• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.3
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• pp.81-90
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• 1993

Groundwater and animal wastes are typical example which are underutilized resources than their value in agriculture. This paper was to investigate the actual patterns of utilization of water curtain for greenhouses and methane gas utilization from swine wastes in a view point of promoting more efficient use of alternative energy. The results from measurements can be summarized as follows : 1.It was estimated that the maximum heating load per l0a was around 23,2804/hr and the heating load at January showed 3.93X 1064 respectively for strawberry greenhouses with insulation by the water curtain. 2.The average heating cost of the greenhouse with water curtain system amounted to about 75,000 Won per l0a. This result suggested that the greater cultivated area provides less heating cost. 3.The operating volume was about 73 percent of the optimum size of the digester. The net available methane gas rates of the produced gas remained close to 62 percent, But the conventional and small size of the digester was maintained at a lower level of around 20 to 29 percent. 4.It appeared that major problems of biogas production system were required to maintain the temperature of the fermentation above ambient temperature and the optimum volume of digester.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.487-496
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• 2021

Microalgae is one of the promising biodiesel feedstock with high growth rates compared to those of terrestrial oil crops. Despite its numerous advantages, biodiesel production from microalgae needs to reduce energy demand and material costs further to go to commercialization. During solvent extraction of microalgal lipids, lipid-extracted algae (LEA) cell residue is generated as an organic solid waste, about 80-85% of original algal biomass, and requires an appropriate recycling or economic disposal. The resulting LEA still contains significant amount of carbohydrates, proteins, N, P, and other micronutrients. This review will focus on recent advancement in the utilization of LEA as: (i) utilization as nutrients or carbon sources for microalgae and other organisms, (ii) anaerobic digestion to produce biogas or co-fermentation to produce CH₄ and H₂, and (iii) conversion to other forms of biofuel through thermochemical degradation processes. Possible mutual benefits in the integration of microalgae cultivation-biodiesel production-resulting LEA with anaerobic digestion and thermochemical conversion are also discussed.

• Journal of Energy Engineering
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• v.28 no.2
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• pp.18-35
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• 2019

The Korea District Heating Corporation operates a gas engine generator with a capacity of $4500m^3 /day$ of biogas generated from the sewage treatment plant of the Nanji Water Recycling Center and 1,500 kW. However, the actual operation experience of the biogas power plant is insufficient, and due to lack of accumulated technology and know-how, frequent breakdown and stoppage of the gas engine causes a lot of economic loss. Therefore, it is necessary to prepare technical fundamental measures for stable operation of the power plant In this study, a series of process problems of the gas engine plant using the biogas generated in the sewage treatment plant of the Nanji Water Recovery Center were identified and the optimization of the actual operation was made by minimizing the problems in each step. In order to purify the gas, which is the main cause of the failure stop, the conditions for establishing the quality standard of the adsorption capacity of the activated carbon were established through the analysis of the components and the adsorption test for the active carbon being used at present. In addition, the system was applied to actual operation by applying standards for replacement cycle of activated carbon to minimize impurities, strengthening measurement period of hydrogen sulfide, localization of activated carbon, and strengthening and improving the operation standards of the plant. As a result, the operating performance of gas engine # 1 was increased by 530% and the operation of the second engine was increased by 250%. In addition, improvement of vent line equipment has reduced work process and increased normal operation time and operation rate. In terms of economic efficiency, it also showed a sales increase of KRW 77,000 / year. By applying the strengthening and improvement measures of operating standards, it is possible to reduce the stoppage of the biogas plant, increase the utilization rate, It is judged to be an operational plan.

• KSBB Journal
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• v.6 no.4
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• pp.351-361
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• 1991

This study is on the investigation of hydrogen production and substrate removal by photosynthetic bacteria. After using of Rhodospillum rubrum KS-301 and IFO 3986, which are photosynthetic bacteria as strains, R. rubrum KS-301 was turned out a better strain. And result of experiment in which glucose and sodium lactate, components of wastewater, were used limiting substrates, showed that the productivity of hydrogen was indifferent with the kind of substrates. In batch experiments using free cells and immobilized whole cells, the decrease in hydrogen productivity was observed in the latter case. From the results of these experiments, specific growth rate of cells, specific utilization rate of glucose, and specific production rate of hydrogen were calculated. And each rate was expressed in the form of Monod equation of which parameters were estimated. Also the optimum condition of hydrogen production for free cells was $30^{\circ}C$, pH 7, and 12,000 Lux, and the optimum immobilized condition was as follows: initial immobilized cell concentration 1.0g/L, sodium alginate concentration 2% and light intensity 12,000 Lux.

• Journal of Biosystems Engineering
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• v.30 no.6 s.113
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• pp.354-359
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• 2005

This is a fundamental study to develop a bio-gas utilization technology using livestock manure. Especially, this study was carried out to develop an engine using bio-gas. A bio-gas engine was designed and manufactured by modification of a diesel engine of 3 cylinders powering 13.31 kW/2800 rpm, changing the fuel supplying system fit for bio-gas. The result showed that, when the Air/Fuel ratio was controlled with fixed spark timing, the power of biogas-fueled engine is about $10.6{\~}14.6\%$ lower then that of LNG-fueled engine because of low volumetric efficiency. The engine output and torque was $11.85{\~}13.3$ kW, $39.5{\~}40.8\;N{\cdot}m$, respectively at the engine speed of 2600 rpm. Bio-gas consumption rate was 260.20 g/kW/hr, 315.20 g/kW/hr in engine speed or 1000 rpm, 2800 rpm, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1198-1205
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• 2017

