yeong koo Yeo | Hanyang University (original) (raw)

Papers by yeong koo Yeo

Korean Journal of Chemical Engineering, 2003

− − − −The conversion of methane to syngas and other hydrocarbons in dielectric barrier discharge... more − − − −The conversion of methane to syngas and other hydrocarbons in dielectric barrier discharge plasma under the presence of CO 2 was investigated. Effects of the input voltage on the conversion of methane and CO 2 and the ratio of syngas were analyzed experimentally. The results of numerical simulations showed good quantitative agreement with those of experiments.

Korean Journal of Chemical Engineering, 1999

Page 1. Korean 3. Chem. Eng., 16(1), 144-149 (1999) SHORT COMMUNICATION A STUDY ON THE PREDICTION... more Page 1. Korean 3. Chem. Eng., 16(1), 144-149 (1999) SHORT COMMUNICATION A STUDY ON THE PREDICTION OF OZONE FORMATION IN AIR POLLUTION Sea Cheon Oh, Sang Hyun Sohn, Yeong-Koo Yeo* and Kun Soo Chang* Dept. of Chem. ...

Korean Journal of Chemical Engineering, 2004

− − − −In this work, we propose a PID control strategy based on the genetic algorithm coupled wit... more − − − −In this work, we propose a PID control strategy based on the genetic algorithm coupled with cubic spline interpolation method for the control of pH processes. The control scheme proposed in the present work consists of closed-loop identification based on the genetic algorithm and cubic spline method. First, we compute the parameters (K C , τ I , τ D) of the PID controller using relay feedback and apply these parameters to control the pH Process. Then approximate linear models corresponding to each pH range are obtained by the closed-loop identification based on closed-loop operation data. The optimal parameters of the PID controller at each pH region are then computed by using the genetic algorithm. From numerical simulations and control experiments we could achieve better control performance compared to the conventional fixed gain PID control method.

Korean Journal of Chemical Engineering, 2004

− − − −A dynamic model representing the wet-end of a paper mill is developed to characterize its ... more − − − −A dynamic model representing the wet-end of a paper mill is developed to characterize its dynamic behavior. The model is based on the mass balance relationships written for the simplified wet-end white water network. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid rate on the major controlled variables are analyzed by numerical simulations. It can be said that the consistency of the model with plant data seems to be reasonably good and can be used as a tool for plant analysis and control.

Korean Journal of Chemical Engineering, 1997

A steady-state optimization for the fractionation unit of an industrial benzene-toluene-xylene (B... more A steady-state optimization for the fractionation unit of an industrial benzene-toluene-xylene (BTX) plant was developed. Because the fractionation unit of the BTX plant has narrow ranges of boiling point and doesn't have any sidecut and side reboiler, we employed the boiling point estimation method in the modeling and simulation of the unit. The well-known Soave-Redlich-Kwong state equation was employed to compute required thermodynamic properties. The results of simulations showed very good agreement with the actual operation data. The objective of the optimization was to maximize profit of fractionation unit. The successive quadratic programming algorithm was uiilized and objective functions for each ffactionation column were set up based on utility and operation costs and selling prices of products. The graphical user interface of the optimization system was developed to provide convenience and flexibility in actual applications.

Korean Journal of Chemical Engineering, 2005

A model representing the wet-end section of a paper mill has been developed to characterize its d... more A model representing the wet-end section of a paper mill has been developed to characterize its dynamic behavior during the grade change. The model is based on the mass balance relationships written for the simplified wetend white water network. From the linearization of the dynamic model, higher-order Laplace transfer functions were obtained followed by the reduction procedure to give simple lower-order models in the form of 1 st-order or 2 nd-order plus dead times. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid flow rate on the major controlled variables were analyzed by numerical simulations. The simple dynamic model developed in the present study can be effectively used in the operation and control.

Korean Journal of Chemical Engineering, 2001

In this study we propose a method to identify tile kinetics of direction estelification reactions... more In this study we propose a method to identify tile kinetics of direction estelification reactions for polyethylene terephthalate (PET) based on a genetic algozJtt=l~. The reaction rate pm~netei~ could be identified successfully by using a genetic algorithm and plant data. The effects of key operating variables (temperature, pressure, monomer feed ratio and residence time) on the reactor performance were also investigated. It was observed that the reactor per-foi~lmnce strongly depends on the degree of dissolution of the solid terephthalic acid (TPA) m the reaction mixtures.

