High Purity Ethanol Research Articles

Computational understanding of Na-LTA for ethanol-water separation.

There is a growing demand for high purity ethanol as an electronic chemical. The conventional distillation process is effective for separating ethanol from water but consumes a significant amount of energy. Selective membrane separation using the LTA-type molecular sieve has been introduced as an alternative. The density functional theory simulation indicates that aluminum (Al) sites are evenly distributed throughout the framework, while sodium (Na+) ions are preferentially located in the six-membered ring. The movement of ethanol molecules can cause Na+ ions to be transported towards the eight-membered ring, hindering the passage of ethanol through the channel. In contrast, the energy barrier for water molecules passing through the channel occupied by Na+ ions is significantly lower, leading to a high level of selectivity for ethanol-water separation.

Facilitated water transport in composite reduced graphene oxide pervaporation membranes for ethanol upgrading

High purity ethanol is one of the most sought-after renewable energy sources. However, standard production methods yield ethanol of insufficient quality. Membrane processes such as pervaporation are recognized as a viable method for upgrading ethanol. Their performance and selectivity depend solely on membrane employed. Hydrophilic polyvinyl alcohol (PVA) membranes are used industrially for this purpose, but there is a trade-off between selectivity and permeability. Among other materials, chemically converted graphene attracts particular attention due to its exceptional water transport properties, however its application is limited by the fabrication of free-standing membranes. In this study, a composite reduced PVA/graphene oxide (rGO) membranes with different rGO content (up to 49 wt%) was synthesized. Polyvinyl alcohol acted as a mediator to improve the mechanical stability of membrane layers by crosslinking rGO flakes with hydrogen bonds. The resulting membranes were fully characterized by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, water contact angle and mechanical tests. Pervaporation tests with water/ethanol mixtures (10/90 wt%) at temperatures between 20 and 50 °C demonstrated an excellent selectivity (over 12000) of membranes and satisfactory flux, even at high temperatures. The total permeate flux for membranes varied slightly as a function of operating temperature, demonstrating a good thermostability of the reduced graphene oxide-based membranes. The pervaporation separation index (PSI) of synthesized membrane exceed 5000 and surpassed majority of rGO containing membranes reported in the literature. Results indicate that rGO membranes noncovalently strengthened with PVA are a promising material for selective ethanol dehydration via pervaporation.

Direct Utilization of Pure and Denatured Ethanol in Metal Supported Solid Oxide Fuel Cells

Metal supported solid oxide fuel cells (MS-SOFC) are integrated with high entropy alloy reforming catalyst for direct internal reforming utilization of pure ethanol, methanol, and denatured ethanol to generate electricity. Internal reforming SOFCs have advantages over the external reforming SOFCs in terms of cost, energy efficiency, and space-saving. Performance and durability with denatured ethanol, mimicking the compositions of widely commercially-available bio-ethanol, varies dramatically with the composition of the denaturant. This evaluation of bio-ethanol fuel for SOFC application extends beyond the previous literature focusing on high-purity ethanol. Mitigation of carbon deposition is critical to extend the lifetime of MS-SOFCs operating with ethanol. Conventional Ni catalyst shows rapid carbon deposition, and in contrast the HEA catalyst has excellent resistance to carbon deposition. The HEA also enables complete internal reforming without localized cooling, resulting in high power density >0.8 W/cm2 at 700°C. Long-term operation (500-1000 hours) at the operating temperature of 600-800°C will be presented. Various strategies are applied to improve the cell stability. The effect of impurities and fuel compositions on the cell performance and stability is evaluated. Other degradation factors such as Cr evaporation and catalyst agglomeration are analyzed by SEM-EDS and EIS. It is found that MS-SOFCs are promising for direct utilization of bio-ethanol, offering a path to rapid-start, carbon-neutral operation.