Objective: An experiment was conducted to isolate and identify new methanogens in Korea from an anaerobic digester that uses pig slurry. Methods: An anaerobic digestate sample was collected from an anaerobic digester using pig slurry. Pre-reduced media were used for the growth and isolation of methanogens. Growth temperature range, pH range, NaCl concentration range, substrate utilization, and antibiotic tolerance were investigated to determine the physiological characteristics of isolated methanogens. The isolates were also examined microscopically for their morphology and Gram-stained. Polymerase chain reaction of 16S rRNA and mcrA gene-based amplicons was used for identification purpose. Results: Four strains, designated KOR-3, -4, -5, and -6, were isolated and were non-motile, irregular coccoid, and 0.5 to $1.5{\mu}m$ in diameter. Moreover, the cell walls of isolated strains were Gram-negative. KOR-3 and KOR-4 strains used acetate for methane production but did not use $H_2+CO_2$, formate, or methanol as a growth substrate KOR-5 and KOR-6 strains utilized acetate, methanol, and trimethylamine for methanogenesis but did not use $H_2+CO_2$ or formate as a growth substrate. The optimum temperature and pH for growth of four strains were $39^{\circ}C$ and 6.8 to 7.2, respectively. The optimum concentration of NaCl for growth of KOR-3, KOR-5, and KOR-6 were 1.0% (w/v). The optimum NaCl concentration for KOR-4 was 0.5% (w/v). All of the strains tolerated ampicillin, penicillin G, kanamycin, streptomycin, and tetracycline; however, chloramphenicol inhibited cell growth. Phylogenetic analysis of 16S rRNA and mcrA genes demonstrated that strains KOR-3, -4, -5, and -6 are related to Methanosarcina mazei (M. mazei, 99% sequence similarity). Conclusion: On the basis of physiological and phylogenetic characteristics, strains KOR-3, -4, -5, and -6 are proposed to be new strains within the genus Methanosarcina, named M. mazei KOR-3, -4, -5, and -6.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.25-33
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• 2018

Renewable energy has been of interests in the area of modern alternative fuels. Biogas is produced in waste landfill sites through anaerobic digestion processes, including hydrolysis, acidogenesis, organic acid fermentation (acetogenesis), and methane fermentation (methanogenesis). High contents of fine dust and moisture limited its utilization for direct combustion, town gas and vehicle fuel. Thus, this study proposed a new design for a cooling device using a centrifugal cyclone for simultaneous removal of fine dust and moisture as a pretreatment in the purification processes. A heat exchanger and an ID fan, which are installed inside and outside of the cyclone, in order to cool the humid gas below the freezing point and form a foggy mist. Such an atmosphere enhanced to capture fine dust as recirculating the cold mist flow. The water removal rate was 80.8% at a relative humidity of 95%, and the particle removal efficiency was 98.3% for $2.5{\mu}m$. Simultaneous removal efficiency was 70.8% and 99.6% for particle and moisture respectively.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.554-567
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• 2019

Recently, concerns regarding the environmental impact due to nutrient input in croplands have increased. Therefore, the government is promoting the introduction of a nutrient management system in croplands to solve the problem of excessive nutrient input. This study was carried out to establish nutrient indicators in regional croplands to facilitate the introduction of the national nutrient management system in Korea. The nutrient load and balance indicators for nitrogen and phosphorus were analyzed for nine provinces (Gang-won, Gyeong-gi, Chung-buk, Chung-nam, Jeon-buk, Jeon-nam, Gyeong-buk, Gyeong-nam, and Jeju). In the correlation analysis between the nutrient load and nutrient balance, the correlation coefficient (r) for nitrogen was 0.2504, which was not statistically significant at the 5% significance level. However, the correlation coefficient for phosphorus was 0.7375, which was statistically significant at the 5% significance level. In the nutrient management index, phosphorus showed mutual compatibility between the nutrient load and the nutrient balance indicators, but nitrogen showed no mutual compatibility between the nutrient load and the nutrient balance indicators. Therefore, utilization of the nutrient balance indicator, reflecting the characteristics of the agricultural environment, was more reasonable as a nutrient management index for regional nutrient management.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.2
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• pp.51-58
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• 2009

In this paper checked up biomass which occurs in the Jeju as are classified as organic waste for integrated management system for review and circulation of resources. Biomass which occurs in the Jeju was the 10,818 tons of sludge, 61,284 tons of food-waste, 1,519,000 tons of livestock. Sludge is treated marine discharge, food-waste is treated regeneration and livestock is treated in the form of recycling. How to establish "System used by mechanism of recycling management on biomass resources" to introduce biomass town created by Hita-city, Oita-ken in Japan. Also there established a model system to building for recycling management of biomass and then checked up the economics. According to the report, it has the difference in facilities, but it will switch to a surplus in 4 years, therefore it was confirmed that the economy. To be considered priority most livestock in "System used by mechanism of recycling management on biomass resources" in Jeju. So it is introduced the urgent problem and the problem awaiting solution on treating livestock in this study.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.3
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• pp.221-226
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• 2015

Ru catalysts supported on $CeO_2$ were synthesized by an impregnation method and characterized by numerous analytical techniques including X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). Upon utilization of these catalysts for methane dry reforming with a $CH_4/CO_2$ ratio of 1:1 at different temperatures ranging from 550 to $750^{\circ}C$, the $Ru/CeO_2$ catalysts have shown to be active. In particular, Ru(0.55wt%) supported on $CeO_2$ (1) prepared by a hydrothermal method exhibited excellent activity with the conversion of > 75% at $750^{\circ}C$. In addition, the catalyst also proved to be highly stable for at least 47 h without catalyst deactivation under the dry reforming conditions.