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Limitations regarding process design, optimization, and control often occur when using particular process simulators. With the implementation of connection methodologies, integrated tools could be made by coupling popular process simulation software with each other or with programming environments. In the current paper, we summarized and categorized the existing research regarding the application of multi-software engineering in the chemical industry, with an emphasis on software connections. CAPE-OPEN, COM, OPC, and native integration were discussed in detail, with the intention to serve as a guide for choosing the most suitable software combination and connection. These hybrid systems can handle complex user-defined problems and can be used for decision support, performing custom unit operations, operator training, process optimization, building control systems, and developing digital twins. In this work, we proposed the use of process simulator Aspen HYSYS linked together with the numeric computing platform MATLAB to solve a reaction kinetic parameter identification problem regarding the production of γ-valerolactone.

γ-valerolactone can be a game-changer in the chemical industry because it could substitute fossil feedstocks in different fields. Its production is from the hydrogenation of levulinic acid or alkyl levulinates and can present some risk of thermal runaway. To the best of our knowledge, no studies evaluate the thermal stability of this production in a continuous reactor. We simulated the thermal behavior of the hydrogenation of butyl levulinate over Ru/C in a continuous stirred-tank reactor and performed a sensitivity analysis. The kinetic and thermodynamic constants from Wang et al.’s articles were used. We found that the risk of thermal stability is low for this chemical system.

The current work studies the reductive catalytic depolymerization (RCD) of lignin from a novel semi-industrial process. The aim was to obtain aromatic mono-, di-, tri-, and tetramers for further valorization. The substrate and products were characterized by multiple analytical methods, including high pressure size-exclusion chromatography (HPSEC), gas chromatography-mass spectrometry, GC-flame ionization detector (FID), GC-FID/thermal conductivity detector (TCD), and NMR. The RCD was studied by exploring the influence of different parameters, such as lignin solubility, reaction time, hydrogen pressure, reaction temperature, pH, type and loading of the catalyst, as well as type and composition of the organic/aqueous solvent. The results show that an elevated temperature, a redox catalyst, and a hydrogen atmosphere are essential for the depolymerization and stability of the products, while the reaction medium also plays an important role. The highest obtained mono- to tetramers yield was 98% and mono- to dimers yield over 85% in the liquid phase products. The reaction mechanisms influenced the structure of the aliphatic chain in the monomers, but left the phenolic structure along with the methoxy groups largely unaltered. The current work contributes to the development and debottlenecking of the novel and sustainable overall process, which utilizes efficiently all the fractions of wood, in line with the principles of green engineering and chemistry.

The solvent is of prime importance in biomass conversion as it influences dissolution, reaction kinetics, catalyst activity and thermodynamic equilibrium of the reaction system. So far, activity-based models were developed to predict kinetics and equilibria, but the influence of the catalyst on kinetics has not been succesfully predicted by thermodynamic models. In this work, the thermodynamic model ePC-SAFT advanced was used to predict the activities of the reactants and of the catalyst at various conditions (temperature, reactant concentrations, γ-valerolactone GVL cosolvent addition, catalyst concentration) for the homogeneously acid-catalyzed esterification of levulinic acid (LA) with ethanol. Different kinetic models were applied, and it was found that the catalyst influence on kinetics could be predicted correctly by simultaneously solving the dissociation equilibrium of H

The aim of this project is to find an appropriate mode for green sustainable manufacturing and production. Thus, the concept of this model encourages the development of synergy and leverage of resource networks in order to reduce waste and pollution, and to share resource efficiently. To the best of our knowledge, there is currently no other general mathematical model for designing and optimizing exchange material/energy flows in an industrial park. The purpose of this work is to propose a relative advanced dynamic multi-objective model. Simulations have been performed by using the NIMBUS (Nondifferentiable Interactive Multi-objective Bundle-based optimization System) method. This model can assure a win-win situation for industries and environment.

The synthesis of γ-valerolactone (GVL), a platform molecule that can be produced from lignocellulosic biomass, was performed in this work by hydrogenation of an alkyl levulinate over Ru/C. Kinetic models reported in the literature are typically not compared with rival alternatives, even if a discrimination study is needed to find the optimum operating conditions. Different surface reaction kinetic models were thus considered in this work, specifically addressing hydrogenation of butyl levulinate to GVL, where the latter was used as a solvent to minimize potential solvent interference with the reaction, including its evaporation. The Bayesian approach was applied to evaluate the probability of each model. It was found that non-competitive Langmuir-Hinshelwood with no dissociation of the hydrogen model has the highest posterior probability.

