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- 저자 : Nhien, L.C. (검색결과 18 건)
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Nhien, Le Cao,Long, Nguyen Van Duc,Kim, Sangyong,Lee, Moonyong Elsevier 2016 Biochemical engineering journal Vol.116 No.-
<P><B>Abstract</B></P> <P>Furfural, which is used as a precursor for the production of many other industrial chemicals, has been identified as one of the major bio-based platform chemicals that can compete with petroleum-based chemicals. On the other hand, the current commercial furfural process has a low yield and is energy-intensive. Therefore, this study develops the biorefinery production process of furfural from lignocellulosic biomass using process heat integration and process intensification. In particular, a distillation unit of the furfural production process requires considerable energy, highlighting the need to improve energy efficiency, which is the motivation of this work. An integrated and intensified distillation sequence, including an innovative bottom dividing wall column with a decanter configuration (BDWC-D) was suggested to enhance the energy and cost efficiency of the furfural production process through a comprehensive and systematic procedure that combines process intensification with heat integration. The structures of the complex columns in all sequences were optimized using the optimization method-response surface methodology (RSM). All simulations were conducted using Aspen HYSYS. The results show the proposed sequence can reduce total annual cost and carbon footprint by 10.1% and 11.6%, respectively compared to the conventional sequence.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Nhien, Le Cao,Long, Nguyen Van Duc,Kim, Sangyong,Lee, Moonyong American Chemical Society 2016 INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH - Vol.55 No.18
<P>A hybrid purification process combining extraction and distillation for the production of levulinic acid (LA), furfural, and formic acid (FA) from lignocellulosic biomass was studied. The effective process depends on the choice of appropriate extraction solvent. A comprehensive procedure of solvent selection for the LA production process was developed. A range of solvents were first evaluated by solvent screening, and processes using the three most promising solvents, including methyl isobutyl ketone (MIBK); furfural and octanol were then designed and optimized using an Aspen Plus simulator. These processes were evaluated in terms of the energy consumption, total annual cost, and environmental impact. As a result, MIRK showed the most favorable equilibrium for the extraction of LA but was unfavorable for FA extraction. Octanol showed not only the most favorable result in the extraction of FA, but was also favorable for the extraction of furfural and LA. Interestingly, furfural could extract more LA than octanol and extract more FA than MIBK. The design results show that the furfural solvent process can reduce energy consumption by up to 25.2% and 21.4%, the TAC by up to 30.6% and 25.9%, and CO2 emissions by up to 27.0% and 25.5% compared to processes using octanol and MIBK as solvents, respectively.</P>
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Nhien, Le Cao,Long, Nguyen Van Duc,Lee, Moonyong Elsevier 2017 Energy Conversion and Management Vol.141 No.-
<P><B>Abstract</B></P> <P>Biofuels have the most potential as an alternative to fossil fuels and overcoming global warming, which has become one of the most serious environmental issues over the past few decades. As the world confronts food shortages due to an increase in world population, the development of biofuels from inedible lignocellulosic feedstock may be more sustainable in the long term. Inspired by the NREL conventional process, this paper proposes a novel heat–integrated and intensified biorefinery design for cellulosic ethanol production from lignocellulosic biomass. For the preconcentration section, heat pump assisted distillation and double–effect heat integration were evaluated, while a combination of heat–integrated technique and intensified technique, extractive dividing wall column (EDWC), was applied to enhance the process energy and cost efficiency for the purification section. A biosolvent, glycerol, which can be produced from biodiesel production, was used as the extracting solvent in an EDWC to obtain a high degree of integration in a biorefinery context. All configuration alternatives were simulated rigorously using Aspen Plus were based on the energy requirements, total annual costs (TAC), and total carbon dioxide emissions (TCE). In addition, the structure of the EDWC was optimized using the reliable response surface method, which was carried out using Minitab statistical software. The simulation results showed that the proposed heat–integrated and intensified process can save up to 47.6% and 56.9% of the TAC and TCE for the purification section, respectively, compared to the conventional purification process.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A compact biorefinery design was proposed for cellulosic ethanol purification. </LI> <LI> Actual fermentation broth from lignocellulosic biomass was considered. </LI> <LI> Process integration and intensification achieves competitive biorefinery context. </LI> <LI> The response surface method optimizes the complex column structure effectively. </LI> <LI> The proposed process could save up to 47.6% of total annual cost. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Andika, Riezqa,Nhien, Le Cao,Lee, Moonyong Elsevier 2017 Journal of industrial and engineering chemistry Vol.54 No.-
