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Bae S.-H.,Korea Institute of Energy Technology Evaluation and Planning
Korean Journal of Chemical Engineering | Year: 2011

Woody biomass has long been used to make heat. Recently, there has been a renewed interest in woodfired energy production because woody biomass is carbon free and it is an abundant energy source in the world. The past 20 years have witnessed an exciting growth in the numbers of wood-fired heating plants, but compared to conventional fossil fuels, its portion in our energy mix is rather insignificant. To promote the use of woody biomass as well as giving a guideline for woody biomass-based energy system, technological and economic feasibility analyses of wood-fired cogeneration facilities and equipment are necessary. The objective of this study is to evaluate the potential of a cogeneration system and to perform reliable economic analysis of an optimal business model. Work should be initiated to establish a multilateral network, taking into consideration institutional infrastructure, scientific capabilities, and cost effectiveness. © 2011 Korean Institute of Chemical Engineers, Seoul, Korea. Source

Park S.S.,Yonsei University | Seo D.K.,KEPCO E&C | Lee S.H.,Korea Institute of Energy Technology Evaluation and Planning | Yu T.-U.,Renew Energy CO. | Hwang J.,Yonsei University
Journal of Analytical and Applied Pyrolysis | Year: 2012

Product yields of liquid, solid, and gas were obtained from pyrolysis experiments on RPF using a tube furnace in a nitrogen atmosphere under three non-isothermal conditions (maximum temperature: 400°C, 600°C, and 800°C). And, the effect of the temperature on the product yields of liquid, solid, and gas were discussed. The gas compositions and liquid compounds were analyzed using gas chromatography (GC) and gas chromatography mass spectrum detector (GC-MSD), respectively. Using a thermogravimetric analysis (TGA) reactor, thermal decomposition characteristics of PS, PVC, LDPE, and PP as well as RPF during pyrolysis were analyzed. Using the single reaction model, the activation energy and pre-exponential factor for RPF pyrolysis were 211.11 kJ/mol and 9.04E+13 l/min, respectively. Using the parallel reaction model, the activation energies of PS, PP, LDPE, PVC {1}, and PVC {2} (subscripts {1} and {2} refer to the first and second degradation of PVC in mass) were 231.83, 193.55, 175.92, 72.26, and 164.94 kJ/mol, respectively, and their pre-exponential factors were 2.27E+17, 4.49E+13, 7.09E+11, 1.24E+06 and 2.16E+11 l/min, respectively. © 2012 Elsevier B.V. Source

Lee D.,Korea Institute of Energy Technology Evaluation and Planning
Electronics Letters | Year: 2015

A 90° fine tuning phase shifter design with low insertion phase-variation a VGA for V-band phased array systems is presented. The vector-sum phase shifters require low phase-variation VGAs with a gain control range of about 10 dB for good digital control performance. The measured data for discrete devices have found that a cascode has 20° better phase variation performance than a common source in the required gain control range at 50 GHz. To demonstrate the design, the Ku-band scaled phase shifter has been fabricated in 0.13 μm standard CMOS process. It consists of 90°/0° hybrids with lumped elements and two cascode VGAs. The 91° continuous phases with the gain of 2.7 ± 0.9 dB are obtained at 13 GHz. © The Institution of Engineering and Technology 2015. Source

Kang D.,Yonsei University | Park S.,Yonsei University | Jo H.,Yonsei University | Min J.,Yonsei University | And 2 more authors.
Journal of Chemical and Engineering Data | Year: 2013

Amino acid salt solutions are useful as carbon dioxide absorbents. In this study, vapor-liquid equilibrium (VLE) experiments were conducted using 4 M K-SAR, 1.5 M K-ALA-PZ, and 1.5 M K-SER-PZ solutions. Partial pressures and solubilities were measured for each absorbent solution at temperatures of 313.15 K, 333.15 K, and 353.15 K. The range of CO2 partial pressure measured at 313.15 K over 4 M K-SAR was from 0 kPa to 812.5 kPa with loadings from 0.06 to 0.98. The partial pressures of CO2 ranged from 0.2 kPa to 1041.7 kPa with loadings from 0.1 to 1.09 at 313.15 K over 1.5 M K-ALA-PZ absorbent solution. The partial pressures of CO2 ranged from 0 kPa to 665.5 kPa with loadings from 0.1 to 1.14 at 313.15 K over 1.5 M K-SER-PZ absorbent solution. © 2013 American Chemical Society. Source

Park S.H.,Hanyang University | Youn I.M.,Korea Institute of Energy Technology Evaluation and Planning | Lim Y.,Transportation Institute | Lee C.S.,Hanyang University
Energy and Fuels | Year: 2012

This study investigates the effect of engine load condition on the injection spray, combustion, and exhaust emissions characteristics of a diesel-bioethanol blended fuel diesel engine. In this study, the injection characteristics, such as the effective flow diameter and the effective flow velocity, were calculated from the nozzle flow model. The macroscopic spray characteristics of diesel-bioethanol fuels were measured and analyzed using a spray visualization system. Using a four-cylinder test engine with 1.5 L of displacement, the combustion pressure, heat release, and emission characteristics were measured and analyzed. In addition, properties of blended fuel were measured and analyzed. This study revealed that the physical properties (density, viscosity, and surface tension) and chemical properties (cetane number, heating value, and distillation) of diesel-bioethanol blended fuels generally decreased with increased bioethanol content. The increase in bioethanol fuel resulted in easy vaporization at the same temperature condition. After energizing, the increase of engine load caused an increase in spray tip penetration. The spray cone angle was mainly affected by the blending of bioethanol, not the engine load. The increase of engine load led to a decrease of ignition delay by the high gas temperature, and it also caused an increase in the combustion duration for the same fuel amount. In the exhaust emissions, the increase of engine load affected the increase in both the NO x and ISNO x emissions, the decrease of CO and HC emissions. At a high engine load, CO and HC emissions were quite similar in D100, DE10, and DE20 fuels due to the increased oxygen content. © 2012 American Chemical Society. Source

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