Number Of Theoretical Stages Research Articles

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.

Experimentation and dynamic modeling of batch packed distillation for star anise essential oil purification

ABSTRACT This study focused on dynamic modeling of the essential oil purification process using a batch distillation column and verified with experimental data. Anethole is the main component in the star anise essential oil with an average content of 80–90 wt.%. The effects of feed, pressure, number of theoretical stages, pot liquid holdup, and reflux ratio to product purity were investigated. The results showed that there are agreements between experimental and simulated data of top and bottom temperatures and anethole composition. The higher purity of anethole is obtained when increasing the number of theoretical stages and the reflux ratio and/or decreasing the pot liquid holdup and the condenser pressure. Star anise essential oils from China and Vietnam could be purified up to 98.4 wt.% and 96.4 wt.% of anethole with recovery efficiencies of 95.8% and 87.1%, respectively. The method combining experimental works and modeling could be applied to scale up the production of not only star anise oil but also other essential oils.

Solvent extraction and separation of zinc-iron from spent pickling solution with tri-n-octylamine

Studies on the effective extraction and separation of zinc-iron from spent pickling solution using tri-n-octylamine (TOA) with solvent extraction were investigated. Single extraction efficiency of 83.75% is obtained under the optimal conditions (organic phase consisting of 30% (v/v) extractant TOA, 20% (v/v) modifier iso-octanol, and 50% (v/v) diluent sulfonated kerosene, organic phase volume: aqueous phase volume of 2:1, and extraction time 10 min), while only 1.8% iron is co-extracted. McCabe-Thiele diagram is employed to analyze the number of theoretical stages needed for the effective extraction of zinc, and it is found that under five-stage counter-current extraction, almost all the zinc ions are extracted. A stripping efficiency of more than 90% from the loaded organic phase is achieved by 2.0 mol/L NH3·H2O and organic phase volume: aqueous phase volume of 1:2. Furthermore, the extraction mechanism of zinc with TOA accompanied by anion exchange is demonstrated by FT-IR spectra analysis and ESI-MS analysis, and the structure of the extracted complex is confirmed as [R3NHZnCl3].

A new energy efficient process for hydrogen purification using ZIF-8/glycol–water slurry: Experimental study and process modeling

Effective recovery of hydrogen from refinery off-gas and coke oven gas, in which hydrogen and methane are key components, is increasingly important for the development of hydrogen energy. In this paper, we introduced a new energy efficient process for hydrogen purification from CH4/H2 mixture. Firstly, we conducted a phase equilibrium experimental study for CH4/H2 in zeolitic imidazolate framework-8 (ZIF-8)/glycol–water slurry. The simple absorption and desorption configuration is adopted for the continuous separation of CH4/H2 using ZIF-8/glycol–water slurry. The multi-stage pseudo-absorption modeling approach was introduced for the modeling and simulation of the absorption–adsorption and desorption columns via using multiple flash modules in Aspen Plus. The binary interaction parameters in the thermodynamic model were fitted by experimental data within an acceptable error (4.93%). The operating conditions (i.e., the number of theoretical stages, feed stage, flash pressure, and desorption pressure) were determined to increase H2 concentration in product and H2 recovery ratio. The energy performance of the process was also evaluated. Given the feed gas contains 50 mol% H2, the gas–slurry volume ratio of 43.27 is required to produce 95 mol% H2 with a high recovery of 97.94%. The total energy consumption per unit volume of product is 0.06254 kW·h/Nm3. Results indicate that the hybrid absorption-adsorption process is a promising energy efficient technique to separate CH4/H2 in the future.

Design study of a cryogenic distillation column for hydrogen isotope separation system

This paper presents a design study of a cryogenic distillation column for hydrogen isotope separation. The column was modeled as a theoretical equilibrium-based stage column. Thermodynamic properties were evaluated with the Peng–Robinson Twu equation of state model. The liquid holdup and pressure drop of each theoretical stage were modeled with a general packed column model. The models were implemented in an equation-oriented optimization framework. The effects of parameters such as the number of theoretical stages, feed location, diameter, flow rate of the distillate, and condenser duty on the tritium inventory, total pressure drop, and product quality were investigated. An optimal design that minimizes the total amount of tritium in the liquid holdup under a tritium product quality constraint and non-flooding constraints is presented.

