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Gyeonggi, South Korea

Beltran A.B.,Myongji University | Nisola G.M.,Myongji University | Vivas E.L.,Myongji University | Cho W.,EnGibbs | Chung W.-J.,Myongji University
Journal of Industrial and Engineering Chemistry | Year: 2013

Supported liquid membranes (SLM) composed of oleyl alcohol (OA) and poly(octylmethylsiloxane) (POMS) in microporous flat sheets were investigated for the pervaporation of 1-butanol. Water contact angle and partition coefficients were used to characterize the SLMs. Optimum pervaporation performance was attained at 30wt% OA SLM wherein high separation factor (α=279) and total flux (JT=95.9g/(m2h)) were achieved from 2.5% (w/v) 1-butanol/water feed, at 60°C. In these conditions, 27% reduction in JT was observed when fed with model fermentation broths but remained highly selective toward 1-butanol (α=76.4). SLM stability was demonstrated with <4% LM loss after operation. © 2012 The Korean Society of Industrial and Engineering Chemistry. Source

Kim S.,Kyungpook National University | Na Y.,Kyungpook National University | Lee J.,Kyungpook National University | Cho W.,EnGibbs
Korean Chemical Engineering Research | Year: 2014

Experiments for a control method that enhances the yield to produce high quality red ginsengs have been performed. In the first steaming process of a series of processes to produce red ginsengs from raw ginsengs, there occur several undesirable defects on ginsengs such as cracks of ginseng body, inside cavity and inside white. These defects lead to deterioration in product qualities. Therefore an improved control method that minimizes these undesirable defects is needed in order to increase the yield of high quality red ginsengs. Until these days, the steaming process control methods such as controlling the steaming temperature and/or pressure have been studied. However, such control methods are not adequate enough to minimize the undesirable defects in steamed ginsengs. On the other hand, in this experiment, we suggest a control method that minimizes the undesirable defects through a weight control of steamed ginsengs, keeping the steaming temperature at 96∼99 oC as usual. Experiments with the weight control show that amount of cracks on the steamed ginseng body can be reduced. Source

Lee J.,Kyungpook National University | Cho W.,EnGibbs | Edgar T.F.,University of Texas at Austin
Industrial and Engineering Chemistry Research | Year: 2014

The SIMC method by Skogestad (J. Process Control 2003, 13, 291-309) to tune the PID controller is revisited, and a new method (K-SIMC) is proposed. The proposed K-SIMC method includes modifications of model reduction techniques and suggestions of new tuning rules and set point filters. Effects of such modifications are illustrated through simulations for a wide variety of process models. The proposed modifications permit the SIMC method to be applied with more confidence. © 2013 American Chemical Society. Source

Cho W.,EnGibbs | Lee J.,Kyungpook National University | Edgar T.F.,University of Texas at Austin
Industrial and Engineering Chemistry Research | Year: 2014

Very simple proportional-integral-derivative (PID) controller tuning rules for a wide range of stable processes are available. However, for unstable processes, the design trend is for controllers to be more complex for better performances. Here, the design concept of "simplicity" is extended to unstable processes. Simple desired closed-loop transfer functions for the direct synthesis method and simple approximations of the process time delay are utilized for unstable processes. Very simple tuning rules for PID controllers and set-point filters are obtained, yielding similar or even improved performances over previous more complicated PID controller tuning methods. © 2013 American Chemical Society. Source

Kim S.,Kyungpook National University | Na Y.,EnGibbs | Cho W.,EnGibbs | Lee J.,EnGibbs
International Conference on Control, Automation and Systems | Year: 2013

In order to increase the active component, saponins, of the ginseng and improve the quality of it, the fresh ginseng is prepared to become the red ginseng through steaming ginseng and drying process. The steaming ginseng, which steam the fresh ginseng at 98∼100°C for 3 hours, of the red ginseng process determine color and amounts of active components of the red ginseng. However, the red ginseng's quality will be low because the occurred cracks on the ginseng's surface expel active components. The cause of crack formation seems due to water absorbed into the ginseng. Therefore, in order to reduce cracks on the ginseng's surface, we propose a control system that maintains constantly the weight of water absorbed during steaming. To conduct the proposed method, an apparatus measuring the weight of ginseng in real-time is constructed and then a control system to keep the ginseng weight by manipulating the steam and hot-dried air is designed. As a result of steam and air inflow control, the crack formation would be minimized, improving yield of the high quality red ginseng. © 2013 IEEE. Source

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