Direct Utilization of Pure and Denatured Ethanol in Metal Supported Solid Oxide Fuel Cells

Metal supported solid oxide fuel cells (MS-SOFC) are integrated with internal reforming catalyst for direct utilization of ethanol to generate electricity. MS-SOFCs are operated up to 500 h at 700°C, with water-ethanol blend fuel using high-purity ethanol and denatured ethanol. Performance and durability with denatured ethanol varies dramatically with the composition of the denaturant. Cells operated with three denatured ethanol fuels containing small amount of methanol, isopropanol, and denatonium benzoate demonstrate similar and relative stable performance after stabilization, suggesting that these fuels are fit for MS-SOFC operation. No or minimum carbon deposits are observed on the high entropy alloy-based reforming catalyst layer. Denatured ethanol containing gasoline and toluene leads to fast degradation. MS-SOFCs are promising for direct utilization of denatured ethanol, offering a path to rapid-start, carbon-neutral operation with widely-available fuels.

Optimized Sieving Effect for Ethanol/Water Separation by Ultramicroporous MOFs.

High-purity ethanol is a promising renewable energy resource, however separating ethanol from trace amount of water is extremely challenging. Herein, two ultramicroporous MOFs (UTSA-280 and Co-squarate) were used as adsorbents. A prominent water adsorption and a negligible ethanol adsorption identify perfect sieving effect on both MOFs. Co-squarate exhibits a surprising water adsorption capacity at low pressure that surpassing the reported MOFs. Single crystal X-ray diffraction and theoretical calculations reveal that such prominent performance of Co-squarate derives from the optimized sieving effect through pore structure adjustment. Co-squarate with larger rhombohedral channel is suitable for zigzag water location, resulting in reinforced guest-guest and guest-framework interactions. Ultrapure ethanol (99.9 %) can be obtained directly by ethanol/water mixed vapor breaking through the columns packed with Co-squarate, contributing to a potential for fuel-grade ethanol purification.

Use of a Reactive Distillation in the Process of Producing Diethyl Ether Using Dewatering of Ethanol

Diethyl ether is considered as one of the simplest and lightest oxygenated fuels, which has higher octane and thermal energy than dimethyl ether. Diethyl ether can be considered as one of renewable fuels and is produced by applying a reactive distillation method. Reaction distillation is a complex process in the chemical industry in which the chemical separation and the chemical reaction are carried out simultaneously. In this paper, applying a high purity ethanol dewatering, the process of reactive distillation in the production of diethyl ether is simulated by using Aspen Hysys software. Different models of activity coefficients have been analyzed in this paper. The best model for molecular diethyl ether was found to be one of the most important cases in simulating a diethyl ether unit to obtain a strong thermodynamic model for highly unrealistic behavior of fluid-liquid-vapor balance in this system. Finally, results of simulation with the data are compared and a very good match has been observed.

Economic, environmental, and exergy analysis of an efficient separation process for recovering low-carbon alcohol from wastewater

Extractive distillation separation is a continuous and effective process for the separation of industrial wastewater components. In this study, a method to recover high-purity ethanol and isopropanol from industrial wastewater via extractive distillation has been proposed. Three enhanced energy-saving processes were developed to reduce the economic costs and environmental impact of distillation processes. The process operation parameters with the best economic performance were obtained based on a sequential iterative optimization method with the total annual cost as the objective function. Results show that, thermally coupled technology can effectively reduce the economic cost. Compared with the conventional extractive distillation process, the total annual cost of the thermally coupled extractive distillation process was the lowest, accounting to a reduction of 33.14%. The heat recovery rate of the heat pump-assisted thermally coupled extractive distillation process was the highest (1979 kW), and the total energy consumption was the lowest (5762.4 kW). The gas emission (2432.72 kg/Y), GWP (1246.42 kg CO2-Eq), AP (2.23 kg SO2-Eq), HTP inf (38.66 kg DCB-Eq), Eco tox (20.04 CTUe), and exergy loss (20.73%) of the heat pump-assisted thermally coupled extractive distillation process were the lowest. This work has important guiding significance for the efficient recovery of low-carbon alcohols from industrial wastewater and promoting cleaner production in the chemical industry.

Self-Assembled Nano-Filamentous Zeolite Catalyst to Realize Efficient One-Step Ethanol Synthesis.

