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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.

The current trends in environmental impact reduction have promoted natural gas and hydrogen either as shortor 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.

QRA procedures applied to industrial equipment require special attention when dealing with unconventional hazard scenarios. In this perspective, the role played by severe natural events on the functionality of an industrial system is surely of interest in any exhaustive risk assessment study. The focus on earthquake initiating events is due to their severity and strong destructive potential that can lead to severe damages, domino effects and cross effects on residential and industrial sites. In this work, a probability approach that includes unconventional initiating events in usual Fault Tree and Event Tree analysis procedures is proposed to ensure a reliable earthquake-related event management. Main relevant parameters are evaluated, in addition to the typical expected structural behaviour of the industrial structure. The comparison between the scenario without the seismic event and that aggravated by the earthquake shows that, depending on the both the seism and structural parameters, such an unconventional initiating event worsen the final outcomes. Variations are depending on the site-epicentre distance and the seism magnitude and peculiar effects on the final outcomes are observed both in the FTA and ETA initiating branches. Copyright © 2019, AIDIC Servizi S.r.l.

The sustainable development has recently become the cornerstone of the environmental policy worldwide and a leading principle for resource management. The philosophy lies in a continuous demand of innovative choices able to ensure the existing productive systems survival through a new design paradigm shift. In this regard, the technological innovation should be always driven by the sustainability concept: the economic, societal and environmental impact ought to be continuously fostered to the systems' sustainable improvement. This demanding goal can be accomplished with a blended Life Cycle (LCA) and Life Risk (LRA) Assessment to highlight the process potential health and environmental impacts. LRA is the process in which imposed risks by the inherent hazards linked to a process are continuously assessed (quantitatively or qualitatively). LCA instead is the process that analyses and assesses the environmental impact of a material, product or service throughout its entire life cycle. LCA and LRA are typically driven by two different approaches, respectively a deterministic and a stochastic approach. This usually drives an unconnected use of LCA and LRA in the quantification of products and processes potential impact and determines controversial decisions with respect to a balance between environmental impacts and operational risks. The new paradigm suggests a unified blended LCA - LRA approach that is applied at a preliminary stage to an innovative Acid Gas to Syngas (AG2S) process for CO2 emission reduction and on-site reuse, avoiding the costly and hazardous transportation step.

Epoxidated vegetable oils are largely employed as plasticizer instead of harmful phthalates and they represent a sustainable choice to produce lubricants and intermediates. In this work, the epoxidation of soybean oil is carried using hydrogen peroxide (H2O2) 32wt.% and acetic acid instead of the commonly used H2O2 at 60wt.% and formic acid to reduce the risk of detonation and corrosion. The efficacy of an acid catalyst (sulfuric acid) is tested. Particular attention is focussed on a proper mixing program.

Peroxyacids are commonly used in chemical processing, synthesis and bleaching. Recently, they have been demonstrated to be very versatile for the epoxidation of unsaturated oil, aiming at the synthesis of polyepoxide (plasticizer, resins and adhesives). These processes are characterized by high yields and selectivity. However, due to their hazard and instability, the peroxy reactants are often obtained from the corresponding organic acid in situ by combination with hydrogen peroxide, in the presence of a mineral (sulphuric or phosphoric) acid as catalyst. In this paper, the kinetic of decomposition of the peroxyacetic acid in water phase have been studied by using simple thermal screening calorimetry, with or without the catalyst.

Natural disasters are able to cause significant damage to chemical plants, structure, infrastructure and lifelines (power plants, fuel storage facilities, water treatment plants, etc.). Failures in these systems could worsen the effects on people, environment and economy due to natural disasters. In the literature such scenarios are known as Natural-Technological (Na-Tech) events; in this frame volcanic eruptions can trigger a wide range of Na-Tech hazards for both human health and environment. This chapter extends a recent study related to the analysis of the potential damage of primary (mechanical) treatments included in wastewater plants due to the fallout of volcanic ash produced by volcanic explosive eruptions. The work aims at the identification of the conditions leading to the functionality reduction of grit removal facilities. An application of the proposed approach to a case study, which is the surrounding Mt. Etna (Italy), is also given

Recent studies of the effects of the volcanic ash fallout on storage tanks have shown the potential causes of failure for both fixed and floating roof tanks. The vulnerability of these facilities has been defined through the estimation of threshold values of the ash load on their roofs and exceedance probabilities of these limits. It has been observed that the amount of the overhead on the roof is much greater when the ash is saturated with rain because of the formation of aggregates. This paper aims to analyse the influence of this phenomenon on the potential damage of tanks located in the area surrounding Mt. Etna. © Copyright 2014, AIDIC Servizi S.r.l.

