Combustible Substances Research Articles

ИССЛЕДОВАНИЕ ВОЗНИКНОВЕНИЯ ПОЖАРА ОТ ВОСПЛАМЕНЕНИЯ И ВЗРЫВА ПАРОВОЗДУШНОЙ СМЕСИ ПРИ ПРОВЕДЕНИИ ГАЗОСВАРОЧНЫХ РАБОТ

Using the example of a real fire that occurred as a result of violations of fire safety requirements during gas welding operations, it is demonstrated how the combined use of instrumental and computational methods makes it possible to determine the cause of the fire. The nature of combustible substances has been determined by fluorescence spectroscopy, gas-liquid chromatography and infrared spectroscopy. Using mathematical calculations, the amount of combustible substances necessary for the formation of an explosive mixture was determined. It is demonstrated how a combination of physical-chemical research methods and computational methods, allows for the determining the causal relationship between gas welding operations and the aforementioned explosion.

Study on the Thermal Effect of Spontaneous Combustion of Coal-Based Activated Carbon By-Products Oxidized and Carbonized Powders

ABSTRACT To investigate the spontaneous combustion thermal effect of the by-products oxidized powder (OP) and carbonized powder (CP) produced during the preparation of coal-based activated carbon (CBAC). First, the changes in composition and pore structure of OP and CP compared with raw coal (RC) were measured by coal quality analysis and nitrogen adsorption experiments. The ability of OP and CP to physically adsorb oxygen was determined. Then, differential scanning calorimetry (DSC) was used to study the whole process thermal effect of the spontaneous combustion of OP and CP. Finally, the thermal effect of OP and CP during low-temperature oxidation process was further explored by the C80 micro-calorimeter, and the thermodynamic characteristics were also probed. The results show that the content of fixed carbon and carbon elements in OP and CP are significantly greater than that in RC, which makes the pore structure of both complicated. In addition, the total pore volume, average pore size, and specific surface area of OP and CP are greater than that of RC, which is more conducive to the physical adsorption of oxygen by both. No transition platform is caused by the decomposition of intermediate products on the DSC curve of CP. The characteristic temperatures of CP (except T D10) are lower than that of OP, indicating that the spontaneous combustion reaction of CP started earlier than that of OP. However, part of the combustible substance of CP was consumed in the dry distillation process, leading to the thermal release and maximum thermal release rate being smaller than that of OP. The apparent activation energy (E a) of stages H2 and H3 in the low-temperature oxidation process of OP is 75.04 and 11.42 kJ mol−1, while that of CP is 83.11 and 30.91 kJ mol−1. The threshold of CP entering stages H2 and H3 is higher than that of OP. Nevertheless, from the pre-exponential factor (A), the low-temperature oxidation process of CP is more rapid.

SIMULATION HEATING PROCESS FOR WEAKLY REACTIVE COAL IN THE HORIZONTAL REACTOR

In this study results of the active medium parameters influence formed by hot air on the thermal heating process of weakly reactive coal from the formation «Maikubensk 3B» for the extraction of additional heat are represented. In the course of the research the regularities of the hygroscopic moisture and volatile combustible substances release for the obtaining additional heat have been determined. Optimal temperature ranges of the stage heating taking into account thermal destruction of coal in the temperature range from 20 C to 600 C, the main steps of the insulated heating process, the moisture content gradient propagation lines and dependence of the heat transfer and mass transfer coefficients on the temperature and the humidity during the thermal heating process in the horizontal coal heating reactor. The results show that it is possible to release volatile combustible gases with a gradual increase of temperatures in the obtained mode. The heating mode comprises a pre-heating stage with hydroscopic moisture release, in the temperature range from 20 C to 105 C, the stage of isothermal heating in the temperature range from 105 C to 400 C and the phase of flame-free combustion in the temperature range from 400 C to 600 C with the temperature rise above the set value. Process simulation was carried out in the Comsol Multiphisics software environment for the weakly reactive coal real-world heating conditions. Keywords: coal heating, weakly reactive coal, isothermal heating, step-by-step heating, Lagrange method, non-liner equation, non-stationary process.

