Gregorius Harvianto | Yeungnam University (original) (raw)

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Papers by Gregorius Harvianto

A hybrid reactive distillation system with high selectivity pervaporation was examined to produce... more A hybrid reactive distillation system with high selectivity pervaporation was examined to produce butyl acetate and methanol via transesterification of methyl acetate with butanol. High selectivity pervaporation was combined with reactive distillation to eliminate a hitherto required column for the separation of a methanol and methyl acetate azeotrope. The polyamide-6 membrane was used for this purpose because of its high selectivity for methanol while also allowing sufficient permeate flux. The high purity methyl acetate recovered in the retentate stream leads to high conversion in the reactive distillation column, which enhances the energy savings (up to 71%) of this process. The feasibility of the proposed hybrid processes and several alternative designs were evaluated by rigorous simulation and optimization using the Aspen Plus software package. The effects of several designs and operating variables were also investigated for the proposed design. The high potential of the hybrid reactive distillation and pervaporation system for butyl acetate production is very promising; it may not only reduce the total annual costs relative to conventional systems but may also provide an attractive strategy to address problems associated with methanol and methyl acetate azeotropes in the effluent generated in the polyvinyl alcohol industry.

This paper presents a novel hybrid process combining thermally coupled reactive distillation with... more This paper presents a novel hybrid process combining thermally coupled reactive distillation with membrane-based pervaporation for enhanced production of n-butyl acetate. A conventional reactive distillation process was used as the base case and first optimized for the transesterification of methyl acetate with n-butanol to produce n-butyl acetate. It was observed that methyl acetate recovered in the recycle stream significantly affects the con-version in the reactive distillation column and overall energy efficiency of the whole process. The existing and proposed configurations were evaluated and optimized by simulation in Aspen Plus. The integration of thermally coupled reactive distillation and pervaporation improved the energy efficiency of the reactive distillation process by preventing remixing effect in the reactive distillation column and eliminating the azeotropic nature of the methanol and methyl acetate in the recycle stream, respectively. Finally, integration of the thermally coupled reactive distillation with a commercial pervaporation membrane was explored to take synergistic advantage of the thermally coupled reactive distillation and pervaporation hybrid configuration. As a result, the proposed hybrid design showed remark-ably improved energy efficiency and economics. The total reboiler duty and total annual cost reduced to 63 and 43%, respectively, compared to those of the base case.

A novel active vapor distributor (AVD) was proposed to address the need for vapor split control d... more A novel active vapor distributor (AVD) was proposed to address the need for vapor split control during dividing wall column (DWC) design and operation. A DWC's energy efficiency can be significantly reduced by a small deviation in the vapor split ratio; therefore, the vapor split ratio needs to be regulated during operation. In the proposed AVD, vapor splitting was implemented by a modified chimney tray with a specially designed cap. The liquid level of the chimney tray on each end side of the dividing wall section could be adjusted to control the vapor flow split. As the proposed AVD adjusts the friction of the vapor flow path efficiently without any mechanical moving parts, it can realize a more reliable operation of a DWC. The performance of the proposed AVD was evaluated, and the results demonstrated its easy implementation and superior ability to regulate vapor flow split during DWC operation.

An extraction and distillation hybrid process using a novel mixed solvent was proposed for enhanc... more An extraction and distillation hybrid process using a novel mixed solvent was proposed for enhancing acetic acid recovery during terephthalic acid production. Feasible hybrid extraction− distillation schemes were designed, simulated, and optimized for two mixed solvents, p-xylene + methyl acetate, and p-xylene + ethyl acetate, based on liquid−liquid equilibrium data for a quaternary system containing methyl acetate or ethyl acetate with p-xylene, acetic acid, and water. A hybrid process using the p-xylene + methyl acetate mixed solvent was found to generate the desired purity of acetic acid with a lower energy consumption and higher product yield than conventional extraction processes. Results showed that the proposed hybrid extraction−distillation process improves the process economics remarkably: the hybrid process using the p-xylene + methyl acetate and p-xylene + ethyl acetate mixed solvent reduced a total annual cost by 14% and 6%, respectively, compared with the conventional hybrid process using the ethyl acetate single solvent. With the important advantage of p-xylene and methyl acetate as internally existing components, the proposed mixed solvent is promising for safe and cost-effective recovery of acetic acid, particularly during terephthalic acid production.

