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The consequences of a successful intentional attack to a process facility can be severe and could propagate among units generating the so-called domino effects, with potential effects on people, the environment, and assets. For these reasons, institutions and practitioners have found interest in determining the entity of damages associated with these events and integrating them into conventional safety and economic analyses. Still, approaches devoted to assessing the economic losses associated with intentional attacks have received less attention in the literature. This work presents a methodology to evaluate asset losses associated to intentional attacks. A probabilistic approach based on Bayesian Networks was adopted to include several factors associated to intrusion scenarios and their interdependencies. The developed methodology was then applied to a case study to demonstrate its potentialities. A demonstrational attack scenario was considered to test the methodology. The results show that a successful intentional attack might indeed lead not only to direct consequences on people, but also to relevant economical losses. Moreover, factoring in the synergistic performance of safety and security barriers allows to improve the estimation of asset losses.

Industrial sites processing and storing hazardous chemicals can be attractive targets of malicious acts of interference. The consequences successful intentional attacks to chemical facilities can be severe and could escalate generating domino effects, potentially affecting people and the environment. Moreover, intentional attacks have a dynamic escalation that is not well depicted by conventional analyses, which are instead static. This works focuses on the development of a comprehensive tool for Integrated Safety-Security risk assessment and related domino effects based on a three-dimensional (3D) real-time approach. Firstly, the plant is inspected using a drone to generate the graphic interface of the tool, which is the 3D reconstruction of the plant. Real-time data are associated with each mapped element, e.g., pressure/temperature conditions. The tool allows for the evaluation of probabilities and 3D consequences of accidents given real time and/or user input data. Potential domino effects of integrated safety-security scenarios will also be included in the tool, allowing for the mapping of plant vulnerability, risk and supporting the evaluation of weaknesses and need of additional countermeasures. In order to provide a sample application, a simplified version of the tool was used on a case study.

The actual energy transition calls for the highest ever engagement of institutions and private sectors in the adoption of renewable energy systems in order to decarbonize all production chains. The high potential of renewable energy sources (RESs) in several locations worldwide is looked at as an important opportunity to both limit the energy supply issues and shift towards a greener society. On the other hand, it is also accompanied by the issues of resource variability, forecasting need and difficult management of the energy surpluses. The contemporary exploitation of multiple RESs in a hybrid renewable energy system (HRES) is a strategic initiative aimed at reducing the energy supply risk in a specific location, while decarbonizing the power generation facilities that satisfy specific energy requests. By means of systems optimally designed that valorize the RESs site-specific features and time trends, it is possible to comply with the identified energy demands while obtaining increased reliability. This contribution introduces an approach for the preliminary design of HRESs which is capable of accounting for the specific geographical constraints and the energy requests to be fulfilled. The approach is simulation-based, thus analyses the performance of all the possible combinations of renewable energy conversion technologies in terms of supply reliability and assesses their sustainability profile through key indicators. The application of the method is exemplified through a case study located on the island of Crete, Greece, for the valorization of the combined exploitation of offshore wind and wave energy. The most sustainable designs of the HRES in the site foresee the installation of 12 offshore wind turbines and maximum 10 wave energy converters for an overall system potentiality higher than 110 MW.

The results of the offshore integration of fossil and renewable energy sources (RESs) to produce an energy vector, namely methanol, are discussed. The methodology developed and hereby presented, allowed at first the selection of the best technology for offshore RESs exploitation, where a near-to-decommissioning platform is used as an energy hub. Based on the availability of natural gas from the depleted reservoir, the most suitable process for offshore methanol production was chosen among various alternative innovative processes. The optimal mix for energy production was then identified by varying the number of converters for each RES. Finally, the methanol production process was designed on the basis of the available electric power, including a backup system based on natural gas, to perform RESs valley filling and to achieve a steady state process.

