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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.
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.
徐成燮 弘益大學校 科學技術硏究所 2002 科學技術硏究論文集 Vol.13 No.-
A numerical simulation on multibed PSA process was performed for hydrogen recovery from a reformer gas which consists of 2.4% CH4, 15% CO2, 23.2% CO and 59.4% H2 in petrochemical plant. Activated carbon and zeolite molecular sieve-5A which have different adsorption capacity for the feed gas components were employed as adsorbent and modified the 9-step 4-bed. Both the length of zeolite layer and that of activated carbon layer were the same at 60cm and ambient temperature was 298K. 50cycle simulation was performed to achieve the cyclic steady stage where hydrogen purity difference of each cycle was near zero. we investigated the hydrogen separation performance as the number of bed was increased from 1 to 10. The increased number of beds means the smaller bed diameter. Hence the net effect is the better heat transfer. The effects of heat transfer rate change on bed temperature profile, concentration profile, product purity and recovery were investigated. As the number of the bed increased and the heat transfer rate increased, the adsorbent temperature decreased and the adsorbed amount increased during the adsorption step. On the contrary, the adsorbent temperature increased and the desorbed amount decreased during the desorption step. These positive effect and negative effect led to the lower purity and the higher recovery of hydrogen.
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.
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.