Korean Journal of Chemical Engineering, 2001

− − − −Operating strategies and optimum feed tray locations were studied in a typical fractionati... more − − − −Operating strategies and optimum feed tray locations were studied in a typical fractionation process of a BTX plant in Korea in order to reduce energy consumption. Control systems with fixed V/F or R/F ratios could be recommended for various feed compositions. By choosing the optimum feed tray location for the columns, about 16% of energy consumption could be reduced.

Korean Journal of Chemical Engineering, 1999

For effective flowsheet-level calculation of a complex chemical plant, the use of suitable partit... more For effective flowsheet-level calculation of a complex chemical plant, the use of suitable partitioning and tearing techniques is inevitable. The partitioning and tearing techniques based on the reachability matrix and the decomposition algorithm were applied to model and simulate a sulfolane extraction plant. Basic concepts were first exploited towards a general representation for the modeling and simulation of the sulfolane extraction process. Six process mlits, which consist of the sulfolane extraction plant, were modeled first and partitioning and tearing techniques were employed to model and simulate the whole extraction plant. The InsideaDut method mad the sequential-modular approach were used in the modeling and simulation. Results of simulations showed good agreement with plant operation data.

Korean Journal of Chemical Engineering, 2000

Liquid sulfur hexafluoride (SF 6) contains carbon tetrachloride (CF 4) and air as main impurities... more Liquid sulfur hexafluoride (SF 6) contains carbon tetrachloride (CF 4) and air as main impurities. It is very difficult to remove these impurities by using a catalyst column or an adsorption column. In this work a new purification method for SF 6 mixture based on batch distillation is proposed. Experimental study showed good purification performance, where SF 6 N50 was obtained from SF 6 N30 feed. In the modeling of the batch purification process of SF 6 mixture, the K-value was calculated based on the regular solution theory and a short cut method was employed. Results of simulations showed good agreement with those of experiments.

Korean Journal of Chemical Engineering, 1999

Abstraet-A new fuzzy model-based predictive control scheme was developed to control a nonlinear p... more Abstraet-A new fuzzy model-based predictive control scheme was developed to control a nonlinear pH process. The control scheme is based on the Takagi-Sugeno type fuzzy model of the process being controlled. In the present fuzzy model predictive control method, the process model maintains a linear representation of the conclusion parts of fuzzy roles. Therefore, it has a significant advantage over other types of models in the sense that nonlinear processes can be handled effectively by embedding the linear characteristic. The fuzzy model of the pH process to be controlled was constructed and used in the predictive control algorithm. Results of computer simulations and experiments demonstrated the effectiveness of the present control method.

Korean Journal of Chemical Engineering, 2005

Korean Journal of Chemical Engineering, 1995

Page 1. Korean J of Chem. Eng., 12(3), 366-371 (1995) MODELING AND SIMULATION OF A NITRIC ACID RE... more Page 1. Korean J of Chem. Eng., 12(3), 366-371 (1995) MODELING AND SIMULATION OF A NITRIC ACID RECOVERY Sea Cheon Oh, Young Se Oh* and Yeong-Koo Yeo t Dept. of Chem. Eng., Hanyang University, Seoul 133-791, Korea *Tech. Res. and Dev. ...

Korean Journal of Chemical Engineering, 1995

Page 1. Korean J of Chem. Eng., 12(4), 472-477 (1995) A STUDY ON THE ADAPTIVE PREDICTIVE CONTROL ... more Page 1. Korean J of Chem. Eng., 12(4), 472-477 (1995) A STUDY ON THE ADAPTIVE PREDICTIVE CONTROL METHOD FOR MULTIVARIABLE BILINEAR PROCESSES Sea Cheon Oh and Yeong-Koo Yeo* Dept. of Chem. ...