Natech accidents have an increasing relevance due to the growing number of such events and to their severe consequences. Climate change and global warming are intensifying the occurrence and the magnitude of climate-related natural events, further increasing the risk of cascading sequences triggered by natural disasters impacting industrial installations. The present study focuses on Natech triggered by heat waves. The features of this specific category of Natech events were investigated by past accident analysis, collecting an extended dataset of past events. The dataset analysis allowed the identification of the key factors that characterize these accident scenarios, such as the direct causes, the technological scenario that occurred, the substance categories, and the equipment items more frequently involved. The main direct cause of accidents resulted in an internal pressure increase, exceeding equipment design limits. Fire scenarios represent the most important category of technological scenarios that occurred. Besides equipment items handling liquid and gaseous hydrocarbons, waste storage and processing systems also resulted frequently in accidents, due to the self-decomposition and self-ignition phenomena. The analysis of past accidents also allowed identifying some lessons learned, useful to identify specific actions aimed at preventing and/or mitigating the possible occurrence of these accident scenarios.

Dimethyl ether (DME) and methanol are proposed as synthetic fuels prone to substitute present fossil propellants in the energy transition framework. Methanol and DME are traditionally synthesised starting from syngas but nowadays new production processes based on the efficient catalytic hydrogenation of CO2 have been introduced. Multiple catalysts, reaction conditions and reactor configurations have been tested to enhance the production performance of both fuels, especially for the case of DME. In fact, DME can be produced indirectly from CO2, i.e. after methanol synthesis and purification. Alternatively, it can be synthesised in a one-pot conversion mode by means of bifunctional catalysts directly receiving CO2. The latter route, avoiding several intermediate separation operations, appears promising from the process intensification viewpoint, thus favouring DME production with respect to methanol. Since safety plays an important role from the standpoint of societal acceptability, it needs to be considered in the selection of sustainable alternatives, especially when dealing with novel processes in the context of energy transition. This contribution aims to address an inherent safety assessment for the comparison of the production processes of methanol and DME production via CO2 hydrogenation. Inherent safety is evaluated through a consequence-based approach using specific Inherent Safety Key Performance Indicators, which proved to be effective in several applications to early process design. The results obtained shed light on the inherent safety performance of these alternative routes, thus helping decision-makers in accounting for process safety issues in the assessment of the sustainability of these alternative energy vectors for Power to Liquid (PtL) applications and in the selection of the best technological alternative.

The present contribution aims at providing an innovative method for the assessment of human barriers, specifically addressing the framework of the energy industry, including offshore operations. Introducing a revised framework to analyse human errors, the methodology developed aims at extending the current Human Reliability Analysis (HRA) methods including psychosocial factors and barriers. The new methodology was developed extending and tailoring to the specific context the well-known framework set by two widely used HRA methodologies (SPAR-H and HEART). An innovative holistic framework, dedicated to the wide range of operations of the energy industry, was developed to assess human error probability (HEP). Human factors were considered safety barriers against human error: more specifically, workers were considered having an active role in shaping their own performance. The method developed introduced a revision of the Generic Task Types (GTT). Each GTT was then associated with a Nominal Error Probability (NEP). The NEP is then modified by the assessment of correction factors obtained from the assessment of conditions affecting task performance, in analogy with the Performance Shaping Factors (PSF) approach introduced by SPAR-H. The method proved to be easy to apply and the results obtained clearly show that human factors play a significant role in preventing workers from making errors while performing tasks by reducing human error probability.

The release of hazardous materials induced by natural events affecting industrial facilities presents peculiar characteristics because of the huge potential extension of the affected areas. The reduction of both the likelihood and the magnitude of such events represents an essential step to reduce the risk associated with Natech accidents. Nevertheless, the evaluation of damage to the environment in Natech events has been poorly addressed. In the present study, past accidents analysis was carried out, using both a detailed description of specific accidents and an extended database of Natech events. Lessons learnt as well as possible common patterns and main features related to such accidents were identified and discussed. The results of the present study can be intended as a preliminary step for the development of models for the quantitative assessment of damage to the environment in major accidents caused by natural events.