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A rigorous mathematical model was developed for a complex liquid–liquid–solid system in a batch reactor. The approach is general but well applicable for the indirect epoxidation of vegetable oils according to the concept of Nikolaj Prileschajew, implying in situ prepared percarboxylic acids as epoxidation agents. The model considers intra- and interfacial mass transfer effects coupled to reaction kinetics. The liquid phases were described with chemical approach (aqueous phase) and a reaction–diffusion approach (oil phase). The oil droplets were treated as rigid spheres, in which the overall reaction rate is influenced by chemical reactions and molecular diffusion. The model was tested with a generic example, where two reactions proceeded simultaneously in the aqueous and oil phases. The example (i.e., fatty acid epoxidation) illustrated the power of real multiphase model in epoxidation processes. The proposed modeling concept can be used for optimization purposes for applications, which comprise a complex water–oil–solid catalyst system.

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International audience; The use of lignocellulosic biomass in the chemical industry has increased due to its non-competition with the food sector. Several platform molecules can be produced from this biomass. Among them, levulinic acid and its esters have been produced on an industrial scale. There are some reviews on the production of levulinic acid (LA) but few on the production of levulinates (LEs). To fill this gap, this review was written by also considering the environmental aspects. In the first stage, recent progress in the production of these platform chemicals was discussed. Production processes of alkyl levulinates from levulinic acid esterification, precursors (HMF, furfural, etc.), sugar monomers (glucose, fructose, etc.), cellulose, hemicellulose, or cellulose directly from lignocellulosic biomass were described. In the second stage, process separation and purification of LA and LEs were discussed. The final stage proposed an economic and environmental consideration for the production of these chemicals.

The production of platform molecules from the valorization of lignocellulosic biomass is increasing. Among these plateform molecules, γ-valerolactone (GVL) is a promising one and could be used for different industrial applications. This molecule is synthesized from levulinic acid (LA) or alkyl levulinates (AL) through a tandem hydrogenation/cyclization (lactonization) cascade. A lot of investigations have been carried out to develop the best catalyst for the hydrogenation step by using solely LA or AL. However, one should keep in mind that in the AL production via fructose alcoholysis, there is also LA production, and both are present in the product mixture during the further conversion. To the best of our knowledge, no article exists describing the hydrogenation of LA and AL simultaneously in one-pot. Also, the literature reporting the use of solid catalyst for the second cyclization step is rare. To fill this gap, the hydrogenation of levulinic acid and butyl levulinate was studied over Ru/C and Amberlite IR-120. Several kinetic models were evaluated via Bayesian inference and K-fold approach. The kinetic assessment showed that a non-competitive Langmuir-Hinshelwood with no dissociation of hydrogen where LA, BL and H2 are adsorbed on different sites (NCLH1.2) and non-competitive Langmuir-Hinshelwood with dissociation of hydrogen where LA, BL (butyl levulinate) and H2 are adsorbed on different sites (NCLH2.2) are the best model to describe this system. The presence of LA and Amberlite IR-120 allows to increase the kinetics of cyclization steps, and in fine to accelerate the production of GVL.

Xylan obtained from birch (betula pendula) by a novel semi-industrial scale aqueous based method was used for studying the hydrolysis and consecutive hydrolysis-hydrogenation processes in continuous reactors. Dowex 50WX2-100 was chosen as the hydrolysis catalyst based on the results of catalyst screening performed previously in batch reactor. It was also observed to perform well in continuous reactor converting xylan to xylose in high yield under the studied reaction conditions. The influence of several reaction parameters were investigated for optimization. Similar experimental conditions used in the hydrolysis were then applied for studying one flow through hydrolysis and hydrogenation of the semi-industrial xylan. A consecutive catalyst bed consisting of ruthenium on carbon was introduced into the continuous reactor downstream from the hydrolysis bed to hydrogenate monosaccharides to xylitol. Hydrogen was co-fed into the reactor with the xylan solution. Reaction parameters, including temperature, residence time and hydrogen pressure, were varied to maximize the xylitol yield. The developed continuous process was demonstrated to be highly selective and efficient for the valorization of the semi-industrial xylan by yielding over 90% xylitol under optimal experimental conditions. It was noticed, that co-feeding hydrogenation decreased the degradation of monosaccharides during hydrolysis, thus improving the selectivity towards the target product and enabling remarkable process intensification. Moreover, mathematical modelling was performed for the hydrolysis and one flow through hydrolysis and hydrogenation processes. The models take into account the consecutive reaction pathways and the influence of the experimental conditions. Good fits of the model to the experimental data were obtained. The conversion of this novel, well characterized wood-based xylan to produce xylose or xylitol in continuous reactors has not been studied previously. The current work contributes significantly to understanding the processing of real feedstock in one flow through employing consecutive reactions and provides necessary data for process intensification.