The non-petroleum synthesis route of ethanol from syngas (H2 +CO) with methyl acetate (MA) as the core intermediate product has been confirmed as an excellent industrialization route for high purity ethanol production. However, as the central part of this tandem-catalysis path, the carbonylation of dimethyl ether (DME) to MA is limited by the undesirable catalytic activity and stability of zeolite catalysts. Herein, a facile inhibitor-assisted strategy was developed for constructing self-assembled nano-Mordenite (nano-MOR) zeolites without using any expensive or complex template. A nano-filamentous MOR zeolite with only 70 nm crystal diameter was successfully synthesized by selectively controlling the crystal growth orientation with a specific inhibitor. The catalytic performance of self-assembled nano-MOR catalysts was remarkably outstanding in DME carbonylation reaction. The highest Space-Time Yield (STY) of MA was achieved over Nanofilament MOR (NF-MOR), which was significantly improved comparing with that of the traditional Ellipsoid-MOR (ES-MOR) [3780 mmol/(kg ⋅ h) vs. 1368 mmol/(kg ⋅ h)]. One-step ethanol synthesis was realized by combining the MOR catalyst and an innovative self-reduced Cu-ZnO/SiO2 (CZ/SiO2 ) catalyst in a rationally designed dual-bed catalysis system. Adopting the tailor-made NF-MOR&CZ/SiO2 combination, it obtained the highest STY of ethanol, about 4 times of the conventional ES-MOR&CZ combination [1800 mmol/(kg ⋅ h) vs. 476 mmol/(kg ⋅ h)]. The present self-assembled nano-MOR zeolites synthetic strategy opens a new way for the fabrication of high-performance zeolites for practical industrial applications in catalytic conversions of one-carbon (C1) small molecules to high value-added chemicals.

Sensitivity Analysis of Bioethanol Simulation from Microalgae with Pressure Swing Distillation Process

Energy is an important parameter in the social and economic development of a country. Thus, it is necessary to seek renewable energy to supply energy needs in Indonesia. The production of bioethanol from microalgae as a biofuel is one way to reduce the use of fossil fuels. Microalgae has an advantage over other types of biomass sources due to its high biomass productivity and do not compete with agricultural crops for land and water resources. In the bioethanol production process, the ethanol and water form an azeotrope mixture of 95.6% of ethanol at 1 atm and 78.15°C. The objective of this research was to analyse and determine the operating conditions and the optimum distillation column configuration which results in high ethanol purity according to fuel specifications (fuel grade ethanol). The method of pressure-swing distillation was applied to separate the azeotrope of ethanol-water and obtain high purity ethanol. A simulation model of bioethanol production with pressure-swing distillation system was conducted by using Aspen Plus V10. In this research, the influence of process parameters such as distillation column pressure, reflux ratio, feed stage location, and the number of theoretical stages was analysed by using model analysis tools. The results showed that the obtained bioethanol purity of 99.9% with the condenser and reboiler duty of the LP column -79.931 kW and 667.651 kW, respectively; while the HP column is -47.627 kW and 57.698 kW.

Multi-objective Optimization and Control of Self-Heat Recuperative Azeoropic Distillation for Separating an Ethanol/Water Mixture.

Azeotropic distillation is an important method for the separation of an ethanol/water mixture, while the main disadvantage of azeotropic distillation is its high energy consumption. Since the self-heat recuperation technology can effectively recover and utilize the heat of effluent stream in thermal processes, it is introduced into the ethanol dehydration process. The conventional azeotropic distillation and self-heat recuperative azeotropic distillation (SHRAD) are simulated and optimized with multiple objectives. There exists a design point in the Pareto solution set for which the total annual cost is the lowest, the thermodynamic efficiency is the highest, and the CO2 emission is the least. Based on the specified design, the dynamic characteristics of the SHRAD configuration are studied, and two control structures are proposed. The improved control structure of the SHRAD process works well under the feed flowrate and composition disturbance, and the SHRAD system can obtain a high-purity ethanol product. The results show that the SHRAD process has significant advantages over conventional azeotropic distillation in terms of economic and environmental benefits. In addition, an effective control structure can ensure the stable operation of the SHRAD process.