In the framework of energy transition, safety is a key requirement to be satisfied by novel process technologies. The aim of this study is to compare, from an inherent safety standpoint, three technologies for the production of green hydrogen via water splitting, powered by Renewable Energy Sources (RESs), in order to identify the inherently safest option and the critical equipment and/or operating conditions to be considered in the scale-up and industrialization of such technologies. The technologies considered for green hydrogen production are: alkaline electrolysis, proton exchange membrane electrolysis and reversible Solid Oxide Cells. The application of a consolidated methodology for inherent safety assessment based on Inherent Safety Key Performance Indicators (IS-KPIs) enabled to identify the most critical units within each process scheme and to select the inherently safest technological solution presently available for green hydrogen production.

Worldwide, several locations are characterized by abundance of natural energy sources, prone to be converted in power for electricity generation and process-related duties. However, the discontinuity of such renewable energy sources (RES) coupled with their conversion difficulties, results in moderate advantages when a steady power demand has to be satisfied using a single energy source. To overcome the forehead mentioned limitations, profitable renewable energy harvesting can be reached by exploiting multiple RES at once. Such possibility is, in principle, very versatile, thanks to the modularity of the integrated power generation plant, that can be designed based on the energy availability and investment options. In the present work, the approach of integrating multiple RES was used to assess the technical feasibility of harvesting solar (via photovoltaic panels) and wave energy (via wave energy converters) to supply a desalination unit for the production of irrigation water in Tenerife (Canary Islands, Spain). The available energy from RES was evaluated through the elaboration of weather-climate hourly data, offered by open-access databases. Then, the proper conversion technologies were selected and single production curves were obtained. The integrated system was conceptually designed overlapping the hourly power generations; its performance was assessed with respect to possible duties of the desalination unit. The self-sustainment level of the integrated system was evaluated by calculating the percentage of time that RES can cover the requested power. Based on this, the selection of the most sustainable RES mixing was set, determining, in turn, the final productivity of the desalination facility. The results demonstrated that the integration of different RES represents a reliable and environmentally sustainable solution, especially for remote areas dependent on fossil fuels importation.

The process industry and similar sectors are undergoing a digital transition towards higher levels of automation. This, while ensuring advantages such as efficient process control, quick and safe response to abnormal conditions, improvement of product quality and continuous process optimization, it exposes the process sites to cybersecurity threats. A cyber-attack, besides economic and reputation damages, can potentially trigger major accidents (e.g. loss of containment of hazardous materials) with severe consequences on workers, population and the environment. In the present study, the cybersecurity-related incidents (CSIs) that occurred in the chemical, petrochemical, energy production, and water/wastewater sectors, were investigated. The analysis is based on the development of a database of 78 cybersecurity-related incidents. The aim of the study is to frame a clear picture of the cyber-attacks on IT-OT (Information Technology - Operational Technology) system of process facilities and to issue lessons learnt from past incidents.

Safety is an aspect of primary relevance in early-process design and can hardly be neglected: the consequences of accidents in chemical plants have always high impact on economics and reputation. In the phase of alternative technologies’ evaluation, applying inherent safety approaches helps in identifying the major safety challenges of process schemes, orienting the final selection. In the present work, an inherent safety assessment was performed to compare two innovative fuels’ production facilities: biodiesel from microalgae and methanol synthesized via CO2 catalytic hydrogenation. The two schemes were developed to fulfil an industrial scale production, considering the best available technologies in terms of yields and energetic economy for both cases. The inherent safety performances were evaluated through a multi-criteria approach using key-performance indicators (KPIs): potential accident scenarios were simulated, followed by the identification of consequences and relative occurrence frequencies, as to quantify the risks affecting human target. The results enabled to identify the inherently safer option among two innovative processes for energy-transition fuels.

The increase both in frequency and magnitude of natural events makes the study of the interaction between natural events and industrial facilities of paramount importance. Natural events may affect facilities leading to major accidents (e.g. explosion, fire, …) and these events are called NaTech (natural hazards triggering technological disasters). Extreme temperatures are one of the causes of NaTechs and the first step in studying their interaction with industrial facilities is given by the historical analysis of past accidents, being essentially the only source of information. To do this, a dataset of 305 past events was collected and analysed in order to highlight the main features of these accidents, such as the trend over the years, the geographical location, the final scenarios and the type of industrial sectors involved.

