Research topics

Computer-aided model development and simulation have become an important part of the research repertoire, supplementing (and in some cases replacing) experimentation. Going from application area to computational results requires domain expertise, mathematical modeling, numerical analysis, algorithm development, software implementation, program execution, results analysis, validation, and the visualization of results. Although it includes elements from computer science, applied mathematics, engineering (or systems engineering) and science (e.g., chemistry and biology), multi-scale simulation in PSE focuses on the integration of knowledge and methodologies from all of these disciplines, and as such is a subject which is distinct from any of them.

1. Main Research Topics

1) Modeling, simulation, and process design: first-principle models and/or data-driven models need a priori in order to simulate dynamic or steady-state behaviors of chemical and biological processes. The models constructed in the multi-scales (nano/micro-scale, meso-scale and macro-scale) are combined with each other for the process development.

- A multi-scale simulation approach starting at the molecular level is studied for the adsorption process development (Son and Lim, 2008). A grand canonical Monte-Carlo (GCMC) method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The flow characteristics in the packed column are analyzed using Fluent as a CFD code. The adsorption chromatographic process is finally simulated and the design and operating parameters are identified, integrating information obtained from the smaller scales.

- Simulated moving bed (SMB) process modeling and simulation (Lim et al., 2004; Lim and Jorgensen, 2004; Lim and Jorgensen, 2007; Lee and Lim, 2009; Lim et al., 2010).

- CFD simulation for NO_x removal processes of hybrid SNCR-SCR (Nguyen et al., 2008, 2009, 2010).

- Gasification process modeling and simulation (Nguyen et al., 2010)- A multi-scale simulation approach for process development is studied for the adsorption process development (Son and Lim, 2008). A grand canonical Monte-Carlo (GCMC) method is used for the prediction of adsorption isotherms of methanol on an activated carbon at the molecular level. The flow characteristics in the packed column are analyzed using ANSYS Fluent as a CFD code. The adsorption chromatographic process is finally simulated and the design and operating parameters are identified, integrating information obtained from the smaller scales.

- Simulated moving bed (SMB) process modeling and simulation (Lim et al., 2004; Lim and Jorgensen, 2004; Lim and Jorgensen, 2007; Lee and Lim, 2009; Lim et al., 2010).

- CFD simulation for NO_x removal processes of hybrid SNCR-SCR (Nguyen et al., 2008, 2009, 2010).

- Gasification process modeling and simulation (Nguyen et al., 2010, 2011; Son et al., 2011).

- Process simulation for conceptual design and techno-economic analysis using ASPEN Plus and Icarus (Industry-funded projects, 2012).

2) Optimization of chemical processes: Using NLP (Non-Linear Programming), MINLP (Mixed-Integer NLP) and MOP (Multiobjective Optimization Programming) techniques, optimum design/operation parameters are identified in terms of energy-efficiency, cost reduction, environmental impacts etc.

- NLP based on SQP (Successive Quadratic Programming)

- MOP for the process design (Lim et al., 1999; Lim et al., 2001)

- GA (Genetic Algorithm) for global optimization

- Artificial neural network approach (Lim et al., 2007)

3) Simulation tool development: An integrated environment with GUI (graphical user interface) has been developed for several specific purposes such as simulation, optimization and parameter estimation of SMB and batch chromatographic processes, FAST-Chrom/SMB GUI (Lim and Lee, AIChE annual meeting, 2006; Lim and Bhatia, Adsorption, 2011).An integrated environment with GUI (graphical user interface) has been developed for several specific purposes such as simulation, optimization and parameter estimation of SMB and batch chromatographic processes, FAST-Chrom/SMB GUI (Lim and Lee, AIChE annual meeting, 2006; Lim and Bhatia, Adsorption, 2011).

2. Research Grants and Outcomes

After having worked in Hankyong National University as a tenure-track from 2005 to now, I have received the scientific research grants (130 k$/yr) funded from the government and several companies, as reported in Table 2.1After having worked in Hankyong National University as a tenure-track professor from 2004 to present, I have received the scientific research grants (130 k$/yr) funded from the government and several companies, as reported.

Table 2.1 Research grants received from 2005 to present.

* the amount is purely charged to our Lab. FACS in the scientific research projects.

