• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.745-748
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• 2009

수소는 지구상에 풍부하게 존재하는 원소로 최근 수소경제시대에 대한 기대와 함께 청정 에너지 carrier로 주목받고 있다. 본 연구에서는 고순도 수소 생산을 위해 water gas shift (WGS) 반응과 $CO_2$의 분리를 하나의 unit operation의 형태로 수행하는 신개념의 thermal swing sorption enhanced reaction (TSSER) 공정의 타당성을 테스트하는데 목적을 두고 있다. Le Chatelier 원리를 기본으로 하는 흡착분리 동시 반응 (sorption enhanced reaction, SER)에서는 수소생산 반응의 열역학적 한계를 극복할 수 있고 정반응의 속도를 증대시킬 수 있다. 본 연구에서는 $K_2CO_3$가 첨가된 hydrotalcite에 대한 고온에서의 $CO_2$ 화학흡착 평형 및 거동 데이터를 실험을 통하여 측정하였다. 또한 WGS 상용촉매와 화학 흡착제를 이용하여 흡착분리 동시 반응을 실험과 수치해석 시뮬레이션으로 수행하였고, 연구결과로부터 연료전지에 사용할 수 있는 고순도의 수소 (~10 ppm CO)를 직접 생산할 수 있으며, 동시에 고압상태의 $CO_2$를 고순도로 포집할 수 있음을 확인할 수 있었다. 고압, 고순도의 $CO_2$ 포집은 이후 $CO_2$ 저장에 용이하게 이용되어 온실가스 저감에 기여할 수 있을 것으로 기대된다.

• Journal of Energy Engineering
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• v.19 no.3
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• pp.188-194
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• 2010

Direct Carbon Fuel Cell(DCFC), unlike gas turbines or engines, is a kind of fuel cell which directly generates electricity by electrochemical reaction from a carbon fuel. The advantages of DCFC are higher efficiency and lower emission in comparison with existing power generation facilities. In this study, the effects of CO and $CO_2$ on theoretical potential are examined using the thermodynamic equilibrium method, and the dependence of product on operating temperature is examined via two dimensional CFD method. As a result, when the reaction of CO production (Boudouard reaction) considered, theoretical potential is higher than that in only $CO_2$ reactions, and its value increases as temperature increases. Two dimensional results of computational fluid dynamics(CFD) confirm that the Boudouard reaction becomes more important to be considered as temperature increases and inert gas affects the equilibrium composition of the Boudouard reaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.592-599
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• 2018

The kinetics and thermodynamics of the adsorption of acid blue 40 from an aqueous solution by activated carbon were examined as a function of the activated carbon dose, pH, temperature, contact time, and initial concentration. The adsorption efficiency in a bathtub was increased at pH 3 and pH 11 due to the presence of sufonate ions ($SO_3{^-}$) and amine ions ($NH_2{^+}$). The equilibrium adsorption data were fitted to the Langmuir, Freundlich and Temkin isotherms. The results indicated that the Langmuir model provides the best correlation of the experimental data. The separation factor of the Langmuir and Freundlich model showed that the adsorption treatment of acid blue 40 by activated carbon could be an effective adsorption process. The adsorption energy determined by the Temkin equation showed that the adsorption step is a physical adsorption process. Kinetics analysis of the adsorption process of acid blue 40 on activated carbon showed that a pseudo second order kinetic model is more consistent than a pseudo second order kinetic model. The estimated activation energy was 42.308 kJ/mol. The enthalpy change (80.088 J/mol) indicated an endothermic process. The free energy change (-0.0553 ~ -5.5855 kJ/mol) showed that the spontaneity of the process increased with increasing adsorption temperature.

• KSBB Journal
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• v.11 no.2
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• pp.225-237
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• 1996

Intrinsic binding kinetics of of 125I-bovine serum albumin (125I-BSA) and immobilized monoclonal anti-BSA (MAb 9.1) were studied. Small non-porous polystyrene beads (0.5${\mu}$m diameter) were used as a solid support to minimize the mass transfer interference on rate measurements. We demonstrated both theoretically and experimentally that the binding reaction is kinetically controlled. Rate measurements show that the association reaction is of second order and the dissociation reaction is of first order. Between 4 and $37^{\circ}C$ the measured equilibrium constant agrees well with the equilibrium constant calculated from the rate measurements. The temperature effects on association are much greater than on dissociation; the activation energy for association is about 9Kca1/mole, as compared to 2Kca1/mole for dissociation. The use of small non-porous beads as a solid support in binding studies essentially avoids mass transfer limitations; such a system makes it possible to determine the intrinsic binding characteristics of any immobilized antibody on a solid surface.

• Solar Energy
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• v.17 no.1
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• pp.3-15
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• 1997

The goal of this paper is to measure and compare the performance of solar heat pump for school classroom heating. To accomplish the goal, solar heat pump with alumium roll bond type evaporator and indoor heat exchanger(condenser) was built and fully instrumented with thermocouples and pressure transducers etc. The test results showed that the COP and capacity of R-134a($CF_3CH_2F$) were higher than those of R-12($CF_2Cl_2$). The solar heat pump system for room heating was designed to show the best efficiency that the room temperature make $18{\sim}20^{\circ}C\;and\;23{\sim}25^{\circ}C$ in Seoul during November, December, and January.