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International audience; The use of hydrogen peroxide as an oxidizing agent becomes increasingly important in chemistry. The example of vegetable oil epoxidation is an excellent illustration of the potential of such an agent. This reaction is traditionally performed by Prileschajew oxidation, i.e., by the in situ production of percarboxylic acids. Drawbacks of this approach are side reactions of ring-opening and thermal runaway reactions due to percarboxylic acid instability. One way to overcome this issue is the direct epoxidation by hydrogen peroxide by using γ-alumina. However, the reaction mechanism is not elucidated: does hydrogen peroxide decompose with alumina or oxidize the hydroxyl groups at the surface? The kinetics of hydrogen peroxide consumption with alumina in homogeneous liquid and heterogeneous liquid-liquid systems was investigated to reply to this question. Bayesian inference was used to determine the most probable models. The results obtained led us to conclude that the oxidation mechanism is the most credible for the heterogeneous liquid-liquid system.

A cyclic Ti32-oxo-cluster (CTOC)/BaTiO3/CuS three-layer heterojunction material that can effectively use visible light and vibration energy for photo-piezoelectric synergistic catalytic degradation of pollutants was synthesized by hydrothermal and ultrasonic methods. Under the conditions of visible light irradiation and mechanical vibration, the three-layer nanomaterial showed a tetracycline decomposition rate that reached ∼100 % within 60 min, which is higher than the degradation rate of 55.67 % and 45.2 % found for photocatalysis and piezoelectric catalysis, respectively. The piezoelectric material BaTiO3 inserted between the p-type CuS and the n-type CTOC can generate a polarized electric field under the action of an external force to promote the separation and migration of photo-generated carriers of the photocatalytic material, and achieve photo-piezoelectric synergistic catalysis effect. This work demonstrates the feasibility of combining photocatalytic technology with a piezoelectric effect, and provides a promising strategy for the development of photocatalytic materials.

A rigorous mathematical model was developed for a complex liquid-liquid-solid system in a batch reactor. The approach is general but particularly well applicable for the indirect epoxidation of vegetable oils according to the concept of N. Prileschajew. The model considers intra- and interfacial mass transfer effects coupled to the reaction kinetics. The liquid phases were described with chemical approach (aqueous phase) and a reaction-diffusion approach (oil phase). The oil droplets were treated as rigid spheres, in which the overall reaction rate is influenced by chemical reactions and molecular diffusion phenomena. The model was tested with a generic example, where two reactions proceeded simultaneously in the aqueous and oil phases. The example (i.e. fatty acid epoxidation à la Prileschajew) illustrated the power of the real multiphase model in epoxidation processes. The proposed modelling concept can be used for optimization purposes for many applications, which comprise a complex water-oil-solid catalyst system.

International audience; The epoxidized group, also known as the oxirane group, can be considered as one of the most crucial rings in chemistry. Due to the high ring strain and the polarization of the C–O bond in this three-membered ring, several reactions can be carried out. One can see such a functional group as a crucial intermediate in fuels, polymers, materials, fine chemistry, etc. Literature covering the topic of epoxidation, including the catalytic aspect, is vast. No review articles have been written on the catalytic synthesis of short size, intermediate and macro-molecules to the best of our knowledge. To fill this gap, this manuscript reviews the main catalytic findings for the production of ethylene and propylene oxides, epichlorohydrin and epoxidized vegetable oil. We have selected these three epoxidized molecules because they are the most studied and produced. The following catalytic systems will be considered: homogeneous, heterogeneous and enzymatic catalysis.

Substitution of fossil feedstock by vegetable oils is growing due to environmental constraints and oil depletion. Among the different valorization routes for vegetable oils, epoxidation of their unsaturation is widely used. The epoxidation is an exothermic reaction which could lead to a thermal runaway. There are different routes for the vegetable oil epoxidation: Prileschajew by performic and peracetic acid, which are the most used. Another promising alternative is the direct epoxidation by hydrogen peroxide by alumina. The goal of this manuscript is to rank the thermal risk of these three epoxidation routes by determining the safety parameter time to maximum rate under adiabatic condition. The Advanced Reactive System Screening Tool was used to conduct these experiments. It was found that the direct epoxidation is safer than the two other routes.

International audience; Biomass valorization to chemicals, biofuels or materials will be more and more important during this century. Production of γ-valerolactone (GVL) from the hydrogenation of levulinic acid is a good illustration of this tendency. GVL can also be produced from alkyl levulinates hydrogenation. Can we find a relationship between the structure and the kinetics of this reaction? Can we predict the kinetics of any alkyl levulinates by knowing the kinetics of another alkyl levulinate? This paper has studied these two questions by developing a kinetic model including the effect of gas-liquid mass transfer. We have demonstrated that the kinetics of hydrogenation of levulinic acid, methyl, ethyl and butyl levulinates to GVL using Ru/C follow the Taft equation, which is derived from Linear Free Energy Relationships. This equation measures the effects of polar and steric on a reaction series. We have demonstrated that polar effect of the reaction series is the most significant effect. This relationship can predict the values of kinetic constants just by knowing their structure.

