수소분리 연속공정 전산모사

徐成燮 弘益大學校 科學技術硏究所 2004 科學技術硏究論文集 Vol.15 No.-

PSA process applying adsorption technology has been extensively studied and developed as an energy-saving separation process in recent years. Applications of PSA process have been extended with growing attention to environmental problems. Two cases (case 1 : blowdown+purge, case 2 : blowdown) of PSA process were studied for hydrogen of production from gas mixtures of CO-H₂ and CO₂-H₂. Restrictions on PSA process and the effects of pressure, feed concentration and gas velocity on recovery have been obtained from material balance on adsorption column using uncoupled linear isotherms and local equilibrium model. Process parameters such as feed gas velocities, purge-to-feed ratio, and the simulation results were analyzed to investigate recovery and purity of products.

전통 Skarstrom cycle의 실험적 연구

徐成燮 弘益大學校 科學技術硏究所 2005 科學技術硏究論文集 Vol.16 No.-

This work presents an experimental study of a pressure swing adsorption (PSA) unit running a traditional Skarstrom cycle for oxygen separation from air using a molecular sieve 5A. Traditional Skarstrom cycle was composed of four steps: pressurization, adsorption, blowdown, and purge step. The effects of step durations (pressurization step duration, adsorption step duration) on the product purity, recovery and productivity were investigate for 4step-2bed process. The optimum operating conditions were observed for given oxygen purity in the product. The experimental results can provide guidance for searching appropriate operating conditions to achieve desired product quality in PSA process

이성분 혼합기체의 동시농축에 관한 연구

徐成燮,黃裕晳 弘益大學校 科學技術硏究所 1995 科學技術硏究論文集 Vol.6 No.-

Four cases of PSA process which includes rinse step following feed step of conventional PSA process were studied with the aim of simultaneous production of two components from gas mixture. Restrictions on PSA process and the effects of pressure, feed concentration and gas velocity on recovery have been obtained from material balances on adsorption column using uncoupled linear isotherms and local equilibrium model. Recoveries of case2 and case4 with no waste were always 1 regardless of variation of Z₂ where two shock waves meet. In other cases, recoveries were dependent on separation factor β, and were 1 for Z₂=1.

흡착탑에서 이산화탄소의 탈착에 관한 연구

서성섭 弘益大學校 科學技術硏究所 2000 科學技術硏究論文集 Vol.11 No.-

PSA process usually consists of several steps such as pressurization, feed, blowdown, and purge steps. Adsorption and desorption repeat for continuous gas production. Desorption step is very important to determine the process performance. In this study mathematical modeling for the adsorption column was performed including mass balances, energy balance, adsorption isotherm. Linear driving force model was used to describe the mass transfer rates. Temperature and composition profiles were simulated for the adsorption column where activated carbon were packed and 100% hydrogen was passed as a purge gas. The column was saturated with a mixture of carbon dioxide and hydrogen before desorption step. Simulation results showed the shape of diffuse wave in the desorption process. The effects of operating conditions on the temperature and composition profiles were investigated by computer simulation. As the carbon dioxide concentration increased and pressure increased, the minimum temperature in the column decreased. Also, the temperature near the column outlet was obviously less decreased. The minimum temperature in the column dropped as the interstitial gas velocity increased.

활성탄 및 제올라이트에 대한 수소, 이산화탄소 및 일산화탄소의 흡착특성에 관한 연구

徐成燮 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.5 No.-

Adsorption equilibria of hydrogen, carbon dioxide, and carbon monoxide on activated carbon and zeolite have been studied by static volumetric method. Experimental results are compared with Langmuir isotherm, Langmuir-Freundlich isotherm, and Flory-Huggins vacancy solution theory(F-H VST). Adsorption equilibria on activated carbon are described fairly well with the above isotherms. Among them, Langmuir-Freundlich isotherm and F-H VST show the best agreement with the experimental results. On the contrary, adsorption equilibria on zeolite are not predicted by Langmuir isotherm. Adsorption of carbon dioxide on ZMS 13X and ZMS 4A reach saturation state above 1 atm. Adsorbed amount of carbon dioxide on zeolite is larger than on activated carbon below 1 atm. Difference between adsorbed amount of carbon dioxide and hydrogen is larger for ZMS 13X than for ZMS 4A. As operating pressure increases activated carbon would be better than zeolite for separation of gas mixture of hydrogen, carbon dioxide, and carbon monoxide.