Simulation study of the production of high purity ethanol using extractive distillation: Revisiting the use of inorganic salts

High purity ethanol can be obtained using extractive distillation with several entrainers; for instance, organic solvents, ethylene-glycol, glycerol, and ionic liquids. However, some of these entrainers are considered toxic; for that reason, in this paper, pilot conventional and dividing wall distillation columns are simulated to test the separation of the ethanol-water mixture using inorganic salts as entrainers for an experimental afterwards evaluation, considering the operational requirements.First, the electrolyte-NRTL model was selected, and the binary interaction parameters were obtained by using reported experimental vapor-liquid equilibrium data. With the selected thermodynamic model, the best operating conditions, of an existing distillation column, are determined by simulation considering several inorganic salts, resulting the calcium chloride as the best option for obtaining high purity ethanol with the lowest energy requirement in the reboiler.Finally, a pilot dividing wall distillation column was simulated for the dehydration process using a mixture of ethanol-water-calcium chloride as entrainer. The results show that it is possible to obtain high purity ethanol (mass purity around 0.99) using the pilot dividing wall distillation column. Also, calcium chloride, with 16% wt in a mixture of ethanol-water, can be reconsidered in extractive distillation processes for the production of high purity ethanol.

Semi-pilot Tests of Ethanol Dehydration using Commercial Ceramic Pervaporation Membranes

Most research efforts about pervaporation in the literature have focused on membrane synthesis, trying to improve the membrane properties (flux and selectivity). However, industrial applications of the pervaporation technology could become attractive if the current available membranes proved to have sufficient and stable performance in order to be integrated in the toolbox of process engineers, as a complementary separation process. In this study, the ethanol dehydration performance of commercial hybrid silica membranes (HybSi®) was assessed in a semi-pilot pervaporation unit from a process-based perspective. The aim of the study is to reveal the high potential of the process and to create a benchmark for future studies in the field. The experimental results revealed that the proposed pervaporation process can efficiently break the ethanol/water azeotrope, allowing the production of high purity ethanol. The overall assessment of the obtained pilot results showed that the proposed process is quite efficient for attracting the industrial interest.

Dehydration – purification of aqueous ethyl alcohol by adsorption over molecular sieves: continuous operation

ABSTRACT Fuel reserves are fast being depleted; hence, alternatives to fossil fuels need to be constantly explored. Ethyl alcohol (ethanol) is an important fuel substitute because it can be blended with the present-day fuels, can be produced via agricultural routes, is comparatively cheap and the technology of production is well known. Fermentation is used to produce dilute (<20 mass %) ethanol, which needs purification. Ethanol forms a minimum boiling azeotrope with water, and hence, advanced distillation methods are employed for purification. Most of these are costly and hence alternative methods of separation are employed: extraction, membrane separation and adsorption. This work has used adsorption for the dehydration – purification of the aqueous mixture of ethanol over various adsorbents. Stainless steel (SS 316 L) column fitted with a sintering plate was employed for adsorption using various adsorbents. Adsorption studies proved that it is possible to obtain high purity (>99.7 mass %) ethanol with molecular sieves. The possibility of continuous operation was successfully demonstrated in this work.

Performance evaluation of different extractive distillation processes for separating ethanol/tert-butanol/water mixture

In this study, a few extractive distillation processes with ethylene glycol as solvent are proposed to separate high-purity ethanol and tert-butanol from industrial effluents, including direct ED, indirect ED and heat pump assisted indirect ED. All these processes are optimized with targeting minimum annual total costs by a sequential iteration algorithm. After that, a head-to-head comparison is completed regarding distributions of cost, energy and CO2 emission. The results showed that the direct ED is the most economical process reducing minimum annual total costs by 30.15 % than the heat-pump assisted indirect ED, while the latter is the most energy-efficient process saving energy consumption and CO2 emissions by 14.78 % and 21.79 % than the direct ED.

Generation of nanoparticles upon mixing ethanol and water; Nanobubbles or Not?

HypothesisThe debate as to whether nanoparticles that are formed upon mixing ethanol and water are nanobubbles or other nanoparticles has continued over the past decade. In this work, we test the hypothesis that long lived bulk nanobubbles are produced upon mixing ethanol and water, using techniques that probe the density and the pressure response of the nanoparticles. ExperimentsNanoparticles were generated spontaneously upon mixing high-purity ethanol and high-purity water. The size distribution of these nanoparticles was obtained using nanoparticle tracking analysis. The mean density of the nanoparticles was determined using resonant mass measurement, and the response of the nanoparticles to the application of external pressure was measured using dynamic light scattering. FindingsThe ethanol-water mixture was found to produce only positively buoyant particles, with a mean density of 0.91 ± 0.01 g/cm3, and the external pressure had only a minimal effect on the size of these nanoparticles. Degassing the solvents before mixing led to a significant reduction in the number of nanoparticles produced. Allowing the solutions to re-gas restored their ability to produce nanoparticles. These experiments reveal that ethanol-water mixing produces nanoparticles that result from the accumulation of material at the interface of dissolving bubbles.