The main aim of this study was to conduct preliminary analysis on the performance of two conceptu... more The main aim of this study was to conduct preliminary analysis on the performance of two conceptual designs that integrate the production of potable water, electricity, and salt. We used reverse osmosis (RO), pressure-retarded osmosis (PRO), and electrodialysis (ED) to produce potable water, electricity, and salt, respectively. The objective of the analysis is to observe how the relative positions of RO and PRO in the integrated process affect the five key parameters, i.e. the total dissolved solids (TDS) of potable water, permeate rate, the total energy requirement of the RO and ED units, net delivered power, and salt potential. We simulated each integrated design using previously validated mathematical expressions of RO, PRO, and ED. We found that the net delivered power is higher when the RO unit is located before the PRO unit. The same sequence also results in lower energy requirement for producing potable water, although the permeate rate is smaller than that of the rival sequence. On the other hand, the salt potential is not affected by the relative positions of the RO and PRO units.

Propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate(PGMEA) are... more Propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate(PGMEA) are representative photoresistor thinners used extensively and generated as waste during the display and semiconductor material manufacturing processes. Although the waste thinner is normally retrieved by distillation, the azeotropes of these two thinner components with water limit the distillation performance. In this paper, an extensive design study of enhanced distillation processes was carried out to determine a favorable path for waste thinner recovery. Appropriate thermodynamic models for the design of a waste thinner recovery process were obtained through the regression and validation of experimental vapor-liquid-liquid equilibrium data. An optimal direct sequence using three conventional distillation columns with a decanter was introduced as a base design to overcome the distillation boundary by azeotropes. Several advanced distillation configurations were examined to further improve the energy efficiency of the conventional recovery process. A novel heterogeneous azeotropic dividing-wall column was developed based on process intensification and integration. The proposed enhanced recovery process reduced the energy requirement for waste thinner recovery significantly by 33.1%. The advanced distillation configuration can be an attractive option for improving the economic and environmental efficiency of the commercial waste thinner recovery and recycling processes.

The experimental liquid–liquid equilibrium (LLE) data of the quaternary (acetic acid + water + px... more The experimental liquid–liquid equilibrium (LLE) data of the quaternary (acetic acid + water + pxylene + methyl acetate) system was investigated at 313.2 K and atmospheric pressure. This research is aimed to examine the potential of the mixture of methyl acetate and p-xylene, which available as the
remaining substances in terephthalic acid production, to be prospective extracting solvent for the acetic acid dehydration. LLE phase diagrams at different ratio of p-xylene to methyl acetate were presented for this quaternary system. The results showed that an enlargement of the LLE two-phase region occurred with increasing p-xylene to methyl acetate mass ratio in the initial solvent phase. The distribution coefficient and selectivity for the extraction of acetic acid were also obtained to evaluate the capability of solvent. LLE data were sufficiently correlated by Othmer-Tobias and Bachman equations. The experimental results were used to obtain binary interaction parameters as correlated by the nonrandom two liquid (NRTL) and universal quasi-chemical theory (UNIQUAC) equation models. The root mean square deviations (RMSD) values as low as 0.0119 and 0.0128 were calculated for NRTL and UNIQUAC, respectively; indicating excellent results for both models were suitable for the determination of LLE data of this quaternary system.

The liquid−liquid equilibria (LLE) data for the quaternary system, acetic acid, water, p-xylene, ... more The liquid−liquid equilibria (LLE) data for the
quaternary system, acetic acid, water, p-xylene, and ethyl
acetate, was obtained at 313.15 K under atmospheric pressure.
The composition distribution of each component on the
aqueous phase and organic phase were investigated. To
examine the effects of the solvent, the LLE phase diagrams at
different p-xylene to ethyl acetate ratios are presented for this
quaternary system. The reliability of the tie-line data of this
study was also confirmed using the Othmer−Tobias and Hand
equation. The distribution ratio and separation factors for the
extraction of acetic acid from the aqueous solutions were
obtained. Furthermore, the equilibrium data of this study was
analyzed using the quasichemical activity coefficient (UNIQUAC)
and nonrandom two liquid (NRTL) models. The experimental data was correlated successfully with both the activity
coefficient models that were extended with each binary interaction parameter. To determine the accuracy of each activity model,
the root-mean-square deviations (RMSDs) and average absolute deviation (AAD) resulting from these models were also
calculated. The RMSDs and AAD of the NRTL models were 0.0196 and 0.0213, respectively, whereas those of the UNIQUAC
model were 0.0166 and 0.0114, respectively. These values showed that the UNIQUAC model is superior to the NRTL model.

