Effect of silver inhibition on the ceramic foam as flame suppression

Aluminium dust explosions pose significant safety and economic challenges in various industrial processes. Due to this, the current research explores an innovative approach by inhibiting the silver nanoparticles (Ag NPs) to ceramic porous form substrate as a flame suppressant in order to mitigate the risks associated with these explosions. The antimicrobial and non-toxic qualities of silver are also attractive to be applied in medical and food technology. However, the interfacial adhesion between the metallic (nanosilver) and non-metallic (silica-based-ceramic) is still vaguely studied due to the mechanical and surface energy mismatch between the organic surface and the inorganic layers. From this study, the physicochemical and mechanical properties of the silver-coated ceramic foam were analyzed using X-ray diffraction, field emission scanning electron microscopy with energy dispersive X-ray, thermogravimetric analysis, and compression test. From the mechanical testing, it was found that the percentage increase of maximum load for silver-ceramic foam from the original ceramic foam was about 60%. The results indicate that silver-coated foam has a better compressive strength of 0.93 MPa as compared to 0.58 MPa by the original ceramic. The inhibition effect of Ag NPs powder on the explosion pressure evolution and flame spread mechanism of aluminium powder at different concentrations and particle sizes was tested using the Hartmann experimental system

Numerical analysis of vapor dispersion from compressed hydrogen (H2) storage vessels

The rising demand for hydrogen fuel, driven by the emergence of fuel cell electric vehicles, underscores the need to optimize refueling station efficiency and affordability while prioritizing safety and performance. Compressed gas hydrogen storage emerges as a practical solution however safety across production, storage, and distribution is paramount for broader acceptance of hydrogen technologies. Any incidents could undermine public trust, emphasizing the importance of mitigating risks such as hydrogen leakage. This study investigates hydrogen dispersion and conducts consequence analyses for potential hazards, considering stability, ambient temperature, wind speed, and process parameters like vessel temperature, pressure, and leakage diameter. It assesses various scenarios, including high-pressure storage vessels and generic refueling station layouts, by employing integral models of ALOHA, PHAST and HyRAM. Findings showed that process parameters significantly influence hazard severity, with leakage diameter having a notable impact. Common safety vulnerabilities in fuel cell vehicles and refueling stations are highlighted, emphasizing adherence to international regulations and standards for enhanced safety protocols

Kinetic analysis of Malaysia type biomasses via thermogravimetric analyser (TGA)

The kinetic behaviour of biomass pyrolysis samples was successfully studied via thermogravimetric analysis. The biomass samples were empty fruit bunch, oil palm trunk, rice husk, coconut copra, sawdust, coconut shell, sugarcane bagasse, and wood bark. The analysis was performed in a nitrogen atmosphere from 30 to 700°C. The effect of heating rate on kinetic behaviour of biomass at two different high heating rates was evaluated at 40°C/min (HR1) and 80°C/min (HR2). The kinetic parameters of biomass samples such as pre-exponential factor (s-1), activation energy (kJ/mol), and reaction order (n) were determined using one-step global kinetic model. The wood bark sample has the lowest activation energy (38.14 kJ/mol), while coconut copra was reported for the highest activation energy (145.42 kJ/mol). High positive activation energy was achieved at a higher heating rate (HR2) than at lower heating rate (HR1) for biomass samples

Dust Explosibility and Severity of Bayan and Tanito Coal

The assessment of the explosibility and severity characteristics of Bayan coal and Tanito coal was investigated over various concentrations in a 20 L Siwek spherical explosion chamber. The coals tested in this study were also compared with other organic dusts such as palm-based soap noodle, tea powder, black rice, and rice flour, which were tested using the same explosion chamber and procedures. The severity and explosibility of the coals increase as their concentration increases. The Pmax of Bayan coal (10.15 bar) is higher than that of Tanito coal (7.35 bar). The Kst of Bayan coal (48.04 bar m s−1) is also higher than that of Tanito coal (16.83 bar m s−1). Among all the dusts studied using the same chamber and procedures, palm-based soap noodle has the highest Pmax at 16 bar, while tea powder has the lowest Pmax at 6.35 bar. The results show that the explosibility and severity of the coals increase as the concentrations increase, and the moisture content, coal ranking, and different types of organic dust have a significant influence on the severity characteristics of dust explosions