BINDERS FROM SECONDARY RAW MATERIALS OF COAL ENRICHMENT WASTE FOR CONSTRUCTION OBJECT ERECTION USING THE 3D PRINTING METHOD

Formulation of the problem. The 3D printing construction technology is one of the modern methods of rapid construction, which allows for a significant automation of the building process while achieving high precision in the fabrication of complex configurations using equipment (3D printers) controlled by software to define precise coordinates of the printed structure model. The main materials for construction 3D printing technology are composite mixtures based on binders. Cement or composite binders can be used as binders [1]. The cement production technology involves the firing of its components at 1 450 °C, which requires significant energy resources and affects its final cost and the overall mixture. The utilization of coal enrichment waste, which contains clay minerals, quartz, pyrite, and a small amount of carbonates, impurities, and combustible substances, allows for reducing the consumption of technological fuel and the firing temperature of the binder by harnessing the heat-generating properties of coal inclusions. Thus, coal enrichment waste can be used as a fuel component in obtaining the binder. The purpose. Based on the conducted research, it can be concluded that the use of component binders derived from coal enrichment waste shows promise in the construction of buildings using 3D printing technology. By harnessing the heat-generating properties of these waste materials, it is possible to reduce the consumption of technological fuel and firing temperature required for binder production, consequently lowering CO2 emissions into the atmosphere and reducing the final cost of the construction mixture for 3D printing.

Bio-based flame retardant coatings for polyester/cotton fabrics with high physical properties using ammonium vinyl phosphonate-grafted chitosan complexes

Polyester/cotton (T/C) blended fabrics are widely utilized in textile due to the dimensional stability and high elasticity provided by polyester, combined with the comfort and moisture absorption offered by cotton. However, simultaneously enhancing the flame retardancy and maintaining the physical properties of T/C blended fabrics for clothing and furniture applications remains a big challenge. This study introduces a bio-based flame-retardant coating using polyelectrolyte complexes (PEC) composed of ammonium vinyl phosphonate-grafted chitosan (AMVP-g-CS). The protonation degree of the PEC coating is controlled by adjusting the pH to solidify and stabilize the complex structure, preparing bio-based PEC flame retardant T/C blended fabric. Flame retardant analysis reveals that the coated fabrics achieved a limiting oxygen index of 30.5 % and a char length of 11 mm, indicating significantly improved flame retardancy. The combustible volatile substances are significantly reduced for the coated fabrics, achieving a gas-phase flame retardant effect, and forming an expansive char layer with thermal insulation and oxygen blocking properties. Importantly, physical analysis proves that the PEC deposition improved mechanical properties, satisfactory whiteness index and hand feeling of the fabrics. This work opens up a pragmatic and industrially feasible strategy for the development of CSs in the field of flame retardant coating.

Effect of ultrasonic-hydraulic coupling cavitation pretreatment on carbon extraction from coal gasification coarse slag by flotation

Coal gasification coarse slag represents a type of low-value solid waste produced in coal gasification. This study investigated how the pretreatment of the pulp obtained from coal gasification coarse slag affects carbon extraction by flotation. Ultrasonic treatment can promote carbon ash separation. Flotation results revealed that at an ultrasonic action time of 15 min, the ultrasonic power was 90 W and the microbubble generator flow rate was 300 ml/min. Moreover, the best flotation effect was observed under these conditions. Compared with the results obtained for conventional flotation, the concentrate ash content decreased from 36.88 % to 25.51 % and the combustible substance recovery index increased from 79.84 % to 92.91 %. After coupled cavitation treatment, coal gasification coarse slag exhibited a reduced particle size, an increased specific surface area, a smooth and clean surface, a reduced number of surface inorganic elements, an increased number of pores and a remarkable carbon ash separation effect. This study can provide a reference for special methods such as ultrasonic-hydraulic coupling cavitation to strengthen the flotation of coal gasification coarse slag.