This study reports the advantages of a cost-effective unit process using a hybrid distillation an... more 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.

For the development of lithium ion recovery process from seawater, a series of experimental rese... more For the development of lithium ion recovery
process from seawater, a series of experimental researches
were performed. Solvent extraction of lithium ion from
aqueous solution using kerosene as solvent was proposed.
Lithium ion is effectively extracted by thenoyltrifluoroacetone–
trioctylphosphine oxide (TTA–TOPO) in kerosene
within 80 min. Extraction efficiency is severely influenced
by stoichiometric parameters. Among the stoichiometric
parameters, volume ratio of aqueous (A) to extraction
(E) solution is the most influential parameter. After extraction,
lithium ion could be easily stripped from the extraction
solution by acidic solutions. Stripping efficiency decreases
with pH of acidic solutions, and the kind of acid does not
affect the stripping efficiency. Extraction efficiency maintains
at more than 93 % even when the extraction solution is
recycled three times. 65 % of lithium ion can be extracted
from seawater by this solvent extraction process when
magnesium ion is precipitated by NH4OH prior to solvent
extraction process. Other metallic ions in seawater decrease
the extraction efficiency of lithium ion.

Solvent extraction of lithium ion using kerosene as solvent is proposed. The extraction of lithiu... more Solvent extraction of lithium ion using kerosene as solvent is proposed. The extraction of lithium ion using various mixed extractants of β-diketone and neutral ligand in kerosene was performed to find the optimum extractant combination. Considering the extraction efficiency, the optimum extractant combination was 0.02 M TTA and 0.04M TOPO. For the development of lithium extraction from seawater, the effects of dominant ions in seawater were examined in various extraction conditions. The extraction efficiencies generally decreased with the concentration of dominant metallic ions and increased with pH of the aqueous solutions, but Cl− ion showed only minor effect on the efficiency, even up to its concentration in seawater. Except for Mg2+ ion, more than 70% of lithium ions could be extracted at pH 10.6 from aqueous solutions with a dominant ion at its concentration in seawater.

A hybrid reactive distillation system with high selectivity pervaporation was examined to produce... more A hybrid reactive distillation system with high selectivity pervaporation was examined to produce butyl acetate and methanol via transesterification of methyl acetate with butanol. High selectivity pervaporation was combined with reactive distillation to eliminate a hitherto required column for the separation of a methanol and methyl acetate azeotrope. The polyamide-6 membrane was used for this purpose because of its high selectivity for methanol while also allowing sufficient permeate flux. The high purity methyl acetate recovered in the retentate stream leads to high conversion in the reactive distillation column, which enhances the energy savings (up to 71%) of this process. The feasibility of the proposed hybrid processes and several alternative designs were evaluated by rigorous simulation and optimization using the Aspen Plus software package. The effects of several designs and operating variables were also investigated for the proposed design. The high potential of the hybrid reactive distillation and pervaporation system for butyl acetate production is very promising; it may not only reduce the total annual costs relative to conventional systems but may also provide an attractive strategy to address problems associated with methanol and methyl acetate azeotropes in the effluent generated in the polyvinyl alcohol industry.

This paper presents a novel hybrid process combining thermally coupled reactive distillation with... more This paper presents a novel hybrid process combining thermally coupled reactive distillation with membrane-based pervaporation for enhanced production of n-butyl acetate. A conventional reactive distillation process was used as the base case and first optimized for the transesterification of methyl acetate with n-butanol to produce n-butyl acetate. It was observed that methyl acetate recovered in the recycle stream significantly affects the con-version in the reactive distillation column and overall energy efficiency of the whole process. The existing and proposed configurations were evaluated and optimized by simulation in Aspen Plus. The integration of thermally coupled reactive distillation and pervaporation improved the energy efficiency of the reactive distillation process by preventing remixing effect in the reactive distillation column and eliminating the azeotropic nature of the methanol and methyl acetate in the recycle stream, respectively. Finally, integration of the thermally coupled reactive distillation with a commercial pervaporation membrane was explored to take synergistic advantage of the thermally coupled reactive distillation and pervaporation hybrid configuration. As a result, the proposed hybrid design showed remark-ably improved energy efficiency and economics. The total reboiler duty and total annual cost reduced to 63 and 43%, respectively, compared to those of the base case.

