Separation of D-psicose and D-fructose using simulated moving bed chromatography

Van Duc Long, Nguyen,Le, Thai-Hoang,Kim, Jin-Il,Lee, Ju Weon,Koo, Yoon-Mo WILEY-VCH Verlag 2009 Journal of Separation Science Vol.32 No.11

<P>Simulated moving bed (SMB) processes have been widely used in the sugar industries with ion-exchange resin as a stationary phase. D-Psicose, a rare monosaccharide known as a valuable pharmaceutical substrate, was synthesized by the enzymatic conversion from D-fructose. The SMB process was adopted to separate D-psicose from D-fructose. Before the SMB experiment, the reaction mixture including D-psicose and D-fructose was treated by a deashing process to remove contaminants, such as buffers, proteins, and other organic materials. Four columns packed with Dowex 50WX4-Ca<SUP>2+</SUP> (200–400 mesh) ion-exchange resins were used in the four-zone SMB. Single-step frontal analysis was performed to estimate the isotherm parameters of each monosaccharide. The operating conditions of the SMB process were determined based on the Equilibrium Theory. According to the simulation of the SMB process, the purity and yield of extract product (D-psicose) achieved were 99.04 and 97.46%, respectively and those of raffinate product (D-fructose) were 99.06 and 99.53%, respectively. Under the optimized operating condition, complete separation (extract purity = 99.36%, raffinate purity = 99.67%) was achieved experimentally.</P>

Novel hybrid-blower-and-evaporator-assisted distillation for separation and purification in biorefineries

Van Duc Long, Nguyen,Hong, Jimin,Nhien, Le Cao,Lee, Moonyong Elsevier 2018 Chemical engineering and processing Vol.123 No.-

<P><B>Abstract</B></P> <P>The production of biofuels and biochemicals from biomass-based feedstock, which is one of the most promising strategies for replacing petroleum-based resources and thus alleviating global warming, has received increasing attention in recent years. However, this strategy is energy-intensive due to the low product concentrations after transformation step. In this study, a novel hybrid-blower-and-evaporator-assisted distillation configuration (HBED) was proposed for enhancing process efficiency in bioproduct production from biomass. Several important industrial cases have been investigated to demonstrate the proposed configuration. By applying HBED, light components are partially removed in an evaporator, and the latent heat can be circulated during the process, leading to a substantial improvement in energy efficiency. A blower can increase the energy efficiency of an evaporator significantly, while the combination of an evaporator and blower can substantially reduce the size, capital cost, and operating cost of the distillation column. The results show that the proposed HBED configuration can achieve significant energy savings. Notably, the operating costs can be reduced by up to 45.4%, 26.3%, and 36.7% for the levulinic acid, 2,3-butanediol, and furfural purification processes, respectively. Furthermore, the CO<SUB>2</SUB> emissions of a conventional column and the proposed configuration are evaluated and compared.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel hybrid-blower-and-evaporator-assisted distillation configurations were proposed. </LI> <LI> An evaporator can reduce the size, investment and operating costs of distillation. </LI> <LI> A blower can increase the energy efficiency of an evaporator significantly. </LI> <LI> The proposed configurations can handle large quantities of water and/or solvent. </LI> <LI> Substantial saving in operating cost could be achieved in biorefineries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Improvement of the Deethanizing and Depropanizing Fractionation Steps in NGL Recovery Process Using Dividing Wall Column

Long, Nguyen Van Duc,Lee, Moonyong The Society of Chemical Engineers, Japan 2012 Journal of chemical engineering of Japan Vol.45 No.4

<P>In this work, our aim is to utilize a dividing wall column to improve the performance of the deethanizing and depropanizing fractionation steps in natural gas liquid processing. Starting from an initial conventional column sequence, the initial designs of the conventional dividing wall column and a top dividing wall column are obtained by maintaining the number of trays. In succession, they are optimized to reduce the energy consumption using factorial design. The results show that the conventional dividing wall column and the top dividing wall column can offer many benefits to the system, e.g., curbing the operating cost including refrigeration cost, and minimizing the reboiler and condenser duty. Furthermore, by using a dividing wall column, both the purity of ethane and its recovery rate are increased. The influence of utility prices on the operating cost saving of the conventional and the top dividing wall columns is also investigated. In addition, to further enhance the dividing wall column performance, heating is integrated on the top and an interreboiling system is installed at the bottom section of the dividing wall column.</P>