Research on flammability of 3,3,3-trifluoropropene and its binary mixtures with flame retardants

3,3,3-trifluoropropene (R1243zf), which has good environmental and cycling characteristics, is a very promising fourth generation new working fluid. However, it is flammable, so studying its combustion characteristics and how to suppress its flammability are of great significance. Firstly, the flammability limits of three binary mixtures composed of a combustible substance (R1243zf) and three flame retardants (R245fa, R1216, and R13I1) were experimentally studied. The results showed that as the proportion of flame retardants increased, the lower flammability limit of the mixture increased, while the upper flammability limit decreased except for R245fa. The critical suppression ratios of R245fa, R1216, and R13I1 on R1243zf were 4, 0.538, and 0.538, respectively. Then, the improved group contribution method was used to predict the minimum inhibitory concentration of R1243zf, with an error of only 4.57 % compared to the experimental values. Finally, the influence of variable ambient temperature (25–100℃) on the flammability of R1243zf was studied, and the calculated adiabatic flame temperature method was used to predict the flammability limit at different temperatures. The error between the predicted values and the experimental values is only 1.7 %. The relevant results are of great significance for the safe application of R1243zf and new binary mixed working fluids.

Devising technology for extinguishing oil tanks using compressed foam by sub-layer technique

Tank facilities storing various combustible substances are a potential source of danger for the environment and human life. Fires in tanks can occur for various reasons: technical malfunctions, human factors, military operations, natural phenomena. One of the effective methods for extinguishing such fires is "sublayer" extinguishing with the help of foam of low multiplicity. The possibility of "sub-layer" extinguishing with the help of compression foam, which has unique properties, has been considered. The object of this study is the processes of stopping combustion during fire extinguishing in steel tanks for the storage of petroleum products with the use of foaming agents of increased stability, which ensure the generation of compression foam in a "sub-layer" way. A mathematical model of the movement of a submerged non-free jet of foam in the medium of motor fuel is given, which adequately describes the real physical processes that occur during "sublayer" quenching of vertical steel tanks. According to the research, it was established that the use of foam with a multiplicity of 10 (K10) is 1.56 times more effective in serving time than the use of foam with a multiplicity of 5 (K5). From an economic point of view, K10 foam also has greater advantages as the costs of the foaming agent during its generation are 3.1 times lower than when using K5 foam. The simulations demonstrated that the foaming agent consumption of the K10 foam is lower than the foaming agent consumption of the K5 foam and results in a different amount of foam coming to the surface. The simulations also showed that the volume of K5 foam increases proportionally with the feeding time, while the volume of K10 foam increases disproportionally and starts to decrease after half the time. The results from the implementation of the mathematical model were fully consistent with the results from experimental studies on extinguishing a model fire of class B

Evaluation of Liver Markers, Kidney Markers, Electroyte Panel and Protein Profile in Pump Attendants Exposed to Petrol Fumes from Selected Filling Stations in Ihiala, State, Nigeria

Environmental hazard in a work place is an inevitable experience especially when it has to do with working in a filling stations where volatile and combustible substances like petrol, diesel and kerosene are dispensed via PMS and other channels of distribution or outlets and in the process pollute or saturate the air with hydrocarbons. Individuals working in a petrol station pose different risk of exposure to these xenobiotics that enter the body via different means (inhalation, ingestion and skin or eye contact) and could be detrimental to the body system resulting to death if not properly handled. This research was aimed at assessing some biochemical indicators of occupational hazard in fuel pump attendant from selected service stations in Ihiala, Anambra state. A total of eighty apparently healthy subjects (40 males and 40females) aged between 28-35 years volunteers participated in the study. Each gender was further categorized into two groups of 20 each for control (unexposed workers) and exposed pump attendants respectively. The pump attendants that volunteered for this study had spent an average of 5-6 years on the job. Blood samples were collected from the volunteers with their informed consent and selected biochemical parameters such as liver function test (ALP, AST ALT), kidney function test (urea, creatinine and uric acid), protein profile (total protein and albumin), and electrolyte levels were investigated using standard methods. The result of the investigations showed that urea and creatinine level of exposed female pump attendants (5.80±0.02 mg/dl and 82.50±2.15 mg/dl)were significantly higher (P<0.05) than unexposed female pump attendants (5.00±0.45mg/dl and 58.00±0.11 mg/dl respectively). Serum sodium (Na+ ) electrolyte levels of exposed male and female exposed pump attendant (143.00±1.05 and 141.00±1.25 mmol/L respectively) were significantly higher (P<0.05) compared to Na+ electrolyte levels in male and female unexposed workers (138.00±0.14 mmol/L and 139.50±2.11 mmol/L respectively) while the chloride ion level in male and female pump attendants were higher compared to male and female unexposed workers. Alanine transaminase and aspartate transaminase (ALT and AST) levels of male and female exposed pump attendant were higher than that in male and female unexposed pump attendant. Petroleum fumes are therefore environmental pollutants that could have serious consequences on biochemical parameters in petroleum product exposed individuals. Therefore, health Safety and Environmental training is recommended for petrol station workers on regular basis to improve their safety and create awareness on the dangers inherent associated with filling station workers exposed to petrol fumes.

