• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.227-234
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• 2002

With the increasing environmental consideration and stricter regulations, gasification of waste is considered to be more attractive technology than conventional incineration for energy recovery as well as material recycling. The experiment for combustible waste mixed with plastic and cellulosic materials was performed in the fixed bed gasifier to investigate the gasification behavior with the operating conditions. Waste pelletized with a diameter of 2~3cm and 5cm of length was gasified at the temperature range of 1100~145$0^{\circ}C$. It was shown that the composition of H$_2$ was in the range of 30~40% and CO 15~30% depending upon oxygen/waste ratio. Casification of waste due to thermoplastic property from mixed plastic melting and thermal cracking shows a prominent difference from that of coal or coke. It was desirable to maintain the top temperature up to foot to ensure the mass transfer and uniform reaction through the packed bed. As the bed height was increased, the formation of H$_2$ and CO was increased whilst $CO_2$ decreased by the char-$CO_2$ reaction and plastic cracking. From the experimental results, the cold gas efficiency was around 61% and heating values of product gases were in the range of 2800~3200㎉/Nm3.

• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.319-327
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• 2007

Incineration has been regarded as the best developed technology available for organically hazardous waste. However, permitting and siting incinerators to treat hazardous waste such as a waste containing PCBs is very difficult due to the public concerns associated with toxic air emissions. Recently, a lot of alternatives to an incineration have been developed and these technologies have the potential of alleviating public concerns by decreasing emissions of hazardous materials such as dioxins and furans. This paper reviews currently available alternative incineration technologies for various hazardous waste streams. Various categories of non-thermal and thermal alternative incineration technologies have been evaluated in terms of their process operating condition, applicability of a waste stream and their emission of secondary waste. Detailed descriptions of operating principles of several technologies are also provided.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.75-78
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• 2006

With the increasing environmental consideration and stricter regulations waste gasification is considered to be more attractive technology than conventional incineration for energy recovery as well as material recycling. The experiment for combustible waste was performed In the fixed bed gasifier to investigate the gasification behavior with the operating conditions in a 5ton/day fixed bed gasifier The experiments of operation with 10-50 hours were carried out to determine the effects of bed temperature and oxygen/waste rat io on the syngas composition, calorific value and carbon conversion. The calorific values of the produced syngas decreased with an Increase of bed temperature because combust ion reaet ion more act ively happened. The syngas composition of wood waste gasification is CO: 34.4%, $H_2: 10.7%,\;CH_4: 6.0%,\;CO_2: 48.9%$ and that of RPF is CO: 33.9%, $H_2: 26.1%,\;CH_4: 10.7%,\;CO_2: 29.2%$. The average calorific values of produced gas were about $1,933kcal/Nm^3,\;2,863kcal/Nm^3$, respectively

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.239-246
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• 2014

Incineration is conceptually sound as a waste treatment technology. There is, however, concern over its emissions when it is improperly designed and operated. An electrostatic precipitator is one of the most commonly used devices to control particulate emissions from boilers, incinerators and some other industrial processes. In this work, a modular electrostatic precipitator with sizing of $1m{\times}1m{\times}1m$ was developed for removal of particulate matter from the exhaust gases of a small waste incinerator. Its design was based on a simple wire-and-plate concept. The corona discharge wires were connected to a positive high-voltage pulse generator, while the collection plates were grounded. The high-voltage pulse generator was used to produce the corona discharge field between the individual discharge wire and the collection plate. The particulate-laden exhaust gas flow was directed across the corona discharge field. The charged particles were deflected outward and collected on the plate. The collection efficiency was evaluated as a mass loading ratio between the difference at the inlet and the outlet to the particulate loading at the inlet of the precipitator. The collection efficiency of this modular electrostatic precipitator design was approximately 80 %.

• Journal of Microbiology and Biotechnology
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• v.22 no.3
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• pp.371-377
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• 2012

The present study describes medium-chain-length polyhydroxyalkanoates (mcl-PHAs) production by the Pseudomonas Gl01 strain isolated from mixed microbial communities utilized for PHAs synthesis. A two-step fed-batch fermentation was conducted with glucose and waste rapeseed oil as the main carbon source for obtaining cell growth and mcl-PHAs accumulation, respectively. The results show that the Pseudomonas Gl01 strain is capable of growing and accumulating mcl-PHAs using a waste oily carbon source. The biomass value reached 3.0 g/l of CDW with 20% of PHAs content within 48 h of cultivation. The polymer was purified from lyophilized cells and analyzed by gas chromatography (GC). The results revealed that the monomeric composition of the obtained polyesters depended on the available substrate. When glucose was used in the growth phase, 3-hydroxyundecanoate and 3-hydroxydodecanoate were found in the polymer composition, whereas in the PHAs-accumulating stage, the Pseudomonas Gl01 strain synthesized mcl-PHAs consisting mainly of 3-hydroxyoctanoate and 3-hydroxydecanoate. The transcriptional analysis using reverse-transcription real-time PCR reaction revealed that the phaC1 gene could be transcribed simultaneously to the phaZ gene.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.437-444
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• 2010