Korean Journal of Chemical Engineering, 2011

A new forecasting scheme is presented of short-term system marginal price (SMP) using past data o... more A new forecasting scheme is presented of short-term system marginal price (SMP) using past data on power supply and demand as well as past cost data. The forecasting of SMP is one of the most significant factors in an electricity market in which power is produced by generators, transmitted by transmission companies, and distributed by suppliers according to new trading agreements. The accurate forecasting of SMP can significantly influence the profit of market participants. In this paper, a new methodology for day-ahead SMP forecasting is proposed using the law of supply and demand on power. The salient feature of the proposed approach is that it exhibits excellent predicting performance in short-term forecasting.

Korean Journal of Chemical Engineering, 2009

A district heating system (DHS) consists of energy suppliers and consumers, heat generation and s... more A district heating system (DHS) consists of energy suppliers and consumers, heat generation and storage facilities and power transmission lines in the region. DHS has taken charge of an increasingly important role as the energy cost increases recently. In this work, a model for operational optimization of the DHS in the metropolitan area is presented by incorporating forecast for demand from customers. In the model, production and demand of heat in the region of Suseo near Seoul, Korea, are taken into account as well as forecast for demand using the artificial neural network. The optimization problem is formulated as a mixed integer linear programming (MILP) problem where the objective is to minimize the overall operating cost of DHS. The solution gives the optimal amount of network transmission and supply cost. The optimization system coupled with forecast capability can be effectively used as design and longterm operation guidelines for regional energy policies.

Korean Journal of Chemical Engineering, 2012

... Simulated economics assessment of hollow fiber CO2 separation modules Yoon Ah Jang*, Young Mo... more ... Simulated economics assessment of hollow fiber CO2 separation modules Yoon Ah Jang*, Young Moo Lee**, and Yeong-Koo Yeo*,† ... The separation model to be used in the economic assessment is based on the existing plant models (Li et al. [11]; Stropnik et al. ...

Korean Journal of Chemical Engineering, 2009

A new proportional-integral-derivative (PID) controller is proposed based upon a simplified gener... more A new proportional-integral-derivative (PID) controller is proposed based upon a simplified generalized predictive control (GPC) control law. The tuning parameters of the proposed predictive PID controller are obtained from the simplified GPC control law for the 1 st-order and 2 nd-order processes with time delays of integer and non-integer multiples of the sampling time. The internal model technique is employed to compensate the effect of time delay of the target process. The predictive PID controller is equivalent to the PI controller when the target process is 1 st-order and to the PID controller when the target process is an integrating process. The performance of the proposed predictive PID controller is almost the same as that of the simplified GPC. The main advantage of the proposed control scheme over other control methods is the ease of tuning and operation.

Korean Journal of Chemical Engineering, 2009

This paper presents a scheme to achieve structural and operational optimization for the heat plan... more This paper presents a scheme to achieve structural and operational optimization for the heat plant in a district energy system. A district energy system consists of energy suppliers and consumers, district heating pipelines and heat storage facilities in a region. Production and consumption of energy and transport of energy as well as storage of heat are taken into account in the model. The problem is formulated as a mixed integer linear programming (MILP) problem where the objective is to minimize the overall cost of the district energy system. Evaluation of the energy production cost is based on the daily operation for every season at the plant located at Suseo in Seoul, Korea. From the results of numerical simulations we can see that the district energy system is well approximated by the proposed model, and that the energy efficiency is improved by the application of the optimal operation conditions provided by the proposed model.

Korean Journal of Chemical Engineering, 2009

We investigate the model for an industrial isothermal HDPE slurry reactor. The model, consisting ... more We investigate the model for an industrial isothermal HDPE slurry reactor. The model, consisting of several nonlinear equations, can be linearized to give sets of linear time invariant state space model. The effectiveness of the linearized model is verified by the numerical simulations. A simple model predictive control scheme is constructed based on the linear state space model. The value of the melt index is obtained from the values of the manipulated and controlled variables generated from the control scheme. The control performance can be evaluated from the comparison between the computed melt index values and measured melt index values. The control scheme shows good tracking performance in the numerical simulations. We believe that the model developed in the present study can be effectively used to predict process variables as well as to control the melt index.