Revealing the mechanism of pack ceiling failure induced by thermal runaway in NCM batteries: A coupled multiphase fluid-structure interaction model for electric vehicles

Structure failure of lithium-ion battery (LIB) pack ceiling leads to the unintended release of combustible and poisonous substances during thermal runaway (TR), resulting in personnel injuries and financial losses. However, limited research has been conducted on the mechanism behind pack ceiling failures. In this study, we developed a coupled multiphase fluid-structure interaction (FSI) model to simulate the evolution of up-cover baffle under the TR impact of a 52 Ah NCM battery. Our findings reveal several important insights:1) the maximum force and temperature on the baffle are 13.01 N and 598.5 °C in experiment; 2) the simulation shows that particles exert higher temperature and greater force on the baffle compared to the gas phase; 3) the overall equivalent stress in the stainless-steel baffle surpasses the tensile strength that incurs crack on the baffles. According to the validated model, we find that the baffle structure failure is caused by the thermal stress from particle-structure heat conduction. Furthermore, this observation is applicable to the structure failure problems associated to the thermal runaway of high-density battery that involves enormous particles. In addition, the insulation layer is found to be more effective than the gap distance in protecting the pack ceiling. These findings offer a valuable insight into the structure design of LIB pack, and provide the guidance toward future battery integration technologies.

О возможности взрыва при применении экологически безопасных хладагентов в холодильном оборудовании

Today, the most common domestic electric equipment is a household refrigerator. The use of flammable substances as refrigerants for refrigerators can lead to severe consequences. As the production of hydrofluorocarbon class refrigerants for refrigeration equipment was restricted by the Kigali amendment to the Montreal Protocol, refrigeration technologies have been transferred from using hydrofluorocarbon class refrigerants to natural refrigerants (propane, butane, isobutane). The replacement of hydrofluorocarbon class refrigerants with natural refrigerants is already noticeable since in many cases isobutane (R-600a) is used as a refrigerant for refrigeration equipment. Isobutane is a combustible substance with a wide explosion limit (1.8–9.5 % vol.); hence, it is classified as an A2 refrigerant class of hazard (combustible substances). As R-600a is classified as an A2 class of fire hazard, its use in refrigeration technologies is limited with the refrigerant mass; therefore, the use of R-600a for refrigeration equipment is considered safe. According to international and Russian data, however, some accidents involving the use of flammable refrigerants in refrigeration equipment were registered. In the US, two explosions of serviceable household refrigerators were registered; in the Russian Federation, one explosion of refrigeration equipment during repair jobs was registered. According to the parameters of refrigeration equipment explosion, R-600а was used as a refrigerant. This study provides a calculation of excess pressure of explosion in case of leakage of R-600a from a refrigerator in the volume of a living accommodation (kitchen) in order to estimate the fire safety of combustible refrigerants. Based on the results of calculations, it has been concluded that the existing norms of the use of combustible refrigerants are insufficient and cannot ensure fire-explosion and fire safety for a person and refrigeration equipment.