Recently, within the past three years, my research grants have been supported only by the industrial side, which means that my research sticks to the real concerns had by the chemical industries. At this time my lab and the chemical industries have developed strong relationship. With the aid of the continuous and successive grants, the research outcomes are shownRecently, my research grants supported by the industrial side have increased, which means that my research sticks to the real concerns that the chemical industries have. At this time my lab and the chemical industries have developed strong relationship. With the aid of the continuous and successive grants, the research outcomes are shown  in Table 2.2.

Table 2.2 Research outcomes from 2004 to present.

3.9 papers/yr were published during the past 7 years. 96% of the 27 papers were published as the first author and/or corresponding author, as shown in3.8 papers/yr were published during the past 9 years. 97% of the 34 papers (33 papers) were published as the first author and/or corresponding author, as shown in Table 2.3. 27 papers (80% of the total paper) appeared in SCI journals.

Table 2.3 Author classification of the published papers.

3 Research Plan and FACS Beyond

Lab. FACS establishes a long-term policy for research, as is shown in Fig. 3.1 My research plan is represented in three dimensions of time, process and fundamentals. The several fundamentals, called multi-physics (adsorption, diffusion, reaction, and hydrodynamics), are integrated in the framework of multi-scale simulation for renewal energy in red, environmental in green, and separation in blue, for which methodologies (PSE tools) required are also shown in yellow. In the past (2000-2010), SMB (simulated moving bed) and membrane processes were investigated for separation of valuable chemicals, in the cadre of modeling with PDE (partial differential equation), GCMC (grand canonical Monte Carlo) and EMD (equilibrium molecular dynamics) solving. Environmental issues on NO_x removal from stationary sources had been intensively studies for hybrid SNCR-SCR processes using urea solution, developing three-dimensional turbulent reacting flow CFD models. First-principle models (i.e., momentum, mass and heat balances) and data-driven models (i.e., principal components analysis and artificial neural networks) were applied for multi-scale simulation.

The recent research program is focused on renewal energy such as coal and biomass gasification for syngas production and we have submitted the following manuscripts to journals:

- Myung Won Seo, Thanh D. B. Nguyen, Young Il Lim, Sang Done Kim^*, Sun Won Park and Yong Jeon Kim (2010), Solid Circulation and Loop-Seal Characteristics of a Dual Circulating Fluidized Bed: Experiments and CFD Simulation, Chemical engineering Journal, in press, supported by SK Energy.

- Thanh D. B. Nguyen, Myung-Won Seo, Young-Il Lim^*, Byung-Ho Song, and Sang-Done Kim (2010), CFD simulation with experiments in a dual fluidized bed gasifier, Computers and chemical engineering, submitted in October, supported by SK Energy.

- Thanh D. B. Nguyen, Ich Son Ngo, Young-Il Lim^*, and Byung-Ho Song (2010), Three-stage steady-state model for biomass gasification in a dual circulating fluidized bed, Energy, submitted in December, supported by SeenTec Co., Ltd.

- Son Ich Ngo, Thanh D. B. Nguyen, Young-Il Lim^*, Byung-Ho Song, Uen-Do Lee, and Jae-Hun Song (2010), Steam gasification of woody biomass in a bubbling fluidized bed, submitted in December, supported by SeenTec Co. Ltd.

Permeabilities of CO₂ and CH₄ in the slit pore have been predicted by using GCMC and EMD simulation (Lim et al., 2010; Lim & Bhatia, 2011). I will continue to work on molecular simulation in more complex pore structures. Since the results obtained from molecular-level simulation (MLS) are not directly related to model parameters of the process or fluid level (PLS/FLS), it is expected that a micro-fluid level simulation (MFLS) using a lattice-Boltzmann method gives us a linkage between MLS and FLS/PLS. The multi-scale models will be integrated for better understanding and efficient development of chemical and bio processes.

Reactive multiphase CFD simulation is one of the most challenging research areas in CFD. Multi-phase, multi-physics and multi-scale approaches will emerge as a promising technology in PSE researches, which are in nature of the real world. In this circumstance, SMB and membrane processes will be first targeted for multi-scale and multi-physics simulation. The expected outcomes of Lab. FACS are shown in the lower part of the table in Fig. 3.1. We shall continuously demonstrate efficient performance with two annual graduate students producing six papers per year.

Fig. 3.1 Lab. FACS Beyond (2010).

- edited May 8, 2013 -