Cell Model에 의한 PSA 공정의 전산모사

徐成燮 弘益大學校 科學技術硏究所 1993 科學技術硏究論文集 Vol.3 No.-

PSA is an important process for separation of gas mixtures and has been commercialized for air drying, hydrogen purification, air separation, and various other separations. In this study, it was developed a simulation program for 4-step Skarstrom PSA process. this program is based on cell model and employs Adams fourth-order predictor-corrector method which is one of the multistep methods. By using the program developed and relevant data, computer simulations were carried out in order to model PSA cycle for air separation. The computation was unstable for time step size larger than 0.001 and stable for time step size less than 0.0005. The oxygen purity in the product was insensitive to step size. As cell number increases, oxygen purity tends to increase. The effect of cell number was more significant for high oxygen purity, and less significant for low oxygen purity. The operation reaches cyclic steady state after 12 or more cycles for pressure ratio higher than 5. Also, concentration profiles in the adsorption column during pressurization were investigated.

메탄과 수소 및 메탄과 질소 혼합물의 흡착분리공정 해석

徐成燮 弘益大學校 科學技術硏究所 2001 科學技術硏究論文集 Vol.12 No.-

PSA process applying adsorption technology has been extensively studied and developed as an energy-saving separation process in recent years. Applications of PSA process have been extended with growing attention to environmental problems. In this work, process simulation was carried out to analyze adsorptive separation process for CH₄-H₂ and CH₄-N₂ mixture. In the analysis using local equilibrium model and non-linear isotherm, recovery of the desired component for CH₄-H₂ and CH₄-N₂ mixture was calculated. Model equations including mass balance, energy balance and LDF equation to describe adsorption were solved using numerical method for the process which consists of five steps including rinse step.

흡착공정에서 압력평등화 단계에 관한 연구

徐成燮,張東根 弘益大學校 科學技術硏究所 1997 科學技術硏究論文集 Vol.8 No.-

One of the simple multibed PSA processes is a three-bed adsorption process which simultaneously includes pressure equalization step, pressurization step using high-pressure product, production step, blowdown step, and a purge step in a cyclic state. Pressure equalization step reduces the loss of feed gas component arising from the depressurization and desorption. In this study, pressure equalization step was studied for local equilibrium model for the separation of hydrogen and carbon dioxide on the molecular sieve 5A and activated carbon. Pressure equalization level after the pressure equalization step was continuously increased as increase of the initial pressure ratio of the two beds. The results of this study would be useful in predicting and calculating the pressure equalization level using different models concerning the transfer phenomena.

Linear Accelerator를 이용한 Stereotactic Radiosurgery

정상섭,윤도흠,오성훈,김선호,서창옥,추성실,노준규,김동익,서정호 대한신경외과학회 1988 Journal of Korean neurosurgical society Vol.17 No.6

A Modified irradiation technique utilizing a linear accelerator for radiation surgery within the brain was performed in 4 patients. Three of them had brain tumors and one small arteriovenous malformation in midbrain. A Hitchcock stereotactic apparatus and a 10 MeV linear accelerator have been adapted and special computer programs for dosimetry were obtained and studied experimentally with a phantom model. Stereotactic radiosurgery is a valuable tool in the treatment of inoperable, deep seated intracranial lesions, the major advantage being high efficacy and smoothness of the procedure, as well as short hospitalization times.

벤젠의 파과곡선을 이용한 물질전달계수의 측정에 관한 연구

강성원,송헌택,민병훈,서성섭 한국공업화학회 2003 응용화학 Vol.7 No.1

VOCs(voatile organic compounds) have been known as the source of pollution materials of the atmosphere. VOCs related to removal technologies such as emission adsorption, absorption and condensation are developed. Recently developing VOCs removal technologies aer bio filtration membrane separation, UV oxidation Not available VOCs removal technologies for VOCs, adsorption has been widely recognized as an effective means of controlling emissions to the atmosphere and recovering recycle materials from process exhaust streams. Experimental study was carried out for benzene adsorption in an activated carbon bed. As benzene concentration increased, breakthrough time was decreased. This results due to the pressure increasing in the bed and the higher interstitial linear gas velocity. In this experiment, mass transfer coefficient was measured by numerical simulation and cure fitting for experimental data. This dynamic adsorption data and mass transfer coefficient will be for design of adsorption process.