• Resources Recycling
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• v.24 no.2
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• pp.29-35
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• 2015

A feasibility test was carried out for upcycling of waste jelly-filled communication cables together with the development of environmentally friendly processes and equipments. High pressure water injection is proved to be an exceptionally environmentally friendly and highly efficient mechanical process. A batch-type cable barking equipment is designed and built on the basis of computational fluid dynamics modelling. It is optimized in terms of energy consumption and productivity with very high copper recovery of 99.5%. Copper nano-powder is prepared by an electrical wire explosion in ethanol media in order to improve the value of final products, and the preliminary economical assessment is also conducted.

• Applied Chemistry for Engineering
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• v.21 no.6
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• pp.616-620
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• 2010

This study was performed to recycle Propylene Glycol Monomethyl Ether Acetate (PGMEA) from Liquid Crystal Display (LCD) industry emission as a waste organic solvent by using a multistage distillation column and tried to decide optimum reflux ratio. From the final experiment result, it was confirmed ; in case the sample A, the PGMEA purity is more than 98% and the moisture is less than 0.05%, on the other hand, in case the sample B, the PGMEA purity is more than 95% when the reflux ratio is 6 and the moisture is less than 0.01% (Refer to Table 1 for the contents of sample A and B). These values means fine level which can be adapted in the LCD manufacture, requiring more than 90% common purity of recycling level.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.2
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• pp.52-60
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• 2004

The basic approach to sewage sludge is organic waste minimization, promotion of energy recovery; volume and weight reduction by final treatment, and environmentally final disposal of natural circulation. Dry and pyrolysis of maize was experimentally investigated in full-scale rotary kiln in semi-continuous operation. The operational parameters varied are the operating temperature $160{\sim}175^{\circ}C$ of dry and $450{\sim}800^{\circ}C$ of pyrolysis, the solids residence time 9 min for pyrolysis. Important parameters studied include the running time, water content of sewage sludge, solids amount of sewage sludge(TS%) by the varied temperature. Also, with the increasing of temperature, how the yield of oil and char product change was observed, and the distribution of gas production components was observed. The gas of $C_1{\sim}C_3$ yield increased and oil of $C_4{\sim}C_6$ yield decreased along with pyrolysis temperature of $670^{\circ}C$ by the run time of 9 min.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.107.2-107.2
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• 2011

억새는 척박한 토양 조건에서도 쉽게 자라며 관리가 용이하다는 장점이 있어 바이오에너지 작물로 주목을 받고 있다. 억새는 주로 Miscanthus sacchariflorus(물억새)와 Miscanthus sinensis(참억새) 그리고 두 억새의 잡종인 Miscanthus giganteus로 구분되며, 최근 기존의 억새보다 생체량을 크게 늘린 거대억새가 개발되기도 하였다. 본 실험에서는 우리나라 전역에서 가장 흔하게 볼 수 있는 물억새와 참억새를 유동층 반응기를 이용하여 급속열분해 하였다. 본 연구의 목적은 억새로부터 얻은 바이오원유와 나무로부터 얻은 바이오원유의 특성을 비교하고, 시료투입속도의 변화를 주어 억새로부터 얻은 바이오원유의 수율과 특성을 알아보고자 함이다. 시료의 투입속도는 200g/h, 300g/h, 500g/h, 1000g/h로 변화를 주었으며, 반응온도($500^{\circ}C$), 공탑속도(0.19m/s), 응축기온도($10^{\circ}C$)는 매 실험마다 동일하게 유지하였다. 수집한 바이오원유는 공업분석을 통해 연료로서의 가치를 알아보았다. 목재를 급속열분해 한 경우 바이오원유의 수율은 56.03wt.%로 동일한 조건에서 억새를 급속열분해 한 경우 보다 약 6wt.%가량 높았다. 바이오원유의 발열량은 큰 차이가 없었으나 수분과 점도에서 큰 차이를 보였다. 투입속도가 증가할수록 바이오원유의 수율은 증가하는 경향을 보였으며, 시간당 1000g을 투입하였을 때는 수율이 감소하였으나 수율의 변화는 크지 않았다. 투입속도가 증가하는 경우 바이오원유의 고위발열량과 점도는 감소하고 수분이 증가하는 경향을 보였다.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.111-120
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• 2010

This study evaluated strength properties of recycled asphalt concretes using warm-mix technology. Granite with maximum size of 13mm and penetration grade of 80-100 virgin binder were used for mixing in recycled mixtures. Mix design was performed using 20% and 30% RAP(coarse : fine= 6 : 4) contents. GPC, penetration, absolute viscosity and kinematic viscosity were measured for determining ratio of two warm-mix additives (Evotherm and Sasobit). Low-density polyethylene(LD) used as asphalt modifier for improving stiffness of recycled WMA mixtures in this study. Therefore, a total of 11 mixtures were prepared in this study; 8 warm-mix recycled mixtures(2 RAP contents${\times}$2 warm-mix additives${\times}$2 modifiers), 2 hot-mix recycled mixtures and 1 HMA virgin mixture(control). Deformation strength, indirect tensile strength, moisture sensitivity, permanent deformation by wheel tracking tests were measured out for evaluating fundamental properties of recycled asphalt concretes using warm-mix technology.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.99-106
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• 2021

