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>

Grid-search-and-box-search-assisted coordinate descent methodology for practical retrofit of the existing distillation columns to dividing wall columns

Van Duc Long, Nguyen,Minh, Le Quang,Lee, Moonyong Elsevier 2018 Chemical engineering research & design Vol.131 No.-

<P><B>Abstract</B></P> <P>A dividing-wall column (DWC) leading to savings in terms of substantial investment and operating costs, and a significant reduction in CO<SUB>2</SUB> emission constitutes an optimal solution for distillation process intensification. Recently, industrial applications of the DWC gradually increased although the need for an efficient, practical, and simple to implement optimization methodology persists. This study proposes a practical method that employs coordinate descent methodology, which is assisted by a grid search to avoid local optimal points and box searches to seek a more promising solution to optimize the retrofit of existing distillation columns to DWCs. The optimal DWC structure and operating conditions are determined in a practical and effective manner that is simple to implement and requires minimal simulation runs, which is suitable for industrial uses. The proposed method is examined in the optimal retrofit of a side stream column and a conventional two-column sequence that are widely used in the chemical process industry. The results show that the grid-search-and-box-search-assisted coordinate descent methodology combining mathematical programing techniques and statistical methods effectively avoids local optimal points but also corresponds to a more promising solution, and thus, it is competitive to coordinate descent methodology and response surface methodology that are popularly used in optimization processes in the chemical process industry. The retrofitted DWC systems lead to a substantial decrease in operating costs while effectively removing the bottleneck problem and mitigating CO<SUB>2</SUB> emission as well. Notably, operating costs are reduced to a maximum of 33.8% and 43.3% in retrofit of side stream columns and conventional two-column sequences, respectively. Both structural and operating variables are effectively and simultaneously optimized. It allows for the identification of interactions between design variables. Furthermore, the carbon dioxide emission is calculated and evaluated when retrofitting to the DWC.</P> <P><B>Highlights</B></P> <P> <UL> <LI> GSBSCD avoids the local optimal points and determines a more promising solution. </LI> <LI> GSBSCD combines mathematical programing techniques and statistical methods. </LI> <LI> The optimal DWC structure and operating conditions are found in a practical manner. </LI> <LI> GSBSCD allows the identification of interactions between the design variables. </LI> <LI> Substantial saving in operating cost could be achieved by using retrofitted DWC. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</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>

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>

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>

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>

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

Economical retrofit of reactive distillation with a total reflux design or a total boil-up design

Van Duc Long, Nguyen,Lee, Moonyong Elsevier 2019 Chemical engineering research & design Vol.145 No.-

<P><B>Abstract</B></P> <P>In many cases, the volatilities of the reactants and products are unfavorable for separation and purification; therefore, special designs for reactive distillation (RD) are required. In this study, RD configurations with total reflux and total boil-up designs are analyzed and evaluated under such scenarios to determine their applicability and disadvantages. Subsequently, simple and economical solutions were proposed to improve the performance of the existing RD using special designs for such cases, such as removing the product in the side stream: this enables more flexibility in design and allows more chances for improving reaction and separation efficiency. Response surface methodology handling both structural and operating variables simultaneously was used for optimizing the proposed configuration. An industrial case was simulated to demonstrate the proposed configuration. Furthermore, a novel dual-effect side stream RD was proposed to improve energy performance. As a result, the proposed retrofitted sequence could enhance energy efficiency up to 54% and reduce CO<SUB>2</SUB> emissions of up to 52% compared to that for the existing sequence. This work also showed that this solution can bring an increase in capacity up to 15% with a small investment and short payback period.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel SSRC configuration was economically and effectively proposed. </LI> <LI> SSRC creates more opportunities to improve reaction and separation efficiency. </LI> <LI> SSRC utilizes remixing phenomenon in RD to reduce the role of the downstream. </LI> <LI> Substantial operating cost saving by using retrofitted SSRC and DESSRC. </LI> <LI> This solution can bring an increase in capacity up to 15% with a small investment. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>[DISPLAY OMISSION]</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>

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>