Korean Journal of Chemical Engineering, 2003

− − − −The conversion of methane to syngas and other hydrocarbons in dielectric barrier discharge... more − − − −The conversion of methane to syngas and other hydrocarbons in dielectric barrier discharge plasma under the presence of CO 2 was investigated. Effects of the input voltage on the conversion of methane and CO 2 and the ratio of syngas were analyzed experimentally. The results of numerical simulations showed good quantitative agreement with those of experiments.

Korean Journal of Chemical Engineering, 1999

Page 1. Korean 3. Chem. Eng., 16(1), 144-149 (1999) SHORT COMMUNICATION A STUDY ON THE PREDICTION... more Page 1. Korean 3. Chem. Eng., 16(1), 144-149 (1999) SHORT COMMUNICATION A STUDY ON THE PREDICTION OF OZONE FORMATION IN AIR POLLUTION Sea Cheon Oh, Sang Hyun Sohn, Yeong-Koo Yeo* and Kun Soo Chang* Dept. of Chem. ...

Korean Journal of Chemical Engineering, 2004

− − − −In this work, we propose a PID control strategy based on the genetic algorithm coupled wit... more − − − −In this work, we propose a PID control strategy based on the genetic algorithm coupled with cubic spline interpolation method for the control of pH processes. The control scheme proposed in the present work consists of closed-loop identification based on the genetic algorithm and cubic spline method. First, we compute the parameters (K C , τ I , τ D) of the PID controller using relay feedback and apply these parameters to control the pH Process. Then approximate linear models corresponding to each pH range are obtained by the closed-loop identification based on closed-loop operation data. The optimal parameters of the PID controller at each pH region are then computed by using the genetic algorithm. From numerical simulations and control experiments we could achieve better control performance compared to the conventional fixed gain PID control method.

Korean Journal of Chemical Engineering, 2004

− − − −A dynamic model representing the wet-end of a paper mill is developed to characterize its ... more − − − −A dynamic model representing the wet-end of a paper mill is developed to characterize its dynamic behavior. The model is based on the mass balance relationships written for the simplified wet-end white water network. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid rate on the major controlled variables are analyzed by numerical simulations. It can be said that the consistency of the model with plant data seems to be reasonably good and can be used as a tool for plant analysis and control.

Korean Journal of Chemical Engineering, 1997

A steady-state optimization for the fractionation unit of an industrial benzene-toluene-xylene (B... more A steady-state optimization for the fractionation unit of an industrial benzene-toluene-xylene (BTX) plant was developed. Because the fractionation unit of the BTX plant has narrow ranges of boiling point and doesn't have any sidecut and side reboiler, we employed the boiling point estimation method in the modeling and simulation of the unit. The well-known Soave-Redlich-Kwong state equation was employed to compute required thermodynamic properties. The results of simulations showed very good agreement with the actual operation data. The objective of the optimization was to maximize profit of fractionation unit. The successive quadratic programming algorithm was uiilized and objective functions for each ffactionation column were set up based on utility and operation costs and selling prices of products. The graphical user interface of the optimization system was developed to provide convenience and flexibility in actual applications.

Korean Journal of Chemical Engineering, 2005

A model representing the wet-end section of a paper mill has been developed to characterize its d... more A model representing the wet-end section of a paper mill has been developed to characterize its dynamic behavior during the grade change. The model is based on the mass balance relationships written for the simplified wetend white water network. From the linearization of the dynamic model, higher-order Laplace transfer functions were obtained followed by the reduction procedure to give simple lower-order models in the form of 1 st-order or 2 nd-order plus dead times. The dynamic response of the wet-end is influenced both by the white water volume and by the level of wire retention. Effects of key manipulated variables such as the thick stock flow rate, the ash flow rate and the retention aid flow rate on the major controlled variables were analyzed by numerical simulations. The simple dynamic model developed in the present study can be effectively used in the operation and control.