International audience; Epoxidation of oleic acid by peracetic acid (PAA) was studied in a recycled reactor system under conventional heating and microwave irradiation. This reaction system consists of several steps. Thus, a kinetic modelling strategy to diminish the number of parameters to be estimated was developed by investigating each reaction step: PAA synthesis and decomposition, epoxidation and ring-opening. The energy balance for microwave heating was correlated with the concentration of the microwave-absorbent species and the total input power of the microwaves. The epoxidation reaction was conducted in the vigorously stirred tank reactor under isothermal conditions within a temperature range of 50–70 °C. The organic phase content was 32–45% v/v. The interfacial mass transfer was supposed to be faster than the intrinsic reaction kinetics suppressing the use of mass transfer correlations. Nonlinear regression was used to estimate the kinetic parameters. Two models were developed for microwave and conventional heating respectively. The perhydrolysis showed to be the slowest reaction, followed by the epoxidation and the ring-opening. The use of microwave irradiation resulted in considerable process intensification for the epoxidation process. By employing microwave heating, the perhydrolysis step in the aqueous phase was enhanced, and the reaction time was reduced by 50% in best cases, which implies that the reactor size can be diminished by microwave technology.

International audience; Vegetable oils are renewable biomass that can substitute fossil raw materials for sustainable development. These oils are made of different types of fatty acids (building blocks), which could lead to differing reactivity toward chemical reaction. In order to investigate the correlation between reactivity and structure of vegetable oils, we have compared the reactivity of epoxidized cottonseed oil (ECSO) and its epoxidized fatty acid methyl ester (EFAME) toward carbonation reaction by using the homogeneous catalyst tetrabutylammonium bromide (TBABr). Mass transfer and physicochemical properties were determined and further applied to estimate the intrinsic rate constants during the kinetic modeling stage. It was found that densities for both systems were similar, but the difference in viscosity was important. Mass transfer coefficients were similar for the carbonated species, but the ones of EFAME and FAME were found to be ca. 100 times lower than those of ECSO and CSO. The solubility of CO2 was found to be higher in FAME derivatives than in CSO derivatives. We have found that the rate constant of carbonation of EFAME can be 1.4 times higher than the one of ECSO. A linear relationship between the carbonation rate constant of epoxidized vegetable oil and its fatty acid methyl ester with temperature was found.

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International audience; The use of lignocellulosic biomass in the chemical industry can significantly contribute to respect the various international agreements on climate change. One of the most promising platform molecules issued from the lignocellulosic biomass hydrolysis is γ-valerolactone (GVL). GVL can be upgraded to valuable chemicals and produced by the hydrogenation of alkyl levulinates. Although these reactions are widely studied, seldom research focused on the solvent effect. To fill this gap, the effect of three different reaction mixtures with an excess of butyl levulinate (BL), of butanol and GVL was studied on the kinetics of BL hydrogenation to GVL over Ru/C. PC-SAFT (Perturbed-Chain Statistical Associating Fluid Theory) shows that the solubility of hydrogen is not constant during the reaction progress, and it was taken into account. To allow a fair comparison, kinetic models were developed using Bayesian statistics for each reaction mixture. The best performances were obtained when the reaction mixture has an excess of GVL.

International audience; The development of a bio-based economy has its foundations in the development of efficient processes to optimize biomass potential. In this context there are a multitude of molecules that can be either synthetized or recovered from biomass, among those the so-called 12 building-blocks reported by the US Department of Energy. Even if their identification and importance is clearly defined, research efforts concerning the purification or separation of these platform molecules are limited. To fill this gap, different configurations for the purification of levulinic acid recovered from lignocellulosic biomass are examined and compared in this work. In particular, hybrid configurations obtained by the combination of liquid-liquid extraction and distillation have been considered. It was demonstrated how a deep understanding of the subspace including all extraction-assisted simple column distillation configurations represents a fundamental step in the synthesis of different process alternatives. From a separation efficiency and economic standpoint, the proposed intensified liquid-liquid thermally equivalent configuration (LL-TE) and liquid-liquid side stream column configuration (LL-SSC) are promising solutions. Nonetheless, their performances are deeply interrelated to the purity target defined by the designer.

