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In the realm of chemical processing, particularly at the industrial scale, safety is of utmost importance. A predominant factor causing accidents within the chemical industry is runaway phenomena, primarily initiated by uncontrolled exothermic reactions. This review critically examines the often‐overlooked decomposition mechanisms as a significant contributor to thermal energy release, necessitating a comprehensive revision and understanding of both experimental and theoretical strategies for assessing thermal degradation. Key to this discourse is the explication of calorimetry as the principal experimental technique, alongside ab initio quantum chemistry simulations as a robust theoretical framework for quantifying the most relevant properties. However, more than mere cognisance of these methodologies is required for a meticulous thermal stability assessment. The review emphasizes identifying and quantifying fundamental parameters through experimental and theoretical investigations. Only upon acquiring these parameters, including kinetic, thermodynamic, onset, and peak characteristics of the exothermic decomposition reactions, can one effectively mitigate risks and hazards in designing and optimizing chemical processes and apparatus. Furthermore, this review delineates qualitative and quantitative methodologies for hazard assessment, proffering strategies for estimating safe operational conditions and sizing relief devices. The paper culminates in exploring future trajectories in thermal stability assessments, focusing on emerging applications in lithium‐ion batteries, electrolyzers, electrified reactors, ionic liquids, artificial intelligence and machine learning approaches. Thus, the paper underlines the evolving landscape of thermal risk management in contemporary and future chemical industries. [ABSTRACT FROM AUTHOR]

This study addresses the critical need for effective risk assessment and mitigation strategies in academic research environments. As research laboratories engage in increasingly complex projects, ensuring the safety of personnel, equipment, and the surrounding environment becomes paramount. These settings are prone to various vulnerabilities, including manual operations, transient states, and diverse training backgrounds. This work presents a case study focusing on the potential hazards and risks associated with Fischer-Tropsch synthesis. The analysis examines critical factors such as catalyst use, high-temperature reactions, potential byproducts, and the influence of human error during manual operations. Utilizing a systematic approach that incorporates interaction matrices and HAZOP analysis, the study identifies potential undesired scenarios, ranging from minor incidents to severe consequences, and evaluates their likelihood and impact. In response to the identified risks, the paper proposes targeted mitigation measures specifically designed for the Fischer-Tropsch experimental setting, structured as layers of protection. The findings of this research offer valuable insights into laboratory safety in academic settings, providing a risk assessment and mitigation model adaptable to various experimental setups. By integrating theoretical frameworks with practical applications, this study aims to enhance safety standards in academic laboratories conducting Fischer-Tropsch synthesis and establish a foundation for continuous improvement in laboratory practices. [ABSTRACT FROM AUTHOR]

The chemical industry often handles, stores, and processes molecules like hydroxylamine (HA) and hydrogen peroxide (HP), which can easily undergo thermal decomposition reactions. Hence, the ideal perspective is to have simple quantitative criteria to use during the equipment design phase, accommodating the possibility of exothermic degradations of substances to enhance process safety and avoid thermal runaways. To this aim, the Frank-Kamenetskii theory of self-heating (FKT) can be involved in determining the critical size of a storage vessel to guarantee the intrinsic safe storage of chemically hazardous materials. Eventually, the proposed design strategy will be implemented to design storage equipment for two commercial aqueous solutions of HA and HP, respectively. In this way, it will be possible to compare the inherent thermal hazard linked to the storage of these mixtures, evaluating the threshold vessel size above which the self-heating phenomenon of the materials becomes no longer controllable. The HA and HP mixtures can be used alone or together in chemical processes as oxidants or precursors for producing hydroxyl radicals. Under comparable conditions free of impurities and organic contamination, the results show that the system made of 50 %w hydrogen peroxide is more stable than hydroxylamine. This is reflected in a larger characteristic size of the storage vessel able to handle appropriately self-heating phenomena potentially leading to runaway. [ABSTRACT FROM AUTHOR]

Seismic events can trigger a NaTech disaster, leading to the release of hazardous materials, fires, and explosions. These can occur within industrial complexes and along distribution networks as a result of natural disasters. Industrial plants, composed of structural and non-structural components, may be damaged when subjected to earthquakes of a given magnitude. Some examples of these disasters occurred in Kobe (1995), Kocaeli (1999), and Tohoku (2011). This study aims to assess the local seismic hazard by the implementation of different analytical approaches in a Major-Hazard Industrial Plant (MHIP) triggering a NaTech event. For the Bussi MHIP area, a geodatabase has been designed where geometric and geotechnical parameters have been associated with each geotechnical unit. The local seismic hazard has been simulated using 1D and 2D codes, considering two seismic hazard scenarios limit state SLV - SLC according to the National Building Code (NTC2018). In this study, the amplification factor AF has been calculated within the natural vibration range of an H2O2 storage tank located in the Bussi MHIP facility. This type of structure was chosen as it represents an element able to generate a relevant accident and consequently, a potential NaTech event. [ABSTRACT FROM AUTHOR]