Korean Journal of Chemical Engineering, 2001

In this study we propose a method to identify tile kinetics of direction estelification reactions... more In this study we propose a method to identify tile kinetics of direction estelification reactions for polyethylene terephthalate (PET) based on a genetic algozJtt=l~. The reaction rate pm~netei~ could be identified successfully by using a genetic algorithm and plant data. The effects of key operating variables (temperature, pressure, monomer feed ratio and residence time) on the reactor performance were also investigated. It was observed that the reactor per-foi~lmnce strongly depends on the degree of dissolution of the solid terephthalic acid (TPA) m the reaction mixtures.

Korean Journal of Chemical Engineering, 2001

− − − −Operating strategies and optimum feed tray locations were studied in a typical fractionati... more − − − −Operating strategies and optimum feed tray locations were studied in a typical fractionation process of a BTX plant in Korea in order to reduce energy consumption. Control systems with fixed V/F or R/F ratios could be recommended for various feed compositions. By choosing the optimum feed tray location for the columns, about 16% of energy consumption could be reduced.

Korean Journal of Chemical Engineering, 1999

For effective flowsheet-level calculation of a complex chemical plant, the use of suitable partit... more For effective flowsheet-level calculation of a complex chemical plant, the use of suitable partitioning and tearing techniques is inevitable. The partitioning and tearing techniques based on the reachability matrix and the decomposition algorithm were applied to model and simulate a sulfolane extraction plant. Basic concepts were first exploited towards a general representation for the modeling and simulation of the sulfolane extraction process. Six process mlits, which consist of the sulfolane extraction plant, were modeled first and partitioning and tearing techniques were employed to model and simulate the whole extraction plant. The InsideaDut method mad the sequential-modular approach were used in the modeling and simulation. Results of simulations showed good agreement with plant operation data.

Korean Journal of Chemical Engineering, 2000

Liquid sulfur hexafluoride (SF 6) contains carbon tetrachloride (CF 4) and air as main impurities... more Liquid sulfur hexafluoride (SF 6) contains carbon tetrachloride (CF 4) and air as main impurities. It is very difficult to remove these impurities by using a catalyst column or an adsorption column. In this work a new purification method for SF 6 mixture based on batch distillation is proposed. Experimental study showed good purification performance, where SF 6 N50 was obtained from SF 6 N30 feed. In the modeling of the batch purification process of SF 6 mixture, the K-value was calculated based on the regular solution theory and a short cut method was employed. Results of simulations showed good agreement with those of experiments.

Korean Journal of Chemical Engineering, 1999

Abstraet-A new fuzzy model-based predictive control scheme was developed to control a nonlinear p... more Abstraet-A new fuzzy model-based predictive control scheme was developed to control a nonlinear pH process. The control scheme is based on the Takagi-Sugeno type fuzzy model of the process being controlled. In the present fuzzy model predictive control method, the process model maintains a linear representation of the conclusion parts of fuzzy roles. Therefore, it has a significant advantage over other types of models in the sense that nonlinear processes can be handled effectively by embedding the linear characteristic. The fuzzy model of the pH process to be controlled was constructed and used in the predictive control algorithm. Results of computer simulations and experiments demonstrated the effectiveness of the present control method.

Korean Journal of Chemical Engineering, 2005

Korean Journal of Chemical Engineering, 1995

Page 1. Korean J of Chem. Eng., 12(3), 366-371 (1995) MODELING AND SIMULATION OF A NITRIC ACID RE... more Page 1. Korean J of Chem. Eng., 12(3), 366-371 (1995) MODELING AND SIMULATION OF A NITRIC ACID RECOVERY Sea Cheon Oh, Young Se Oh* and Yeong-Koo Yeo t Dept. of Chem. Eng., Hanyang University, Seoul 133-791, Korea *Tech. Res. and Dev. ...

Korean Journal of Chemical Engineering, 1995

Page 1. Korean J of Chem. Eng., 12(4), 472-477 (1995) A STUDY ON THE ADAPTIVE PREDICTIVE CONTROL ... more Page 1. Korean J of Chem. Eng., 12(4), 472-477 (1995) A STUDY ON THE ADAPTIVE PREDICTIVE CONTROL METHOD FOR MULTIVARIABLE BILINEAR PROCESSES Sea Cheon Oh and Yeong-Koo Yeo* Dept. of Chem. ...