A novel active vapor distributor (AVD) was proposed to address the need for vapor split control d... more A novel active vapor distributor (AVD) was proposed to address the need for vapor split control during dividing wall column (DWC) design and operation. A DWC's energy efficiency can be significantly reduced by a small deviation in the vapor split ratio; therefore, the vapor split ratio needs to be regulated during operation. In the proposed AVD, vapor splitting was implemented by a modified chimney tray with a specially designed cap. The liquid level of the chimney tray on each end side of the dividing wall section could be adjusted to control the vapor flow split. As the proposed AVD adjusts the friction of the vapor flow path efficiently without any mechanical moving parts, it can realize a more reliable operation of a DWC. The performance of the proposed AVD was evaluated, and the results demonstrated its easy implementation and superior ability to regulate vapor flow split during DWC operation.

An extraction and distillation hybrid process using a novel mixed solvent was proposed for enhanc... more An extraction and distillation hybrid process using a novel mixed solvent was proposed for enhancing acetic acid recovery during terephthalic acid production. Feasible hybrid extraction− distillation schemes were designed, simulated, and optimized for two mixed solvents, p-xylene + methyl acetate, and p-xylene + ethyl acetate, based on liquid−liquid equilibrium data for a quaternary system containing methyl acetate or ethyl acetate with p-xylene, acetic acid, and water. A hybrid process using the p-xylene + methyl acetate mixed solvent was found to generate the desired purity of acetic acid with a lower energy consumption and higher product yield than conventional extraction processes. Results showed that the proposed hybrid extraction−distillation process improves the process economics remarkably: the hybrid process using the p-xylene + methyl acetate and p-xylene + ethyl acetate mixed solvent reduced a total annual cost by 14% and 6%, respectively, compared with the conventional hybrid process using the ethyl acetate single solvent. With the important advantage of p-xylene and methyl acetate as internally existing components, the proposed mixed solvent is promising for safe and cost-effective recovery of acetic acid, particularly during terephthalic acid production.

The main aim of this study was to conduct preliminary analysis on the performance of two conceptu... more The main aim of this study was to conduct preliminary analysis on the performance of two conceptual designs that integrate the production of potable water, electricity, and salt. We used reverse osmosis (RO), pressure-retarded osmosis (PRO), and electrodialysis (ED) to produce potable water, electricity, and salt, respectively. The objective of the analysis is to observe how the relative positions of RO and PRO in the integrated process affect the five key parameters, i.e. the total dissolved solids (TDS) of potable water, permeate rate, the total energy requirement of the RO and ED units, net delivered power, and salt potential. We simulated each integrated design using previously validated mathematical expressions of RO, PRO, and ED. We found that the net delivered power is higher when the RO unit is located before the PRO unit. The same sequence also results in lower energy requirement for producing potable water, although the permeate rate is smaller than that of the rival sequence. On the other hand, the salt potential is not affected by the relative positions of the RO and PRO units.

Propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate(PGMEA) are... more Propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate(PGMEA) are representative photoresistor thinners used extensively and generated as waste during the display and semiconductor material manufacturing processes. Although the waste thinner is normally retrieved by distillation, the azeotropes of these two thinner components with water limit the distillation performance. In this paper, an extensive design study of enhanced distillation processes was carried out to determine a favorable path for waste thinner recovery. Appropriate thermodynamic models for the design of a waste thinner recovery process were obtained through the regression and validation of experimental vapor-liquid-liquid equilibrium data. An optimal direct sequence using three conventional distillation columns with a decanter was introduced as a base design to overcome the distillation boundary by azeotropes. Several advanced distillation configurations were examined to further improve the energy efficiency of the conventional recovery process. A novel heterogeneous azeotropic dividing-wall column was developed based on process intensification and integration. The proposed enhanced recovery process reduced the energy requirement for waste thinner recovery significantly by 33.1%. The advanced distillation configuration can be an attractive option for improving the economic and environmental efficiency of the commercial waste thinner recovery and recycling processes.

