1,721,190 research outputs found
Investigating the properties of fireproofing materials for an advanced design of equipment protection
No full textFire scenarios in process industry have a high potential to cause severe asset damage. Fireproofing is a consolidated technique for passive fire protection for units and supporting structures. Since several materials are available for passive fire protection, it is important to choose the best solution for the protected equipment and critical fire scenarios. Current practice in rating fireproofing materials does not provide sufficient information about the protection granted to process equipment: for example, the 'time-to-failure' of pressurized vessels protected by fireproofing materials cannot be predicted from the results of standardized fire tests. This study investigates the key properties (e.g. density, geometrical structure, thermal degradation and thermal conductivity) of representative fireproofing materials, in order to better understand the elements underlying the actual protection performance. An experimental activity was focused on the definition of fundamental models to describe the thermo-physical properties of the materials. The investigation cast the foundations of a better understanding of the dynamics underlying the effective design for passive fire protection, identifying the criticalities and limits of the alternative fireproofing options. The changes in the physical properties of materials during fire exposure were confirmed to play a major role on the protection performance. Such effects could not be accounted for complex geometries by conventional simplified approaches alone: thus, the proposed approach paves the way for a safer and more cost effective design of passive fire protection systems
Lightweight alkali activated composites by direct foaming based on ceramic tile waste and fly ash
Full text linkThis study aims at investigating for the first time if ceramic waste coming from the rectifying process of porcelain stoneware tiles are suitable to prepare alkali activated lightweight composites. After successfully designing alkali activated materials based on ceramic waste, different foaming agents were added alone or in combination with sodium dodecyl sulfate acting as pore stabilizing agent. Addition of expanded perlite as lightweight constituent was also tested. Different properties, such as geometric density, water absorption, porosity and pore size distribution by mercury intrusion porosimetry and SEM observations, and thermal conductivity, were measured in view of their potential future applications. The results highlight that combining ceramic tile waste as raw materials, hydrogen peroxide as foaming agent, sodium dodecyl sulfate as pore stabilizing agent and expanded perlite allow the preparation of optimized lightweight composites with a density of 0.75 g/cm3, a water absorption greater than 70 % and a thermal conductivity of 0.26 W/mK
Optimization of catalytic upgrading of pyrolysis products
No full textBiofuel production is an attractive alternative to conventional fossil fuel, effectively solving problems like resource depletion and greenhouse gas emission. Use of solid feedstock and organic wastes to produce biofuel is seen as a promising route from the economical and sustainability point of view. Pyrolysis is one of the possible thermochemical methods to convert solid biomasses to valuable liquid and gas products. However, the bio-oil obtained from pyrolysis can be used as biofuel only after an upgrading step. In facts, raw bio-oil contains various oxygenated organic compounds, which make it instable, and has high average molecular weight, high viscosity, and low heating value. A suitable method for upgrading bio-oil is catalytic cracking of the pyrolysis products. Catalytic upgrading converts high molecular weight compounds of the biooil into lower-weight molecules. This work investigated the slow pyrolysis and in-situ catalytic cracking of chicken manure in a lab-scale fixed bed reactor. The application to chicken manure is of upmost practical interest, since the pyrolysis process would provide an environmentally safe manner for solving the current problems about disposal of this waste. The catalyst considered was pellet-extruded zeolites (zsm-5). In order to study the effect of influential factors (temperature and catalyst to biomass ratio) on the obtained products, experimental design techniques were used. The process was investigated in both the absence and presence of the in-situ catalyst. The results were statistically analyzed and the influential factors were optimized with the aim of obtaining products with higher quality and heating value. The results can give a clue on how to compromise between the quality of the two potentially valuable products of pyrolysis process (bio-oil and biogas) and the energy requirement of the process
Critical Cybersecurity Scenarios in Drinking Water Treatment Plants
No full textThe increasing interconnectivity with external networks and the higher reliance on digital systems make chemical and process industries, including waste and drinking water treatment plants, more vulnerable to cyberattacks. Historical evidence shows that these attacks have the potential to cause events with severe consequences on property, people, and the surrounding environment, posing a serious threat. While the risks deriving from the malicious manipulation of the Basic Process Control System (BPCS) and the Safety Instrumented System (SIS) in chemical and Oil&Gas facilities have been systematically analysed in the available literature, including previous works of the Authors, the analysis of the consequences of cyber-attacks to drinking water treatment plants has not been conducted to date. To fill this gap, in the present study the methodology POROS 2.0 (Process Operability Analysis of Remote manipulations through the cOntrol System) developed by the Authors was applied to a drinking water treatment plant, providing valuable insights on possible critical scenarios originated by cyber-attacks in these facilities
A two-tier approach to the optimization of a biomass supply chain for pyrolysis processes
No full textThe optimal supply chain configuration for biomass production on a given territory is identified by a two-tier approach, which considers both the environmental and the economic points of view. The first tier performs a quick evaluation of the supply chain, based on simplified assumptions and on average values of the parameters characterizing the geographical territory. The second tier allows for the inclusion of spatially explicit parameters of the territory and realizes a more detailed optimization of the supply chain using a multi-objective Mixed Integer Linear Programming framework. A demonstrative case study is presented for the bio-fuel supply to a centralized electric power plant. The considered supply chain is based on miscanthus, cultivated in marginal terrains and converted to pyro-oil in a number of delocalized plants for long distance shipment. The results obtained from the two tiers of the model provide quantitative information, to support quick and effective decision making on the optimal configuration of the supply chain in terms of plant size, location, transport logistics and cultivation
Key Performance Indicators for Implementing Sustainability and Environmental Protection in Early Process Design Activities
Full text linkThe adoption of a sustainability perspective in chemical industry shall start from the early phases of process
design (e.g. conceptual design, technology selection, process development) where the key drivers in the
environmental, economical, and hazard fingerprint of a process are defined. These phases also allow the
opportunities for the lower cost of design change. A sound support of design activities requires quantitative
tools, allowing for the assessment of the sustainability profile of a process, the identification of possible
improvements and supporting informed tradeoffs.