Korean Journal of Chemical Engineering, 2011

A new forecasting scheme is presented of short-term system marginal price (SMP) using past data o... more A new forecasting scheme is presented of short-term system marginal price (SMP) using past data on power supply and demand as well as past cost data. The forecasting of SMP is one of the most significant factors in an electricity market in which power is produced by generators, transmitted by transmission companies, and distributed by suppliers according to new trading agreements. The accurate forecasting of SMP can significantly influence the profit of market participants. In this paper, a new methodology for day-ahead SMP forecasting is proposed using the law of supply and demand on power. The salient feature of the proposed approach is that it exhibits excellent predicting performance in short-term forecasting.

Korean Journal of Chemical Engineering, 2009

A district heating system (DHS) consists of energy suppliers and consumers, heat generation and s... more A district heating system (DHS) consists of energy suppliers and consumers, heat generation and storage facilities and power transmission lines in the region. DHS has taken charge of an increasingly important role as the energy cost increases recently. In this work, a model for operational optimization of the DHS in the metropolitan area is presented by incorporating forecast for demand from customers. In the model, production and demand of heat in the region of Suseo near Seoul, Korea, are taken into account as well as forecast for demand using the artificial neural network. The optimization problem is formulated as a mixed integer linear programming (MILP) problem where the objective is to minimize the overall operating cost of DHS. The solution gives the optimal amount of network transmission and supply cost. The optimization system coupled with forecast capability can be effectively used as design and longterm operation guidelines for regional energy policies.

Korean Journal of Chemical Engineering, 2012

... Simulated economics assessment of hollow fiber CO2 separation modules Yoon Ah Jang*, Young Mo... more ... Simulated economics assessment of hollow fiber CO2 separation modules Yoon Ah Jang*, Young Moo Lee**, and Yeong-Koo Yeo*,† ... The separation model to be used in the economic assessment is based on the existing plant models (Li et al. [11]; Stropnik et al. ...

Korean Journal of Chemical Engineering, 2009

A new proportional-integral-derivative (PID) controller is proposed based upon a simplified gener... more A new proportional-integral-derivative (PID) controller is proposed based upon a simplified generalized predictive control (GPC) control law. The tuning parameters of the proposed predictive PID controller are obtained from the simplified GPC control law for the 1 st-order and 2 nd-order processes with time delays of integer and non-integer multiples of the sampling time. The internal model technique is employed to compensate the effect of time delay of the target process. The predictive PID controller is equivalent to the PI controller when the target process is 1 st-order and to the PID controller when the target process is an integrating process. The performance of the proposed predictive PID controller is almost the same as that of the simplified GPC. The main advantage of the proposed control scheme over other control methods is the ease of tuning and operation.

Korean Journal of Chemical Engineering, 2009

This paper presents a scheme to achieve structural and operational optimization for the heat plan... more This paper presents a scheme to achieve structural and operational optimization for the heat plant in a district energy system. A district energy system consists of energy suppliers and consumers, district heating pipelines and heat storage facilities in a region. Production and consumption of energy and transport of energy as well as storage of heat are taken into account in the model. The problem is formulated as a mixed integer linear programming (MILP) problem where the objective is to minimize the overall cost of the district energy system. Evaluation of the energy production cost is based on the daily operation for every season at the plant located at Suseo in Seoul, Korea. From the results of numerical simulations we can see that the district energy system is well approximated by the proposed model, and that the energy efficiency is improved by the application of the optimal operation conditions provided by the proposed model.

Korean Journal of Chemical Engineering, 2009

We investigate the model for an industrial isothermal HDPE slurry reactor. The model, consisting ... more We investigate the model for an industrial isothermal HDPE slurry reactor. The model, consisting of several nonlinear equations, can be linearized to give sets of linear time invariant state space model. The effectiveness of the linearized model is verified by the numerical simulations. A simple model predictive control scheme is constructed based on the linear state space model. The value of the melt index is obtained from the values of the manipulated and controlled variables generated from the control scheme. The control performance can be evaluated from the comparison between the computed melt index values and measured melt index values. The control scheme shows good tracking performance in the numerical simulations. We believe that the model developed in the present study can be effectively used to predict process variables as well as to control the melt index.