Catalytic upgrading of biomass-derived pyrolysis vapour over metal-modified HZSM-5 into BTX: a comprehensive review

This paper provides an updated and comprehensive review on the catalytic upgrading of biomass-derived pyrolysis vapours over metal-modified HZSM-5 catalyst into bio-aromatic hydrocarbons. The catalytic upgrading of biomass pyrolysis vapours seems to be a promising technology in generating gasoline-type bio-aromatic hydrocarbons, i.e. benzene, toluene and xylene (BTX). Biomass-derived raw pyrolysis oil has high oxygenated compounds that deteriorate pyrolysis oil properties and limits its applications. Metal modification of hydrogen exchanged Zeolite Socony Mobil Five (HZSM-5) catalyst has gained attention in a biomass pyrolysis research area due to the beneficial effects on upgrading the oxygenated pyrolysis vapours into BTX-enriched pyrolysis oils. The influence of metals (alkali and alkaline earth metals, transition metals and rare earth metals) as bi-functional or multifunctional activity on HZSM-5 catalyst during pyrolysis has been addressed. The effect of reaction temperature, the type of metals, metal contents, the silica-to-alumina ratio of catalyst and the catalyst-tobiomass ratio are critically discussed for maximum production of monocyclic aromatic hydrocarbons during the upgrading of pyrolysis vapours. Finally, concluding remarks on metal-modified zeolite catalyst and future recommendation in upgrading biomass pyrolysis vapours are presented

Thermal characterization of Malaysian biomass via thermogravimetric analysis

In this work, thermal degradation behavior of six local biomasses such as empty fruit bunch, rice husk, coconut pulp, saw dust, coconut shell, and sugarcane bagasse in Malaysia via pyrolysis was studied. The pyrolysis process was carried out from 25 to 700 °C under nitrogen atmosphere flowing at 150 ml/min via a thermogravimetric analyzer. The effect of biomass type was investigated on pyrolysis behavior. The particle size of biomass was in the range of 0.3 ≤ dp1 < 0.5 mm, whereas the heating rate was fixed at 80 °C/min. The thermogravimetric analysis (TGA) data were divided into three phases of degradation: moisture evolution, hemicellulose-cellulose degradation, and lignin degradation. The results showed that all biomass samples degraded between 25 and 170 °C in Phase I of moisture evolution. Among the biomass samples, coconut pulp achieved the highest mass loss (81.9%) in Phase II of hemicellulose-cellulose degradation. Lignin in all biomass samples gradually degraded from 450 to 700 °C in Phase III of lignin degradation. This study provides an important basis in understanding the intrinsic thermochemistry behind degradation reactions

Interaction insight of pullulan-mediated gamma-irradiated silver nanoparticle synthesis and its antibacterial activity

The production of pure silver nanoparticles (Ag-NPs) with unique properties remains a challenge even today. In the present study, the synthesis of silver nanoparticles (Ag-NPs) from natural pullulan (PL) was carried out using a radiation-induced method. It is known that pullulan is regarded as a microbial polysaccharide, which renders it suitable to act as a reducing and stabilizing agent during the production of Ag-NPs. Pullulan-assisted synthesis under gamma irradiation was successfully developed to obtain Ag-NPs, which was characterized by UV-Vis, XRD, TEM, and Zeta potential analysis. Pullulan was used as a stabilizer and template for the growth of silver nanoparticles, while gamma radiation was modified to be selective to reduce silver ions. The formation of Ag-NPs was confirmed using UV-Vis spectra by showing a surface plasmon resonance (SPR) band in the region of 410-420 nm. As observed by TEM images, it can be said that by increasing the radiation dose, the particle size decreases, resulting in a mean diameter of Ag-NPs ranging from 40.97 to 3.98 nm. The XRD analysis confirmed that silver metal structures with a face-centered cubic (FCC) crystal were present, while TEM images showed a spherical shape with smooth edges. XRD also demonstrated that increasing the dose of gamma radiation increases the crystallinity at a high purity of Ag-NPs. As examined by zeta potential, the synthesized Ag-NP/PL was negatively charged with high stability. Ag-NP/PL was then analysed for antimicrobial activity against Staphylococcus aureus, and it was found that it had high antibacterial activity. It is found that the adoption of radiation doses results in a stable and green reduction process for silver nanoparticles

