• 공업화학
• /
• 제28권5호
• /
• pp.559-564
• /
• 2017

본 연구에서는 폐식용유를 이용한 바이오디젤 제조공정에 반응표면분석법 중 중심합성계획모델을 이용하여 최적화 과정을 수행하였다. 공정변수로는 폐식용유의 산가, 반응시간, 반응온도, 메탄올/유지 몰비, 촉매량 등을 선택하였고, 반응치로는 FAME 함량(96.5% 이상) 및 동점도(1.9~5.5 cSt)를 설정하였다. 기초실험을 통해 계량인자범위를 반응시간 (45~60 min), 반응온도($50{\sim}60^{\circ}C$), 메탄올/유지 몰비(8~12)로 정하고, 중심합성계획모델을 이용한 최적화 결과 바이오디젤의 제조공정의 최적조건은 반응시간 55.2 min, 반응온도 $57.5^{\circ}C$, 메탄올/유지 몰비 10으로 나타났다. 이 조건에서 바이오디젤의 예측 FAME 함량은 97.5%, 동점도는 2.40 cSt이었으며, 실제 실험을 통해 확인한 결과 FAME 함량(97.7%), 동점도(2.41 cSt)로 측정되어 오차율은 각각 0.23, 0.29%로 나타났다. 따라서 폐식용유 원료 바이오디젤 제조공정 최적화 과정에 반응표면분석법 중 중심합성계획모델을 적용할 경우 매우 낮은 오차율을 얻을 수 있었다.

• Tribology and Lubricants
• /
• 제26권2호
• /
• pp.97-104
• /
• 2010

A new magnetoelastic technique of oil viscosity measurement, where the oil viscosity is estimated by frequency shift of natural oscillations of magnetoelastic ribbon, is implemented in this study. Laboratory tests of the detector prototype are performed for measurement of viscosity of base synthetic and mineral oils. It was found that measurement accuracy was better when damping factor was estimated in comparison with accuracy of frequency of damped oscillations. Thus the oil viscosity was calibrated as a function of number of pulses of the damped oscillations of magnetoelastic ribbon. Result generally showed that developed detector is promising for in line oil viscosity measurement in wide viscosity range from 10 cSt up to 600 cSt, while the viscosity measurement was relatively instable when the viscosity of test oil was over 400 cSt.

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

• 대한기계학회논문집A
• /
• 제37권5호
• /
• pp.625-630
• /
• 2013

본 연구는 직경 45 nm인 원통형 나노동공을 가진 산화알루미늄(AAO) 박막에 오일을 함침시켰을때 동점도가 마찰 마멸에 미치는 영향을 규명하고자 실시하였다. 양극산화법으로 제조한 AAO 박막을 직경 1 mm의 440C 스테인리스 강구를 상대재로 하여 왕복동 미끄럼 접촉시험을 실시하였다. 마찰면과 마멸입자는 주사전자현미경과 에닥스(Energy-dispersive X-ray)를 이용해 분석하였다. 높은 동점도 오일의 윤활효과가 저점도 오일에 비해 크게 향상되었다. 동점도가 낮은 경우엔 모든 하중조건에서 심한 마찰흔적과 함께 두꺼운 소성변형층이 넓게 형성되었으며 경계윤활막의 손상으로 접촉면에 물질전이와 화학적 반응 현상이 모두 발생하였다. 오일의 점도가 높은 경우 마찰면에 존재하는 경계윤활막이 파괴되지 않아 마찰흔적과 소성변형층의 형성이 매우 적었으며 물질전이와 화학적 반응이 방지되었다.

• 한국응용과학기술학회지
• /
• 제24권2호
• /
• pp.190-195
• /
• 2007

The transesterifications of beef tallow and the mixture of beef tallow and rapeseed oil were conducted at $65^{\circ}C$ respectively using TMAH, NaOH and their mixed catalysts. The reactants were emulsified with 1vol% emulsifier and propylene glycol. The overall conversion of beef tallow was 95% at such optimum conditions as the 1:8 of molar ratio and 0.8 wt% TMAH. The overall conversion of mixed fat at the 1:8 of molar ratio and mixed catalyst of 70 wt% TMAH 30 wt% NaOH was close to 97% which appeared at 0.8 wt% TMAH in 80min. And the kinematic viscosity of biodiesel mixture using the mixed catalyst was $6.5mm^2/s$ at $40^{\circ}C$.

