Review and Thermodynamic Modeling with NRTL Model of Vapor–Liquid Equilibria (VLE) of Aroma Compounds Highly Diluted in Ethanol–Water Mixtures at 101.3 kPa

A review of the vapor-liquid equilibrium data of aroma compounds highly diluted in hydroalcoholic mixtures at 101.3 kPa is presented. The study includes 44 aroma compounds present in distilled beverages from seven chemical families: acetals, alcohols, carbonyl compounds, carboxylic acids, esters, furans, and terpenes. The equilibrium data are modeled using the ideal gas hypothesis (with a correction term for dimerization in the case of carboxylic acids) and the NRTL model. A set of binary interaction parameters is generated, and the quality of the representation is evaluated. A classification of the aroma compounds in terms of their relative volatility with respect to ethanol and water is proposed over the whole ethanol composition range in the liquid phase. Finally, a comparison with the representation obtained when using interaction parameters calculated from binary and ternary mixture data at high concentrations is performed in order to evaluate the extrapolation capability of the NRTL model

Vapor–Liquid Equilibrium of Ethyl Lactate Highly Diluted in Ethanol–Water Mixtures at 101.3 kPa. Experimental Measurements and Thermodynamic Modeling Using Semiempirical Models

A thermodynamic study of the vapor–liquid equilibrium for the ternary system ethyl lactate–ethanol–water was performed at 101.3 kPa and infinite dilution regarding ethyl lactate, for boiling temperatures ranging from (352.3 to 370.0) K. The experimental measurements were carried out with a recirculation still and the equilibrium compositions of ethyl lactate were determined by gas chromatography. The volatility of ethyl lactate decreases when the ethanol content in the liquid phase is increased. The investigated system was correctly correlated by the NRTL and UNIQUAC models, with an average absolute relative deviation below 10%. The comparison with the results obtained from interaction parameters fitted to experimental data of the binary systems ethyl lactate–ethanol and ethyl lactate–water at 101.3 kPa, proves that the parameters calculated in this work give a better description of the ethyl lactate volatility, a key parameter in distillation, at low concentrations. These latter parameters are therefore recommended for process simulation and optimization in alcoholic beverages production

Simulation of spirits distillation for a better understanding of volatile aroma compounds behavior: Application to Armagnac production

A methodology for the simulation of spirits continuous distillation was developed and applied to the analysis of an Armagnac unit, using the software ProSimPlus®. Distillation data for 66 aroma compounds were acquired during an experimental campaign and 32 of these species were simulated with the NRTL model, using interaction parameters estimated from equilibria data at high dilution. Validation of static simulations against reconciled experimental data showed that the recovery of aroma compounds from wine to distillate can be predicted with good precision. Considering relative volatilities and composition profiles, three main groups of aroma compounds were proposed: (I) light compounds (recovered in distillate), (II) intermediary compounds (distributed between distillate and vinasse) and (III) heavy compounds (recovered in vinasse). After validation of the nominal point, the influence of some operating parameters was investigated. According to simulation, three parameters, namely, tails extractions, ethanol concentration in distillate and distillate temperature, have a real impact on Spirit composition. They permit a preferential reduction of intermediary and heavy species with respect to ethanol. Comparison with experimental and literature data confirms that simulation is a powerful and reliable approach to analyze the synergy between process operation, its performance and Spirit composition

Two industrial examples of coupling experiments and simulations for increasing quality and yield of distilled beverages

The aim of this study was to check the ability of ProSim® software to model both continuous and batch distillations of two specific industrial units in order to obtain both a better understanding of the behaviour of aroma volatile components and a tool to optimise the still's operation. Simulations of multistage continuous distillation to produce neutral spirit from raw alcohol and of batch distillation to produce bitter orange distillate from bitter orange peels macerate were carried out with ProSimPlus and BatchColumn software. Simulations were compared with distillations performed in two industrial plants. For each case, the industrial plants were studied to determine all the operating parameters and the behaviour of certain compounds selected for their high concentration or quality impact. Then, the NRTL and Henry's law thermodynamic models were chosen. Simulation results of particular compositions of the selected compounds in the different extractions were analysed and compared with experimental measurements. Simulations represented faithfully the behaviour of compounds in the industrial plants. Therefore, it was possible for two totally separated cases to illustrate the interest of simulation software; for neutral spirit production to determine new operation set points in order to maximise productivity and improve quality for neutral spirit production and for bitter orange distillate production, to explain the choice of different cuts and the role of the presence of peels during distillation

Bitter orange peel essential oil: A review of the different factors and chemical reactions influencing its composition