Polyurethane polymer is more and more famous because of its versatile properties. The current production process requires the use of isocyanate, which is a hazardous chemical. An alternative eco-friendly route of production is the aminolysis reaction between a cyclic-carbonate, from carbonated vegetable oil, and a diamine. Nevertheless, the kinetics of this reaction system is slow, which might be due to steric hindrance. In order to predict and evaluate this steric hindrance, different amines were tested for the aminolysis of carbonated methyl oleate. Four amines were used: n-butylamine, methylbutylamine, ethylbutylamine and dibutylamine. Kinetic models for the aminolysis with each amine were developed. A relationship between structure and reactivity of each substituent was found through the concept of Linear Free Energy Relationships.

International audience; The use of lignocellulosic biomass as a raw material can sustain the chemical industry. There is a lack of knowledge in kinetics and thermodynamics of some of these processes, making difficult the cost analysis. For instance, the thermodynamic investigation of the hydrogenation of alkyl levulinates to γ-valerolactone (GVL) is seldom. This system is a two-step reaction comprising a hydrogenation and cyclization step. The experimental measurement of the two reaction enthalpies is challenging, and a method was developed in this manuscript. The hydrogenation of methyl levulinate (ML) and butyl levulinate (BL) in the GVL solvent was found to be an exothermic step, and the cyclization an endothermic one. The reaction enthalpy for the hydrogenation of ML in the GVL solvent, calculated to -53.25 kJ/mol, is higher than the one of BL in the GVL solvent, calculated to -38.66 kJ/mol. The reaction enthalpies for the cyclization step are similar for ML and BL system, i.e., +7.00 kJ/mol and +6.50 kJ/mol, respectively. Hence, the hydrogenation step governs the reaction temperature. A thermal risk assessment based on experiments performed under adiabatic condition was done. The thermal risk was found to be medium for this reaction system under the operating conditions used in this study.

Heterogeneous catalysts are widely used in the chemical industry. Compared with homogeneous catalysts, they can be easily separated from the reaction mixture. To design and optimize an efficient and safe chemical process one needs to calculate the energy balance, implying the need for knowledge of the catalyst&rsquo, s specific heat capacity. Such values are typically not reported in the literature, especially not the temperature dependence. To fill this gap in knowledge, the specific heat capacities of commonly utilized heterogeneous catalytic supports were measured at different temperatures in a Tian&ndash, Calvet calorimeter. The following materials were tested: activated carbon, aluminum oxide, amberlite IR120 (H-form), H-Beta-25, H-Beta-38, H-Y-60, H-ZSM-5-23, H-ZSM-5-280, silicon dioxide, titanium dioxide, and zeolite 13X. Polynomial expressions were successfully fitted to the experimental data.

Highlights • Greener and safer production of epoxidized vegetable oil. • Positive effect of semibatch operation on the reaction performance. • Kinetic modelling based on plausible mechanism for the alumina catalyzed epoxidation., Heterogeneously catalyzed epoxidation of vegetable oils by hydrogen peroxide represents a greener route for the production of epoxides and a thermally safer reaction route compared to the classical Prileschajew epoxidation approach. The epoxidation kinetics of the heterogeneous system formed by aluminium oxide catalyst, hydrogen peroxide and methyl oleate as a model compound was studied with semibatch experiments in laboratory scale. It was found that semibatch operation improved the performance significantly compared to classical batch operation, a low and constant volumetric flowrate of hydrogen peroxide increased the final oxirane yield considerably. A semibatch reactor model and a kinetic model were developed, featuring the reaction temperature, the reactant molar ratio, the catalyst loading and the mass flow rate as the most significant experimental parameters. The mathematical model was able to well describe the experimental data. The approach can be applied to other liquid–solid catalyst systems in future in order to optimize the semibatch operation policy for complex reaction systems.

International audience; Tall oil fatty acids (TOFA) are a byproduct from the Kraft pulping process, and they represent a renewable and inexpensive alternative with high potential as a renewable feedstock. Epoxidized TOFA have great potential as chemical intermediates. Epoxidation of oleic acid, TOFA, and distilled tall oil (DTO) was conducted in an isothermal batch reactor with in situ-formed peracetic acid using hydrogen peroxide as the reactant and acetic acid as the reaction carrier. Amberlite IR-120 was used as the solid heterogeneous catalyst. The catalyst loading effect, the reactant ratios, the reaction temperature (40–70 °C), and the influence of microwave irradiation on epoxidation and ring opening were studied. The application of microwave irradiation resulted in an improvement of the epoxidation rate in the absence of the catalyst. Lower product yields were obtained for the epoxidation of DTO than for TOFA because of the higher viscosity and high content of rosin acids which presumably promoted ring opening reactions. At higher temperatures, the selectivity to oxirane decayed due to ring opening. Titration analysis and NMR analysis confirmed that microwave irradiation induces the ring opening reactions for TOFA epoxidation, and it accelerates this process for DTO. The rapid nature of the microwave heating might have unchained a series of ring opening reactions between neighboring oxirane groups and with the nucleophilic agents in the reaction mixture.

