• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.113.1-113.1
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• 2011

미세조류 내의 엽록소는 바이오디젤 전환 반응에서 산 촉매의 활성을 억제 할 뿐만 아니라, 짙은 색상을 띄게하여 바이오디젤 품질규격으로부터 벗어나게 한다. 미세조류의 엽록소 분석은 용매에 의해 엽록소를 추출한 후, 흡광도를 측정하여 그 함량을 계산하는 방법을 널리 사용하고 있다. 건조된 미세조류의 분석은 선택되는 용매에 따라 최대 추출량이 달라지는 것을 제외하고 큰 문제가 없지만 미세조류를 lipid 오일로 변환하면, 용매에 녹지 않아 추출이 되지않는 문제가 발생하여 흡광도 측정을 어렵게 한다. 따라서 미세조류의 형태가 powder일 때와 오일인 경우를 구분하여 용매를 선택해야 하며, 오일 또는 powder 형태 구분 없이 사용할 수 있는 분석법을 적용하여 서로 다른 엽록소 함량을 비교한 후 분석법 간의 상호 장단점을 파악해야한다. 본 연구에서는 메탄올을 용매로 사용하는 분석법(porra et al.)과 아세톤을 용매로 사용하는 분석법(Humphrey and Jeffrey)을 적용하여 엽록소 함량을 비교하였고, AAS(Atomic Absorption Spectrometer)를 통한 Mg 함량 측정을 통해 엽록소 함량을 계산하는 분석법간의 차이를 확인하였다.

• KSBB Journal
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• v.25 no.4
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• pp.337-343
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• 2010

It has been well known that organic solvents like t-butanol and n-hexane can protect lipases from the inhibition by short-chain alcohols in the enzymatic transesterification. However, use of the organic solvents should be minimized considering their negative effects on environment and human health. Therefore, use of the greener solvents has been pursued in various are as including the enzymatic biotranformation. In this study, the liquid carbon dioxide ($LCO_2$) was employed as an alternative media for the enzymatic transesterification of canola oil. The conversion in the $LCO_2$ was comparable with those in organic solvents and the supercritical carbon dioxide, and under optimum conditions, the value reached 99.7%. It is expected that this method can provide a new type of biodiesel production process with higher energy efficiency and lower environmental impact.

• Applied Chemistry for Engineering
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• v.17 no.2
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• pp.125-131
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• 2006

Dimethyl ether (DME) is a new clean fuel as an environmentally-benign energy resource. DME can be manufactured from various energy sources including natural gas, coal, biomass and spent plastic. In addition to its environmentally friendly properties, DME has similar characteristics to those of LPG. Therefore, it is considered as an excellent substitute fuel for LPG, fuel cells, power plant, and especially diesel and is expected to be the alternative fuel by 2010. The experimental study of the direct synthesis of DME was investigated under various conditions over a temperature range of $220{\sim}280^{\circ}C$, syngas ratio 1.2~3.0. All experiments were carried out with a hybrid catalyst, composed of a methanol synthesis catalyst ($Cu/ZnO/Al_2O_3$) and a dehydration catalyst (${\gamma}-Al_2O_3$). The observed reaction rate follows qualitatively a Langmiur-Hinshellwood model as the reaction mechanism. Such a mechanism is considered with three reactions; methanol synthesis, methanol dehydration and water gas shift reaction. From a surface reaction with dissociative adsorption of hydrogen, methanol, and water, individual reaction rate was determined.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.621-626
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• 2005

The esterification reaction of free fatty acid with methanol was investigated in the presence of catalyst, Amberlyst-15, producing fatty acid methyl ester, namely, biodiesel. In this paper, the effects of the reaction parameters such as reaction temperature, mole ratio of alcohol to oleic acid and mass of catalyst on the catalytic activity have been examined. The results showed that the reaction rate increased about twice as the temperature increased every $20^{\circ}C$ in the reaction temperature range from 333 K to 373 K. The equilibrium conversion rate of oleic acid increased with the feed mole ratio of alcohol to acid ranging from 6:1 to 44:1. When the feed mole ratio was higher than 44:1, all the results were similar to that of 44:1. As for the influence of the mass of catalyst, the initial reaction rate increased from 1.2 to 1.3 times as the mass of catalyst doubles in the range of the catalyst weight from 5 to 20 wt%. The experiment data obtained were well described by the second reaction rate using a pseudo-homogeneous model.

• Clean Technology
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• v.18 no.1
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• pp.102-110
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• 2012

In this study, the production of bio-diesel from animal oil by esterification and trans-esterification was investigated. There were three different extraction methods for oil extraction from raw animal fat. Heterogeneous catalysts such as Amberlyst-15 and Amberlyst BD-20 and a homogeneous catalyst such as sulfuric acid were used for esterification. Among three catalysts, the removal efficiency of Free Fatty Acid (FFA) was the highest in sulfuric acid. Response surface method was carried out to find the optimal esterification condition of sulfuric acid and methanol. After the esterification under the optimal condition, this animal fat was used for the trans-esterification. Animal oil used for trans-esterification was below 1% of FFA content and 0.09% of water content. The catalysts for trans-esterification were KOH, NaOH and $NaOCH_3$. To investigate the effects of catalyst type and amount on trans-esterification, The amount of catalyst were changed with 0.3, 0.6 and 0.9 wt%. The molar ratio of methanol/oil was changed with 4, 6, 9 and 12. The amount of catalyst was fixed to 0.8 wt%. The KOH catalyst showed the highest FAME conversion for trans- esterification, and the optimal methanol/oil weight ratio was 6. In the experiments of various catalysts and methanol molar ratios, the highest content of FAME is 96%. However, this FAME content was below Korean bio-diesel standard which is 96.5% of FAME content. After distillation, FAME content increased to 98%.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.155-160
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• 2011