International audienceThis review summarizes the findings and discusses the results on the different factors that can influence the bitter orange peel oil composition. Small changes in composition can result in noticeable modifications of the odour profile of the essential oil. The analysis method appears to have a crucial effect on the number of compounds identified in the essential oil. Growing location, cultivar, ripening stage, storage conditions and extraction methods are reported to impact the bitter orange essential oil. Bitter orange peel oil should be stored at -21 degrees C to prevent changes in the composition and formation of artefacts when storing for a period of several months. The influence of cultivars should not be neglected, since a few cultivars differ a lot from the main cluster of Citrus aurantium L. The geranyl pyrophosphate forms most of the terpenes present in the bitter orange, especially limonene which is the majority compound, by the action of the terpene synthases during growing of the fruit. The extraction method can also be responsible for some differences in the composition due to the absence of water-soluble compounds in cold-pressed oils and to acid-catalysed reactions in hydrodistilled oils such as the decomposition of the linalyl acetate forming many different terpene derivatives

Reducing energy requirement for drying of beet-pulp: Simulation of energy integration between superheated steam and air drying systems

Beet-pulp dehydration in the sugar industry is a highly energy intensive unit operation. Producing 1kg of dried beet-pulp requires approximate to 2-3kg of water to be removed. The cost saving is a real challenge in sugar factory as the current dryers are underperforming (around 3MJ/kg of water evaporated) because the heat recovery is limited and only a small proportion of dryer exhaust can be reused. The aim of this study was to investigate by simulation the energy efficiency of an independent multistage drying method that combines superheated steam drying (SHSD) and hot air drying (AD). Two case studies awarding the two types of energy coupling (AD then SHSD or SHSD then AD) are presented and compared. An approach of optimization is developed from energy balance. A number of operating parameters of the two drying configurations are investigated using sensitivity analysis. It proves that both cases allow an energy economy around 40% compared to the conventional dryer. Nevertheless, the SHSD-AD plant may present more benefits for a better quality product

Computer-aided process engineering for environmental efficiency: industrial drying of biomass

The idea of taking into account environmental impact criteria in the process design becomes a necessity for both the industry and governments, due to increased binding regulations. Moreover, to address the issue of integrating sustainable processes, environmental impact must be weighed and balanced against other concerns, such as economic performance, product quality, and long-term sustainability. Therefore, this study introduces a methodology for environmental impact minimization and optimization of multiple conflicting criteria. A general eco-design method for biomass drying process is proposed. The main target is to develop an assessment computer-aided process engineering tool that compares environmental impacts of different operating conditions and fuel types to support decision-makers for an improved compliance to environmental criterion and sustainability

Generation and thermodynamic modelling of vapour-liquid equilibrium data for aroma compounds in hydroalcoholic mixtures - Application to the simulation of spirits distillation units

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A concept and industrial testing of a superheated steam rotary dryer demonstrator: Cocurrent-triple pass design

International audienceThis study aims to provide a pertinent demonstration of the feasibility of superheated steam drying (SHSD) at industrial demonstrator scale. The dryer is of co-current, direct contact, and triple pass rotary type. The dryer is designed to operate under pressure (up 2 bar abs.) and at high temperatures (up 600 degrees C). Given the operating conditions of pressure and temperature, the control and the instrumentation of the dryer were the subjects of a special study to ensure safe tests and measurements. The demonstrator was manufactured and set-up on an industrial site. Drying experiments on pressed beet pulp are being carried out. At the end of this study, we hope to show first results to demonstrate the drying feasibility and also to provide relevant data concerning the operation of SHSD

Batch distillation of spirits: experimental study and simulation of the behaviour of volatile aroma compounds

International audienceThis paper focuses on the behaviour of volatile compounds during batch distillation of wine or low wine, in traditional Charentais copper stills, heated with a direct open flame at laboratory (600 L) and industrial (2500 L) scale. Sixty-nine volatile compounds plus ethanol were analysed during the low wine distillation in the 600 L alembic still. Forty-four were quantified and classified according to their concentration profile in the distillate over time and compared with previous studies. Based on the online recording of volume flow, density and temperature of the distillate with a Coriolis flowmeter, distillation was simulated with ProSim (R) BatchColumn software. Twenty-six volatile compounds were taken into account, using the coefficients of the 'Non-Random Two Liquids' model. The concentration profiles of 18 compounds were accurately represented, with slight differences in the maximum concentration for seven species together with a single compound that was poorly represented. The distribution of the volatile compounds in the four distillate fractions (heads, heart, seconds and tails) was well estimated by simulation. Finally, data from wine and low wine distillations in the large-scale alembic still (2500 L) were correctly simulated, suggesting that it was possible to adjust the simulation parameters with the Coriolis flowmeter recording and represent the concentration profiles of most of the quantifiable volatile compounds