Research of qualitative properties of soils during construction works

The development of mankind leads to an increase in the number and diversity of sources of environmental pollution. In urban conditions, environmental pollution occurs due to exhaust emissions coming from various cars, leaks of fuel and lubricants coming from various equipment, etc. Analysis of the current state of urban areas shows that the highest concentration of pollutants is present in soils. The article deals with the problem of the territories of construction sites contaminated with combustible substances coming from construction equipment. Based on the conducted studies of the process of penetration of contaminants in the soil, conclusions are drawn about the permissible time interval for the elimination of contaminants. This data can also be used to eliminate leaks in oil pipelines.

Facile fabrication of adenosine triphosphate/chitosan/polyethyleneimine coating for high flame-retardant lyocell fabrics with outstanding antibacteria

Addressing highly flammable and easily breeding bacteria property via environmentally friendly approach was critical for the large-scale application of lyocell fibers. Herein, a bio-based coating constructed by layer-by-layer deposition of adenosine triphosphate (ATP), chitosan (CS), and polyethyleneimine (PEI) was successfully fabricated to obtain excellent fire-resistant and antimicrobial lyocell fabrics (LBL/Lyocell). The resulted fabrics with add-on of 11.5 wt% achieved the limiting oxygen index (LOI) of 32.0 %. Meanwhile, compared with the pure lyocell fabrics, the peak of heat release rate (PHRR), total heat release (THR), and fire growth rate (FIGRA) of LBL/Lyocell fabrics decreased by 75.2 %, 61.0 % and 69.8 % in cone calorimetric test (CCT), respectively. By characterizing the gaseous products and solid residues, the presence of the ATP/CS/PEI coating could not only quickly form the dense expanded carbon layer by itself, but also promote the conversion of cellulose into thermal-stability residues, thus reducing the release of combustible substances during combustion and protecting the lyocell fabrics. In addition, LBL/Lyocell showed excellent antimicrobial properties with 99.99 % antibacterial rates against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). This bio-based coating was a promising candidate for efficiently flame-retardant cellulose fibers with excellent antibacteria.

Экспериментальная оценка объёмной концентрации и размеров твёрдых частиц дыма, образующихся при терморазложении горючих материалов

Purpose. The purpose of the work is the experimental assessment of size as well as mass and calculated volumetric concentration of smoke solid particles formed during burning of combustible materials, using wood, insulation of cables and microelectronics elements as the examples. Methods. The authors used the experimental method for measuring the amount, size and mass of suspended solids particles in a gaseous medium formed in a small-scale experimental installation during the combustion of various substances and materials. Findings. The enhancement of experimental installation has been carried out and the experimental methodology has been developed that allows measuring the parameters of solid smoke particles. Experimental dependencies on the time of mass and countable volumetric concentration of smoke particles depending on their size have been obtained during testing wood samples, insulating cables and microelectronics elements. It has been found that the most dangerous, in terms of the effect on a human body during evacuation in case of a fire, finely dispersed solid particles of smoke are formed throughout the entire burning time. It is shown that the maximum mass and countable volume concentration of particles is formed at the incipient stage of combustion, and the mass volume concentrations of particles of all sizes significantly exceed their critical values. Research application field. The results can be applied at determining the blocking time of escape routes by visibility loss, and the consequences of human body exposure to smoke particles. Conclusions. It is necessary to conduct further studies in order to justify the introduction of a new fire hazard into regulatory documents on fire safety – the concentration and size of smoke particles, as well as create a database on the size of smoke particles formed during combustion of modern combustible substances and materials, and their mass and calculated volumetric concentrations.

