• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.468-471
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• 2015

Microalgae have the advantages of being able to utilize the solar energy and culturing at a low cost. In particular, microalgae have a great potential in the production of biodiesel due to the high lipid content. Lipids produced from microalgae are converted to fatty acid methyl ester (FAME) by trans-esterification reaction and FAME is called a biodiesel in general. In addition, microalgae can also be utilized as a substrate for ethanol fermentation after saccharification reaction. In this study, three types of microalgae (Nanochloris, Dunaliella tertiolecta, Tetraselmis) were cultured and their lipid contents were compared. In addition, the effects of lighting period on the growth rate and lipid content were studied. Finally, the amounts of glucose produced from each saccharified microalgae were investigated. As a result, we demonstrated that D. tertiolecta has 43.6% higher lipid content and 22% higher glucose conversion than two others.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.795-796
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• 2010

Interest has been increasing worldwide in Fischer-Tropsch synthesis (F-T) as a method of producing synthetic liquid fuels from biomass. Hydroisomerization of $C_7-C_{15}$ paraffins applies to production of diesel fuel with high cetane number and improved cold flow properties, such as viscosity, pour point and freezing point. The commercial products such as fuel jet produced from F-T synthesis should have low freezing and pour points. In this study, our major aim is to develop a catalyst for hydroisomerization of synthesis-oil for bio-jet fuel. Effects of zeolites and platinum loading on hydroisomerization of dodecane were investigated as a model reaction in a batch reactor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.658-663
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• 2010

With petroleum reserves dwindling, interest has been increasing worldwide in Fischer-Tropsch synthesis (FT) as a method of producing synthetic liquid fuels and chemicals from coal, natural gas or biomass. In general, FT synthesis is operated through the gas phase fixed-bed reaction system. Recently, there are lots of study in supercritical fluid due to unique characteristics such as the quick diffusion of reactant gas, effective removal of reaction heat, and the in-situ extraction of high molecular weight hydrocarbon, such as wax. In this study, our major aim is to obtain a deeper insight into the effect of the type of support on the reaction performance over a supported cobalt catalyst in a fixed bed reactor.

• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.1-9
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• 2012

Densified fuels from biomass are widely used in North America and Europe as a regenerable and clean bioenergy. In this study, the fuel characteristics and densification characteristics of Japanese larch and Hyunsasi poplar were studied using a piston-type briquetting machine. The effects of pressure, pressure holding time, species, and particle size on briquette characteristics were studied. At room temperature, the highly densified briquettes of Japanese larch and Hyunsasi poplar can be produced at a compression pressure of 110~170 MPa. The produced briquettes have densities between 0.66 and 0.94 g/$cm^3$ after 28 days of storage at room temperature. The optimum pressure holding time was found to be 12 seconds. There is a linear increase in pressure with increase in density. The densities of briquettes from Japanese larch were higher than those of briquettes from Hyunsasi poplar. Also, the coarser particle size resulted in higher densities in briquettes than the finer particle size.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.3
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• pp.15-21
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• 2011

With petroleum reserves dwindling, interest has been increasing worldwide in Fischer-Tropsch synthesis (FT) as a method of producing synthetic liquid fuels and chemicals from coal, natural gas or biomass. In general, FT synthesis is operated through the gas phase fixed-bed reaction system. Recently, there are lots of study in supercritical fluid due to unique characteristics such as the quick diffusion of reactant gas, effective removal of reaction heat, and the in-situ extraction of high molecular weight hydrocarbon, such as wax. In this study, our major aim is to obtain a deeper insight into the effect of the type of support on the reaction performance over a supported cobalt catalyst in a fixed bed reactor.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.583-592
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• 2014

This study was carried out to investigate the operational time and productivity of logging operation by chain saw, yarder attached on tractor, tower-yarder, mini-truck, mini-forwarder, and chipping operations by mini-chipper, large-chipper in order to develop the efficient logging operation system for utilization of forest-biomass. As a result, the average felling and bucking time using chain saw at the site 1 and 2 was observed to be 182.7 sec/cycle and 518.5 sec/cycle respectively. The average yarding time was 202.5 sec/cycle using yarder attached on tractor and 295.1 sec/cycle using tower-yarder. The average forwarding time was 2,073 sec/cycle using mini-truck and 2,248.4 sec/cycle using mini-forwarder. The operational time of felling and bucking using chain-saw can be delayed according to the direction of fallen trees. The selection of felling direction is very important to yarding operation because the direction between width-yarding and felling are interrelated. Productivity can be improved through educating and training operators in the yarding operations. Mini-forwarder is needed to use because of higher productivity and lower cost than mini-truck. The operational productivity of felling and bucking by chain saw was $66.96m^3/man{\cdot}day$ and $43.86m^3/man{\cdot}day$ at site 1 and 2 respectively. The yarding productivity was $5.68m^3/man{\cdot}day$ by yarder attached on tractor, $10.74m^3/man{\cdot}day$ by tower-yarder. The forwarding productivity was $21.29m^3/man{\cdot}day$ by mini-truck, $28.57m^3/man{\cdot}day$ by mini-forwarder. The chipping productivity was $4.42m^3/man{\cdot}day$ by mini-chipper, $21.87m^3/man{\cdot}day$ by large-chipper.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.13-28
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• 2023