Study of lanthanum-didymium separation by solvent extraction from a liquor conditioned with lactic acid

Rare earth elements (REE) have increased in importance in the world due to the diverse applications in high-tech industries. The fact that Brazil has the world’s second largest REE reserves makes it a potential producer of these elements. However, for that to occur, it is necessary to have knowledge about the production technologies of rare earths, mainly the technologies used in the refining stages, in which China predominates. Generally, the leached solution contains a mixture of REE and the main challenge is to improve selectivity during their separation and purification. For this reason, techniques to improve the efficiency of the separation of these elements have been widely studied in recent years. In the present study, we seek to define efficient routes for the separation of lanthanum (La) from didymium (Pr and Nd) by the solvent extraction technique (SX), using the organophosphorus extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507) from a liquor conditioned with lactic acid. Isotherms were constructed using the McCabe-Thiele method to estimate the number of theoretical stages and the aqueous/organic ratio (A/O) necessary to achieve efficient separation during the process. In continuous solvent extraction experiments, REE recovery percentages and purity of didymium and lanthanum above 90% were obtained. Didymium with 99.9% purity was obtained in a circuit with nine extraction stages (extraction A/O ratio of 4:1) and seven scrubbing stages (scrubbing A/O ratio of 2:1). The results presented here show that the use of lactic acid can be a promising alternative to boost the efficiency of the solvent extraction process for the separation of these light rare earth elements.

A graphical method for the preliminary design of ternary simple distillation columns at finite reflux

The present study proposes a graphical method for the design of ternary distillation systems at finite reflux. Here key design parameters are determined, in particular feed stage location and the number of theoretical stages required for separation at finite reflux for ideal and nonideal systems in simple columns. The procedure provides designers with a visual tool to determine the design parameters simultaneously and no additional calculations are required unlike current approaches. The proposed graphical method correlated to the Fenske-Underwood-Gilliland (FUG) method for ideal systems. The parameters obtained from the proposed graphical allow for implementation in rigorous simulators as starting values to achieve a converged column with the first simulation and less computational difficulty.

Reactive extraction of cis,cis-muconic acid from aqueous solution using phosphorus-bonded extractants, tri-n-octylphosphineoxide and tri-n-butyl phosphate: Equilibrium and thermodynamic study

• The muconic acid extraction by TOPO and TBP have been done firstly in the literature. • Different solvents used to solve TOPO and TBP. • Kinetic studies of the extraction mucconic acid was studied firstly in the literature. cis,cis- Muconic acid falls under the category of carboxylic acids and finds application mostly in biodegradable polymers, agrochemicals, and the food industry. Owing to the high thermal reactivity based upon the two-terminal carboxylic groups present in their structure, the chemical industry has widely used carboxylic acids. The major obstacle encountered during the production of carboxylic acids is their recovery from aqueous solutions and fermentation media. Therefore, the recovery of HccMA by reactive extraction as a particular product capture method, using tri- n -octylphosphine oxide (TOPO) and tri- n -butyl phosphate (TBP) in organic diluents such as 1-butanol, isoamyl alcohol, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisobutyl ketone, isobutanol, n -hexane, dimethyl glutarate, ethyl propionate, and diethyl carbonate (DEC) was executed in this study. This method was experimentally conducted to explore the most proper extractant and diluent combination. Extraction experiments were also conducted with pure diluents alone to examine the extractant effect on the extraction system. The important extraction parameters like distribution coefficient ( K D ), extraction efficiency ( E %), loading ratio ( Z ), dimerization constant ( D ), partition coefficient ( P ), and complexation constant ( K E 11 ) were determined. Mass action law model interpreted the obtained results. For HccMA/TOPO extraction system, the maximum extraction efficiency was found 93.19% in the presence of n -hexane as a diluent. For HccMA/TBP extraction system, the maximum extraction efficiency was found 90.37% in the presence of ethyl propionate as a diluent. Thermodynamic studies at variable temperatures were also carried out to estimate ΔH, ΔS, and ΔG of the process. To investigate the feasibility of designing a counter-current liquid–liquid extraction column, the number of theoretical stages (NTS) were assessed by theodified Kremser equation and found between 3 and 5 to et the desired extraction efficiency.