• Korean Chemical Engineering Research
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• v.55 no.4
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• pp.514-519
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• 2017

Adsorption characteristics of acid green 27 dye using activated carbon were investigated as function of adsorbent dose, pH, initial concentration, contact time and temperature. Freundlich isotherm explained adsorption of acid green 27 dye very well and Freundlich separation factors (1/n=0.293~0.387) were found that this process could be employed as effective treatment method. Kinetic studies showed that the kinetic data were well described by the pseudo second-order kinetic model. Pseudo second rate constant ($k_2$) decreased with the increase in initial acid green 27 concentration. Activation energy (10.457 kJ/mol) and enthalpy (79.946 kJ/mol) indicated that adsorption process was physisorption and endothermic. Since Gibbs free energy decreased with increasing temperature, spontaneity of adsorption reaction increased with increasing temperature in the temperature range of 298 K~318 K.

• Journal of Drive and Control
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• v.11 no.4
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• pp.15-24
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• 2014

It is difficult to analytically derive a volumetric displacement formula for a gerotor hydraulic motor due to the complexity of the geometric shape of its gear lobes. This work proposes an analytical method for the volumetric displacement, a relatively easy method based upon two physical concepts: conservation between hydraulic energy and mechanical shaft energy, and torque equilibrium for the rotor's motion. The first research using these concepts was conducted on inner and outer rotors rotating with respect to each rotor axis. This work represents the second report conducted on an inner rotor revolving as a planetary motion on the stationary outer rotor. The formula equations regarding the volumetric displacement and flow rate are derived, and the proposed formula about the volumetric displacement is proven to be the same as another analytical displacement formula: the so-called vane length method. From the formula, volumetric displacement is calculated for an example geometry of the gear lobes. The resultant displacement is confirmed to be the same as the value calculated from the chamber volume method. The proposed analytical formula can be utilized in the analysis and design of gerotor hydraulic motors. Because it is based on torque equilibrium, this formula can provide a better understanding of torque performance, such as torque ripple, in designing a gerotor type motor.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.15 no.4
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• pp.675-691
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• 2002

The focus of this work is on the development of large-scale numerical optimization methods for optimal control of steady incompressible Navier-Stokes flows. The control is affected by the suction or injection of fluid on portions of the boundary, and the objective function of fluid on portions of the boundary, and the objective function represents the rate at which energy is dissipated in the fluid. We develop reduced Hessian sequential quadratic programming. Both quasi-Newton and Newton variants are developed and compared to the approach of eliminating the flow equations and variables, which is effectively the generalized reduced gradient method. Optimal control problems we solved for two-dimensional flow around a cylinder. The examples demonstrate at least an order-of-magnitude reduction in time taken, allowing the optimal solution of flow control problems in as little as half an hour on a desktop workstation.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.632-638
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• 2014

Batch adsorption studies including equilibrium, kinetics and thermodynamic parameters for the adsorption of new fuchsin dye using granular activated carbon were investigated with varying the operating variables such as initial concentration, contact time and temperature. Equilibrium adsorption data were fitted into Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherms. Adsorption equilibrium was mostly well described by Langmuir Isotherm. From the estimated separation factor of Langmuir ($R_L$ = 0.023), and Freundlich (1/n = 0.198), this process could be employed as an effective treatment for the adsorption of new fuchsin dye. Also based on the adsorption energy (E = 0.002 kJ/mol) from Dubinin-Radushkevich isotherm and the adsorption heat constant (B = 1.920 J/mol) from Temkin isotherm, this adsorption is physical adsorption. From kinetic experiments, the adsorption reaction processes were confirmed following the pseudo second order model with good correlation. The intraparticle diffusion was a rate controlling step. Thermodynamic parameters including changes of free energy, enthalpy, and entropy were also calculated to predict the nature of adsorption. The change of enthalpy (92.49 kJ/mol) and activation energy (11.79 kJ/mol) indicated the endothermic nature of adsorption processes. The change of entropy (313.7 J/mol K) showed an increasing disorder in the adsorption process. The change of free energy found that the spontaneity of process increased with increasing the adsorption temperature.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.679-686
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• 2019

Characteristics of adsorption equilibrium, kinetic and thermodynamic of aniline blue onto activated carbon from aqueous solution were investigated as function of initial concentration, contact time and temperature. Adsorption isotherm of aniline blue was analyzed by Langmuir, Freundlich, Redlich-Peterson, Temkin and Dubinin-Radushkevich models. Langmuir isotherm model fit better with isothermal data than other isotherm models. Estmated Langmuir separation factors ($R_L=0.036{\sim}0.068$) indicated that adsorption process of aniline blue by activated carbon could be an effective treatment method. Adsorption kinetic data were fitted to pseudo first order model, pseudo second order model and intraparticle diffusion models. The kinetic results showed that the adsorption of aniline blue onto activated carbon well followed pseudo second-order model. Adsorption mechanism was evaluated in two steps, film diffusion and intraparticle diffusion, by intraparticle diffusion model. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy for adsorption process were estimated. Enthalpy change (48.49 kJ/mol) indicated that this adsorption process was physical adsorption and endothermic. Since Gibbs free energy decreased with increasing temperature, the adsorption reaction became more spontaneously with increasing temperature. The isosteric heat of adsorption indicated that there is interaction between the adsorbent and the adsorbate because the energy heterogeneity of the adsorbent surface.