 필요로 한다. 에스테르화 반응에서는 반응 부산물로 물이 생성되며, 생성된 물은 바이오디젤 생산 반응을 저해하고 역반응을 유도하며 촉매의 활성을 감소시킨다. 본 연구에서는 고유리지방산 함량 오일의 에스테르화 반응에서 수분의 영향을 검토하였다. 산 촉매로 액상 촉매인 황산과 고체 산 촉매인 Amberlyst-15를 사용하였다. 초기 수분 함량이 0, 1, 2, 5, 10, 20%로 증가하였을 때, 지방산 메틸 에스테르 함량이 크게 감소하였으며, 1%의 수분 함량에서도 반응이 크게 저해받는 것으로 나타났다. 따라서 고유리지방산 함량 오일의 에스테르화 반응에서 수분에 의한 저해가 중요한 변수라는 것을 알 수 있다. Amberlyst-15는 황산보다 수분의 영향에 의해 지방산 메틸 에스테르 함량이 빠르게 감소하였다. 이는 다공성의 Amberlyst-15에서 생성된 물이 반응물질들이 active site에 접근하는 것을 방해하였기 때문인 것으로 생각된다. 황산을 사용하였을 경우에는 오일 대 메탄올 몰비를 1:3에서 1:6으로 증가시킴으로써 정반응 속도가 증가하여 수분에 대한 영향이 감소하는 현상이 나타났다. 에스테르화 반응 종료 12시간 후에 바이오디젤과 메탄올 내에 수분 함량을 분석한 결과 12%의 수분이 바이오디젤 층에 존재하며 88%의 수분은 메탄올 층에 존재하였다. 반응 중에 생성된 수분을 제거하기 위해, 에스테르화 반응 30분 후에 물을 포함하는 메탄올과 촉매 층을 새 메탄올과 촉매로 교환하는 2단계 반응을 수행함으로써 지방산 메틸 에스테르 함량을 향상시킬 수 있었다. 반응 초기에는 황산이 Amberlyst-15보다 높은 활성을 보였지만, 시간이 지날수록 두 촉매 사이의 에스테르화 성능 차이는 감소하였다. 따라서 2단계 에스테르화 반응이 수분의 저해작용을 줄이는 한 가지 대안으로 제안될 수 있다. 또한 에스테르화 반응에서 물의 저해 작용을 줄이기 위해 앞으로 투과증발막의 적용 또는 물에 저해작용을 받지 않는 구조의 촉매 사용을 검토할 필요가 있다.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.4
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• pp.130-136
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• 2011

This study describes the effect of EGR rate on the combustion and emissions characteristics of a four cylinder CRDI diesel engine using biodiesel (soybean oil) blended diesel fuel. The test fuel is composed of 30% biodiesel and 70% ULSD (ultra low sulfur diesel) by volumetric ratio. The experiment of engine emissions and performance characteristics were performed under the various EGR rates. The experimental results showed that ignition delay was extended, the maximum combustion pressure and heat release gradually were decreased with increasing EGR rate. Comparing biodiesel blended fuel to ULSD, the injection quantity of biodiesel blended fuel was further increased than ULSD. The emission results showed that $NO_x$ emission of biodiesel blended fuel becomes higher according to the increase of EGR rate. However, in the case of biodiesel blended fuel, HC, CO and soot emissions were decreased compared to ULSD.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.2
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• pp.252-258
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• 2009

Engine bench tests has been done on a common-rail diesel engine with bio-diesel fuel to study effects of B100 and B20 on output power, fuel consumption and emissions. Test results show that B100 and B20 could reduce PM, HC, CO emission and smoke, but power decrease, fuel consumption increase and NOx increase obviously, B100 reduce PM and DS with $50%{\sim}70%$ and $80%{\sim}85%$ compared with diesel fuel, while B20 reduce PM and DS with $25%{\sim}35%$ and $30%{\sim}40%$. NOx of B100 and B20 increase $5%{\sim}20%$ compare to diesel.

• Journal of Power System Engineering
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• v.13 no.6
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• pp.29-34
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• 2009

Recently, we have a lot interest in a sudden rise of oil prices and a change weather for the earth warmming, so, development of new alternative fuels need in order to spare fossil fuel and reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel in diesel engine of compression ignition engine. In this paper, the combustion characteristics between neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were tested using four stroke, direct injection diesel engine, especially this biodiesel was produced from soybean oil at our laboratory. This analysis showed that cylinder pressures, the rate of pressure rises and the rate of heat releases were decreased as the blending ratios of biodiesel to diesel oil increased because of lower heating value of biodiesel in spite of increased oxygen content in biodiesel.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.8
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• pp.1022-1027
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• 2011

A diesel engine works in high compression ratio due to injection of diesel fuel after compression of air. Therefore the engine has a high thermal efficiency, while nitrogen oxide is produced a lot in high flame temperature regions. In order to solve the problem this study HHO gas is added into the intake air of the industrial diesel engine. The test conditions are loads of 0%, 50% and 100% and engine speeds of 700 to 1900 rpm. The results show the maximum torque and pressure is increased, fuel consumption, smoke and CO emissions are decreased and NOx emission is remained at same level.