This work is the result of the experimental analysis of the effect of different alkyl anilines (accelerators) on the self-polymerisation of methyl methacrylate. The state of the art before this study suggested that there should have been no significant increase in the rate of polymerisation reaction until the initiator (typically a peroxide) is added to the stabilised mixture of monomer and accelerator. All the experimental results found during this investigation indicated instead that the accelerators can affect the rate of polymerisation even if no peroxide is present in the system. Different kinds of alkyl anilines in methyl methacrylate have been tested by differential scanning calorimetry and adiabatic calorimetry. The experimental data allowed us to define safety ranges for the polymerisation reaction.

The volcanic ash fallouts are able to affect the human health and the integrity of industrial facilities. The study of the effects associated with ash emissions was the objective of the PRIN project carried on by the authors of this paper. The activities of the project allowed to define a simplified procedure for the vulnerability assessment of human and industrial targets, that has been applied to the area surrounding Mt. Etna. Recent several ash fallouts from this volcano have caused significant problems to the resident population, traffic and industrial activities. The application of the study to this territory provided a vulnerability mapping to support the decision making both in terms of the definition of protection measures and of the emergency planning and management. Copyright © 2013, AIDIC Servizi S.r.l.

Following recent natural disasters, which have had a significant impact on chemical plants, the study of Natural-Technological risks (Na-Tech) has increased worldwide. This work is focused on the study of volcanic Na-Tech events and aims at defining a procedure for the representation of the vulnerability of industrial facilities in areas with the potential volcanic ash fallout using a Geographic Information System (GIS). The methodology has been applied to the area surrounding Mount Etna (Sicily, Italy). Indeed, this volcano has had recently explosive eruptions with consistent ash fallout and is surrounded by a number of industrial installations and also petrochemical plant. This paper is focused on the choice of the most suitable interpolation procedure for the vulnerability mapping in areas where input data is available only for few points, finally comments on the procedure validation are also provided. © 2013, AIDIC Servizi S.r.l.

The use of different calorimetric techniques for process design and scale up is well consolidated, allowing the definition of the kinetic and thermodynamic of the process and the evaluation of several parameters useful to optimization and process safety. During a calorimetric analysis temperature (or a temperature difference) is measured; from experimental data it is for example possible to calculate the heat flow and the heat evolved by the reaction and consequently the conversion and the reaction rate constant just if kinetics of the reaction is known. To overcome these limitations and to obtain additional information about the reaction, it is possible to couple to a calorimeter different type of sensors such as densitometers, refractometers, electrochemical, chromatographic and spectrophotometric probes. Some of these sensors are able to log data on line during the process and so to monitor the reaction at the same time of the calorimetric analysis. For safety aims, it is important to choose a sensor whose time for the analysis is comparable to the reaction time in order to have an accurate profile of the monitored parameter during the reaction (Moritz, 1989). In a previous study (Parisi, 2002) an Ultra Violet - Visible spectrophotometer was integrated to a reaction calorimeter to analyse the kinetic of a specific reaction. In this work a similar UV - Vis probe has been coupled to an isoperibolic reaction calorimeter in order to study the feasibility of the application of an Early Warning Detection System (EDWS) to a spectrophotometric signal. The innovation of this integration of techniques is the analysis of the spectrophotometric signals with a reactor stability criterion based on divergence theory in order to check if this method of monitoring allows detecting runaway reactions at an early stage of the process, when it is still possible to take protective measures.

The fallout of ash from Mt Etna has caused significant problems to the resident population, road/rail and air traffic and production activities. This work is focused on the study of the potential damage to industrial structures caused by the fallout of volcanic ash and describes the main objectives of a research project aimed at defining the potentially critical scenarios for industrial installations and infrastructures due to eruptions of Mt. Etna. In the first part of this paper, a description of the method used for the analysis of the potential damage to storage tanks due to ash fallout will be given. The second part will provide the results of the application of the method. Copyright © 2012, AIDIC Servizi S.r.l.

