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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.

Technological accidents can be triggered by the impact of natural events on industrial areas. Recent studies highlight the problem and the need to assess possible damage to process pipelines involved in flooding scenarios. The present study proposes for the first time a vulnerability model for this equipment category impacted by floods and suitable for the implementation in quantitative risk assessment (QRA) studies for the process industry. A mechanical model was first developed and compared against data available from the historical analysis of past accidents. The model is then applied to several geometries of process pipelines, with the aim of extending the range of conditions for failure prediction and developing a set of simplified correlations for the evaluation of pipelines failure. A simplified approach is finally adopted to develop the vulnerability model, in order to estimate the pipelines failure probability based on the analysis of critical design parameters and flooding conditions. In order to test the potentialities of the method, the vulnerability model proposed was implemented in the framework of a QRA and applied to an industrial case-study.

Biodiesel is an emerging green fuel that is finding increasing applications. The further improvement of the sustainability of biodiesel production processes is a key element in the energy transition scenario. Among the social pillars of sustainability, safety is a specific requirement. However, several major accidents were experienced in biodiesel facilities, involving the inventory of hazardous substances. In the present study, an inherent safety methodology is proposed as a specific design criterion for the screening of technology alternatives, supporting the selection of the safest and most sustainable production process. Four reference process alternatives for the transesterification of rapeseed oil to produce biodiesel were conceptualized. Inherent Safety Key Performance Indicators (IS-KPIs) were defined to assess the safety performance of the alternative process technologies and to support the selection of the safest design option. A sensitivity analysis was performed in order to verify the robustness of the results with respect to possible uncertainties. The results allowed the comparative assessment of the inherent safety performance of the main biodiesel production technologies, enabling a deeper understanding of the safety-critical aspects of the novel processes proposed for industrial application. The IS-KPIs were integrated in a wider system of KPIs, addressing also the environmental and economic aspects, obtaining an overall assessment of the sustainability performance of the alternative design options considered.

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.

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.

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; The rapid progress of innovative biorefinery technologies raises the issue of emerging risk and major accident hazard in biorefineries, as process safety aspects of such technologies are not developing at the same pace with respect to their dissemination and scale-up.To address such problem, in the present work a consequence-based approach was integrated in the framework of a consolidated QRA methodology (ARAMIS), formerly developed in the context of Seveso Directive in the process industries (mainly oil&gas). Among all the possible scenarios identified using ARAMIS, Relevant Accident Scenarios (RAS) were selected by calculating hazard distances using threshold values for the evaluation of damages on human target derived from existing regulations on the control of major accident hazards.The method has been described and used to quantify the risk associated to a biorefinery process: the conversion of lignocellulosic biomass materials to levulinic acid and gamma-valerolactone, where the use of hazardous substances and severe process conditions are required.Using the proposed approach allowed to reduce the number of scenarios to be retained for further analysis. The RAS resulted 1/3 of the scenarios initially identified, simplifying the rest of the risk assessment procedure.The integrated methodology enabled to depict a risk figure for the plant analysed which is not over-conservative, being beneficial during the risk management phase, when risk reduction measures have to be selected and implemented in order to achieve risk tolerance.

The Canary Islands are still largely dependent on expensive imported fossil fuels, are stressed by the increasing touristic impact and are extremely vulnerable to climate change due to water scarcity. Water desalinisation is an energy-demanding process and is essential to the sustainable development of these islands. The aim of this study is to explore the potential advantages of a hybrid installation, exploiting two different renewable energy sources, specifically waves and solar, to supply a large desalination plant in Tenerife. The paper ultimately provides a generally applicable procedure for the design of hybrid installations, including three steps: the assessment of available renewable energy sources, the optimal combination of these sources and finally the economic assessment. The wave and solar resources are assessed first, then the hybrid installation is conceptually designed, proposing a criterion for the optimal mixing of the renewable energy sources that can be applied to other resources and other sites. The basic idea is to maximise the exploitation of the renewable power, minimizing the need of the fossil-based back-up system. The costs of the hybrid installation are finally assessed considering the sensitivity to government incentives, showing that the project parity point is reached within the lifetime of typical desalination plants (i.e. 40 years) and can be significantly more attractive in case of Feed-In-Tariffs available in other European countries.

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.

With more than 350 GWh per year and thousands of installations around the world, biogas is an appealing strategy in the field of energy production and industrial waste optimization. In this sense, it is of paramount importance to address the risk associated with such plants, as an increasing trend of accidents have been recorded in the last 20 years. In this work, a representative biogas production plant was considered, and a risk assessment was carried out through the combination of Recursive Operability Analysis and Failure Mode and Effects Criticality Analysis. The methodology is rigorous and allows for both the identification and the quantification of accidental scenarios due to procedural errors and equipment failures, which miss in the literature for the case of biogas. The analysis allows the automatic generation of the Fault Trees for the identified Top Events, which can be numerically solved. Results show that the most critical accidental scenario in the biogas plant here considered is the formation of an explosive air-biogas mixture, which can occur in both anaerobic digester and condensate trap. The calculated probabilities agree with the results available in literature on similar plants. Pumps and Distributed Control System were found to be the most critical components.

The present paper aims at verifying the awareness and preparedness of urban and local planners to cope with NaTech risk, together with the availability of dedicated tools. Since most of the natural events that can trigger technological hazards are influenced by climate change (i.e. flood, heavy rains, storms, etc.), NaTech risk is expected to be strongly increasing in the next years. However, dedicated NaTech planning actions and methods or tools to support them are still rarely available. The requirements of European Adaptation Strategy for Climate were examined considering the issues posed by the Seveso III Directive in terms of NaTech, focusing on the strategies adopted in the European countries, and in particular in Italy. Based on such analysis, a ‘NaTech tool’ dedicated to local planners was developed. Practical and easy to use methods and procedures were proposed in order to allow the use of the method by the local authorities, in the absence of sectorial experts.