Quantitative risk assessment of industrial hot work using Adaptive Bow Tie and Petri Nets

Hot work poses great hazards to industrial operation site. Although regulatory and guidance exist, accidents caused by hot work continue to occur. Risk assessment has proved to be an effective method for risk control. However, current studies paid less attention to the evolution process of industrial hot work accidents and the quantitative risk assessment seems to be insufficient. In this context, we aimed to perform comprehensive risk evolution analysis and quantitative risk assessment of hot work using adaptive bow tie (ABT) and Petri nets (PNs). The ABT model is improved to analyze deep causes, consequences, and their relationships. PNs are employed to conduct quantitative risk assessment. To address uncertainties, the triangular membership function and improved regional center method are proposed to calculate the confidences of all places and transitions in the PNs. The probabilities are finally obtained by data fitting method. The study found that the most likely consequence of hot work accident is near miss. The results also indicate that hot work accident prevention measures should emphasize on the isolation of workplace, combustible gases test, removal of combustible substances, job organization, and job training. Besides, emergency devices maintenance and emergency drilling are critical to prevent accidents from expanding.

Correlation of properties in hydrocarbons homologous series

Correlations between combustible substances properties in the homologous series of n-alkanes and n-alcohols with a length of nС=1–20 were studied in order to determine ways to increase the methods convergence for assessing fire hazard parameters. The cluster length was added to the substance modulating parameters set. It should be noted that substances properties are often predicted using a molecule coarse-grained model, which has discreteness, does not describe short molecules, and requires an individual approach. It is shown that there are substance "arithmetic" parameters that directly depend on the certain atoms number. Among them, "length" better reflects isomeric, conformal, cluster differences, which are associated with parameters anomalies of hydrocarbons. A vaporization heat linear description from nС separately for n-alkanes and n-alcohols gives R=0,999. Exponential approximation of the n-alkanes boiling point tbp and flash point tfp by nС change fractions has R=0,999. It is shown that there is a correlation between tfp and tbp, but with a systematic difference, which indicates that the cluster composition is not completely similar at these temperatures; between tfp and tmp there is a smaller correlation, but its presence indicates clusters partial similarity. A universal formula for predicting hydrocarbons vaporization heats of 10 homologous series has been created, which has R=0,996. The description change hydrocarbons pulsations of in tmp was carried out on the cluster schemes alternation basis in homologous series, as well as taking into account their length and molar mass, which gives R=0,9997. According to similar principles, a formula for the hydrocarbons solubility in the water has been developed, which has the satisfactory accuracy. The study showed that the cluster length is a determining factor by which substance properties are modulated.

Synergistic P-N charring agents to enhance flame retardancy of ethylene-vinyl acetate (EVA): Insights from experimental and molecular dynamic simulations

Previous charring agents had nonignorable defects, such as a low charring rate and poor compatibility with acid and gas sources in intumescent flame retardants (IFRs), leading to poor flame retardant efficiency. Thus, we designed a novel P-N macromolecule charring agent named poly(piperazinyl phosphamide) (PA) and confirmed the chemical structure of PA. A small amount of 7.5 wt% PA in EVA/ammonium polyphosphate (APP)/PA improved the limit oxygen index (LOI) to 35.7 ± 0.58% from 19.0 ± 0.33% and reached the level of UL-94 V–0. This implies that PA was an efficient charring agent in IFRs. Moreover, the peak heat release rate (PHRR) and total heat released (THR) dramatically declined by 90.73% and 97.70%, respectively. This suggests that the addition of PA further hinders the diffusion of combustible substances, forming a dense and sturdy char layer in the condensed phase. In detail, the decomposition of PA produces many aromatic structures, such as C = N, C = C, P = O, and P–N. Simultaneously, APP can defer the cleavage of C–N bonds for PA and promote the formation process of the benzene ring, which is clearly conducive to charring. To estimate the flame retardant micromechanism of EVA/APP/PA at high temperatures, this work utilized molecular dynamics simulation based on reaction force field (ReaxFF-MD) to research at the atomic scale. The potential energy, decomposition time, main gas products, and free radical products of the materials were simulated, which demonstrated that EVA/APP/PA has better flame retardancy than equal amounts of EVA/APP owing to the addition of PA. Suppressing the generation of combustible gases (CH4, C2H4, C6H6) and facilitating the binding of molecular products into char residues to form organic molecular structures with good stability is consistent with the experimental results. Proving that the PA was the key to boosting the flame retardancy of EVA by hindering the spread of combustible gases. A novel way for analysing and predicting the flame-retardant mechanism of EVA at the atomic level was proposed.

