Release Of Toxic Gases Research Articles

Threat and Risk Analysis-Based Neural Network for a Chemical Explosion (TRANCE) Model to Predict Hazards in Petroleum Refinery.

Risk analysis and prediction is a primary monitoring strategy to identify abnormal events occurring in chemical processes. The accidental release of toxic gases may result in severe problems for people and the environment. Risk analysis of hazardous chemicals using consequence modeling is essential to improve the process reliability and safety of the refineries. In petroleum refineries: toluene, hydrogen, isooctane, kerosene, methanol, and naphtha are key process plants with toxic and flammable chemicals. The major process plants considered for risk assessment in the refinery are the gasoline hydrotreatment unit, crude distillation, aromatic recovery, continuous catalytic reformer, methyl-tert-butyl-ether, and kerosene merox units. Additionally, we propose a threat and risk analysis neural network for the chemical explosion (TRANCE) model for refinery incident scenarios. Significantly, 160 attributes were collected for the modeling on the basis of the significance of failure and hazardous chemical leaks in the refinery. Hazard analysis shows that the leakages of hydrogen and gasoline at the gasoline hydrotreatment unit, kerosene at the kerosene merox plant, and crude oil at crude-distillation units were areas of profound concern. The developed TRANCE model predicted the chemical explosion distance with an R2 accuracy value of 0.9994 and MSE of 679.5343.

ANALYSIS AND RECOMMENDATIONS ON THE USE OF POLYMER AND PHENOL-BASED MATERIALS FOR COAL MINES

In this study, besides summarizing the properties of polymer materials used in underground coal mines, the problems that may arise in the use of polymer materials used in coal mines and the deficiencies of the relevant existing standards are discussed. Most of the safety accidents of polymer materials are encountered with results such as spontaneous combustion of materials, combustion of coal seams due to these combustions, and the release of toxic and harmful gases. The main causes of combustion accidents can be summarized as high reaction temperature, insufficient flame retardant, uncontrollable reaction process, defective standards and awareness of insufficient safety materials. Within the scope of this study, health problems that may be encountered due to the carcinogenic formaldehyde content of phenol-based filling materials will also be mentioned, and reasonable suggestions and measures will be discussed to prevent these and similar situations. The aim and including of this study is to establish a guide on the safe use of polymer materials in underground coal mines and correct understanding of the possible risk associated.

Establishment of Control Room Habitability Analysis Methodology Postulating the Event of Pressurized Tank/System of Hazardous Gas Release

A new methodology using a free turbulent flow model to evaluate control room habitability is developed, and the theoretical model can be applied to the postulated event of rupture or line break of the on-site hazardous gas pressurized tank/system. Based on the conservation of mass law and momentum equations, correlations of the control room ventilation hazardous gas intake concentration and the control room buildup toxic concentration were established and can be used to evaluate control room habitability. Compared with current methodology widely used in the industry (introduced by NUREG-0570), the developed theoretical analysis methodology is applicable to events occurring without any constraint on the distance between the site of toxic gas release and the inlet of the control room fresh air intake or the control room. With a given amount of hazardous gas release source, the analysis results indicate that maximum control room toxic gas concentration will depend on the mass release rate or its break size, the density of the hazardous gas, and the distance between the site of the toxic release and the control room fresh air intake. The limiting case of the control room habitability analysis will occur at the break size resulting in the highest control room toxic gas concentration. The control room toxic gas transient concentration at the limiting break size can be predicted by the model and compared with its acceptance criteria of short-term exposure limit and time-weighted average to evaluate the control room habitability whether protection actions of the control room operators are required to prevent incapacitation or death due to the postulated events of toxic gas release.

