• Advances in environmental research
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• v.2 no.1
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• pp.19-33
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• 2013

Microalgae are receiving an increasing attention because of their potential use as $CO_2$ capture method and/or as feedstock for biofuels production. On the other hand the current microalgae-based technology is still not widespread since it is characterized by technical and economic constraints that hinder its full scale-up. In such contest the growth kinetics of Nannochloris eucaryotum (a relatively unknown marine strain) in batch and semi-batch photobioreactors is quantitatively investigated with the aim of obtaining the corresponding kinetic parameters suitable for process engineering and its optimization. In particular the maximum growth rate was evaluated to be 1.99 $10^{-3}\;h^{-1}$. Half saturation concentrations for nitrates ($K_N$) and phosphates uptake ($K_P$) were evaluated as 5.4 $10^{-4}\;g_N\;L^{-1}$ and 2.5 $10^{-5}\;g_P\;L^{-1}$, respectively. Yield factors for nitrogen ($Y_N$) and phosphorus ($Y_P$) resulted to be 5.9 $10^{-2}\;g_N\;g^{-1}$ biomass and 6.0 $10^{-3}\;g_P\;g^{-1}{_{biomass}}$, respectively. The possibility of using 100% (v/v) $CO_2$ gas as carbon source is also evaluated for the first time in the literature as far as N. eucaryotum is concerned. The strain showed a good adaptability to high concentrations of dissolved $CO_2$ as well as to low pH. The lipid content under 100% $CO_2$ is about 16.16 %wt $wt^{-1}$ and the fatty acid methyl esters composition of the extracted oil is in compliance with the European regulation for quality biodiesel.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.540-559
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• 2018

The utilization of sewage sludge for liquid biofuel production is considered as a approach for achieving better energy security, sustainable productivity and economical raw material. Thermochemical technologies of sewage sludge into energy and fuel has been considered as one of the most effective process. Generally, sewage sludge contains more than 80% of moisture, has high metal contents and 14 ~ 20 MJ/kg of calorific value. This paper reviews the technologies of converting sewage sludge to liquid biofuel via three main thermochemical conversion processes namely pyrolysis, transesterification and supercritical. The fuel properties of liquid fuels produced by different technologies from sewage sludge and definition in relevant laws for liquid biofuels in Korea are also discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1163-1168
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• 2011

Compared with the spark-ignition gasoline engine, the compression-ignition diesel engine has reduced fuel consumption due to its higher thermal efficiency. In addition, this reduction in the fuel consumption also leads to a reduction in $CO_2$ emission. Diesel engines do not require spark-ignition systems, which makes them less technically complex. Thus, diesel engines are very suitable target engines for using biofuels with high cetane numbers. In this study, the spray characteristics of biofuels such as vegetable jatropha oil and soybean oil were analyzed and compared with those of diesel oil. The injection pressures and blend ratios of jatropha oil and diesel oil (BD3, BD5, and BD20) were used as the main parameters. The injection pressures were set to 500, 1000, 1500, and 1600 bar. The injection duration was set to $500{\mu}s$. Consequently, it was found that there is no significant difference in the characteristics of the spray behavior (spray angle) in response to changes in the blend ratio of the biodiesel or changes in the injection pressure. However, at higher injection pressures, the spray angle decreased slightly.

• Carbon letters
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• v.17 no.1
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• pp.1-10
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• 2016

Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.277-280
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• 2014

Global energy demand has continued to rise due to population increase and economic development. National governments and international bodies try to seek the ways to reduce the demand growth. Energy Technology Perspectives (ETP) have provided the current status of energy system, technology developments and external events that have changed ETP scenario since 2006. The status and prospects for key energy technologies of transport sector are presented. Technology portfolio for the transport sector should be needed to meet very low CO2 targets. The portfolio includes improved fuel economy of current internal combustion engine vehicles, advanced technologies such as electric and fuel-cell vehicles, advanced biofuels and demand-side management.