The use of biomass, particularly, a second generation one, as a renewable raw material is crucial to sustain the chemical industry. To favor the development of such processes, one needs to make a cost evaluation, which requires the knowledge of process thermodynamics and kinetics. In this paper, measurements of different physicochemical properties (viscosity, density, refractive index, and specific heat capacity) were done for the systems: hydrogenation of levulinic acid or its esters to γ-valerolactone. From those physicochemical measurements, it was possible to extract the ones of the intermediates and perform a thermodynamic model assessment by using Aspen Plus. It was found that the Hysys Redlich−Kwong−Soave cubic equation of state and Benedict−Webb−Rubin−Starling virial equation of state are suitable to describe these chemical systems.

Phosphoric acid, a non-renewable chemical, is used in different industries. Production of this chemical from natural phosphate can be done by two routes: wet process and thermal process. The nature of the natural phosphate, i.e., its chemical composition, plays an important role in the kinetics and thermodynamics of phosphoric acid production. Thus, the establishment of a kinetic model, based on reaction mechanism, for the dissolution of natural phosphate is cumbersome due to the presence of impurities. Besides, one should use an online analytical method because the dissolution reaction is fast. The dissolution of two natural phosphates with different percentages of phosphorus pentoxide (P2O5), phosphate samples (28 mass% of P2O5) from Gafsa region (Tunisia) and phosphate samples (18 mass% of P2O5) from Cheketma-Kasserine region (Tunisia), was studied from a kinetic and thermal aspect. Experiments were performed by using a Tian—Calvet calorimeter. Two acid solutions were used for the dissolution: one with phosphoric acid (S1) and the other a mixture of phosphoric and sulfuric acid (S2). For both natural phosphates, it was found that in case of using S1 solution the heat released due to the dissolution was lower than in case of using solution S2. This difference was explained by the precipitation of monohydrate sulfate calcium to its dihydrate form. By using a granulometry distribution lower than 500 μm, heat released during the dissolution of both phosphates by S1 was similar, i.e., − 230 J g−1, and the same observation was done by using S2 solution, i.e., between − 300 and − 350 J g−1. We have demonstrated that granulometry distribution plays an important role, and by using a granulometry lower than 120 μm for Cheketma-Kasserine region phosphate, the heat released during the dissolution was higher, i.e., − 400 J g−1 with solution S2. Avrami model was found to describe the precipitation of calcium sulfate, and three distinguished domains were obtained by using Gafsa region phosphate compared to two domains with Cheketma-Kasserine region phosphate.

The influence of inlet parameters on the production and thermal risk of complex chemical systems can be cumbersome to evaluate. To determine the optimum safe operating conditions, one needs to solve complex differential equations derived from energy and material balances. This robust approach cannot be made on-site, and it is essential to propose simplest tools to evaluate rapidly the performance and safety of some operating conditions. This is the aim of this paper that establishes explicit relationships between the production and thermal risk parameters, and the inlet parameters. In addition, it also proposes a Pareto chart that can be used to make the tradeoff between safety and performance. Such relationships and chart were developed for the production of epoxidized cottonseed oil under isoperibolic and semi-batch mode. The kinetic model developed by Zheng et (Zheng et al., 2016). was used. First, a numerical approach, i.e., least square method, was used to find explicit relationships between thermal risk parameters, production parameters and six inlet parameters. The use of such an approach allows a better understanding of this process. Second, safety and performance indicators are proposed and discussed to evaluate the operating conditions thanks to a simple and intuitive schema. Besides, this approach can be used to find the optimum conditions more rapidly.

International audience; Fossil depletion and global warming have pushed industrial and academic communities to rethink the present way of consumption by diminishing waste and by using renewable raw materials. For this reason, several research programs are focused on the valorization of biomass and carbon dioxide. To promote the use of these feedstocks in industrial scale, kinetic and thermodynamic data are needed for a better energy integration and cost optimization. Industrial production of methanol, urea and inorganic carbonate from carbon dioxide should be used as examples. A kinetic model including mass transfer phenomena for the carbonation of epoxidized cottonseed oil was proposed. We observed that the absorption rate of CO2 increases in the following order: cottonseed oil (CSO)> epoxidized cottonseed oil (ECSO)> carbonated cottonseed oil (CCSO), which was confirmed by our model. For liquid temperature exceeding 120 °C, the Henry’s coefficients increase in the following order: HeCCSO > HeCSO ⩾ HeECSO. Kinetic experiments were conducted at different temperatures (110–140 °C), catalyst tetra-n-butylammonium bromide (TBABr) concentrations (0.06–0.30 mol/L), epoxidized group concentrations (1.67–3.80 mol/L) and CO2 pressure (21.1–49.7 bar). The kinetic parameters identified by nonlinear regression fit the experimental data well.