Al2O3/ZnO composite-based sensors for battery safety applications: An experimental and theoretical investigation

Lithium-ion batteries are vital in one of the key nanotechnologies required for the transition to a carbon-free society. As such, they are under constant investigation to improve their performance in terms of energy and power densities. At the same time, safety monitoring is crucial, as defects in the battery cell can lead to serious safety risks such as fires and explosions as a result of the enormous heat generated in the electrolyte, causing the release of toxic and flammable gases in the so-called thermal runaway. Therefore, early and rapid detection of the gases that form before thermal runaway is of particular interest. To this end, solid-state sensors based on new heterostructured materials have gained interest owing to their high stability and versatility when used in the harsh battery environment. In this work, heterostructures based on semiconductor oxides are employed as sensors for typical components of battery electrolytes and their decomposition products. The sensors showed a significant response to vapors produced by battery solvents or degassing products, making them perfect candidates for the development of successful new prototypes for safety monitoring. Here, we have used a simple and versatile method to fabricate the Al2O3/ZnO heterostructure, consisting of atomic layer deposition (ALD) and thermal annealing steps. These Al2O3/ZnO heterostructures have shown a response to the vapours of 1,3-dioxolane (DOL, C3H6O2), 1,2-dimethoxyethane (DME, C4H10O2), LiPF6, ethylene carbonate (EC) and dimethyl carbonate (DMC), which are typically used as components of the electrolytes in LIBs. The sensors showed a significant response to vapors produced by battery solvents or degassing products, significantly increasing the chances of developing new successful prototypes for safety monitoring. Density functional theory (DFT) calculations were employed to systematically compare the surface reactivity of the α-Al2O3(0001) and the ZnO101̅0 facets, as well as the Al2O3/ZnO101̅0 interface, towards C3H6O2, C4H10O2, nitrogen dioxide (NO2) and phosphorous pentafluoride (PF5), in addition to H2O to assess the impact of relative humidity on the performance of the gas detector. The scanning tunnelling microscopy (STM) images and molecular binding energies compare well with our experiments. The energies of molecular adsorption at the heterostructure suggest that humidity will not affect the detection of the volatile organic compounds. The results presented here show that the potential to detect vapors of the components used in the electrolytes of LIBs, combined with the size control provided by the synthesis method, makes these heterostructures extremely attractive in devices to monitor battery safety.

Pre-to-post Diwali air quality assessment and particulate matter characterization of a western coastal place in India.

Diwali has become an occasion of air and noise pollution, and the release of particulate matter and toxic gases has chronic and acute effects on people and their environment. Thus, an air quality assessment study was done by CSIR-CSMCRI covering the pre-to-post Diwali 2021 period (5days) in the three locations (traffic, residential, and control) of Bhavnagar. The average 24-h concentration of PM10 (380µg/m3), PM2.5 (182.2µg/m3), and SPM (403µg/m3) was significantly higher during Diwali, exceeding the National Ambient Air Quality Standards (NAAQS). The concentrations of SO2 and NO2 were 121.8µg/m3 and 102.1µg/m3. Metals like Zn, Al, Pb, and Mn were found in higher concentrations during the study. The air quality index (AQI) was maximum on Diwali, resembling very poor air quality. More elements and oxides were detected in PM2.5 (S, Al, Mg, Ba, and Zn and their oxides) than in PM10 (Fe and S) through WDXRF. Water-soluble anions like SO42-, Cl-, and NO3- were observed during the study, with a higher SO42- (64%) on Diwali. The PM10 morphology and mapping of elements were done using SEM-EDX. Emerging contaminants, specifically phthalate groups, were detected through GCMS. The enrichment factor (EF) showed Zn and Pb originating from anthropogenic activities. The air quality data was validated using a variance test, least significance difference (LSD), correlation, and principal component analysis (PCA). This paper is the first to highlight the air quality assessment during Diwali for a western coastal place in India. It is time to implement regulations on burning firecrackers for pollution reduction, aiming to achieve a sustainable atmosphere.

Release of toxic gases in the process of cemented backfill with phosphorus waste

Release of toxic gases in the process of cemented backfill with phosphorus waste

Effect of a palladium catalyst and initial pressure on methane-air catalytic combustion process in a helical coil microchannel: A molecular dynamics approach