Total indirect greenhouse gas (GHG) emissions from oil and gas operations today are around 5,200 Mt of carbon dioxide equivalent (CO2-eq) yearly, 15% of total energy sector GHG emissions. Most of these emissions occur due to natural gas leaks. Methane, a much more potent GHG than CO2, is the most significant single component of natural gas and, therefore, of these emissions. Part of these emissions results from routine operations such as flaring and venting, representing both an economic and an environmental issue. Many solutions have been developed to recover and use this natural gas instead of venting and flaring it. Three possibilities were simulated with AVEVA PRO/II, and a preliminary economic assessment was carried out with Guthrie's method. 30 kmol/hr of natural gas fed was assumed, according to average site data, therefore, small-scale plants are suitable. A first solution based on compression, though requiring high OPEX (> 280 k$/y), produces very low emissions yearly (1,140 t CO2-eq/y). Another possibility is to couple flaring to a microturbine for energy generation, but this solution is both uneconomical and has a high environmental impact (> 10,000 t CO2-eq/y). The last technology analysed is thermal methane pyrolysis. This possibility, often disregarded in environmental studies, involves the production of turquoise hydrogen and carbon black. Although characterised by high capital costs (almost 3 M$), it can reduce gaseous emissions since it stores the carbon part of hydrocarbons in the solid matrix that is formed. [ABSTRACT FROM AUTHOR]

The world annual hydrogen demand continues to increase with a direct impact on the global CO2 emissions. A potential solution is the production of CO2-neutral hydrogen (green hydrogen) using renewable resources. In addition to electrolytic hydrogen, biogenic hydrogen can increase productivity and enable the expansion of the H2 economy for regions with low availability of solar and wind, such as central Europe. In this work, the design of a decentralized biogas-to-hydrogen process (50 Nm3 h-1 H2 productivity) based on an electrically heated reformer was developed. An economic analysis has established the viability of this suggested production route: the Hydrogen production price remains below 6 € kg-1. It results that this innovative process requires approximately 0.6 Nm3 of biogas and 1.25 kWh of renewable electricity to produce 1 Nm3 of hydrogen. [ABSTRACT FROM AUTHOR]

Carbon dioxide is the leading anthropogenic greenhouse gas in terms of emissions from carbon-intensive industries, such as cement plants, steel mills and refineries. The deployment of CO2 (carbon) capture and sequestration (CCS) technologies plays an important role in reducing CO2 emissions on a global scale. When optimizing the CCS supply chains for the Italian peninsula, additional complexity is brought up by the Country seismic profile. This contribution provides a techno-economic assessment and optimization of a comprehensive CCS from Italian industrial stationary sources by aim of a multi-objective mixed-integer linear programming modeling framework. In particular, the model is conceived to simultaneously optimize the economic (i.e., minimum cost) and seismic (i.e., minimum risk) performance of a CCS system in the geographic setting of Italy. In this work, a case study aiming at a carbon reduction target of 50 % is presented by discussing the corresponding set of Pareto optimal solutions. Results show a trade-off between the two conflicting objectives, where the configuration with the minimum specific CO2 avoidance cost (68.8 €/t) is characterized by the highest value of risk (13.5 ruptures/year). [ABSTRACT FROM AUTHOR]

The data about illegal activities connected to the waste cycle refer to an alarming situation linked to the development of waste fires in Italy and the world in the last few years. Hence the interest in implementing new methodologies to study fires in piles of waste, understand the incidental dynamics, and draw scientific evidence on the nature of combustion is crucial. The investigation focused on a real case waste disposal fire in a company in northern Italy. Initially, the trigger involved a heap of unsorted municipal waste, with flames spreading to other heaps of twigs, wood, and paper and plastic storage areas. The damage was limited by the prompt intervention of the Fire Brigade, who took a few hours to tame and extinguish the flames. The entire dynamic was captured by internal security cameras and made available for investigations. This key element made it possible to compare the real evolution to model estimations. Therefore, the present work aimed to approach an actual case study via numerical simulation to give insight into the fire accident. To this end, it was decided to use the Fire Dynamics Simulator (FDS) for an open field application. The application produced interesting results and paved the way for further research questions and debates regarding the effectiveness of this strategy for investigating incidental scenarios. In particular, it was possible to recreate the incidental dynamics assuming different compositions of the initial fuel matrix and their impact on the fire dynamics. However, some issues have emerged, including the lack of reliable data concerning fuel matrixes and their behaviour in open spaces. Another limitation is linked to the software unsuitability to implement heterogeneous material properly. On the contrary, internal safety distances among piles of stored waste were defined through empirical models and compared to what is embodied in the technical fire prevention rule draft concerning waste disposal facilities. [ABSTRACT FROM AUTHOR]