The use of calorimeter in chemical reaction engineering is a powerful tool to estimate kinetic constants. Indeed, reaction temperature is used as an online analytical signal. Nevertheless, the thermal characterization of the calorimeter must be done to avoid wrong estimation. The hydrolysis of acetic anhydride was used as a reaction model in a handmade calorimeter, because it is a fast and exothermic reaction. Several research groups have studied this reaction without taking into account the autocatalytic effect due to the production of acetic acid. To fill this gap, a kinetic model was developed by taking this phenomenon and in a thermally characterized handmade calorimeter. The estimated kinetic constants in the handmade calorimeter were found to be similar than in the established calorimeter Mettler Toledo RC1.

International audience; Epoxidized fatty acids and fatty acid esters are used as chemical intermediates and environmentally friendly bio-lubricants. The epoxidation is carried out by the Prileschajew reaction, which implies the use of hydrogen peroxide as oxidation agent and a percarboxylic acid as the oxygen carrier. The epoxidation process is slow in the two-phase system (aqueous phase and oil phase), but it can be considerably enhanced by incorporating a heterogeneous acid catalyst. The results for the epoxidation of a model compound, oleic acid were presented. A cation-exchange resin (Amberlite IR-120) was used as the heterogeneous catalyst and acetic acid was the reaction carrier. Experimental data on oleic acid epoxidation were obtained at 40–50 °C under conventional heating and microwave irradiation. The experimental set was focused on studying the catalytic effect of the solid resin. The kinetic results revealed that the presence of the heterogeneous catalyst completely masked the enhancing effect of microwave radiation. An extensive set of kinetic data obtained from a laboratory-scale loop reactor was modelled with a realistic heterogeneous model taking into account the co-existence of three phases in the chemically complex reaction system. Rate equations were presented for all the reaction steps involved: the perhydrolysis, epoxidation and ring-opening steps. The rate equations were included in the three-phase reactor model and the kinetic parameters of the system were determined by non-linear regression analysis.

International audience; Process safety is an important topic in the curriculum vitae of a chemical engineer. It can be a difficult course for the students and professors, because it is a frontier course between chemical engineering and safety. How to introduce this course? We think that this course should be introduced during the chemical reaction engineering, and more particularly during the mass and energy balances lectures. Thus, the students can more easily understand the concept of isoperibolic mode, secondary reactions, heat-flow rate due to chemical reactions, Semenov curves, etc. In this manuscript, we propose a pedagogical method to introduce this concept by using numerical simulation. In the first section, the roots of energy balance for the different reactors is derived. In the second section, mass and energy balances coupling is derived for the different chemical reactors. In the third section, the different thermal modes, i.e., isothermal, isoperibolic and adiabatic are described. Then, a tutorial by using a batch reactor with several exothermic reactions is treated and corrected. At this moment of the course, the instructor can introduce the last section about safety criteria by using the zero-order approximation. The rigorous mass and energy balances coupling should be introduced to the students before the current approximation made by the safety community, i.e., zero order, in process safety.

Epoxidized vegetable oils are used as chemical intermediates and biolubricants. Epoxidation of oleic acid as model compound for vegetable oils was performed in a batch-loop reactor. The system comprised a loop where the mixture was pumped through a cavity in which microwaves were irradiated. The reaction was executed by peroxyacetic acid formed in situ from acetic acid and hydrogen peroxide. An extensive kinetic study of oleic acid epoxidation in the batch-loop reactor was conducted by varying the reaction temperature (40–60 °C), the stirring and pumping speeds as well as the molar ratios of the components. Both conventional heating and microwave irradiation were used in the experiments. Epoxidation of the double bonds in oleic acid proceeded as the main reaction, while acid-catalyzed ring opening of the epoxide appeared as the side reaction. The results obtained showed that temperature, acetic acid amount and hydrogen peroxide amount accelerated both rate of epoxidation and ring opening processes. A clear enhancement of the epoxidation kinetics was accomplished with microwave heating in comparison to conventional heating, which was attributed to selective heating by the microwaves that enabled a higher interfacial mass transfer. Microwave application to epoxidation of vegetable oils is a promising process that successfully meets all the green chemistry requirements: energy saving and eco-friendly process and products.