This study assessed the biochemical methane potential (B_u-P) of three grass species-Poa pratensis (PP), Zoysia japonica (ZJ), and Agrostis stolonifera (AS). B_u-P values were determined as 0.330 Nm³/kg-VS_added for PP, 0.297 Nm³/kg-VS_added for ZJ, and 0.261 Nm³/kg-VS_added for AS. Notably, PP exhibited superior suitability for methane production. The investigation also examined the impact of silage storage duration on PP grass clippings, revealing a 19% decline in B_u-P from an initial value of 0.269 Nm³/kg-VS_added on day 0 to 0.217 Nm³/kg-VS_added on day 180. Throughout the storage period, there were significant increases in neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) contents, rising from 67.59%, 39.68%, and 3.02% on day 0 to 77.12%, 54.65%, and 6.24% on day 180, respectively. These findings highlight the influence of storage duration on the anaerobic digestibility of PP grass clippings. To effectively utilize grass clippings as a renewable resource for methane production, further studies considering factors such as initial moisture content, pretreatment methods, and potential effects of residual pesticides are necessary to optimize anaerobic digestion efficiency for herbaceous biomass.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.299-307
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• 2011

This study was carried out to obtain the basic data for selecting the cultivatable bioenergy crops through application of solidified sewage sludge in reclaimed lands. The experimental plots consisted of the mixing with solidified sewage sludge plot (SS50), the covering with solidified sewage sludge plot (SS100), and the original reclaimed land plot (ORL) on reclaimed land for the intended landfill in Sudokwon Landfill Site Management Corporation (SLC). The growth of energy crops (Geodae-Uksae 1, Miscanthus sacchariflorus, and Phragmites australis) were investigated from May to October, 2010 in each experimental plot. The soil from ORL showed higher salinity with high contents of exchangeable $Na^+$ cation than that of SS50 and SS100. Soil properties on reclaimed land used in this study must be improved by increasing the buffering capacity of saline with the treatment of solidified sewage sludge due to the fact that the contents of organic matter (OM) in both of SS50 and SS100 were higher than that of the ORL. Thus the growth of energy crops cultivated in the solidified sewage sludge plots were better than in ORL. Geodae-Uksae 1 which showed an excellent adaptability on reclaimed land treated with the solidified sewage sludge has considerably higher biomass than those of other energy crops (M. sacchariflorus and P. australis). This study suggested that Geodae-Uksae 1 is the most suitable biomass feedstock crop for bioenergy productions, and the solidified sewage sludge may be possible to utilize as a soil cover materials for cultivation of bioenergy crops in reclaimed land.

• Clean Technology
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• v.28 no.1
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• pp.24-31
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• 2022

Petroleum-based plastics are used for various purposes and pose a significant threat to the earth's environment and ecosystem. Many efforts have been taken globally in different areas to find alternatives. As part of these efforts, this study manufactured alginate-based polyvinyl alcohol (PVA) blended films by casting from an aqueous solution prepared by mixing 10 wt% petroleum-based PVA with biodegradable, marine biomass-derived alginate. Glutaraldehyde was used as a cross-linking agent, and cardanol, an alkyl phenol-based bio-oil extracted from cashew nut shell, was added in the range of 0.1 to 2.0 wt% to grant antibacterial activity to the films. FTIR and TGA were performed to characterize the manufactured blended films, and the tensile strength, degree of swelling, and antibacterial activity were measured. Results obtained from the FTIR, TGA, and tensile strength test showed that alginate, the main component, was well distributed in the PVA by forming a matrix phase. The brittleness of alginate, a known weakness as a single component, and the low thermal durability of PVA were improved by cross-linking and hydrogen bonding of the functional groups between alginate and PVA. Addition of cardanol to the alginate-based PVA blend significantly improved the antibacterial activity against S. aureus and E. coli. The antibacterial performance was excellent with a death rate of 98% or higher for S. aureus and about 70% for E. coli at a contact time of 60 minutes. The optimal antibacterial activity of the alginate-PVA blended films was found with a cardanol content range between 0.1 to 0.5 wt%. These results show that cardanol-containing alginate-PVA blended films are suitable for use as various antibacterial materials, including as food packaging.

• Clean Technology
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• v.28 no.4
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• pp.269-277
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• 2022

With the recent development of the biological enzymatic reaction industry, lactic acid (LA) can be mass-produced from biomass sources. In particular, a catalytic process that converts LA into acrylic acid (AA) is receiving much attention because AA is used widely in the petrochemical industry as a monomer for superabsorbent polymers (SAP) and as an adhesive for displays. In the LA conversion process, NaY zeolites have been previously shown to be a high-activity catalyst, which improves AA selectivity and long-term stability. However, NaY zeolites suffer from fast deactivation due to severe coking. Therefore, the aim of this study is to modify the acid-base properties of the NaY zeolite to address this shortcoming. First, base promoters, Ca ions, were introduced to the NaY zeolites to tune their acidity and basicity via ion exchange (IE) and incipient wetness impregnation (IWI). The IWI method showed superior catalyst selectivity and stability compared to the IE method, maintaining a high AA yield of approximately 40% during the 16 h reaction. Based on the NH₃- and CO₂-TPD results, the calcium salts that impregnated into the NaY zeolites were proposed to exit as an oxide form mainly at the exterior surface of NaY and act as additional base sites to promote the dehydration of LA to AA. The NaY zeolites were further treated with KOH before calcium impregnation to reduce the total acidity and improve the dispersion of calcium through the mesopores formed by KOH-induced desilication. However, this KOH treatment did not lead to enhanced AA selectivity. Finally, calcium loading was increased from 1wt% to 5wt% to maximize the amount of base sites. The increased basicity improved the AA selectivity substantially to 65% at 100% conversion while maintaining high activity during a 24 h reaction. Our results suggest that controlling the basicity of the catalyst is key to obtaining high AA selectivity and high catalyst stability.