Solvent Extraction of Boric Acid: Comparison of Five Different Monohydric Alcohols and Equilibrium Modeling with Numerical Methods

Solvent extraction is one of the common methods for the recovery of boric acid (or boron) from aqueous solutions. A wide variety of different compounds including monohydric alcohols has been tested, and there is wide recognition that they are rather ineffective compared to other extractants such as diols. Nevertheless, monohydric alcohols find application in industrial processes, demonstrating their efficiency. The intention of this study is to clarify this discrepancy and to provide an overall picture of monohydric alcohols as an extractant for boric acid. Five different monohydric alcohols are the object of this study: n-octanol, 2-ethyl-1-hexanol, 2-butyl-1-octanol, 2-octanol and 3,7-dimethyl-3-octanol. A special focus of this work is the examination of the effect of the structure of the carbon chain and the effect of the composition of the aqueous phase on the extraction efficiency. As well as the extraction efficiency for boric acid, other important properties are examined such as the viscosity of the organic phase, the solubility of alcohols in the aqueous phase and the co-extraction of salts used as a salting-out agent (NaCl, Na2SO4, MgCl2, LiCl, LiNO3). Finally, a numerical algorithm is developed to calculate the relationship between the number of theoretical stages and the phase ratio at equilibrium for selected extraction systems.

Separation performances of a multi-stage continuous bubble cap foam fractionation column

ABSTRACT A multi-stage continuous bubble cap foam fractionation column was developed to achieve high separation performance using cetyltrimethyl ammonium bromide (CTAB) as a model surfactant. The effect of design and operating parameters on the overall performances was investigated at a steady state. The results illustrated that with increasing the airflow rate, the enrichment ratio of CTAB was decreased and its recovery percentage increased. When the feeding concentration of CTAB was greater than 0.2 g/L, the adsorption of CTAB at the gas-liquid interface was closed to equilibrium. Based on mass balances and equilibrium relationships, a new method of the number of theoretical stages by stage-to-stage calculation and graphics were presented on the foam fractionation column.

Computational design applied to equilibrium-staged and rate-based absorption processes

Simulators are of great interest in Chemical Engineering because they facilitate process optimization and help evaluate different solutions through the so-called �what-if� approach. They include the most advanced thermodynamical models and complete libraries for the calculation of physicochemical properties and estimation of phase equilibria data which are successfully integrated in the process design. Moreover, simulators allow addressing both stationary and batch operations. For this reason, their use in the design of Industrial Chemistry processes has gained much acceptance in the last decades. Even so, simulations should be accompanied by another computational tool which allows the professionals to implement specific algorithms which relate inputs and outputs, so as to get the most out of the computing power. We herein exemplify how Aspen Plus and Mathcad Prime software packages were successfully integrated in a case study on the removal of carbon disulphide by contact with a paraffinic oil in an absorption tower. This absorption operation was studied in both trayed and packed columns. Regarding the first contact type, i.e. trays, Mathcad�s powerful programming tool and graphical interface enabled to corroborate and to better understand the effect of temperature on the number of theoretical stages previously observed with Aspen Plus.

Acetone-Methanol Mixture Separation by Extractive Distillation Using 1-Allyl-3-Methylimidazolium Chloride

Acetone with methanol form a minimum boiling point azeotrope. To separate the mixture components, extractive distillation in the presence of new ionic liquid, 1-allyl-3-methylimidazolium chloride ([Amim]Cl), was assumed. The aim of the present study was the design of an extractive distillation column (number of theoretical stages, position of input stages, reflux ratio) in which acetone with the purity of 99.5 mole % is obtained at the minimum heat duty of the column reboiler. Higher acetone–methanol separation efficiency of [Amim]Cl in comparison with e.g. 1-ethyl-3-methylimidazolium trifluoromethanesulfonate [Emim][triflate] IL was reflected in the resulting parameters of the optimised extractive distillation column: for solvent to feed ratio of 0.42, the number of theoretical stages of the extractive distillation column was 13 and the reflux ratio was 0.1. Heat demand in the reboiler of the extractive distillation column was about four times lower than that in the extractive distillation column employing [Emim][triflate] solvent. Based on the obtained results, [Amim]Cl seems to be a very good solvent for the acetone–methanol azeotropic mixture separation.

Sclareol purification using the supercritical fractionation process: A modeling case study

The aim of this study was to model experimental results obtained for the supercritical CO2 fractionation of a liquid mixture containing 24% of sclareol in order to recover a raffinate with increased sclareol content. First, supercritical CO2 fractionation experiments were carried out at pressures (10–12) MPa, and temperatures (313–338) K. Secondly, the modeling of the raffinate and extract compositions for 12 selected compounds including sclareol was performed using the group method. The modeling was carried out at a temperature of 323 K and pressures of (10–11) MPa, and at a temperature of 338 K and a pressure of 12 MPa. The calculation of the raffinate and extract compositions required the adjustment of the number of theoretical stages and of the distribution coefficients for the selected compounds. Experimental raffinate and extract compositions were represented by the model with a relative error of about 15%.