A hybrid technology combining heat pump and thermally coupled distillation sequence for retrofit and debottlenecking

Long, Nguyen Van Duc,Lee, Moonyong Elsevier 2015 ENERGY Vol.81 No.-

<P><B>Abstract</B></P> <P>Increasing the capacity of an existing distillation process has been a major focus of the chemical process industry. On the other hand, entrainment flooding can occur as a result, which can create a bottleneck in the distillation process. This paper reports the results of a techno-economic feasibility study to debottleneck the distillation column using a proposed hybrid process combining a heat pump and thermally coupled distillation sequence. Fractional utilization of the area was used to identify flooding problems in the column as well as how much area is available for vapor flow on an existing stage. A heat pump aided thermally coupled distillation sequence (HPTCDS) was designed and optimized using a response surface methodology. Two cases were examined to test the proposed sequence. The results showed that the proposed sequence can achieve significant energy savings and remove the bottleneck problem.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Energy efficient hybrid technology was efficiently proposed for debottlenecking. </LI> <LI> Optimal design is efficiently done by response surface methodology. </LI> <LI> Significant saving in operating cost could be achieved. </LI> <LI> The proposed sequence is an attractive option for industrial implementation. </LI> </UL> </P>

Novel acid gas removal process based on self-heat recuperation technology

Van Duc Long, Nguyen,Lee, Moonyong Elsevier 2017 INTERNATIONAL JOURNAL OF GREENHOUSE GAS CONTROL Vol.64 No.-

<P><B>Abstract</B></P> <P>Chemical absorption is the most common technology used in the acid gas removal unit (AGRU) for treating natural gas. On the other hand, the regenerator requiring large amounts of energy needed for the latent heat of a phase change makes this an energy intensive process. In this study, several distillation columns with a modified heat circulation module based on self-heat recuperation technology were proposed to enhance the energy efficiency of the AGRU. This innovative self-heat recuperation technology circulates the latent and sensible heat in the thermal process. All simulations were conducted using ASPEN HYSYS V8.6, while KG-TOWER<SUP>®</SUP> software was employed to size all the columns. The results showed that the proposed modified configuration can save up 62.5% and 45.9% in terms of the reboiler duty and operating cost, respectively, compared to a conventional AGRU. This brought a saving of 38.0% in terms of the total annual cost. The results also indicated that the carbon emissions could be saved up to 45.4%. The proposed process can be employed to both close-boiling mixtures and wide-boiling mixtures. In addition, a sensitive analysis of the utility costs on the performance of the suggested AGRU configuration were investigated. The retrofit an existing acid gas removal process was performed to enhance both the energy efficiency and capacity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel energy-efficient SHRT-based AGRU configurations were proposed. </LI> <LI> The proposed configuration could save up to 38.0% of the total annual cost. </LI> <LI> Pre-heating can enhance the energy efficiency of a heat pump. </LI> <LI> Energy requirement is reduced significantly lowering the electricity/steam cost ratio. </LI> <LI> The proposed configurations are also promising in a retrofit project. </LI> </UL> </P>

Purification of R-12 for refrigerant reclamation using existing industrial-scale batch distillation: design, optimization, simulation, and experimental studies

Nguyen Van Duc Long,이동영,Thi Hiep Han,박선용,황병봉,이문용 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.11

Many design variables and constraints, such as operating temperature and pressure of existing batch distillation or operating temperature of existing cooling and heating media, must be verified and satisfied during design and optimization when an existing batch distillation column is utilized for new mixture. The convergence of batch distillation simulation is sensitive with the initial values of these variables. Thus, a new systematic methodology was proposed to design and optimize separation of a new mixture using an existing batch column. The systematic methodology was based on an industrial case study of dichlorodifluoromethane (R-12) reclamation from a waste refrigerant mixture. Based on a comparison of the Pxy diagram with experimental data, “REFerence fluid PROPerties” was selected as the thermodynamic model. After design and optimization using shortcut and rigorous methodologies, the existing batch distillation unit was operated to validate the proposed methodology. The experimented performance match well with the simulated results. Under the optimized operating condition, complete purification of R-12 (purity=99.5%) was achieved experimentally after 28.3 h. The advantages and disadvantages of the proposed methodology were then discussed.

