Composition Of Combustion Products Research Articles

Табиғи және техногендік сипаттағы өрттердің зиянды шығарындыларын талдау

Over the past decade, the number of natural and man-made fires has increased, which lead to great casualties, serious environmental pollution and large economic losses. The paper presents the statistics of forest and steppe fires for 2022 in the Republic Kazakhstan, and the statistics of deaths in emergencies associated with a fire. During forest fires, the composition of combustion products depends on the composition of wood and the conditions of its combustion. Accordingly, the emissions are carbon dioxide, nitrogen, carbon monoxide and sulfur dioxide. Also, the calculation of the explosion radius in the diesel fuel warehouse was made. It has been established that the maximum explosion pressure and flame temperature for mixtures of limiting composition are practically constant at different initial pressures. For a mixture of constant composition, these characteristics change significantly with an increase in the initial pressure. The composition of combustion products is analyzed at various initial pressures. From the analysis of time scales, area, facilities and equipment, ignition sources, types of emergency substances and liability, statistical results show that the most dangerous area is the loading and unloading area and the most vulnerable facility and equipment are storage tanks. Meanwhile, the proportions of ignition sources are distributed so evenly that the prevention of fire and explosion must be equally focused on several factors of influence. A vapor cloud explosion may be the most common type of accident at oil depots, and management responsibility dominates all accident causes. A visual interpretation of the obtained results is presented.

Analyzing Burner Performance and Combustion Phenomenon in an Olefin Plant's Industrial Furnace: A CFD Study.

This work presents a comprehensive study of the combustion performance of an industrial furnace in an olefin plant using computational fluid dynamics (CFD) simulations. The focus was on analyzing the heat release pattern of bottom burners to optimize the furnace efficiency in steam-cracking processes. The study developed an accurate computational fluid dynamics (CFD) model for predicting combustion behavior in a cracking furnace. The computational model was validated by comparing the simulation results with industrial data and was used to investigate the impact of burner clogging and the importance of small holes in the body of burners in the furnace. The results also provided insights into the influence of excess air, temperature distribution, fluid behavior, composition of combustion products, and thermal efficiency of the furnace. The presented results contributed to a better understanding of parameters controlling combustion performance in steam-cracking furnaces.

Influence of the type of woody biomass on energy and environmental characteristics of the thermal preparation processes and ignition of bio-water-coal fuel particles

The article presents the results of studies of ignition and combustion processes of droplets (during the initial period of heating), and then particles (after drying the surface layer) of bio-water-coal fuel (Bio-WCF) under conditions corresponding to typical furnace spaces of boiler units of thermal power plants (TPPs). The ignition delay times for Bio-WCF droplets of typical (for modern spray devices) sizes (diameter d=3 mm) have been established. The component compositions of the combustion products of significantly inhomogeneous bio-water-coal suspensions have also been established in a wide range of variations in the temperature of the oxidizing medium. A large-scale analysis of the influence of the type and concentration of woody biomass in a bio-water-coal suspension on energy (ignition delay time of WCF) and environmental (intensity of formation of anthropogenic combustion products of fuel) characteristics was carried out. It is shown that the addition of woody biomass to the water-coal suspension leads to a significant acceleration (by 10–20%) of the ignition process. An analysis of the component composition of combustion products showed that the introduction of wood biomass into the composition of water-coal fuel leads to a decrease in the intensity of the formation of anthropogenic combustion products. It has been established that an increase in the concentration of the vegetable component of the fuel leads to a significant sequestration of sulfur and nitrogen oxides.

Theoretical analysis on applying steam reforming to the primary combustion of the boron-based fuel-rich propellant