• 한국응용과학기술학회지
• /
• 제20권1호
• /
• pp.57-63
• /
• 2003

An intermediate, tetramethylene bis (orthophosphate), was prepared by the esterification of pyrophosphoric acid and l,4-butanediol. Then pyrophosphoric-containing modified polyesters (ATTBs) were synthesized by polycondensation of tetramethylene bis(orthophosphate), trimethylolpropane, adipic acid, and l,4-butanediol. The content of l,4-butanediol was varied from 10 to 20wt% for the reaction. The increase of the amount of l,4-butanediol in the synthesis of ATTBs resulted in increase in average molecular weight and decrease in kinematic viscosity owing to the excellent flowability and reactivity of l,4-butanediol.

• 한국응용과학기술학회지
• /
• 제25권3호
• /
• pp.275-281
• /
• 2008

The esterification of free fatty acid in Jatropha oil added by propylene glycol using p-TSA catalyst was done, and then the transesterification of Jatropha oil added by 1.0vol% GMS as an emulsifier using TMAH, and mixed catalyst(60wt%-TMAH+ 40wt%-KOH) respectively was followed at $60^{\circ}C$. The esterification conversion at the 1:8 molar ratio of free fatty acid to methanol using 8.0wt% p-TSA was 94.7% within 60min. The overall conversion at the 1:8 molar ratio of Jatropha oil to methanol and $60^{\circ}C$ using mixed catalyst was 95.4%. The kinematic viscosity of Biodiesel using TMAH and mixed catalyst in 24h met the ASTM D-6751 above $30^{\circ}C$, and showed a little more than its criterion.

• 한국분무공학회지
• /
• 제17권3호
• /
• pp.121-127
• /
• 2012

The study is to investigate the mixing stability, fuel properties, and macroscopic spray characteristics of diesel-gasoline blended fuels in a common-rail injection system of a diesel engine. The test fuels were mixed diesel with gasoline fuel, which were based volume fraction of gasoline from 0 to 100% in 20% intervals. In order to analyze the blended effect of gasoline to diesel fuel, the properties of test fuels such as density, viscosity, and surface tension were measured. In addition, the spray behavior characteristics were studied by investigating the spray tip penetration and spray angle using a spray images through a spray visualization system. It was revealed that the density, kinematic viscosity and surface tension of diesel-gasoline blending fuels were decreased with the increase of gasoline fuel. The injection quantity of test fuels were almost similar level at short energizing duration condition. On the other hand, the increase of energizing duration shows the decrease of injection quantity compared to short energizing duration. The test blending fuels have similar growth in Spray tip penetration and Spray cone angle.

• 한국도로학회:학술대회논문집
• /
• 한국도로학회 2010년 추계학술대회 논문집
• /
• pp.121-126
• /
• 2010

• 한국분무공학회지
• /
• 제14권3호
• /
• pp.122-130
• /
• 2009

Vegetable oil and its derivatives as an alternative diesel fuel have become more attractive recently because of its environmental benefits and the fact that they are made from renewable resources. Viscosity is the most significant property to affect the utilization of vegetable oil and its derivatives in the compression ignition engines. This paper presents the existing correlations for predicting the viscosity of vegetable oil and its derivatives for compression ignition engines. According to the parameter considered in the correlations, the empirical correlations can be divided into six groups: correlations as a function of temperature, of proportion, of composition, of temperature and composition, of temperature and proportion, and of fuel properties. Out of physical properties of fuel, there exist in the literature several parameters for giving the influence on kinematic viscosity such as density, specific gravity, the ratio of iodine value over the saponification value, higher heating value, flash point and pressure. The study for the verification of applicability of existing correlations to non-edible vegetable oil and its derivatives is required.