• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.25-31
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• 2007

In a petrochemical complex, large amount of hydrogen is produced as a by-product and used as a fuel in petrochemical and oil refinery plants. By recycling this byproduct hydrogen as a raw material, the value of hydrogen can be greatly improved. This paper proposes a design methodology for optimal hydrogen recycle network between plants in petrochemical complex by analyzing the hydrogen pinch, required cost and constraints.

• Elastomers and Composites
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• v.54 no.1
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• pp.7-13
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• 2019

Recycling of waste polyvinyl chloride plastics has attracted much attention due to environmental problems, but the poor mechanical properties, low thermal stability, frequent breakage of strands, and melt cracking of the waste plastics have limited their widespread use. To overcome these disadvantages of waste PVC (W-PVC), recycled PVC powder blend was prepared by adding high-density polyethylene (HDPE) and ethylene vinyl acetate (EVA) as a heat stabilizer and compatibilizer, respectively. An intermeshing co-rotating twin screw extruder was used to prepare the blend, and the characteristics of the blend were analyzed by SEM and TGA, and by using a UTM and Izod impact tester. The impact strength was improved as the EVA content increased for the W-PVC/HDPE (80/20 wt%) blend. As the HDPE and EVA contents increased in the W-PVC/HDPE/EVA blend, the impact strength increased. SEM observations also revealed the improved interfacial adhesion for the EVA-containing blend.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.181-184
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• 2003

본 연구에서는 열 필라멘트 화학증착 방법에 의한 나노 다이아몬드 박막 증착을 위해 핵 생성 밀도를 증가시키기 위해서 다이아몬드 특성을 갖는 탄소(Diamond-Like Carbon)박막들을 연속 및 펄스 플라즈마를 이용한 화학 증착법에 의하여 증착하여 그 특성을 SEM, XPS, Raman 및 Nano-Tester를 이용하여 분석하였으며 열 필라멘트 화학 증착법에 의하여 나노 다이아몬드 박막 형성에 대한 핵 밀도와 다아이몬드 특성을 갖는 탄소 박막의 특성의 연관성을 관찰하여 공구(WC-Co)의 표면 사전 처리 없이 나노 다이아몬드 박막 형성을 용이하게 하는 실험을 수행하였다.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.196-200
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• 2003

A novel prepurification method was developed aiming at increasing yield and purity, also reducing solvent usage for purification of paclitaxel. The use of a micelle and precipitation in the prepurification process allows for rapid separation of paclitaxel from interfering compounds and dramatically reduces solvent usage compared to alternative methodologies. The prepurification process serves to minimize the size and complexity of the HPLC operations for paclitaxel purification. The process is readily scalable to a pilot plant and eventually to a production environment where multikilogram quantities of material are expected to be produced. As much as possible, the process has been optimized to minimize solvent usage, complexity, and operating costs.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.190-195
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• 2003

A novel microwave-induced pyrolysis of polystyrene in motor oil was performed using a quartz tube reactor with silicon carbide as the microwave absorbent. Different pyrolysis conditions were investigated, such as time range from 30 minutes to 1 hour and power range from 180 to 250 watt. The distillate components were analyzed with GC-MS, and styrene, 1-methyl styrene, toluene, ethyl benzene were the four main products. Among these, styrene took over 70 percentages. Temperature of the complete pyrolysis using microwave was much lower than that of conventional thermal pyrolysis method.

• Journal of Institute of Convergence Technology
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• v.2 no.1
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• pp.7-12
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• 2012

Spent fuels are discharged from nuclear reactors as a result of power generations. The spent fuels would be considered as a useful resources because the main constituent is uranium and some other actinides are included in them. In order to utilize the resources chemical processes should be developed to treat the spent fuels and obtain uranium and other actinides to be fueled in a fast reactor. The technologies are categorized into wet and dry processes. In this study, the current status of such technologies is summarized to give a insight and a deep understanding on nuclear fuel cycles.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.894-899
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• 2012

In recent years, recycling process has come to be necessary for separating metals, glass fibers and polymer from WPCBs (waste printed circuit boards) due to an increasing amount of electronic device waste. In this study, dimethylformamide (DMF) and attrition mill reactor were used to separate the component such as metals, glass fiber and epoxy resin from WPCBs. Separation of glass fiber from WPCBs was carried out under stirring rates 300~600 revolution per minute (rpm) for 1~2 h as the various agitator. The recycled glass fibers (RGF) were analyzed by thermogravimetric analyzer (TGA) for degree of separation of epoxy resin in the WPCBs. The degree of separation of epoxy resin of WPCBs increased in attrition mill agitator as a mechanochemical process for recycling WPCBs. The RGF separated in the WPCBs was applied as a reinforcement in the RGF/unsaturated polyester composites to reuse as a reinforcement.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.55-59
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• 2009

As one of the methods for recycling the FRP from the small and medium waste ships, separation of roving layer from the mat has some merits in a sense of the recycling energy and the environmental effects. Similar characteristics, however, between the roving and the mat even with different ratio of the resin and the glass and the thickness of the roving, much thinner than the mat, make the mechanically automatic differentiation difficult. In this study spectrochemical differentiation between the two layers has been made using (1) boiling concentrated sulfuric acid which can dissolve the resin in the FRP layer, (2) methanol and isopropanol solution saturated with KOH which can dissolve the glass, or (3) hydrogen fluoride(HF) solution which can reacts with $SiO_2$ fragments of the glass. Furthermore coloring water-soluble dye following the HF treatment makes the roving layer more distinguishable photo-physically.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.105-112
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• 2005

This study aims at evaluating the environmental impacts stemmed from the End-of-Life Vehicle(ELV) treatment systems in Korea, using Life Cycle Assessment(LCA) method. In this study, both environmental burden from the ELV dismantling process & recycling processes and environmental benefit which were derived from the avoided environmental impacts by substituting recycled materials for virgin materials were considered. First of all, the key issues which were defined as the environmental aspects that account for more than $1\%$ out of the total environmental impacts were identified from the Life Cycle Impact Assessment(LCIA). $CO_2$, crude oil, natural gas, coal, etc. were found out to be the key issue parameters. From the LCI Analysis and LCIA studies, it was shown that the significant environmental aspects were related with the recycling process of ferro scrap, the shredding process of compressed car bodies and the dismantling process of end-of-life engines. In particular, the recycling process of ferro scrap has the most significant effects on the environmental impacts of the ELV treatment systems. Based on these results, it is recommended to improve the recycling process of ferro scrap in order to make the ELV treatment systems more environmentally sound.

• Resources Recycling
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• v.20 no.2
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• pp.45-53
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• 2011

We devised a procedure for the recovery of silicon and tempered glass from waste photovoltaic (PV) modules using optimized conditions. The tempered glass was recovered without any damage using organic solvents. The surface material is removed by applying an acid solution on the surface of the PV cell. Through our proposed method, we offer a much more efficient approach for recycling solar cells with a surfactant than the conventional method. This process, we obtained pure silicon with a yield of 90% by chemical treatment with the surfactant at room temperature for 18 min. The silicon yield was characterized using an inductively coupled plasma-atomic emission spectrometer.