Catalytic combustion is a flame-free process which occurs at low temperatures and reduces less release of nitric oxide (NOx). Although catalysts help reduce the release of toxic gases, they have detrimental environmental effects. Therefore, by simulation these reactions, a constraint on the flammability limits and improving their performance can be achieved. In this research, using the molecular dynamics (MD) simulation, the catalytic combustion process of air-methane was studied in a helical microchannel. Palladium (Pd) was used as the catalyst. The results show that adding a Pd catalyst further improved the simulated structure's thermal performance(TP). The heat flux(HF) and thermal conductivity (TC) of atomic samples increased from 2067 W/m2 and 1.28 W/m.K to 2096 W/m2 and 1.45 W/m.K with an increase in atomic ratio Pd catalyst from 1 to 4%. Finally, the combustion efficiency (CE) converges to 93% in the presence of 4% Pd catalysts. By increasing the initial pressure (IP) from 0 to 10 bar, the maximum density did not change much, and the velocity and temperature values decrease in terms of the limitation in atomic oscillations. Increasing the IP reduces the HF and TC from 2096 W/m2 and 1.45 W/m.K to 1981 W/m2 and 1.19 W/m.K. Regarding different types of combustion processes, such as catalytic combustion, were considered in different types of industrial applications, it is expected to study the effect of the parameters of the atomic ratio of Pd catalyst and the IP, propose an optimal mechanism to create catalytic combustion in real and practical samples.

Environmental Sustainability in Fashion Industry through Sharing Economy

The fashion industry is among the leading global pollution contributors. Overproduction and underutilization of clothes have resulted in a phenomenon of environmental pollution through the release of toxic gases and dumping. The sharing economy offers an incredible solution to the problem. Renting clothes utilized for special occasions instead of purchasing new ones can reduce pollution created by the continuous production of new ones and premature dumping. The Business Model Canvas provides an overview of how the sharing economy can be implemented in the fashion industry.

Facile Synthesis of Zinc‐Containing Mesoporous Silicate from Iron Tailings and Enhanced Fire Retardancy of Rigid Polyurethane Foam

AbstractIron tailings (ITS), as solid decay absolved afterward beneficiation, are adverse to the environment. ITS to prepare zinc‐containing mesoporous silicate (MAO‐Zn) by a calcination‐crystallization method are used. An admixture of ammonium polyphosphate (APP) and MAO‐Zn can solve the problem of poor flame retardancy in rigid polyurethane foam (RPUF), giving them higher thermal stability and lower heat release. The total heat release rate and smoke factor values exhibited by RPUF‐3 are 24.52 MJ m−2 and 234.29 MW m−2 respectively, a decrease of 38.45% and 29.60% respectively compared to pure RPUF. Lower combustible and toxic gas release intensities are in RPUF‐3. Meanwhile, RPUF‐3 possesses enhanced compactness char residue with higher graphitization degree, endowing RPUF‐3 with excellent fire observed performance. This work demonstrates the potential of ITS in the fire retardancy field.

Investigation of the Distribution of Heavy Metals in the Soil of the Dahuangshan Mining Area of the Southern Junggar Coalfield, Xinjiang, China

Coal mining activities have a series of impacts on the local eco-environment, such as air pollution due to the release of toxic gases, contamination of soil with heavy metals, disturbance and contamination of surface and subsurface water, and damage to land resources with surface subsidence and accumulation of solid waste materials. This study investigated the distribution of heavy metals in mining sites by analyzing the heavy metal content in soil samples from different sites in the Dahuangshan mining area of the southern Junggar coalfield (Xinjiang, China). The results show that area C has the highest Cu content; and area B has the highest Mn content, the highest Zn content, the highest As content, and the highest Cd content, which indicate that area B underwent potential multiple heavy metal contamination. It also shows that the Cd is the major heavy metal for all three areas. The different eco-environmental indices, including the Nemerow comprehensive pollution index, the geo-accumulation index, and the potential ecological risk index, all show the same results, i.e., that Cd is the major potential contaminant in all three types of soil.

Self-interlocked MXene/polyvinyl alcohol aerogel to enhance flame retardancy, dynamic mechanical properties and electrical conductivity of carbon fibre/epoxy composites