The purpose of this study was to evaluate the performance of novel process with thermal hydrolysis and separation as pre-treatment of anaerobic digestion (AD). The dewatered sludge was pre-treated using THP, and then separated. The separated liquid used as substrate for AD and separated solid was returned on THP(Thermal Hydrolysis Process). The degree of disintegration (DD, based on COD) using only THP found 45.1-49.3%. The DD using THP+separation found 76.1-77.6%, which was higher than only THP. As result from dual-pool two-step model, the ratio of rapidly degradable substrate to total degradable substrate found 0.891-0.911 in separated liquid, which was higher than only THP. However, the rapidly degradable substrate reaction constant (kF) of only THP and THP+separation were similar. This results found that dewatered sludge was disintegrated by THP, and then rapidly degradable substrate of hydrolyzed sludge was sorted by separation.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.5-11
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• 2023

This study was conducted to improve energy efficiency and problems such as clumping and fouling in the glue zone that occur in the moisture content range of 40 to 60% when sewage dehydration residue is directly fed into the dryer. The temperature of the hot air is low at 270~300℃, and the paddle-type flotation method and dehydrated residue are applied to the circulated heat storage media to increase the contact area with the hot air, thereby reducing energy recovery and gas emissions. The water content of the dried residue is 2.7. ~7 .5%, the heat of evaporation of moisture was 608.0~690.6 kcal/kg·H₂O, which confirmed an energy saving effect of about 8.8% compared to the heat of evaporation of moisture of 714.5 kcal/kg·H₂O when no heat storage media was used.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.152-159
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• 2003

This study was conducted to analyze the water consumption in closed transplants production system (CTPS) for the production of quality transplants and to investigate the effect of relative humidity on the water balance in CTPS. Potato (Solanum tuberosum L. cv. Dejima) plug seedlings were grown for 15 days at air temperature of 20$^{\circ}C$, relative humidity of 70%, photoperiod of 16/8 h, and photosynthetic photon flux (PPF) of 200 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-l}$ following rooting for 5 days in CTPS. Amount of humidified, dehumidified, irrigated and evapotranspirated water were 67.9 kg${\cdot}m^{-2},\;196.9{\cdot}m^{-2},\;44.3\;kg{\cdot}m^{-2},\;33.5\;kg{\cdot}m^{-2}$, respectively. Water content of media and plants were 1.2 kg${\cdot}m^{-2},\;6.9\;kg{\cdot}m^{-2}$, respectively. Three relative humidity levels of 60, 70, and 80% were provided to analyze the effect of humidity on the water balance in CTPS. Amount of humidified, dehumidified, irrigated, evapotranspiratad water and water contents of media and plants increased with increasing relative humidity. Since the water consumption required to produce plug seedlings in CTPS dec1eased with decreasing relative humidity, the available water utilization efficiency of CTPS increased with decreasing relative humidity. CTPS showed high available water utilization efficiency of 0.92 - 0.97 if dehumidified water in CTPS was recycled. The development of CTPS with recycling system of dehumidified water will not only reduce the water consuming for the production of transplants but contribute to the establishment of plant production economizing in water consumption.

• Resources Recycling
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• v.18 no.1
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• pp.22-29
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• 2009

To design and construct a moving bed stoker incinerator for incineration treatment of the domestic oil fly ash, operating condition and moving bed area of incinerator were determined by performing incinerate experiment of the oil fly ash in the muffle furnace which simulates moving bed stoker incinerator in all conditions. Incineration process of the oil fly ash could be divided into 3 stages, every stage needs the appropriate operating condition for effective incineration. The optimum content of water in the heavy oil fly ash was found to be 20 wt% to prevent the ash from flying and reduce the volume. Science combustion rate of oil fly ash depends on the oxygen content, the incinerator must have a equipment to control the oxygen content in the combustion air. The optimum temperature was $750{\sim}800^{\circ}C$ in order to prevent adhesion to the stocker and evaporation of metal compounds of low melting point. Uniform combustion reaction and acceleration of combustion rate required agitation during the combustion of oil fly ash. The incineration rate was $12.53kg/m^2hr$ and the working area of moving bed incinerator was found to be $60m^2$ to incinerate 18 tons of oil fly ash per day.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.60-67
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• 2021

This study presented techno-economic analysis of a 500 MWe oxy-coal power plant with CO2 capture. The power plant included a circulating fluidized-bed (CFB), ultra-supercritical steam turbine, flue gas conditioning (FGC), air separation unit (ASU), and CO2 processing unit (CPU). The dry flue gas recirculation (FGR) was used to control the combustion temperature of CFB. One FGR heat exchanger, one heat exchanger for N2 stream exiting ASU, and a heat recovery from CPU compressor were considered to enhance heat efficiency. The decrease in the temperature difference (ΔT) of the FGR heat exchanger that means the increase in heat recovery from flue gas enhanced the electricity and exergy efficiencies. The annual cost including the FGR heat exchanger and FGC cooling water was minimized at ΔT = 10 ℃, where the electricity efficiency, total capital cost, total production cost, and return on investment were 39%, 1371 M$, 90 M$, and 7%/y, respectively.