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조순행,서성섭,김종남,신흥수,장동근 한국화학공학회 1999 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.37 No.6
석유화학공장에서 나오는 배가스인 수소, 이산화탄소, 일산화탄소, 메탄의 원료혼합가스로부터 수소를 회수할 수 있는 다탑 PSA공정을 orthogonal collocation법에 의해 전산모사하였다. 고순도 수소를 생산하기 위하여 흡착성능이 다른 두 흡착제를 연속으로 충전시킨 4탑 9단계 공정을 대상으로 하였다. 제올라이트와 활성탄의 충전비율은 제품의 순도 및 회수율에 영향을 미치며 각 흡착제에 대한 최적의 충전길이는 각각 60 ㎝이었다. 주어진 충전비율에 대해서 최적의 흡착 압력과 원료기체 공급 속도가 각각 19 atm 및 11.0 ㎝/s로 결정될 수 있었다. 고압에서 저압으로 떨어지면서 세정기체를 공급하는 항류 감압단계에서 압력 변화의 크기(DP) 즉, 세정 단계로 공급되는 세정기체의 양이 제품의 회수율과 순도에 크게 영향을 미쳤다. DP가 1.3 atm이상에서는 DP가 증가함에 따라 순도가 크게 변하지 않았지만 회수율은 계속 감소하였다. DP가 커질수록 압력균등화 병류감압단계에서의 압력이 낮아지고 세정단계 다음에 이어지는 압력균등화 항류가압단계에서의 균등 압력도 낮아졌으며, 이에 따라 생성물 가압단계에서 압력을 높이는데 필요한 기체 생성물의 양이 증가하였다. Numerical simulation for hydrogen-recovery multibed PSA process was performed by orthogonal collocation method for the feed mixture gas of hydrogen, carbon dioxide, carbon monoxide, and methane in petrochemical plant. A fourbed and nine-step process using a layered-bed which was consecutively packed with two different adsorbents in one bed was employed to produce high-purity hydrogen. The packing ratio of zeolite to activated carbon affected the purity and recovery of the product. The optimum length of zeolite layer and that of activated carbon layer were 60 ㎝ each. The optimum adsorption pressure and feed velocity could be determined to be 19 atm and 11.0 ㎝/s, respectively, for the given packing ratio. The recovery and purity of the product were strongly affected by Difference-Pressure(DP) which was defined as the difference between the initial high pressure and the final low pressure at the cocurrent blowdown step which delivers purge gas to the low pressure bed. When the DP was larger than 1.3atm, the purity did not change much and the recovery was continuously decreased with increasing DP. As DP increased, the pressure at the pressure-equalization cocurrent depressurization step was lowered and the pressure at the pressure-equalization countercurrent pressurization step following purge step was also lowered. Therefore, the amount of the high-pressure product to pressurize the low-pressure column increased.
Vacuum Swing Adsorption Process for the Separation of Ethylene/Ethane with AgNO3/Clay Adsorbent
조순행,박종호,김종남,한상섭 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1
The performance of the 4-bed and 3-bed VSA process using AgNO3/clay adsorbent for the ethyleneseparation from C2 fractionator feed (83.56% C2H4, 16.4% C 2H6) was investigated experimentally and theoretically.With the 4-bed VSA proces, extremely high recovery of ethylene, over 99%, was obtained at ethylene purity of 9.8%.The recovery of the 3-bed proces was lower about by 1% than that of the 4-bed VSA process. But, the productivityof the 3-bed VSA was higher about by 33% than that of the 4-bed VSA process. The productivity of the 3-bed VSAproces was 3.7 mol/kg/hr at the ethylene purity of 99.8%. Efects of the rinse flow rate in the 3-bed VSA proces wereinvestigated by both experiment and simulation. The purity of ethylene was not significantly improved by the increaseof the rinse flow rate after it reached 99.8%. At the rinse flow rate where the purity was 99.9%, the recovery became70%. It might be attributed to the slow difusion of ethane. Acording to the simulation, ethylene purity of over 99.9%could be obtained with recovery of over 90% only when the mass transfer rate of ethane is lower than 1.010-4 s-1 orhigher than 0.2 s-1. The productivity of the process could be improved by increasing the feed flow rate at the expenseof the recovery. Acording to the simulation, at the feed flow rate of 5,0 ml/min, the productivity of 5.2 mol/kg/hrwas obtained at the ethylene purity of 99.5%.