Carbon fiber (CF) reinforced polymer composites (CFRPs) are often damaged by impact, fire and lightning strikes, which limit their wide applications. In this work, the flame retardancy, impact resistance and electrical conductivity of CF reinforced epoxy (EP) composites have been simultaneously improved through the self-interlocked 3D skeleton of Ti3C2Tx/polyvinyl alcohol (PVA) aerogel (TPA). The CF/EP and TPA/CF/EP composites have been characterized using Cone tests, split Hopkinson bar tests, and current tests. It is shown that TPA can suppress the release of heat, smoke particles and toxic gases in virtue of heat trapping, catalytic and barrier mechanisms at high temperature. The stitching effect of TPA can effectively limit the delamination failure and promote the absorption of fracture energy. Compared with the CF/EP composites, the Young's modulus of TPA/CF/EP composites has been increased by 22.7% in the range from 1967 s−1–2003 s−1. The crack initiation time of the TPA/CF/EP composites was delayed by about 50%. Moreover, the 3D skeleton of TPA facilitates the formation of current channels within the TPA/CF/EP composites, which enables the overall improvement of the electrical conductivity of the TPA/CF/EP composites in the longitudinal, transverse, and through-thickness directions. Among them, the electrical conductivity increases up to 61% in the through-thickness direction has been attained.

Thermal Stability between Sulfide Solid Electrolytes and Oxide Cathode.

In pursuit of high-energy/power density, lithium-ion batteries suffer from increasing safety risks that need to be urgently solved. These safety problems promisingly might be solved by replacing liquid electrolytes (LEs) with inorganic solid electrolytes (SEs), because of their high thermal stability and nonflammability. However, thermal stability studies on sulfide SEs have been rarely reported, due to their extremely high reactivity, strong corrosiveness, instability to air, toxic gas release, etc. To fill this gap, thermal stability performances of sulfide SEs are verified from the perspectives of essential combustion elements in this work. Simple and effective experimental devices/approaches have been developed to systematically study the thermodynamic and kinetic properties of thermal stability between typical sulfide SEs (Li3PS4, Li7P3S11, Li6PS5Cl, LSPSCl, Li4SnS4) and oxide cathode Li1-xCoO2 with different delithiation states. Practical improved methods are realized to block the thermochemical interfacial reaction for enhanced thermal stability between sulfide SEs and oxide cathodes.

Characterization and Purification of Groundwater Using Carbon Dot Impregnated into Biosand Filters: A Case of Warri and its Environs, Niger Delta, Nigeria

The release of toxic gases and spills into the ecosystem prior to anthropogenic activities can increase the level of pollutants in hydrological systems. This possibly influences the number of harmful substances that percolate into aquifers. The drilling of polluted aquifers for domestic and drinking purposes and consuming such water untreated consequently increases the risk of developing water-related health issues. The study presents the quality and purification of groundwater samples in the Warri metropolis through water-quality analysis and biosand filtration method Aappropriatemethod (Appropriate Technology Enableds Development technique), respectively. The pH results were very low in all the groundwater samples presented with values ranging from 5.16±0.03 to 6.81±0.09, except for table water samples serving as controls. Total iron concentration was above the regulatory limits of 1.00 mg/L in some locations, recording concentrations between 0.758±0.340 mg/L and 1.204±0.740 mg/L. Groundwater samples contaminated with coliform bacteria were recorded in some locations. It suggests that the groundwater quality of the studied locations is relatively poor and unsafe for drinking untreated. This is possibly due to high hydrocarbon exploration and production activities, together with other anthropogenic activities in the area. Nevertheless, the filtration of the groundwater samples with biosand filter effectively improved the taste, reduced the iron content, removed particles, and eliminated microbial contaminations. However, the pH was relatively low after filtration and was further enhanced in the filtration with the carbon dots. The carbon dot filtration can be viewed as a better substitute to for granites in the filter beds of the biosand filter unit to influence pH conformance.

Geospatial alternatives for quantification of bio-thermal influence zone in the vicinity of a solid waste dump.

Owing to the release of toxic gases, leachate and thermal emissions that originate from waste dumps, these sites significantly impact environmental sustainability. The study attempts to assess the deleterious impact of municipal solid waste (MSW) dump on surrounding forested landscape by employing geospatial technologies, which are cost and time-effective. For this purpose, temporal period ranging from 2015 to 2020, having 41 valid satellite observations has been selected for study. Firstly, the radii of intense hazardous zone and hazardous zone have been measured, as two separate parameters, which are 580 ± 30 m and 1260 ± 30 m, respectively. Secondly, average spatial extent of bio-influence zone is measured to be 1262 m while the average thermal influence zone extends up to 530 m around the MSW dumping site. A detailed analysis of influence zone variations reveals that the bio-influence zone depends on multitude of meteorological parameters, whereas the thermal influence zone relies mainly on seasonal temperature fluctuations. Moreover, the level of severity of emissions from MSW decomposition directly depends upon temperature. The long-term variability analysis of these hazardous zones reveals the stationarity of their spatial extents, signifying forest resilience. This study has proved significance of geospatial techniques as an alternate of expensive and time intensive assessment methods involving in situ measurements. So the proposed technique is beneficial for environmentalists, decision-makers and municipal authorities for analysing the extent and severity of MSW pollutants for forest community to address the problem of ecological degradation.