Pineapple peel based biocomposites for green packaging

In this research, pineapple peel fiber (PAPF) based low density polyethylene (LDPE) biocomposites for green packaging was studied. The PAPF was first being treated with alkali before compounded with LDPE. Then, the mixture was compounded using twin screw extruder and the test samples were prepared using hot press machine. The compatibility of the PAPF as biocomposites was observed through the characterization and biodegradation analysis. Melt flow index (MFI) analysis was conducted to determine the process ability of the biocomposites. As the fiber loading in the biocomposites increases, the MFI values were decreased. The amount of water absorption was increased with the increases of PAPF loading due to the higher cellulose content. The biocomposites was buried in the soil for a month for biodegradation analysis and the highest PAPF/LDPE loading biocomposites degraded the most

A review on the effects of flame retardant additives towards the environment and human health

Flame retardant additives (FRAs) are normally the addition of chemicals that function to prevent or slow the spread of fires. These chemicals are used in consumer products and industries and could retain in the environment even after several decades. The toxicity mechanism and risk assessment methods of FRAs are also discussed in this paper. Papers from Scopus, Elsevier, Environmental health perspectives (EHP), Research gate, Semantic scholar, Hindawi, and Pubmed from 2003 to recent years were reviewed to provide some views on the possible risks of FRAs and their pathways into our environment as well as into human body. While FRAs could enter the environment during the manufacturing process and the usage period, consumer items are treated with FRAs, through waste streams, during illegal open burning of solid wastes, from incineration plants from landfill leachate and wastewater treatment plant (WWTP) sludge. FRAs are hazardous to humans and the environment, therefore, toxicology assessment should also be consistently conducted on the latest FRAs to ensure that they would not have adverse effects on humans and the environment

Explosion characteristics assessment of premixed biogas/air mixture in a 20-L spherical vessel

The understanding of biogas explosion characteristics is needed to describe the severity of the explosion. Biogas is a flammable gas and will explode when ignited. This study reports the experimental results on biogas explosion characteristics in a standard 20-L spherical vessel under quiescent conditions using electric spark (10 J) as an ignition source. Computational Fluid Dynamic (CFD) code FLame ACcelaration Simulator (FLACs) was used to simulate the biogas explosion based on the experimental case study. The dependence of explosion characteristics such as explosion pressure (Pmax), rate of pressure rise (dP/dt), and deflagration index (KG), on biogas concentration and carbon dioxide, CO2 composition is demonstrated. The data allow for the evaluation of the potential severity of biogas explosion, which in turn helps engineers design the explosion mitigation and prevention device related to this gas. The experimental data reported from this study concluded that Pmax = 8–8.50 bar, the dP/dt = 100–400 bar/ms and the KG = 32.7–121 bar m/ms were recorded at equivalence ratio, (ER) = 1.2 with CO2 composition in the biogas = 30% vol/vol. It was found that the severity of the biogas explosion increased proportionally with the biogas concentration. On the contrary, the explosive intensity was weakened by increasing the CO2 concentration due to the physical effects of CO2 and thermal instability. This study also recorded that the biogas explosion was categorized under hazard level = St-3 indicating a catastrophic explosion. These data are important for preventing and mitigating the biogas explosion