Kinetic Analysis of Thermal Decomposition of Polyvinyl Chloride at Various Oxygen Concentrations

PVC plastic products are common combustible substances seen in fires, but their thermal degradation behavior under different oxygen concentrations has not been adequately studied. The thermal degradation behavior of PVC materials in atmospheres with different oxygen concentrations was analyzed via thermogravimetric–Fourier transform infrared spectroscopy (TG-FTIR). The TG results show that the thermal degradation process of PVC under a non-oxygenated atmosphere occurred in two stages, and the activation energies of the two stages were 130–175 KJ mol−1 and 230–320 KJ mol−1, respectively; under the oxygenated atmosphere, the thermal degradation process occurred in three stages. The activation energies of the three stages were 130–175 KJ mol−1, 145–510 KJ mol−1 and 75–190 KJ mol−1, respectively. And the reaction mechanism of the second stage of thermal degradation was changed from D-ZLT3 to En by the higher oxygen concentration. Infrared spectroscopy (FTIR) was used to analyze the pyrolysis process of PVC in the non-oxygenated atmosphere, and the eight major components were as follows, in descending order according to amount released: C-H stretching > HCl > C-Cl stretching > H2O > CO2 > C-H bending > C-H aliphatic bending > CH2. For the reaction of PVC at an oxygen concentration of 7%, the nine major components, in descending order according to amount released, were as follows: CO2 > HCl > H2O > CO > C-H stretching > C-Cl stretching > C-H aliphatic bending > C-H bending > CH2. For PVC reactions at oxygen concentrations of 14% and 21%, the five major components, in descending order according to amount released, were CO2 > HCl > CO > C-Cl stretching > H2O.

Improvement of the Prototype of the Compressed Air Foam System and its Testing

The prototype of the compressed air foam system was improved based on the evaluation of the numerical parameters obtained with the help of the developed mathematical model of the foam generation process and the pneumatic-hydraulic scheme. The prototype provides the possibility of foam generation both in autonomous mode, due to the installation of cylinders with compressed gas, and in stationary mode, due to the supply of compressed air from an external source. This allows the use of an improved model of the compressed air foam system both in stationary mode (dry pipes, gas stations, etc.) and for use on heavy and light fire trucks, which is important for large cities. Testing of the improved prototype of the system for extinguishing model fires was carried out. The system provides extinguishing of model fires of class 183 B and 144 B when using both a general-purpose foaming agent and a special film-forming foaming agent. When using a film-forming foaming agent, the extinguishing time was reduced by 1.75 times, the consumption of fire extinguishing solution by 1.47 times. But at the same time, it should be taken into account that the cost of the film-forming foaming agent Sofir (sofirafff 6 %) is more than 3.2 times the cost of the general-purpose foaming agent Sofir. The effectiveness of the improved model in extinguishing class A fires was also confirmed. The autonomous compressed air foam system ensures extinguishing of a class 4 A model fire in 90 seconds. Dry foam with a factor of 14 is noted to be more effective in extinguishing solid combustible substances.

Innovative Complex of Block-modular Fire Extinguishing System for Offshore Oil Terminals

The purpose of the study is offshore oil terminals, which are objects of increased fire danger in terms of fire safety. In this regard, the main requirements of fire safety include the implementation of a set of measures to create modern and efficient systems of port fire extinguishing of offshore oil terminals. The article investigates and analyzes the technological features of the modern complex of a block-modular system of foam fire extinguishing and water cooling of offshore berthing complexes of oil terminals. Unlike the traditional ones, the feature of the foaming agent of the intended purpose is the high efficiency of foams of low multiplicities based on the foaming agent of the intended purpose of the AFFF model. The content of a mixture of hydrocarbon and fluorocarbon film-forming surfactants ensures its effective use in fresh and marine aquatic environments.The use of a complex block-modular system of foam fire extinguishing and water cooling of offshore oil terminals allows you to implement a wide range of operations for extinguishing fires with effective isolation of combustible substances from oxidants and cooling of combustion centers of objects with a significant reduction in water consumption gorenje