Design Calculation of the Optimum Number of Stages in a Binary Distillation Column Using Excel Spread Sheet

In this study, distillation, as used in process industries, was explained and the effect of the minimum number of stages in theseparation process in a distillation column was examined. The study looked at the design steps of a binary distillation columnusing the principles of the McCabe and Thiele Method. The Excel software which is cheap, common and can be easily gotten wasused to determine the number of stages and trays. The theoretical number of stages, the actual number of trays and the optimum number of stages in a binary distillation column were calculated using an Excel spreadsheet. The study showed that the minimum number of stages obtained in the specified design were approximately seven, the theoretical number of stages were ten, the actual number of trays were thirteen and the optimum number of stages were twelve for a partial reboiler and a total condenser. Thus a column with fewer than the minimum number of trays, cannot achieve the desired separation, even at very high reflux.

Experimental and Theoretical Study on Sm/Eu-Gd Extraction by P204 and [A336][P204

Extraction of rare earth using ionic liquid as extractant become an alternative practice to replace the common volatile organic solvents in recent years. In general, the work to extract rare earth element, require a large number of extraction stage, and different extractant used resulted in different number of extraction needed. Therefore an analysis on the theoretical number of stages is necessary prior to laboratory work. This study was designed to compare between the number of extraction stages required by 2-ethylhexyl phosphoric acid mono 2-the ester (P204), a common rare earth extractant with a bifunctional ionic liquid, and [A336][P204] in a counter-current extraction process for the separation of Sm in Sm-Eu-Gd mixed solution. The value of the separation factor (β) of both extractants, was obtained from the experimental work, while other process parameters were calculated using the counter-current theory developed by Xu Guangxian. Extraction of Sm using [A336] [P204] was optimum in 3.0 M of nitric acid, with organic to aqueous (O/A) ratio of 4:1, while the optimum condition for P204 was when the medium was 2.0 M of hydrochloric acid and 7:3 of O/A ratio. The β value for the optimized condition for P204 was lower compared to the condition for [A336][P204] at β:1.93 and β:2.81, respectively. To derive an optimum extraction condition to calculate the number of extraction stage, target purity and recovery ratio were set to 99.9% and 90%, respectively, for both extractants. As a result, [A336][P204] was able to reduce the number of extraction stage by 5 compared to P204. The result indicated that [A336][P204] is preferable over P204 from the viewpoint of economic efficiency.

Simulation and Optimization of Isopropyl Lactate Manufacturing Process

The new chemical processes are investigated in laboratory, usually in batch, with pure reactants, and specific laboratory methods applied for the purification of the products. Scaling-up processes means passing from batch to continuous process, using feed with impurificators, industrial equipment for separation and recirculation or purge for an economic operation with special care for safety and environment. This is why, following a study in laboratory for isopropyl lactate obtaining by transesterification in reactive distillation system, a flowsheet of the industrial process was proposed in this paper. Simulations of the transesterification process were performed. The purpose of these simulations has been to find the optimum solution from energy consumption point of view. Optimum parameters of the reactive distillation were found: the molar ratio isopropanol/methyl lactate R= 1.06, the number of theoretical stages in the distillation zone NTS=2.4 and the reflux ratio RR=2, in a process that produces 1.3 t/h IPL of 96% wt purity.

Separation of butanol using natural non-toxic solvents and conventional chemical solvents

Abstract Butanol is a second generation biofuel capable of numerous industrial and non-industrial applications, but, first and foremost, it should be considered as a viable alternative to gasoline. It displays favourable combustion characteristics and, as a fuel additive, it is superior to widely used in replace of conventional petroleum fuels in many aspects (e.g. lower volatility, higher energy content, better miscibility with diesel fuel and gasoline). The present research article focused on separation of butanol using natural non-toxic solvents (Castor oil, Mustard oil, Sesame oil, Almond oil, Eucalyptus oil, Clove oil) and conventional solvents (tri-N-butyl phosphate, Aliquat 336) at 298.15 ± 1 K and evaluation of process parameter as distribution coefficient Kd, separation efficiency %E, diffusion coefficient, minimal S/F ratio and theoretical number of stages respectively. Trend for the average experimental average %E and Kd values was found as eucalyptus oil (83.74%, 5.2) > clove oil (82.85, 4.9) > castor oil (82.5, 4.5) > mustard oil (56.91, 1.4) > sesame oil (56.52, 1.3) > almond oil (54.31, 1.2) for natural extractants and aliquat-336 (93.74, 13) > tri-N-butyl phosphate (87.97, 9) for conventional solvents. Maximum diffusion coefficient was observed for eucalyptus oil.

