查看更多>>摘要：Thermal protection of adjacent equipment such as chemical storage tanks is very important when a fire accident occurs. In this paper, a new intumescent insulation emergency material, potassium polyacrylate & organically modified hectorite & intumescent flame retardant (PPHI), was prepared successfully. The material was characterized by Fourier Transform Infra-Red (FTIR) and X-ray photoelectron spectroscopy(XPS). Thermal insulation performance and thermal stability of the material were studied by cone calorimeter, fire resistance test, scanning electron microscope and energy dispersive spectroscopy (SEM/EDS), and thermogravimetric analysis (TGA), respectively. The results showed that thermal insulation performance of PPHI was the best when the addition content of intumescent flame retardant (IFR) reached 0.54 wt%. The morphology and structures by SEM gave positive evidence that char layers formed from the PPHI composites were improved greatly due to the addition of intumescent flame retardant. Finally, a possible thermal insulation mechanism of PPHI was presented.
查看更多>>摘要：Hazard and operability analysis (HAZOP) is a safety evaluation method that is vital in the chemical process. HAZOP analysis uses the form of "brainstorming " and "counterfactual reasoning " to determine the potential events for danger in the chemical process. However, this method relies too much on expert experience and a large amount of existing HAZOP information has not been shared and reused. Herein we prompt a semi-automated HAZOP knowledge graph to overcome the problem of information reuse and sharing. In the implementation of the knowledge graph, the construction of the HAZOP ontology is completed by the seven-step rule in the top down ontology construction. The named entity recognition task is one of the key tasks for the construction of knowledge graphs. The deep learning method is adopted in this paper and is based on the existing HAZOP data to recognize the named entity of HAZOP text. We adopt the deep neural network of BI-GAT-CRF, which has an accuracy of 90.75, a recall rate of 91.53, and an F1 score of 91.14 in the HAZOP Chinese text. BI-GAT-CRF aims to solve the problem of unclear entity boundary recognition and word ambiguity in named entity recognition tasks. The results show that the model performs well in HAZOP named entity recognition. BI-GAT-CRF can effectively determine entity boundaries and recognize named entity categories. BI-GAT-CRF also solves the problem of word ambiguity and improves the accuracy of named entity recognition tasks. Finally, a HAZOP analysis report of a certain oil equipment was used as an example to construct a HAZOP knowledge graph to verify the effectiveness of the construction method.
查看更多>>摘要：The coupling effect of the side explosion vent and wire mesh on suppressing methane explosion has been investigated in this study, aiming to prevent huge losses caused by a methane explosion in industrial organic waste gas treatment. It constructed a closed simulation duct with a length of 3000 mm and an internal dimension of 120 mm x 120 mm containing a side explosion vent at different positions, in which flame behaviours and overpressure characteristics accompanying methane explosion were analyzed to get conclusions. The results indicate that side explosion vents located in the same duct section have a similar explosive flame development trend, and the suppression effect is better as closer to the ignition source. Besides, it is necessary to avoid the redevelopment of flame and the backfire downstream of a side explosion vent. In addition, the overpressure released through side explosion vents is significantly suppressed. However, the wave-absorbing and heat absorbing properties of the wire mesh installed in the duct are only effective for some configurations with low flame speeds. Moreover, the side explosion vent closed to the ignition source effectively suppresses undeveloped flame. In this case, it leads to a complete application of the porous media quenching performance. To sum up, the coupling suppression effect of the side explosion vent and wire mesh on flame is complementary. However, there is an opposite conclusion for the experimental configurations where side explosion vents are downstream of the duct; a high-speed turbulent flame is difficult to be suppressed by the wire mesh and side explosion vent in a flame acceleration mechanism.
Dubaniewicz, Thomas H.Barone, Teresa L.Brown, Connor B.Thomas, Richard A....
9页
查看更多>>摘要：Mining vehicle manufacturers are developing lithium-ion (Li-ion) battery electric vehicles as an alternative to diesel-powered vehicles. In gassy underground mines, explosion-proof (XP) enclosures are commonly used to enclose electrical ignition sources to prevent propagation of an internal methane-air explosion to a surrounding explosive atmosphere. Li-ion batteries can create pressurized explosions within sealed enclosures due to thermal runaway (TR). NIOSH researchers measured TR pressures of nickel manganese cobalt (NMC) cathode type 18650 Li-ion cells, model MH1, as a function of free space within sealed enclosures and observed an inverse power relationship. TR pressure-rise rates, gas quantities, and temperatures were also measured. A confined NMC cell with 92.5 mL of free space produced 232 bar of pressure, far exceeding minimum pressure containment specifications for conventional XP enclosures. Approximately 287 times the cell volume of free space would be needed to reduce the TR pressure of these cells to 8.62 barg (125 psig) per U.S. Code of Federal Regulations, Title 30, Part 18. The NMC cell TR pressures were significantly higher than those measured previously for iron phosphate cathode Li-ion cells under comparable confinement conditions.