• Journal of Power System Engineering
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• v.19 no.2
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• pp.90-95
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• 2015

Recently worldwide concern and research is being actively conducted on green energy which can reduce environmental pollution. A plant such as the natural rapeseed oil, soybean oil, palm, etc. is used as a bio source in home and industry. Biofuels is a sustainable fuel having economically benefits and decreasing environmental pollution problems caused due to fossil fuel, and it can be applied to the conventional diesel engine without changing the existing institutional structure. Waste vegetable oil contains a high cetane number and viscosity component, the low carbon and oxygen content. A lot of research is progressing about the conversion of waste vegetable oil as renewable clean energy. In this study, waste oil was prepared to waste cooking oil generated from the living environment, and applied to diesel engine to confirm the possibility and cost-effectiveness of biodiesel blend waste oil. As a result, brake specific fuel consumption and NOx was increased, carbon monoxide and soot was decreased.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.529-532
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• 2006

Recently the production of ethanol from lignocecllulosics has received much attention due to immense potential for conversion of renewable biometerials into biofuels and chemicals. Fomitopsis palustris causes a typycal brown-rot and is unusual in that it rapidly depolymerize the cellulose in wood without removing the surrounding lignin that normally prevents microbial attack. This study demonstrated that the brown rot basidiomycete F. palustris was able to degrade crystalline cellulose. This fungus could also produce the three major cellulases (BGL, EXG and EG) when the cells were grown on 2.0% Avicel. The fungus was able to degrade both the crystalline and amorphous forms of cellulose from woody biomasses. Moreover, we found that this fungus has the processive EG like CBH which are able to degrade the crystalline region of cellulose. To establish the cellulase system in relation with degradation of woody biomass, we performed that purification, characterization and molecular cloning of a BGL, EGs and GLA from F. palustris grown on Avicel.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.4
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• pp.35-44
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• 2010

Biofuel based on available biomass in rural area could contribute to increase the vitality and income of rural residents. This study estimates the potential production and environmental benefits of biofuel production from surplus rice, rice straw, cow manure, and food waste in South Korea. We could produce about 2.4 billion liters of ethanol using surplus rice and rice straw and 841 million $m^3$ of methane from cow manure and food waste. 1.7 billion liters of gasoline and 800 million liters of diesel could be replaced with these potential biofuel productions, which can annually reduce 4.9 million ton $CO_2$ eq. GHGs.

• Environmental Engineering Research
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• v.21 no.3
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• pp.265-275
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• 2016

In this study, the microalga Neochloris oleoabundans was cultivated in a sustainable manner using diluted anaerobic digestate to produce biomass as a potential biofuel feedstock. Prior to microalgae cultivation, the anaerobic digestate was characterized and several pretreatment methods including hydrogen peroxide treatment, filtration, and supernatant extraction were investigated and their impact on the removal of suspended solids as well as other organic and inorganic matter was evaluated. It was found that the supernatant extraction was the most convenient pretreatment method and was used afterwards to prepare the nutrient media for microalgae cultivation. A bench-scale experiment was conducted using multiple dilutions of the supernatant and filtered anaerobic digestate in 16 mm round glass vials. The results indicated that the highest growth of the microalga N. oleoabundans was achieved with a total nitrogen concentration of 100 mg N/L in the 2.29% diluted supernatant in comparison to the filtered digestate and other dilutions.

• KSBB Journal
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• v.26 no.6
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• pp.561-564
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• 2011

In this study, we carried out the development of high performance photobioreactor, which can be used to develop the biological $CO_2$ fixation technology as well as the renewable biofuels, the microalgae Botryococcus braunii. When B. Braunii was cultured in Anti-biofouling photobioreator, growth rate of it showed about 3 times higher than that of bubble column photobioreactor at the same conditions. In case of photobioreactor without bead, after 3 days culture time, biofouling occur rapidly in wall of the photobioreactor. However, with bead 5% (V/V), biofouling do not occur all experimental days.