<P><B>Abstract</B></P> <P>In this study, the rigorous simulation and design of an industrial Sulfinol-M-based acid gas removal (AGR) process was developed. All simulations were performed using Aspen HYSYS with extended NRTL activity coefficient model for the liquid phase and the Peng–Robinson state equation for the vapor fugacity coefficients. The simulation results from VMGSim and Aspen HYSYS were compared with design data from an integrated gasification combined cycle power plant. Several enhanced absorber–regenerator configurations were presented to improve AGR process efficiency. Sustainability analysis was conducted to assess these process alternatives in terms of energy requirements, costs, and environmental impacts. The results showed that the proposed self-heat recuperation configuration could reduce the energy requirements, total annual costs, carbon footprint by 74.7%, 40.1%, and 48.9%, respectively, compared with the conventional configuration.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An industrial Sulfinol-M-based AGR process was simulated and validated. </LI> <LI> A cost-effective absorber–regenerator design was proposed for AGR process. </LI> <LI> Sustainability analyses were carried out to evaluate configuration alternatives. </LI> <LI> The proposed process could save up to 40.1% of total annual cost. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Proposed self-heat recuperative AGR process using Sulfinol-M as a solvent in an IGCC power plant.</P> <P>[DISPLAY OMISSION]</P>
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Riezqa Andika,Le Cao Nhien,이문용 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.54 No.-
In this study, the rigorous simulation and design of an industrial Sulfinol-M-based acid gas removal (AGR) process was developed. All simulations were performed using Aspen HYSYS with extended NRTL activity coefficient model for the liquid phase and the Peng–Robinson state equation for the vapor fugacity coefficients. The simulation results from VMGSim and Aspen HYSYS were compared with design data from an integrated gasification combined cycle power plant. Several enhanced absorber–regenerator configurations were presented to improve AGR process efficiency. Sustainability analysis was conducted to assess these process alternatives in terms of energy requirements, costs, and environmental impacts. The results showed that the proposed self-heat recuperation configuration could reduce the energy requirements, total annual costs, carbon footprint by 74.7%, 40.1%, and 48.9%, respectively, compared with the conventional configuration.
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Harvianto, G.R.,Ahmad, F.,Nhien, L.C.,Lee, M. Elsevier Scientific Pub. Co 2016 Journal of membrane science Vol.497 No.-
This study reports the advantages of a cost-effective unit process using a hybrid distillation and vapor permeation unit for isopropanol dehydration. The feasibility of numerous hybrid membrane distillation schemes for isopropanol dehydration was evaluated by simulation and optimization in Aspen Plus. A built-in model for a membrane separation system was proposed by developing a mathematical model in an Aspen Custom Modeler and integrating it simultaneously with an Aspen Plus. The output results of the rigorous membrane models were consistent with the experimental data from the literature. The influence of the decisive operational parameters, which will be used as an optimization variable to examine the different configurations of hybrid systems, was analyzed. Furthermore, this study also employed the response surface methodology (RSM) to optimize the economical calculation and find the best design for the desired product. The RSM optimization effectively connected the interception of the optimizing variables and its predictions agreed well with the results of rigorous simulations. The most significant savings in the total costs could be achieved by applying a distillation-vapor permeation configuration (approximately 77% compared to azeotropic distillation). Therefore, it is economically beneficial to employ distillation-vapor permeation over the previously proposed hybrid systems of the distillation-pervaporation and distillation-pervaporation-distillation.
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A LQR Neural Network Control Approach for Fast Stabilizing Rotary Inverted Pendulums
Huynh Vinh Nghi,Dinh Phuoc Nhien,Dang Xuan Ba 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.1
Rotary inverted pendulum (RIP) is a well-known system that is commonly employed as an ideal benchmarking model for verifying linear and nonlinear control algorithms thanks to unique unstable and highly nonlinear natures. In this paper, an intelligent control method is developed for stabilizing such the RIP system in upright posture. The controller is structured from a linear quadratic regulator (LQR) and an online radial basis function (RBF) Neural-Network compensator. The LQR term plays a crucial role in yielding the nominal control signal based on a linearized model. Meanwhile, the neural control term is adopted to suppress the systematic deviation and external disturbances as the system is far from the equilibrium state. A damping segment-wise adaptation rule is proposed to activate the network operation. Stability of the closed-loop system is then proven by Lyapunov analyses. Effectiveness and feasibility of the advanced controller are confirmed throughout comparative simulation and real-time experiments.
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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>
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