Effect of boiling point rankings and feed locations on the applicability of reactive distillation to quaternary systems

Reactive distillation (RD) offers major benefits such as costs reduction and energy saving, but the understanding and design of RD processes usually demand complex tasks that include extensive studies and rigorous simulations. To reduce this complexity and the time required, this study applies a novel mapping method to quickly provide insights into the RD applicability to reversible quaternary systems (A + B ⇌ C + D). Generic cases are used to produce applicability graphs (i.e. plots of reflux ratio vs number of theoretical stages) and multiple RD column configurations. The systems are assumed to have ideal properties and fixed key parameters (i.e. relative volatilities and chemical equilibrium constants). This study focuses on quaternary reactions considering different boiling point rankings and feed locations. Using the mapping method, quick results are achievable regarding the preliminary economic ranking of RD processes and the optimal feed locations with reduced energy requirement (i.e. lower reflux ratio). Ultimately, this study provides a much better understanding of the effect of boiling point orders and feed locations on the RD applicability and conceptual design, being a valuable tool in early techno-economic evaluations.

Assessment of the Efficiency of Aliquat 336+Rice Bran Oil for Separation of Acrylic Acid from Aqueous Solution Using Reactive Extraction

Abstract Biomass is an attractive target in process development for the emerging renewable resources based bio-refinery industry. Due to the ample range of application of acrylic acid, its production through bio-route received more awareness in scientific fraternity. In this view, an attempted was made to study the reactive extraction of acrylic acid with aliquat 336 in rice bran oil. Moreover, Box-Behnken matrix was employed to corroborate the effects of process variables viz. concentration of acrylic acid [CAA]aq, concentration of aliquat 336 [CR4N + Cl], and temperature on the extraction efficiency (η%). In physical extraction, average extraction efficiency was found in the order as: 43.55 > 35.36 > 29.14 at 303 K, 323 K, and 343 K respectively in rice bran oil. The correlation coefficient, R2 = 0.988 % indicates the appropriateness of proposed model to predict the extraction efficiency in terms of independent variables, and the predicted values were found in close agreement with that of experimental results. Further, R2 (Pred) = 0.806 is in reasonable agreement with the R2 (Adj) = 0.972. The optimum conditions for extraction of acrylic acid using aliquat 336 as an extractant in rice bran oil are [CAA]aq = 0.0.5 (mol/kg); [CR4N + Cl] = 1.98 (mol/kg); temperature = 323 K and the model predicted extraction efficiency 77.5 % was found to be an excellent fit with the experimental value 75 %. Further, number of theoretical stages was found to be 3 and S/F ratio 0.247.

Study of radon reduction in gases for rare event search experiments

The noble elements, argon and xenon, are frequently employed as the target and event detector for weakly interacting particles such as neutrinos and Dark Matter. For such rare processes, background radiation must be carefully minimized. Radon provides one of the most significant contaminants since it is an inevitable product of trace amounts of natural uranium. To design a purification system for reducing such contamination, the adsorption characteristics of radon in nitrogen, argon, and xenon carrier gases on various types of charcoals with different adsorbing properties and intrinsic radioactive purities have been studied in the temperature range of 190–295 K at flow rates of 0.5 and 2 standard liters per minute. Essential performance parameters for the various charcoals include the average breakthrough times (τ), dynamic adsorption coefficients (ka) and the number of theoretical stages (n). It is shown that the ka-values for radon in nitrogen, argon, and xenon increase as the temperature of the charcoal traps decreases, and that they are significantly larger in nitrogen and argon than in xenon gas due to adsorption saturation effects. It is found that, unlike in xenon, the dynamic adsorption coefficients for radon in nitrogen and argon strictly obey the Arrhenius law. The experimental results strongly indicate that nitric acid etched Saratech is the best candidate among all used charcoal brands. It allows reducing total radon concentration in the LZ liquid Xe detector to meet the ultimate goal in the search for Dark Matter.