Dry Process(natural drying, hot-air drying, oil fry drying), optimized mixture ratio and the condition of carbonization was carried out in order to improve the product durability develop eco-friendly solid fuel mixing food waste and paper sludge. As a result of the experiment, oil fry drying process was the fastest method for drying food waste and paper sludge mixture that contains 80% water inside, and the optimized mixture ratio to minimize the generating concentration of chlorine gas against caloric value of mixture ratio was 7:3. Additionally proper temperature of product carbonization was about $200^{\circ}C$ and shown increasing product durability through the carbonization. Therefore, the pelletized solid fuel be shaped diameter around 0.5cm, length 2cm under which was pulverized and molded using 7:3 mixture of food waste, and paper sludge was the eco-friendly solid fuel possible to be industrialized which is consist of chlorine concentration of below 2.0wt% and the lowest caloric value of over 5,000kcal/kg. In conclusion, this developing manufacturing process of the solid fuel can be interpreted to contribute alternative energy development in accordance with low carbon and green growth era.

• Korean Journal of Materials Research
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• v.27 no.12
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• pp.672-678
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• 2017

In the production of zirconium cladding tube, a pickling acid solution is used to remove surface contaminants, which generates tons of pickling acid waste. The waste pickling solution is a valuable resource of Hf-free Zr. Many studies have investigated separating the Hf-free Zr source from the waste pickling acid. The results showed that $Ba_2ZrF_8$ precipitates prepared from the waste pickling acid were useful as an electrolyte for the electrorefining of Zr in molten salt. In the present work, electrorefining was performed in a $Ba_2ZrF_8-LiF$ binary electrolyte to recover Zr from a Hf-free CuZr ingot anode prepared by electroreduction. Before electrorefining, two pretreatments are performed. First, electrolyte melting was carried out to determine the eutectic temperature, and second, the electrolyte was treated to eliminate impurities, mainly hydride. After electrorefining, the cathode deposits were analyzed by $O_2$ gas analyzer and SEM-EDX to explore the possibility of recovering nuclear-grade Zr metal. Moreover, the anode was analyzed by SEM-EDX to determine the Zr dissolution depth.

• Nuclear Engineering and Technology
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• v.50 no.2
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• pp.313-317
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• 2018

Licenses for the storage of spent nuclear fuel (SNF) and vitrified highly active waste in casks under dry conditions are limited to 40 years and have to be renewed for prolonged storage periods. If such a license renewal has to be expected since as in accordance with the new site selection procedure a final repository for spent fuel in Germany will not be available before the year 2050. For transport and possible unloading and loading in new casks for final storage, the integrity and the maintenance of the geometry of the cask's inventory is essential because the SNF rod cladding and the cladding of the vitrified highly active waste are stipulated as a barrier in the storage concept. For SNF, the cladding integrity is ensured currently by limiting the hoop stress and hoop strain as well as the maximum temperature to certain values for a 40-year storage period. For a prolonged storage period, other cladding degradation mechanisms such as inner and outer oxide layer formation, hydrogen pick up, irradiation damages in cladding material crystal structure, helium production from alpha decay, and long-term fission gas release may become leading effects driving degradation mechanisms that have to be discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.160-161
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• 2022

Hydrogen is bridge fuel with high energy content and environmentally friendly to satisfy the stringent IMO regulation relating to greenhouse gas (GHG) emissions. There is growing interest in hydrogen in numerous nations and regions illustrated by an extensive range of research and development in technology. Regarding maritime applications, researchers have recognized the utilization of hydrogen as a fuel for fuel cells, a device that converts the chemical energy of the fuel to electrical energy. Solid oxide fuel cell (SOFC), with high working temperature, is easy to combine with the waste heat recovery cycles/devices to increase output power and thermodynamic performances as well. Furthermore, the cold energy from liquid hydrogen supplied to SOFC can also be used to generate more power. In this study, we proposed a SOFC integrated system with the idea of combining the waste heat recovery from the SOFC exhaust stream and cold energy utilization from LH₂. The designation is aimed to target small-scale vessel which uses electric propulsion for short distances voyage.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.4
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• pp.11-20
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• 2016

Depletion of natural resources and reduction of greenhouse gas emissions are an important issue which we have to solve. The recycling of waste has emerged as a global concern. In Korea, the development of cost-effective treatment and recycling technologies also need to be improved. In this study, we compared and analyzed the cost per unit of treatment and recycling of organic waste, and presented an effective recycling scheme. We investigated the current status of treatment and costs for six types of organic wastes from 80 workplaces, including organic wastewater treatment sludge, processed organic sludge, and plant residues. In addition, environmental costs for greenhouse gas reduction were calculated. It's an economic way that organic waste is composted and used as cement additives. In particular, the economic analysis was done by realistic results of the survey target companies. In conclusion, in order for reliable processing and recycling of organic wastes, wastewater treatment sludge and sewage sludge need to be classified based on hazard characteristics. Finally, technical difficulties need to be further resolved such as odors, leachate, and debris on recycling organic wastes.