The experimental liquid–liquid equilibrium (LLE) data of the quaternary (acetic acid + water + px... more The experimental liquid–liquid equilibrium (LLE) data of the quaternary (acetic acid + water + pxylene + methyl acetate) system was investigated at 313.2 K and atmospheric pressure. This research is aimed to examine the potential of the mixture of methyl acetate and p-xylene, which available as the
remaining substances in terephthalic acid production, to be prospective extracting solvent for the acetic acid dehydration. LLE phase diagrams at different ratio of p-xylene to methyl acetate were presented for this quaternary system. The results showed that an enlargement of the LLE two-phase region occurred with increasing p-xylene to methyl acetate mass ratio in the initial solvent phase. The distribution coefficient and selectivity for the extraction of acetic acid were also obtained to evaluate the capability of solvent. LLE data were sufficiently correlated by Othmer-Tobias and Bachman equations. The experimental results were used to obtain binary interaction parameters as correlated by the nonrandom two liquid (NRTL) and universal quasi-chemical theory (UNIQUAC) equation models. The root mean square deviations (RMSD) values as low as 0.0119 and 0.0128 were calculated for NRTL and UNIQUAC, respectively; indicating excellent results for both models were suitable for the determination of LLE data of this quaternary system.

The liquid−liquid equilibria (LLE) data for the quaternary system, acetic acid, water, p-xylene, ... more The liquid−liquid equilibria (LLE) data for the
quaternary system, acetic acid, water, p-xylene, and ethyl
acetate, was obtained at 313.15 K under atmospheric pressure.
The composition distribution of each component on the
aqueous phase and organic phase were investigated. To
examine the effects of the solvent, the LLE phase diagrams at
different p-xylene to ethyl acetate ratios are presented for this
quaternary system. The reliability of the tie-line data of this
study was also confirmed using the Othmer−Tobias and Hand
equation. The distribution ratio and separation factors for the
extraction of acetic acid from the aqueous solutions were
obtained. Furthermore, the equilibrium data of this study was
analyzed using the quasichemical activity coefficient (UNIQUAC)
and nonrandom two liquid (NRTL) models. The experimental data was correlated successfully with both the activity
coefficient models that were extended with each binary interaction parameter. To determine the accuracy of each activity model,
the root-mean-square deviations (RMSDs) and average absolute deviation (AAD) resulting from these models were also
calculated. The RMSDs and AAD of the NRTL models were 0.0196 and 0.0213, respectively, whereas those of the UNIQUAC
model were 0.0166 and 0.0114, respectively. These values showed that the UNIQUAC model is superior to the NRTL model.

This study reports the advantages of a cost-effective unit process using a hybrid distillation an... more 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.

For the development of lithium ion recovery process from seawater, a series of experimental rese... more For the development of lithium ion recovery
process from seawater, a series of experimental researches
were performed. Solvent extraction of lithium ion from
aqueous solution using kerosene as solvent was proposed.
Lithium ion is effectively extracted by thenoyltrifluoroacetone–
trioctylphosphine oxide (TTA–TOPO) in kerosene
within 80 min. Extraction efficiency is severely influenced
by stoichiometric parameters. Among the stoichiometric
parameters, volume ratio of aqueous (A) to extraction
(E) solution is the most influential parameter. After extraction,
lithium ion could be easily stripped from the extraction
solution by acidic solutions. Stripping efficiency decreases
with pH of acidic solutions, and the kind of acid does not
affect the stripping efficiency. Extraction efficiency maintains
at more than 93 % even when the extraction solution is
recycled three times. 65 % of lithium ion can be extracted
from seawater by this solvent extraction process when
magnesium ion is precipitated by NH4OH prior to solvent
extraction process. Other metallic ions in seawater decrease
the extraction efficiency of lithium ion.

Solvent extraction of lithium ion using kerosene as solvent is proposed. The extraction of lithiu... more Solvent extraction of lithium ion using kerosene as solvent is proposed. The extraction of lithium ion using various mixed extractants of β-diketone and neutral ligand in kerosene was performed to find the optimum extractant combination. Considering the extraction efficiency, the optimum extractant combination was 0.02 M TTA and 0.04M TOPO. For the development of lithium extraction from seawater, the effects of dominant ions in seawater were examined in various extraction conditions. The extraction efficiencies generally decreased with the concentration of dominant metallic ions and increased with pH of the aqueous solutions, but Cl− ion showed only minor effect on the efficiency, even up to its concentration in seawater. Except for Mg2+ ion, more than 70% of lithium ions could be extracted at pH 10.6 from aqueous solutions with a dominant ion at its concentration in seawater.