International audience; Levulinic acid (LA) is one of the most important platform chemicals as it is a versatile building block for a variety of high value-added products, fine chemicals and pharmaceutical intermediates. Catalytic esterification of LA with alkyl alcohols leads to levulinate esters which can be used as fragrances, flavoring agents and fuel additives. In the present work, the kinetics of the levulinic acid esterification with ethanol in the presence of Amberlite IR120 was investigated in a batch reactor. The collected experimental data were interpreted with a reliable model taking into account also for the mass transfer phenomena involved in the reaction network. The kinetic model was further validated by conducting experiments in a fixed bed reactor. The reactor was characterized in terms of fluid-dynamics and the collected kinetic data were interpreted with a reliable reactor model, considering the extent of the reaction and fluid-solid mass transfer limitation.

Fossil materials are widely used raw materials in polymerization processes, hence, in many cases, the primary goal of green and sustainable technologies is to replace them with renewables. An exciting and promising technology from this aspect is the isocyanate-free polyurethane production using vegetable oil as a raw material. Functional compounds can be formed by the epoxidation of vegetable oils in three reaction steps: epoxidation, carbonation, and aminolysis. In the case of vegetable oil carbonation, the material properties vary strongly, with the composition affecting the solubility of CO2 in the reaction mixture. Many attempts have been made to model these interactions, but they generally do not account for the changes in the material properties in terms of spatial coordinates. A 2D CFD model based on the combination of the k-&epsilon, turbulence model and component mass balances considering the spatial inhomogeneities on the performance of the reactor was created. After the evaluation of the mesh independence study, the simulator was used to calculate the carbonation reaction in a transient analysis with spatial coordinate-dependent density and viscosity changes. The model parameters (height-dependent mass transfer parameters and boundary flux parameters) were identified based on one physical experiment, and a set of 15 experiments were used for model validation. With the validated model, the optimal operating temperature, pressure, and catalyst concentration was proposed.

International audience; Production of polyurethane is increasing since the recent years. Nevertheless, this production uses hazardous chemicals, which is isocyanate. Academy has put a lot of effort to develop some non-isocyanate polyurethane routes. One of the most promising is the aminolysis of cyclic-carbonate by diamine. To industrialize this way of production, kinetic and thermodynamic data are needed. The first steps were to optimize the production of methyl oleate, epoxidized methyl oleate and carbonated methyl oleate. Then, a kinetic model was built for a model reaction which is the aminolysis of carbonated methyl oleate by n-butylamine by taking into account the side reaction of amidation. The model fits correctly the experimental data. A Tian-Calvet calorimeter was used to determine the different reaction enthalpies. It was found that the reactions of aminolysis and amidation were low exothermic reactions.

Risk of thermal runaway for epoxidation is not negligible and should be analyzed and assessed. In industry, epoxidation of vegetable oils is carried out by the oxidation of Prileschajew, involving the in situ production of percarboxylic acid from hydrogen peroxide and the corresponding carboxylic acid. Different research groups have developed kinetic models under isothermal or isoperibolic mode for this liquid-liquid reaction system. Nevertheless, none of them have built a kinetic model under adiabatic mode. Such kinetic model under adiabatic condition is important to evaluate the thermal risk of a process. During this study, a kinetic model was built for the epoxidation of cottonseed oil by peracetic acid by using ARSST system, which works under near-adiabatic condition. This kinetic model can fit the experimental reaction temperature. Then, based on this model, the influence of different inlet parameters (i.e. initial temperature and concentrations) on safety parameters, i.e., Time-to-Maximum rate under adiabatic conditions and adiabatic temperature rise was investigated.

The use of biomass as feedstock to produce chemicals or biofuels is increasing. This renewable, biodegradable and ecofriendly feedstock could present some new risks that should be taken into account. In this context, a thermal risk assessment of levulinic acid (LA) hydrogenation to γ-valerolactone (GVL), which is a platform molecule produced from lignocellulosic biomass process, catalyzed by Ru/C in water was performed. A kinetic model including an energy balance under near-adiabatic conditions was built. For that, different experiments at different operating conditions (levulinic acid concentration and catalyst loading) were performed by using an Advanced Reactive System Screening Tool (ARSST) to estimate the kinetic constants of this reaction system. To make a thermal risk assessment of a chemical reaction system, two safety parameters should be defined: Time-to-Maximum Rate under adiabatic conditions (TMRad) and adiabatic temperature rise (ΔTad). The parameter TMRad defines the time to reach the maximum temperature rate and characterizes the probability of risk. The parameter ΔTad is the difference between the maximum and initial reaction temperature and characterizes the severity of risk. Based on this kinetic model, these two parameters were determined at different operating conditions. With the aid of a risk matrix, it was possible to determine the safe operating conditions (temperature, levulinic acid concentration, hydrogen pressure and catalyst loading).