Evaluating the potential of using ethanol/water mixture as a refrigerant in adsorption cooling system by using activated carbon - sodium chloride composite adsorbent

Thermal properties and adsorbent - refrigerants compatibility, influence heat and mass transfer dynamics in adsorption cooling systems (ACS). Activated carbon (AC) + NaCl (10–35.7% w/v) composite adsorbents were paired with either high purity (99.7%) or low-grade ethanol (60% ethanol/ 40% water) refrigerants to assess the potential of ethanol/water mixture as a refrigerant. The ACS with activated carbon-sodium chloride (AC + NaCl) composites adsorbent had a coefficient of performance and specific cooling power of up to 0.091 and 79 W kg−1, respectively, when paired with high purity ethanol, which increased to about 0.146 and 150 W kg−1, respectively, when paired with low-grade ethanol. About 16–25 MJ per cycle was needed for evaporation of refrigerants in AC + NaCl composites adsorbent when paired with the low-grade ethanol, whereas more energy, 27 MJ per cycle, was required to evaporate low-grade ethanol when paired with unmodified AC in ACS. The study has shown that the thermal and mass transfer performances of AC + NaCl composites adsorbents superseded that of unmodified AC providing the potential for low-grade ethanol to be used as a potential alternative refrigerant in ACS especially in areas where pure ethanol is limited.

Extractive Fermentation of Ethanol from Sweet Sorghum Using Vacuum Fractionation Technique: Optimization and Techno-Economic Assessment

Abstract Direct extraction of high purity ethanol from fermentation broth was investigated using a vacuum fractionation technique. Batch and repeated-batch extractive fermentation of ethanol were carried out using concentrated sweet sorghum as a carbon source. The effect of product inhibition was reduced by continuous removing ethanol from the fermented broth. About 60 % relative viability was observed in fermented broth with a higher productivity value. Due to the high value of living cells presented in the medium, repeated-batch extractive fermentation was subsequently performed. The ethanol was continuously fractionated out from the system at the average rate of 10.2 g/h with the concentration of approximately 80 wt%. There were 8 cycles of fermentation using only 1 time inoculation. Nevertheless, the calculated ethanol productivity and relative viability for each fermentation cycle were decreased gradually due to the accumulation of toxic substances in fermented broth. The simulation of 200 liters continuous extractive fermentation system using ASPEN PLUS was studied including process optimization and economical consideration. 18.5 liters of ethanol solutions 82 wt% with insignificant amounts of by-product was produced from a 200 liters extractive fermentation system per day. Production cost including raw material and utilities cost was approximately 0.71 €/liter. The economic and systemic performance process were subsequently analyzed, and including that ethanol loss was recovered using a gas scrubber connected to the vapor exiting the venturi tank as well as in the stillage stream. The calculated utility costs after process modification were 0.5 €/liter of ethanol, approximately 30 % of production cost was reduced.

Simulation and experiment for ethanol dehydration using low transition temperature mixtures (LTTMs) as entrainers

In this work, the separation of ethanol-water azeotrope which was choosing low transition temperature mixtures (LTTMs) as entrainers was investigated through process simulation and batch extractive distillation experiment. Based on the vapor-liquid equilibrium (VLE) curves of ethanol-water with LTTMs and the residual curves of LTTMs-ethanol-water, glycolic acid–choline chloride 3:1(GC3:1) was selected as the entrainer to simulate ethanol-water mixtures separation, and the sensitive analysis was performed in order to determine the main design variables. On this basis, the traditional process was further improved through the optimization of heat exchanger network, and the energy consumption was reduced by 46.24% and 37.00% compared with the ethylene glycol and 1-Ethyl3-methylimidazolium tetrafluoroborate ([EMIM][BF4]), respectively. In addition, GC3:1 was synthesized and used as solvent to separate the mixture of ethanol-water in the batch extractive distillation, which can obtain high-purity ethanol at the top of distillation column. Fourier Transform Infrared Spectrum (FT-IR) was used to analyze the recycled GC3:1, and it suggested that the chemical properties of GC3:1 were stable and GC3:1 could be reused depending on the infrared spectrum of used GC3:1. The advantage of GC3:1 as entrainer for the separation of ethanol-water azeotrope was proved through the combination of process simulation and experiment.