In the framework of design and installation of fire detection and fire alarm system in buildings, when high ceilings are involved, it is likely to run into the limits of the more common standards. Several regulations fix a ceiling height limit beyond which heat, smoke, and combustion gas detectors should not be mounted. Among the available technologies, the aspirating smoke detection (ASD) systems have the highest limit (i.e., 40 m according to BS 5839-1:2017). Nevertheless, this technology should not be used when processes that yield smoke, fumes, dust, etc., are present, and an alternative type of fire detector needs to be employed. This is due to the necessity to avoid false alarms, which is critical for successful fire detection and alarm systems. The concomitance of these two situations, i.e., dusty environments and high ceiling height, is not unusual in the industrial sectors. To investigate it, the state-of-the-art solution is adopting the principles of Fire Safety Engineering (FSE). The FSE is based on calculations that consider the conservation of mass and energy and permit to predict several crucial quantities such as the smoke temperature, smoke volume (and layer height), and species concentrations resulting from a fire of a given size (ISO/TS 13447:2013). In this work, a series of Computational Fluid Dynamics (CFD) simulations were conducted to assess the performances of a fire detection system composed of heat detectors installed at heights up to 20 m larger than the standard limit. The characteristics of an actual building adopted for storage of hazardous materials and a real heat detector system were considered. The temperature field resulting from two different types of t2-growth fire, i.e., one ultra-fast and one with slow evolution, were analyzed. The corresponding alarm times were evaluated and compared with ASD characteristics timings, recognized as a benchmark for its high sensitivity. [ABSTRACT FROM AUTHOR]

Developing sustainable solutions for power generation and transportation is crucial for reducing greenhouse gases (GHGs). The tendency in fundamental and practical research on this field has been characterized by investigating low or net zero-carbon sources. Among the available options, hydrogen may be employed as a possible energy carrier to reduce the local emissions of harmful gases. However, the intensive use of gaseous hydrogen is still limited by the issues related to its storage and transportation systems. In this framework, injection of compressed hydrogen into the existing natural gas pipelines is seen as a way forward to reduce the quantity of carbon-based fuel and will be studied in this work. Compared to building a dedicated hydrogen infrastructure, this solution permits lower capital costs and ensures system scalability (i.e., the possibility to add hydrogen gradually). However, the possible consequences of a gas pipeline failure can be altered. In this paper, a numerical evaluation is conducted to characterize hydrogen-methane mixture jet fire. The analysis is performed using integral models and computational fluid dynamics (CFD). In the case of the computational fluid dynamic approach, an accurate thermodynamic properties database is employed. The distance from the releasing point at which the maximum temperature is reached (i.e., the length of the jet flame) is used as a monitoring parameter for the comparison. Results are compared with existing literature data and discussed to evaluate the safety impact of adding hydrogen to the natural gas network. [ABSTRACT FROM AUTHOR]

The release and dispersion of toxic materials from industrial equipment may pose severe concerns and have tragic consequences. The assessment of such scenarios relies on broad literature, approaches, and modelling tools that support estimating the impact area. However, hazard assessments do not generally embed the egress modelling and the impact of a toxic release on people evacuating. The present work couples a gas dispersion model with evacuation dynamics to estimate the near-field impact on people approaching a safe place. It is applied to a hypothetical case study concerning a release of dense chlorine, in which the effect of adopting different assumptions is discussed. [ABSTRACT FROM AUTHOR]

The current trends in environmental impact reduction have promoted natural gas and hydrogen either as short-or long-term solutions. In both cases, liquid transportation in cryogenic form is associated with new concerns in terms of safety aspects. So far, infrastructures based on utilizing the liquefied natural gas (LNG) in port areas have been developed and realized worldwide. However, a uniform guideline and set of monitoring criteria are missing because of the lack of knowledge of the phenomenological aspects. This work deals with the numerical characterization of the visible cloud boundaries in the case of an unintentional release during bunkering operations and its comparison with the standard value for the flammability of cloud, based on the lower flammability limit. To this aim, real-scale computational fluid dynamics (CFD) simulations were performed. Results showed that both flammable and visible clouds were dramatically sensitive to the heat transfer with the substrate in an unconfined environment. Besides, turbulence seems to affect the flammable cloud expansion rather than the visible cloud. Eventually, results indicate that the flammable cloud can be up to 50% larger than the visible for confined and 20% large for unconfined environments, conservatively, on the safe side. These values can be adopted for design and emergency purposes. [ABSTRACT FROM AUTHOR]

Dealing with pressurized releases of CO2 from Carbon Capture and Storage systems is of topical interest for the safety assessment of such infrastructures. Evidence shows that a sublimating bank of CO2 can be formed following a loss of containment, which acts as a delayed source of heavy CO2 gas. This source of hazard requires estimation in terms of sublimating mass flow rate, flux, and thermal features. In this work, we illustrate an experimental apparatus to measure the main properties of sublimating CO2 banks for estimating safety parameters. Data concerning mass flow rate, fluxes and temperature were successfully estimated. We measured mass fluxes in the range from 160 to 240 g/(min·m2) of CO2, and we observed a relevant temperature variation. From experimental data, we proposed an approach to evaluate a representative driving force that includes the central feature of the CO2 to accumulate in the vicinity of the sublimating bank. [ABSTRACT FROM AUTHOR]