하수소독을 위한 자외선의 Bacillus subtilis spore 불활성화 특성
조순행,윤제용,정현미,염철민,정해웅 대한상하수도학회 2001 상하수도학회지 Vol.15 No.4
Wastewater disinfection is becoming more important to protect the water source not only for drinking but also for recreation. This study was conducted to find the inactivation characteristics of Bacillus subtilis spore in wastewater effluent by collimated low pressure ultraviolet (UV) radiation in a stirred reactor. The effect of water quality parameters such as pH, turbidity, and dissolved organic carbon (DOC) on the inactivation of Bacillus subtilis spore was investigated. The major findings are as follows. First, pH dependence of the inactivation of Bacillus subtilis spore was partly observed. For three log inactivation of Bacillus subtilis spore, 34mWs/㎠ were required at pH 7 and pH 9. However, 35% more UV radiation dose was required at pH 5. Second, as expected, UV transmittance was the most significant water quality parameter in corm parison with pH, turbidity, and dissolved organic carbon. Third, slight inverse relationship between UV transmittance of sample water and UV dose to achieve a certain level of inactivation of Bacillus subtilis spore was observed with not only commercial DOC solutions but also real wastewater effluents.
조순행,윤제용,변석종,김해심 한국물환경학회 2001 한국물환경학회지 Vol.17 No.4
Ammonia is sometimes considered as a indicator parameter for organic pollution in fresh water. The presence of ammonia in fresh water could be harmful to aqueous ecosystem, depending upon its concentration and pH. In addition, the reaction of ammonia with chlorine may produce organic chloramines causing taste and odor problems in treated water. We investigated the characteristics of ammonia concentration (NH₃-N) in raw water and treated water in Korea. The water quality data during 5 years (1994-1998) were collected from the Ministry of Environment. The number of ammonia data in raw water and treated water was 7,091 from 592 raw water monitoring sites, and 34,134 from 600 water treatment plants, respectively. Ammonia was detected in 37.6% out of 7,091 raw water monitoring data. 88.4 out of the ammonia detected samples were below 0.1 ㎎/L. The frequency of ammonia detection in both raw water and treated water has been gradually decreased for last five years. The number of data exceeding 0.5 ㎎/L was 283(3.6%) and many of these samples occurred in winter. It is attributed to the lack of nitrification of ammonia due to low temperature.
파일롯 공정에서 클로라민에 의한 소독부산물 생성특성 연구
조순행,윤제용,변석종,김충환,채선하,염철민 한국물환경학회 2002 한국물환경학회지 Vol.18 No.1
Chloramine is one of the disinfectants and it is produced from the reaction between ammonia and chlorine. It has long been used to curb microorganisms and disinfection byproducts from drinking water. In this study, we investigated the characteristics of Trihalomethanes (THMs), Haloacetic acids (HAAS) and Total Organic Halides (TOX) (which means a surrogate of chlorinated byproducts) as chloramine process was applied in S pilot plant near downstream of Keum river and also compared with the results of bench scale experiments. Major findings were that chloramination process reduced up to 74% of THMs, 79% of HAAS and 73% of TOX when compared with those of the breakpoint chlorination practice in pilot plant experiments. In bench experiments, the percentage of reduction increased up to approximately 90% of THMs and HAAs, and 80% of TOX. In all experimented cases, HAAs was more highly detected than those of THMs. And the least formation of HAAS was found at the Cl₂/NH₃-N ratio of 4 as a mass basis. From these results, chloramine was feasible as a secondary disinfectant in S pilot plant.