An animal fat is an attractive biodiesel energy source for its high stability against oxidation and low incomplete combustion ratio due to the high heating value and cetane value. However, it requires a refinery process because of the high content of saturated acid and impurity which increas the boiling point. In this study, the optimum biodiesel synthetic process of lard is suggested. Indeed, we demonstrate new biodiesel production processes to alter conventional process of heating and mixing by applying ultrasonic energy. While the optimum reaction temperature and mole ratio of methanol and lard, when using conventional mixing and heating process, were $55^{\circ}C$ and 12, respectively, the reaction time were reduced to 30 minutes by applying ultrasonic irradiation power of 500 W. The new process applying ultrasonic irradiation yielded synthetic biodiesel properties as followings: 3.34 cP of the viscosity, 37.0 MJ/kg of the caloric value and below 0.25 mgKOH/g of the acidic value, which satisfy biodiesel quality criteria.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.683-693
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• 2017

Transport biofuels have been recognized as a promising means to resolve the following issues like global warming, oil depletion and environmental pollutions. Among various biofuels, biodiesel has several advantages such as less emission of air pollutants and higher cetane values compared to diesel oil. Demand for biodiesel in Korea is increasing that leads to higher dependence on the imported feedstocks. Therefore, it is important to utilize the waste materials collected domestically for biodiesel production. Food waste oil collected in waste treatment facility has not been used for biodiesel production due to high free fatty contents in the oil. In this work, biodiesel conversion of food waste oil by Amberlyst 15 was studied. Synthetic and actual food waste oils have been used in the study. First, the effects of the major operating parameters including reaction temperature, methanol to oil molar ratio and catalyst loading on the conversion rates and yields were determined with synthetic waste oil. Kinetic modelling work was also done to determine the activation energy of the reaction. From the work, optimization reaction conditions were determined to be 383K, 1: 26.1 for methanol molar ratio to oil, 10 wt.% for catalyst loading and 360 min for reaction time. Activation energy of the reaction is determined to be 29.75 kJ/mol, lower than those reported in the previous works. So the solid catalyst, Amberlyst 15, was more efficient for esterification than the solid catalysts employed in the other works. Agitation rates have the negligible effects on the conversion rates and yields. With the identified optimization conditions, conversion of the actual food waste oil was also carried out. The esterification yield of actual food waste oil in 60 min was 13% lower than that of synthetic waste oil but the final yields in 240 min were similar each other, 98.12% for synthetic oil and 97.62% for actual waste oil.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.583-588
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• 2010

Esterification of free fatty acid with methanol to biodiesel was investigated in a batch reactor using various solid acid catalysts, such as polymer cation-exchanged resins with sulfuric acid functional group(Amberlyst-15, Dowex 50Wx8), acidic ionic liquids (ILs)-modified silica gels respectively with $-SO_3H$ and $-SO_2Cl$ functional group ($SiO_2-[ASBI][HSO_4]$, $SiO_2-[ASCBI][HSO_4]$) and grafted silica gels respectively with $-SO_3H$ and $-SO_2Cl$ functional group ($SiO_2-R-SO_3H$, $SiO_2-R-SO_2Cl$). The effects of reaction time, temperature, reactant concentration(molar ratio of methanol to oleic acid), and catalyst amount were studied. Allylimidazolium-based ILs on modified silica gels were superior to other tested solid acid catalysts. Especially, the performance of $SiO_2-[ASBI][HSO_4]$ (immobilized by grafting of 3-allyl-1-(4-sulfobutyl)imidazolium hydrogen sulfate on silica gel) was better than that of a widely known Amberlyst-15 catalyst at the same reaction conditions. A high conversion yield of 96% was achieved in the esterification reaction of the simulated cooking oil at 353 K for 2 h. The high catalytic activity of $SiO_2-[ASBI][HSO_4]$ was attributed to the presence of strong Brønsted acid sites from the immobilized functional groups. The catalyst was recovered and the biodiesel product was separated by simple processes such as decantation and filtration.

• Clean Technology
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• v.30 no.1
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• pp.47-54
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• 2024

Jatropha oil extracted from the seeds of Nepalese Jatropha curcas, a non-edible crop, was used as a raw material and converted to biodiesel through a two-step process consisting of an esterification reaction and a transesterification reaction. Amberlyst-15 catalyst was applied to the esterification reaction between the free fatty acids contained in the Jatropha oil and methanol. The acid value of the Jatropha oil could be lowered from 11.0 to 0.26 mgKOH/g through esterification. Biodiesel was synthesized through a transesterification reaction between Jatropha oil with an acid value of 0.26 mgKOH/g and methanol over NaOH/γ-Al₂O₃ catalysts. As the loading amount of NaOH increased from 3 to 25 wt%, the specific surface area decreased from 129 to 28 m²/g and the pore volume decreased from 0.249 to 0.129 cm³/g. The amount and intensity of base sites over the NaOH/γ-Al₂O₃ catalysts increased simultaneously with the NaOH loading amount. It was confirmed that the optimal NaOH loading amount for the NaOH/γ-Al₂O₃ catalyst was 12 wt%. The optimal temperature for the transesterification reaction of Jatropha oil using the NaOH/γ-Al₂O₃ catalyst was selected to be 65 ℃. In the transesterification reaction of Jatropha oil using the NaOH/γ-Al₂O₃ catalyst, the reaction rate was affected by external diffusion limitation when the stirring speed was below 150 RPM, however the external diffusion limitation was negligible at higher stirring speeds.