查看更多>>摘要：Whether it is through crisis mapping or event simulation, Artificial Intelligence (AI) is a pioneering new method of emergency planning. It uses the analysis of information or data from deep learning to predict the evacuation routes, allocate emergency resources reasonably and estimate the location of disaster. To overcome the difficulties of handling many resources emergency information and the variability of production environment, AI provides advanced analytics tools for processing and analyzing big data of emergency management. This paper presents a comprehensive survey of emergency planning technologies based on AI and discusses their applications in making emergency planning robust and efficiency. The development of AI technologies of emergency planning and their advantages over conventional data-driven emergency technologies are firstly discussed. Several representative emergency planning technologies based on deep learning models are compared. Finally, future trends and opportunities related to AI for emergency planning technologies are summarized.
查看更多>>摘要：An important technical measure to ensure drilling safety is to use advanced well-control technology to detect the early gas-kick. This research proposed an early gas-kick detection method based on the propagation character-istics of measurement-while-drilling (MWD) pressure wave, which was completely different from the conven-tional detection method, to timely detect gas-kick. In this work, we simulated the propagation characteristics of the pressure wave in the annulus gas-liquid two-phase flow by establishing an unsteady mathematical model for the first time, breaking through the limitations of testing the propagation characteristics of the pressure wave through physical experiments and revealing the law of propagation and attenuation of the pressure wave under arbitrary variable values. Second, we conducted field tests on the application effects of this technology based on the time difference of the pressure wave propagation in the gas-liquid two-phase flow and liquid single-phase flow, which confirmed the feasibility and advancement of this technology. Research results showed that gas volume fraction, system pressure, angular frequency, virtual mass force, drag force, and shear stress would affect the propagation and attenuation of the pressure wave in the annulus gas-liquid two-phase flow to varying de-grees. Moreover, the application effects showed that using this technology to detect the occurrence of early gas-kick could be approximately 7-9 min earlier than the conventional detection method.
查看更多>>摘要：The proper design of an emergency relief system (ERS) is usually an expensive operation in multipurpose chemical reactors (such as in the polymer or pharmaceutical industry). In fact, the application of standard techniques would usually suggest to change the entire ERS every time the product to be synthesized is changed. Additionally the knowledge of the physical-chemical properties of the contents of the reactor should be determined. This work provides a simple way to design the filling level of a reactor already equipped with an ERS in order to allow a safe relief in case of emergency. This way, there is no need to change the ERS every time the recipe is changed. Moreover, a few classes of chemical compounds were identified allowing to find general correlations for the filling level of the reactor, based on few simple and easily-measurable quantities, without the need to run complex calculations and, most importantly, without having to find the physical-chemical properties of the system analyzed.
查看更多>>摘要：Apart from human-error, lack of awareness in handling analytical tools and models avert process thermal hazards, misinterpretation of the exothermic dataset of hazardous chemicals have led to numerous catastrophic incidents in the past. The heating mechanism during the runaway reaction is unclear and important to understand for designing safer reactors. The aim of this study was to analyze thermokinetic parameters using non isothermal calorimetric studies including differential scanning calorimetry and isothermal methods including thermal activity monitor III for both reactive groups. Furthermore, overpressure and overtemperature of hazardous materials were assessed using an adiabatic calorimeter, namely vent sizing package 2, enabling the use of alerting equipment for various operations. The pure decomposition behavior of 2,2 '-azobis (2-methylbutyronitrile) (AMBN) was analyzed with depictions of the short-term release of high pressure and temperature using an infrared thermal imaging camera. Thermokinetic parameters of AMBN, including apparent activation energy E-a, were assessed. Thermal tests elucidated the potential hazard while handling these compounds and delineated the nature of the decomposition reaction of the n-th order or autocatalytic model. These results suggested that energy released from isothermal reactions and gas chromatography/mass spectrometer for decomposition products of azo and peroxide compounds simultaneously to understand the reaction mechanisms of compounds of interest.
查看更多>>摘要：In this work, the flame and explosion suppression performance of copper foams with five apertures of 10 PPI, 20 PPI, 30 PPI, 40 PPI and 60 PPI were investigated. The combustion characteristics of hydrogen/air premixed gas with stoichiometric ratio were investigated under three experimental schemes. The experiments were carried out in a circular cross-sectional pipe with aspect ratio of 108. Under the influence of copper foam, there are four phases of flame propagation, namely, laminar rapid expansion, backflow, rapid turbulence and pulsation deceleration. The results show that continuous copper foam sheets with aperture of 60 PPI can effectively prevent flame from spreading to the downstream of the pipe and make flame quenching. At the same time, the phenomenon of "negative pressure suction" was observed. The upstream overpressure was reduced to 0.06 MPa and the flame velocity was 25 m/s. As the aperture of copper foam decreased, shock wave and flame velocity decreased. The process of deflagration to detonation transition was effectively inhibited. Widely spaced copper foams can effectively prevent the impact of reflected shock wave and hindrance the flame from downstream. The results can provide a significant reference for designing hydrogen flame arrestors to improve the safety of hydrogen pipeline transportations and engineering applications.
NSTL
Elsevier