Intensified Distillation‐Based Separation Processes: Recent Developments and Perspectives

Long, Nguyen Van Duc,Minh, Le Quang,Ahmad, Faizan,Luis, Patricia,Lee, Moonyong VCH VERLAGSGESELLSCHAFT 2016 Chemical Engineering & Technology Vol.39 No.12

<P><B>Abstract</B></P><P>Greater sustainability can be achieved by decreasing the production costs, energy consumption, equipment size, and environmental impact as well as improvement of the raw material yields, remote control, and process flexibility. Process intensification (PI) as the main route for improving the process performance is used widely in heat transfer, reactions, separation, and mixing, which results in plant compactness, cleanliness, and energy efficiency. Some of the main intensified separation processes and improvement mechanisms are reviewed briefly with the main focus on the PI of distillation processes, which are the most important separation methods. In addition to these technologies, the potential and reliability of reactive separation processes are addressed briefly, which will enable higher efficiency and capacity.</P>

Solvent-gradient SMB to separate o-xylene and p-xylene

Nguyen Van Duc Long,구윤모,이주원,Thai-Hoang Le,Jin-Il Kim 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4

In batch chromatography, solvent-gradient operations (SG) produce significant improvement in terms of the enrichment of products and the separation time and the solvent consumption as compared with isocratic operations. This work studied solvent-gradient operation in reversed-phase simulated moving bed unit to separate ortho-xylene and para-xylene. In a solvent-gradient mode, different mobile phase compositions lead to a different retention behavior of solutes, i.e., different adsorption isotherms. Frontal analysis experiments for ortho-xylene and para-xylene were carried out with a reversed-phase column to measure adsorption parameters at several different mobile phase compositions,such as 45%, 50%, 60%, 75% and 90% acetonitrile. Therefore, the parameters in the retention model for solvent-gradient operation in the case of reversed-phase chromatography were estimated and applied to the design of an SMB system. A modified design method for solvent-gradient simulated moving bed chromatography (SG-SMB)was proposed. The robust operating conditions were obtained within the separation region on ( ϕ_R, ϕ_E) plane ( ϕ_R and ϕ_E are the volumetric content of organic modifier in the raffinate and the extract streams, respectively). The performance results of isocratic and solvent-gradient SMB were compared. A partial-discard strategy and increasing of the solvent gradient level were also applied to improve the performance of the SG-SMB.

Review of Retrofitting Distillation Columns Using Thermally Coupled Distillation Sequences and Dividing Wall Columns to Improve Energy Efficiency

Long, Nguyen Van Duc,Lee, Moonyong The Society of Chemical Engineers Japan 2014 Journal of chemical engineering of Japan Vol.47 No.2

Optimal retrofit and debottlenecking using novel multi-effect dividing wall column

Van Duc Long, Nguyen,Pham, Tram Ngoc,Lee, Moonyong ELSEVIER 2018 CHEMICAL ENGINEERING AND PROCESSING Vol.127 No.-

<P><B>Abstract</B></P> <P>This paper proposes several novel multi-effect dividing wall column (MEDWC) configurations to retrofit and debottleneck side-stream columns or two-column sequences for multiple objectives such as increasing the column throughput, maximizing energy efficiency, and reducing carbon dioxide (CO<SUB>2</SUB>) emissions. This paper also proposes a new practical method that employs a coordinate descent methodology, which is assisted by a random search to avoid local optimal points and box search to overlook more promising solutions for optimal retrofitting. One industrial case was studied and analyzed to demonstrate the proposed configuration. The results show that the proposed modified coordinate descent methodology not only effectively avoided the local optimal points but also overlooked more promising solutions. The proposed method is competitive with the coordinate descent methodology and response surface methodology, which are popular optimization methods used in the chemical process industry. Both the structural and operating variables are effectively and simultaneously optimized. The proposed MEDWC sequence removes the bottleneck problem effectively and achieves substantial energy savings and CO<SUB>2</SUB> emissions reduction. Notably, a 73.2% and 73.6% reduction in operating costs and CO<SUB>2</SUB> emissions, respectively, can be achieved in the ethylene dichloride separation processes. The proposed configuration can be applied to both close-boiling and wide-boiling mixtures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel multi-effect dividing wall column (MEDWC) configurations were proposed. </LI> <LI> MCD avoids the local optimal points and determines a more promising solution. </LI> <LI> The optimal distillation structure and operating conditions are found in a practical manner. </LI> <LI> A huge increase in production capacity can be achieved. </LI> <LI> 73.2% and 73.6% reduction in operating costs and CO<SUB>2</SUB> emissions, respectively. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>