Covalent grafting diazotized black phosphorus with ferrocene oligomer towards smoke suppression and toxicity reduction.

In comparison with the thermal hazard of polymers, noxious smoke and gas produced by the combustion of polymers make the environment self-purification a huge challenge. As a new type of a highly effective flame retardant, black phosphorus (BP) can effectively decrease the thermal hazard of polymers, but its performances in smoke suppression and toxicity reduction are unsatisfactory. In this article, a method of covalently grafting diazotized BP with a ferrocene oligomer was applied to promote the smoke suppression and toxicity reduction efficiency of BP. In our work, the BP-NH nanomaterials with a mass of amino groups on the surface were acquired by diazotizing the BP. Then, the BP-Fe was obtained by covalently grafting the ferrocene chloride salt and nitrogen-containing heterocycles on the surface of BP. The smoke production rate (SPR) and total smoke production (TSP) values of the epoxy resin (EP) decreased by 49.8% and 52.5% with the addition of 2wt% BP-Fe, respectively. In comparison with previous studies, this work was far more effective than the previous work in smoke suppression and flame retardant. The release of toxic gases (CO and HCN) and volatile organic compounds in the EP was also effectively inhibited at the same time. In addition, the storage modulus and tensile strength of nanocomposites increased by 35.1% and 27.2% with the addition of 1wt% BP-Fe. This work also provides a new idea on how to simultaneously strengthen the toxic smoke suppression, mechanical properties, and flame retardant of polymer materials.

Understanding and managing hazards of lithium‐ion battery systems

AbstractOver the last decade, the rapid development of lithium‐ion battery (LIB) technology has provided many new opportunities for both Energy Storage Systems (ESS) and Electric Vehicle (EV) markets. At the same time, fire and explosion risks associated with this type of high‐energy battery technology have become a major safety concern. Many advances have been made in understanding reactive chemistry and fire‐safety issues related to both thermal runaway and fire hazards presented by LIBs. Thermal runaway or fire can occur from battery manufacturing defects, charging system malfunctions, extreme abuse conditions that may result from a faulty operation or traffic accidents, and end‐of‐life battery handling. Failure of the battery is often accompanied by the release of toxic gas, fire, jet flames, and explosion hazards, which present unique exposures to workers and emergency response personnel. LIB fires often present complex emergency response challenges, requiring extensive amounts of water applied over several hours to cool batteries, extinguish the fire, and prevent reignition. This paper overviews the fundamental principles required to establish a basis of safety for proper storage, handling, and use of LIBs. Starting with an overview of the technology used in LIB systems, the paper will provide a review of common sources for thermal runaways and fire events and practical ways used to prevent their occurrence. While regulatory coverage for LIB storage, handling, and use is still in various stages of development, a growing body of international best practices and consensus views have emerged. Finally, to safely address thermal runaway and fire events, an overview of global best practices for emergency response activities involving LIBs is provided.

Performance and emission analysis of a CI engine fueled with parsley biodiesel–diesel blend