One of the most common but promising processes for the production of paints and coatings is the free radical emulsion polymerization reaction involving different types of monomers. As it is also demonstrated by statistics concerning accidents in chemical industries, polymerizations are one of the most frequent causes of thermal runaway; therefore such syntheses require a very high level of control of all the operating variables, especially at full plant scale where safety problems are of paramount importance. The main aims of this work were the modeling and the industrial scale optimization of a complex polymerization process. Since four different monomers are involved in different proportions in such a process, the pseudo-homopolymer approach together with available literature correlations for the estimation of the main constitutive parameters of the system were used to solve the mathematical model and simulate the dynamics of the synthesis at the full plant scale. The proposed model and all the constitutive parameters estimates were validated through the comparison with both laboratory and full-scale experimental data, demonstrating a good agreement. Finally, the results of the optimization procedure were validated at laboratory scale.

Industrial infrastructures, in particular those where hazardous substances are stored or handled, may be the target of malicious acts aiming at the disruption of normal operations. In the present study a toolbox of complementary and synergic techniques (Correspondence Analysis (CA), Fishbone Diagrams, Cause-Consequence Chains, Adversary Sequence Diagram, Root Cause Analysis) was applied to the in-depth analysis of physical security- and cybersecurity-related events that affected the process industry. The unprecedented original set of information obtained provides novel insights concerning these events. Clear correlations among security threats, including cyber-threats, and specific industrial sectors, as well as among the final scenarios and the different security threats from which they originate were identified by CA. In particular, vandalism resulted strongly correlated with the transportation of hazardous substances, and theft of materials with oil and gas pipelines. When considering chemical and petrochemical sites, cyber-attacks and the use of improvised explosives resulted to be the most common attack modes performed by the threat actors. Personnel and vehicle gateways resulted key elements when designing the Physical Protection System (PPS) of a facility. Insiders having the permission to enter the site bypass such controls, and were responsible of several successful attacks. Overall, the results confirm the concreteness of security-related events in the process industry and provide an original structured and detailed insight on the attack patterns experienced to date. Moreover, the results and the data obtained provide a novel set of baseline information for the application of SVA (Security Vulnerability Assessment) or SRA (Security Risk Assessment) methodologies in facilities where hazardous substances are stored or processed.

Security threats are becoming an increasing concern for chemical sites and related infrastructures where relevant quantities of hazardous materials are processed, stored or transported. In the present study, security related events that affected chemical and process sites, and related infrastructures, were investigated. The aim of the study is to frame a clear picture of the threats affecting the chemical and process industry, and to issue lessons learnt from past events. A database of 300 security-related accidents was developed and populated, starting from European and American sources. Threat categories that caused such events were identified and analyzed. The attack modes were investigated. Important differences were found with respect to geographical areas and industrial sectors affected. The use of explosives (both military and improvised explosive devices) is by far the more frequent attack mode, although armed attacks and arson are also frequent events and may result in an in-depth penetration of the attackers. In recent years, cyber-attacks are also posing important threats. Lessons learnt call for the implementation of a specific security management system in the chemical and process industry, aiming at the physical and cyber protection of industrial sites.

Summary In the formulation of acrylic coatings, monomer blends are required to cure in situ using a peroxide initiator. Curing accelerators (typically alkyl anilines) are added to the blend in order to initiate the curing process at room temperature. This was proved to cause a process safety issue related to the presence of accelerators that increase the possibility of runaway reactions especially at industrial scale. In this paper, the polymerization of methyl methacrylate containing different curing accelerators has been studied. Based on Differential Scanning Calorimetry tests, a simplified kinetic model for the polymerization process has been developed, describing the induction time due to the presence of stabilizers, the global kinetic rate, and the influence of diffusion phenomena, based on a free volume theory approach specifically modified for the free radical polymerization of methyl methacrylate added with different types of accelerators.

The number of biodiesel production plants is rapidly growing around the world, and the related “green” technologies are developing to full industrial scale within a brief time. The exploitation of these relatively new technologies with a low operational experience is however leading to an increase in the number of accidents in this industrial sector. To better address and characterise the problem of the high accident rate in the “green” technologies in biodiesel production, an in-depth statistical analysis of past accidents has been performed. The set of records analysed (93 events, from 2003 to 2017) has been selected to depict the most relevant factors affecting the accident rate, e.g. the age of the plant and its status at the time of the accident or unit and substances involved. Correlations between characteristics of the unwanted events, such as scenario and causes, have been evidenced. The analysis of the frequency and severity of past accidents allowed an estimate of the risk figure with respect to major accident hazard for biodiesel industry, unveiling the misconception for which green technologies as biodiesel production are often perceived as safer.

In the last 10 years biogas production tripled, resulting in an increasing number of related facilities. The present study addresses safety issues of such activity on the basis of past accident analysis. A database of accidents related to biogas supply chain was created and data on 169 accidents were collected from different literature sources. Trends, causes of accidents, scenarios, and consequences were analysed also using Multi Correspondence Analysis to obtain correlations between causes of accidents and scenarios. The study showed that almost 12% of the past accident analysed can be classified as major accidents. The number of accidents is growing faster than biogas production. A risk assessment was carried, based on the analysis of accident frequencies and consequences. A non-negligible risk profile, typical of ALARP zone, was obtained for this industrial sector, revealing an emerging risk issue. The main lessons learnt are the need of developing and adopting specific safety standards and of improving the safety culture and risk awareness in the biogas production sector.