REPLACING SODA ASH (NaOH) WITH KALIUM HYDROXYDE (KOH) IN DESTILATION OF BINARY ETHANOL-WATER MIXTURE

&lt;p class="Default"&gt;Soda ash (NaOH) has been used in bioethanol production in the second step destillation to increase the purity up to 90%. The destillation process will produce waste water with a high sodium content. The soda ash itself serve as an electrolyte to modify the colligative properties of the water-ethanol mixture allowing the disappearance of azeotropic point. This research aims to study the replacement of NaOH with KOH, in which the kalium is a nutrient to maintain soil fertility. This research study the thermodynamics properties, vapor-liquid equilibrium, colligative properties and also its azeotropic point in the destillation of water-ethanol mixture when KOH and NaOH were used as the additive. A model of water-ethanol mixture at a various composition of 0-100 weight % of ethanol was used. The electrolyte addition was 0.1 mol electrolyte/total weight of ethanol-water. The result shows that the addition of electrolyte into ethanol-water mixture eliminate the azeotropic point and allows the ethanol molecules to separate from water. The enthalpy of mixing between water-ethanol is 239.601 kJ/mol. It becomes 259.796 kJ/mol and 264.793 kJ/mol after the addition of NaOH and KOH, respectively. It confirming the endothermic mixing process due to different polarity between water and ethanol. The presence of electrolyte even reduce more their molecular interaction. However, the change to irregularity result a high positive entropy values that result the negative Gibbs free energy. It confirms the spontaneity of mixing. The vaporization enthalpy, H&lt;sub&gt;vap&lt;/sub&gt;, of water-ethanol mixture is 76.229 kJ/mol and it becomes 235.366 kJ/mol and 126.189 kJ/mol after the addition of NaOH and KOH. It indicates that the presence of electrolyte inhibites vaporization of water as the major component and allowing ethanol molecules to vapor producing more high purity ethanol.&lt;/p&gt;

REPLACING SODA ASH (NaOH) WITH KALIUM HYDROXYDE (KOH) IN DESTILATION OF BINARY ETHANOL-WATER MIXTURE

&lt;p class="Default"&gt;Soda ash (NaOH) has been used in bioethanol production in the second step destillation to increase the purity up to 90%. The destillation process will produce waste water with a high sodium content. The soda ash itself serve as an electrolyte to modify the colligative properties of the water-ethanol mixture allowing the disappearance of azeotropic point. This research aims to study the replacement of NaOH with KOH, in which the kalium is a nutrient to maintain soil fertility. This research study the thermodynamics properties, vapor-liquid equilibrium, colligative properties and also its azeotropic point in the destillation of water-ethanol mixture when KOH and NaOH were used as the additive. A model of water-ethanol mixture at a various composition of 0-100 weight % of ethanol was used. The electrolyte addition was 0.1 mol electrolyte/total weight of ethanol-water. The result shows that the addition of electrolyte into ethanol-water mixture eliminate the azeotropic point and allows the ethanol molecules to separate from water. The enthalpy of mixing between water-ethanol is 239.601 kJ/mol. It becomes 259.796 kJ/mol and 264.793 kJ/mol after the addition of NaOH and KOH, respectively. It confirming the endothermic mixing process due to different polarity between water and ethanol. The presence of electrolyte even reduce more their molecular interaction. However, the change to irregularity result a high positive entropy values that result the negative Gibbs free energy. It confirms the spontaneity of mixing. The vaporization enthalpy, H&lt;sub&gt;vap&lt;/sub&gt;, of water-ethanol mixture is 76.229 kJ/mol and it becomes 235.366 kJ/mol and 126.189 kJ/mol after the addition of NaOH and KOH. It indicates that the presence of electrolyte inhibites vaporization of water as the major component and allowing ethanol molecules to vapor producing more high purity ethanol.&lt;/p&gt;