Pollution-induced environmental deterioration is one of the serious aspects that must be solved. As a result, biodiesel was made from a novel material (Parsley seed oil) through an alkali-induced transesterification reaction. The efficiency, as well as exhaust emission tests, were performed by running the prepared parsley biodiesel blends (mixture of biodiesel and diesel fuel in different proportions) in an engine. The ideal blend for enhancing engine performance was discovered to be B20, which displayed steady performance attributes without requiring any modifications to the diesel engine. The B20 parsley biodiesel blend had fewer emissions than diesel, notably hydrocarbons, and carbon monoxide except for nitrogen oxides and carbon dioxide. B20 Parsley blends were also shown to emit less pollution than other blends (B5 and B10). A high reduction in CO, CO2 and HC emissions for B20 was recorded at 33.9%, 29.73%, and 11.38% relative to diesel except for NOx. Brake-specific energy consumption decreases and thermal efficiency of the engine increases for all biodiesel blends. In addition, from the performance results, BTE and BSFC of B20 are relatively close to those of pure diesel fuel (B0). The use of parsley biodiesel as a diesel engine fuel was shown to be a promising strategy to promote the use of green fuels (biofuels from renewable materials) while simultaneously mitigating the release of toxic greenhouse gases from the combustion of fossil fuel.

Safety barrier performance assessment by integrating computational fluid dynamics and evacuation modeling for toxic gas leakage scenarios

Toxic gas leakage represents a type of major process accident scenario threatening human life. Technical and non-technical safety barriers are employed to prevent toxic gas leakage accidents or mitigate the possible catastrophic consequences. Evacuation must be executed in severe toxic gas release scenarios. The performance assessment of technical safety barriers and evacuations in these accident scenarios, although very important, has never been investigated in previous studies. This paper proposes an approach integrating event tree analysis (ETA), computational fluid dynamics (CFD) simulation, and evacuation modeling (EM), for risk assessment of toxic gas leakage accidents in chemical plants. In the proposed approach, the spatiotemporal distribution of toxic gas is predicted by CFD simulations. A dynamic evacuation is determined by a cellular automaton (CA)-based model. Synergistic interventions resulting from technical safety barriers and evacuations are considered in the risk assessment. Considering safety barrier failures in the event tree analysis, individual fatality risks due to toxic gas leakage scenarios are calculated. For illustrative purposes, the proposed method is applied to a case of ammonia leakage. The results show that worse scenarios would be ignored without considering the failure probabilities of technical safety barriers, which can cause underestimated individual fatality risks. Timely gas detection & alarm has the potential to expedite the starting time of evacuations and thus may shorten the time that evacuees stay in the toxicity area to reduce individual fatality risks.

Fuzzy fault tree analysis of chlorine gas release hazard in Chlor-Alkali industry using [formula omitted]-cut interval-based similarity aggregation method

In chemical industries, the release of toxic gases and chemicals is always a serious concern as it has the potential to harm human life and the environment, leading to significant losses. Risk assessment in chemical industries is essential to identify and prevent such type of unwanted hazards. Conventional fault tree analysis has been used effectively to identify the system failure causes and evaluate the system reliability, but it requires quantitative historical failure data of system components. In many real-world applications, it can be difficult to obtain precise and sufficient quantitative failure data of system components. This research paper proposes a novel fuzzy set theory-based fault tree analysis to evaluate system failure probability by utilizing the available qualitative data such as expert opinions/views when quantitative historical failure data of system components is unavailable or insufficient. To aggregate the different opinions of selected experts, a new similarity aggregation method is developed by using interval distance-based similarity measure function. The proposed fuzzy fault tree analysis applies system fault tree, α-cut intervals of fuzzy membership functions, and interval arithmetic operations. To validate the applicability and effectiveness of proposed approach, the basic event probabilities in fault tree analysis of chlorine release from storage and filling facility are generated using proposed approach and then compared with the known probabilities. Further, importance analysis is performed to evaluate the contribution of each basic event in top event “chlorine release” occurrence that would help the decision makers to identify the risk factor of chlorine release. The obtained results may be helpful for decision makers to decide whether and where to take protective actions in the risk management process.

A method for real-time estimation of gas leakage flow from leakage source based on point detection data

Chemical leakage accidents may lead to significant hazards such as fire, explosions and the release of toxic gases. And the estimation of real-time accident hazards is of critical importance for emergency response. In this study, a method was proposed to predict the gas flow in real-time based on the simulated database. Based on datasets generated by numerical computations, a machine-learning algorithm was trained and used to then be validated by data from real-world scenarios. Compared with the full-scale experimental data, for the scenarios in which the relative error of the simulation was within the range of 0%–25%, the relative error of the developed model prediction was 9.8%. When the error of the simulation was within the range of 0%–25%, the machine learning model trained by simulated data can predict the gas leakage in real world with high accuracy.