Though several tools for process development were proposed in last decades, application is still limited in the
current practice because of issues on data requirement, indicator definition and customization to specific
application needs (e.g. PFD definition in design of polypropylene production plants).
This study focuses on the application to the early process design of environmental and exergy Key Performance
Indicators (KPIs) to support sustainability-oriented design activities. It was tailored on the specific industrial
application of polypropylene production plants. The choice of a specific sector allowed customization of the
method, promoting ease of application and allowing the assessment of multiple scenarios (e.g. sensitivity on
material and energy supply strategies, comparison of different technologies). Results obtained draw up
sustainable guidelines to improve design activities within the scope in a lifecycle perspective
Indirect environmental benefits of a variable set-point for HCl emission in waste-to-energy flue gas cleaning
No full textHydrogen chloride (HCl) is a typical contaminant generated in waste combustion, whose emission is strictly regulated. In order to cope with severe limits issued by local authorities on the annual mass flow of HCl emitted, several European waste-to-energy plants perform at least a two-stage abatement of the pollutant and operate with a set-point for HCl concentration at stack well below the hourly emission limit imposed by the Industrial Emissions Directive. Even though the operating conditions in a WtE facility are highly variable (both in terms of HCl release from the burnt waste and of operating temperature of the HCl removal system), it is common industrial practice to keep both the set-point for HCl concentration at stack and the set-point for HCl concentration between the two abatement stages at a constant value. However, this might force the abatement system to operate far from its design conditions and from the optimal reactivity window of the adopted HCl removal agent, thus increasing the consumption rate of reactant and the consequent generation rate of process residues. Both the supply chain of reactants and the management of residues generate environmental impacts. The present work demonstrates that the adoption of variable values for both set-points can provide cost savings and indirect environmental benefits, thanks to the reduction of reactant consumption and residue generation. By considering as case study a WtE plant equipped with a two-stage dry HCl removal system, a year of operation of the plant was analysed. The operating costs and life cycle impacts generated by the actual operation of the HCl treatment system with constant set-points were compared with those generated if the plant had operated with variable set-points, simulated with a semi-empirical model for HCl removal tuned on historical process data from the plant. A 13 % reduction of the life cycle global warming impact and an 8 % reduction of the life cycle acidification impact, in addition to 10 % cost savings, were associated to the utilisation of variable set-points
Risk Identification for Cyber-Attacks to the Control System in Chemical and Process Plants
No full textCyber-attacks are becoming a growing concern for process facilities that highly rely on Operational Technology (OT) systems for the potential severity of the consequences on humans, assets, and the environment that can be generated. The study is based on the development of synergic tools aimed at filling the gap in the availability of specific approaches to support cyber risk identification phase required by Security Vulnerability/Risk Assessment methodologies and the cybersecurity risk assessment proposed by ISA/IEC 62443 series of standards on cybersecurity of Industrial Automation and Control Systems (IACS)
A Bow-Tie Approach for the Identification of Scenarios Induced by Physical Intentional Attacks to Chemical and Process Plants
Full text linkThe possibility of inducing major accident scenarios by physical intentional attacks (e.g. terrorist attacks) to chemical and process plants processing and storing hazardous substances, has been increasingly recognized in the last decades. The identification of the credible security scenarios (chain from attack scenarios to major accident scenarios) is required by Security Vulnerability/Risk Assessment (SVA/SRA) methodologies, but an evident lack of supporting tools is present in the literature. The present study proposes a Bow-Tie approach for the identification of reference security scenarios to support hazard identification phase in SVA/SRA. The potential use of the results is demonstrated on a test case (industrial atmospheric tank storing a flammable liquid)
Carbon balance of a waste biomass supply chain: The integration of a pyrolysis-Based valorization process
Full text linkIn the present work, the valorisation of waste biomass (olive wood) was analysed from an environmental standpoint. A process of thermo-catalytic reforming in which bio-char, bio-oil and syngas are produced, have been integrated to olive wood waste supply chain. In particular, the energy efficiency evaluation was carried out by solving energy and mass balances on the system. Furthermore, the capacity of the systems in energy-self- sustainability has been evaluated along with thermal recovery methods and different uses for the products obtained. The entire supply chain was examined in order to identify its optimal configuration, minimizing environmental charges. Environmental performance is assessed by considering greenhouse gases (GHGs) expressed in terms of CO2equivalent as an indicator: this approach allows to define the supply chain incidence on the global warming relative to each of the phases involved in the process. In order to obtain the better configuration in terms of thermal and electrical power for the self-sustainability of the process, and also in terms of CO2emission, different scenarios for the use of the products obtained by the process were evaluated. The results have shown that it is possible to self-sustain the process through the proper use of the products. The right combination of use of syngas, bio-oil and char allows to satisfy the thermal and electrical demands of the system by avoiding the use of the energy by the grid. In addition, the choice of the optimal configuration for the use of the products (eg use of gas in a cogeneration plant and use of char to field as fertilizer) allows to reduce environmental impacts by reducing CO2emissions and making the whole process eco-friendly
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