In the last decade, the importance of risk analysis in the transport of dangerous goods has been evidenced by several studies showing that in some cases the risk associated with the transport of hazardous substances can be compared to those in chemical plants (processing units and storage). In this work the analysis of an accident in transport of dangerous goods is described. The objective of this study is to contribute to the determination of the causes that brought about the self-polymerization of commercial divinylbenzene (DVB 63%) contained in an isothermal-container, in order to prevent future occurrence of this type of accidents. Residence time and conditions during transport and storage of monomers, in particular the storage temperature, are very important factors that affect their self-polymerization aptitude. Concerning the cause of accidents it has been supposed that the quantity of oxygen in the tanker probably was insufficient to activate properly the inhibition mechanism to prevent the self-polymerization. According to this consideration the self-polymerization of DVB and the inhibition mechanism of 4-tert-Butylcatechol (TBC) have been studied as a function of temperature and monomer exposure to air with Differential Scanning Calorimetry and Adiabatic Calorimetry.

The effect of high-flux hemodialysis membranes on patient survival has not been unequivocally determined. In this prospective, randomized clinical trial, we enrolled 738 incident hemodialysis patients, stratified them by serum albumin < or = 4 and >4 g/dl, and assigned them to either low-flux or high-flux membranes. We followed patients for 3 to 7.5 yr. Kaplan-Meier survival analysis showed no significant difference between high-flux and low-flux membranes, and a Cox proportional hazards model concurred. Patients with serum albumin < or = 4 g/dl had significantly higher survival rates in the high-flux group compared with the low-flux group (P = 0.032). In addition, a secondary analysis revealed that high-flux membranes may significantly improve survival of patients with diabetes. Among those with serum albumin < or = 4 g/dl, slightly different effects among patients with and without diabetes suggested a potential interaction between diabetes status and low serum albumin in the reduction of risk conferred by high-flux membranes. In summary, we did not detect a significant survival benefit with either high-flux or low-flux membranes in the population overall, but the use of high-flux membranes conferred a significant survival benefit among patients with serum albumin < or = 4 g/dl. The apparent survival benefit among patients who have diabetes and are treated with high-flux membranes requires confirmation given the post hoc nature of our analysis.

Climate Change is caused by greenhouse gases such as CO2. Worldwide increases in energy demand coupled with a continued reliance on flues derived from fossil resources have contributed to a significant and severe increase in atmospheric levels of CO2. Scenarios for stabilizing the emissions of CO2 suggest its stabilization through a portfolio of mitigation actions including the deployment of Carbon Capture and Storage projects (CCS). One of the process step consists in the transportation of the CO2 to a storage location and this work focuses on dry ice formation following the accidental release of pressurized CO2 from CCS pipelines. The main aim is to investigate the dynamic and thermal fluid dynamic behaviour of a dry ice particle travelling down to the ground through air after the expansion to atmospheric conditions. This is achieved analyzing the influence of all the variables involved in the phenomenon, that is to say: particle initial diameter, post – expansion velocity and temperature, position and direction of the release point, air temperature, relative humidity and Pasquill atmospheric class of stability. The effect of these parameters on the in – flight life of the particle is discussed assembling an analytical model of equations of motion and of mass and heat transfer in order to establish which one is the most influential.

BACKGROUND: This study is part of a 3-country study testing whether normal levels of hemoglobin (Hgb) delay the progression of left ventricular (LV) growth in chronic kidney disease (CKD) patients not on dialysis. METHODS: This was an open-label, randomized, multicenter, controlled trial conducted in 27 tertiary-care hospitals in Italy. Treated subjects (n=46) received epoetin-alpha (EPO-alpha) to maintain Hgb levels in the range 12-14 g/dL. Control subjects (n=49) were not treated unless their Hgb decreased to 9.0 g/dL. Primary outcome was LV mass index (MI) change after 24 months. Subcutaneous EPO-alpha was withdrawn in Europe and the study prematurely terminated; therefore, a 12-month analysis was carried out. RESULTS: Mean age was 57 years (38% were women, 18% with diabetes, 76% taking ACEI or ARB and 22% statins). EPO-alpha median final dose was 2,000 IU/week. Hgb significantly increased (12.4 -/+ 1.1 g/L) for the treatment group and decreased for controls (11.3 -/+ 1.3 g/L; p