In the last decade, microalgae cultivation has become an attractive solution for biomass valorisation. From an industrial standpoint, one important aspect is the combination of the mixotrophic growth of microalgae with the biosynthesis of fatty acids, which represents a sustainable feedstock for the biodiesel chain. Nevertheless, the actual energy-effectiveness of the whole process is doubtful as the indispensable biomass recovery and drying steps are energy-intensive. To discuss this issue, this work presents a comparison between a 3rd generation biodiesel production plant and a methanol synthesis facility, powered by photovoltaic (PV) electricity from sunlight. The objective is to evaluate the energy efficiency of the two production processes (by means of KPIs) given the same solar incidence area. The two process designs assume the best available technologies for the operations involved, in terms of reaction conversions and separation performances to maximise the yield in the final product.

Nowadays most of energy supply and chemicals are produced from fossil fuels. However, environmental concerns like global warming, depletion of non-renewable resources and pollution, force to search for more sustainable alternative feedstocks. In this framework, the valorization of renewable resources is currently one of the most promising strategies for the next future. In particular, the use of biomass is ranked first for production of chemicals. One of the most attractive compounds that can be obtained from lignocellulosic biomass is Levulinic acid (LA). The present work analyses, from a technical, economic and safety standpoint, the valorization of waste biomass (OPEFB, oil palm empty fruit bunch) to LA with different methodologies. Energy demand of the plant and the separation efficiency are evaluated carrying out process simulations by the commercial software Aspen HYSYS V10. The obtained results allowed an economic analysis of the alternatives, based on the evaluation of investment and main operating costs. The alternatives were screened on the basis of net present value (NPV) of costs. Safety performance was investigated by an inherent safety assessment method. This considered toxic dispersion and fire scenarios, calculating the damage distances associated with the potential outcomes of an accident and allowing for the evaluation of a potential hazard index for each main process equipment. The choice of the optimal layout configuration for the production of LA in early phases of design allowed to address, in a time and cost-effective way, further design activities in reducing the energy demand and ensuring potentially safer plants making the whole process more sustainable.

NaTech events (Natural Hazard Triggering Technological Disasters) are becoming an increasing concern in the Chemical and Process Industry (CPI). From a risk management standpoint, a better understanding of such events is of paramount importance. In this perspective, the analysis of past accidents is crucial, being almost the only source of information on the possible interactions between natural threats and CPI. To this aim, the present work collected 438 past NaTechs that affected CPI, analysing the trends of accidents with respect to the trend of natural disasters, the geographical localization, the type of natural hazard triggering the accident, the final scenarios (e.g. fire, explosion,…) and the consequences on human and assets. For each type of NaTech, significant accidents have been reported and discussed.

The present work focuses on process safety related to bioprocess engineering, meant as the integration between chemical engineering and biotechnology. A specific checklist has been created in order to perform a first step in bioprocesses hazard identification aimed at meeting not only personnel safety issues, but also process safety ones. The bioprocess of biogas production from anaerobic digestion of livestock slurry was taken as a case study to show the methodology.

In the present paper, a methodology for the determination of inherent safety distances for escalation and layout optimization has been introduced. A survey of past domino accidents triggered by thermal explosions have been carried out and analysed with the aim of a deeper understanding of the possible primary scenarios and related escalation vectors.

Maximum temperature of reactant mixture is an important parameter regarding reactor safety. If the control of reaction temperature is lost, then side or decomposition reactions may be triggered leading to thermal runaway situation. This study concerns a liquid phase reaction system. This paper explores the influence of parameters on the thermal safety of a pilot tubular reactor. The following parameters were studied: the inlet temperature of the coolant, the volumetric flow rate, and the co-current flow and the counter-current flow configurations. The aim was to identify the main parameters that control the reaction temperature in the presence of a fast exothermic reaction system. The results showed that co-current configuration allows to control the maximum temperature. By changing the configuration, the cooling power can be reduced compared to a change in the inlet temperature of the coolant. A criterion of stability has been implicated in order to confirm this result.