• Clean Technology
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• v.11 no.4
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• pp.171-179
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• 2005

Biodiesel is synthesized by transesterification of vegetable or animal oils with alcohols. Since it has similar characteristic with diesel fuel, it can be used as a fuel by mixing with diesel fuel. Moreover, it is advantageous that biodiesel can reduce air pollution emitted from fuel combustion and is produced from sustainable energy, biomass. Recently, many researchers have investigated biodiesel synthesis using supercritical methanol since it is economical due to shorter reaction time and simple separation/purification process, compared with conventional alkali- or acid-catalyzed process. By the development of biodiesel production process from waste edible oil using supercritical methanol, it can be expected to utilize potential energy resources, reduce carbon dioxide emission, and improve environmental conditions.

• Korea Petroleum Association Journal
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• s.287
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• pp.59-64
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• 2012

금년초부터 지식경제부의 발주로 한국석유관리원(이하 석관)에서 RFS(신재생연료의무보급제도) 국내 도입방안 연구를 수행중에 있으며, 연료업계, 지동차업계, 전문가 등이 참여하는 TF가 구성 운영되고 있다. 이미 2007 년부터 바이오디젤 0.5%가 자동차용경유에 혼합되어 사용되고 있는 가운데, 지경부에서는 신재생에너지법 상에 동 제도를 담아 고시가 아닌 법의 형태로 운용하려는 계획을 갖고 있다. 또한, 국회 지경위에서도 RFS 제도 시행 법안이 논의되었으나 계류된 바 있다. 국내 전체 차량이 1,870만대에 달하고 있는 상황에서 바이오연료 의무보급제도 시행은 전체 국민에게 영향을 미치는 중요사항이나 만큼 반드시 사전검토가 필요한 사항 등에 대해 논하고자 한다.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.515-519
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• 2014

The fuel properties of biodiesel produced by changing the mixing ratio of methanol and ethanol in trans-esterification of soybean oil and lard were evaluated in this paper. The solubility of oil and fat in ethanol was higher than that in methanol. Also the more homogeneous biodiesel was produced as increasing the mole ratio of ethanol. The conversion characteristics of lard was the best at the mixing mole ratio of methanol and ethanol was 6 : 6 at the reaction temperature of $60^{\circ}C$. On the other hands, the best biodiesel conversion characteristics for soybean oil was obtained at the mixing mole ratio of 3 : 3. The kinematic viscosities of soybean oil and lard based biodiesel were 4.17~4.35 cSt and 4.69~4.93 cSt, respectively. The oxidation stability and higher heating value increased with increasing the mole ratio of ethanol. The oxidation stability satisfied the criteria of biodiesel quality of 6 hours. And finally, the higher heating value was approximately 40 MJ/kg.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.8-12
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• 2015

Non-esterified bio-diesel fuel saves cost by no esterified process and its performance was more similar to diesel oil than esterified bio-diesel fuel when the fuel blended 95% diesel oil and 5% it was used on diesel engine with electronic control system. A performance optimization is necessary for application of non-esterified bio-diesel fuel blended with diesel oil 95% on the latest diesel engine. In this study, test using fractional factorial design was accomplished at 25% and 50% partial load in order to evaluate influence of controllable 6 factors on responses such as specific fuel consumption, nitrogen oxides and coefficiency of variation of indicated mean effective pressure as basic experiment for performance optimization of this fuel. It is cleared that the injection timing and common rail pressure of 6 factors are mainly effective and its effect level is different according to load.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.238-244
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• 2011

Biodiesel, mono-alkyl esters of long chain fatty acids, is one of the alternative fuels derived from renewable lipid feedstock, such as vegetable oils or animal fats. For decade, various lipases have been used for the production of biodiesel. However, the production of biodiesel by enzymatic catalyst has profound restriction in industry application due to high cost. To overcome these problems, many research groups have studied extensively on the selection of cheap oil sources, the screening of suitable lipases, and development of lipase immobilization methods. In this study, we produced biodiesel from plant oil using Proteus vulgaris lipase K80 expressed in Escherichia coli cells. The recombinant lipase K80 was not only expressed in high level but also had high specific lipase activity and high stability in various organic solvents. Lipase K80 could produce biodiesel from olive oil by 3-stepwise methanol feeding method. The immobilized lipase K80 also produced biodiesel using the same 3-stepwise method. The immobilized lipase could produce biodiesel efficiently from various plant oils and waste oils.