The primary combustion products of boron-based fuel-rich propellant contain a significant amount of condensed boron, which poses challenges for complete burnout of the primary combustion products during the secondary combustion process. To enhance the ignition and combustion characteristics of these primary combustion products, a pioneering theoretical analysis on applying steam reforming to the primary combustion of the boron-based fuel-rich propellant was conducted. The results demonstrate that steam reforming improves the ignition and combustion characteristics of the primary combustion products through three main aspects: optimizing the composition of combustion products, improving energy distribution between the primary combustion and secondary combustion process, and elevating combustion temperature, respectively. It theoretically confirms the feasibility of this innovative combustion organization method for solid rocket scramjet. Furthermore, it has been found that there is an optimal steam-fuel ratio (the value is 1.0 for B35), which facilitates the conversion of combustible components in the primary combustion products from a gas–solid state to a pure gaseous phase. Simultaneously, the temperature of combustion products after steam reforming reaches the highest. Therefore, theoretically speaking, the steam-fuel ratio of solid rocket scramjet with steam reforming should not exceed the optimal steam-fuel ratio to ensure better ignition and combustion characteristics of the combustion products after steam reforming. This analysis provides valuable theoretical support for the design of solid rocket scramjets with steam reforming.

Sediment record of polycyclic aromatic compounds and black carbon over the last ~400 years in Sanjiaolongwan Maar Lake, northeast China

Fuel usage is an important catalyst for socio-economic development and human well-being. Human activities have resulted in significant increases in emissions from biomass burning (BB) and fossil fuel (FF) combustion which have significantly adversely affected human, ecosystem, and planetary health in this era of the Anthropocene. Sanjiaolongwan Maar Lake (SJLW), as a typical crater lake, uniquely receives atmospheric deposition from long-distance transport, and thus, its sediments reflect environmental change and human impacts on a broad scale. In this study, the concentrations and compositions of combustion products, including polycyclic aromatic compounds (PACs, i.e., polycyclic aromatic hydrocarbons (PAHs) and their oxygenated (OPAHs) and nitrogen heterocyclic derivatives (AZAs)) and black carbon (BC and its constituents char and soot), in SJLW over the past 400 years were investigated. The results showed that the PACs and soot concentrations and fluxes in SJLW have rapidly increased since 1950. The concentrations of the total PACs increased ~4 times after the 1950s. Such a fast increase is consistent with the rapid industrialization after the establishment of the People's Republic of China (PRC), which has further accelerated beginning with the implementation of the reform and opening up policy of the PRC in 1978. Moreover, the variations in the compositions of PACs, as well as the decrease in the char/soot ratio, demonstrate a transition in energy usage from BB to FF combustion. The decrease in the benzo[e]pyrene/benzo[a]pyrene ratio indicated an increase in local emissions (because of increasing industrialization in northeast China). The temporal profile of perylene concentrations, fluxes, and perylene/5-ring PAHs ratios strongly suggest that perylene mainly originated from non-pyrogenic sources. The records of PACs and BC in SJLW offer valuable perspectives on human impacts and provide important references for the start of the Anthropocene.

Low-Emission Waste-to-Energy Method of Liquid Fuel Combustion with a Mixture of Superheated Steam and Carbon Dioxide

Waste-to-energy approaches, aimed at using cheap energy carriers (oil production and refining waste, etc.), require the creation of new technologies with high energy efficiency and low emissions. One of the environmentally friendly methods is a superheated steam injection (SIM) into the combustion zone. At the same time, trends in CO2 reduction and recycling make carbon dioxide more attractive to use together with, or instead of, steam. This paper experimentally investigated the possibility of upgrading SIM to steam and the carbon dioxide injection method (SCIM) or the carbon dioxide injection method (CIM), where superheated steam and carbon dioxide are supplied together or completely replaced by CO2. In the example of diesel fuel, the characteristics of the combustion of liquid hydrocarbons in the presence of a mixture of superheated steam with CO2 in a spray burner are obtained and compared. It shows that a high completeness of fuel combustion is observed for all the studied modes. The analysis of combustion product composition demonstrates that when replacing the superheated steam with carbon dioxide, the levels of CO and NOx in the combustion products increase by 25%. All the investigated regimes comply with the EN:267 standard. The results obtained show that it is possible to realize SCIM and CIM approaches for waste-to-energy with the use of CO2.

The thermal decomposition and combustion of building and finishing materials

The paper investigates specific aspects of the methods for studying the composition of thermal decomposition and combustion products of typical indoor synthetic and natural materials. The purpose of this research is to build up an experimental database with the concentrations of gaseous pyrolysis products during the thermal decomposition of typical materials in compartments. The utilized techniques are gas and liquid chromatography, effusion mass spectrometry, IR spectroscopy, gas analysis equipment (laboratory and industrial gas analyzers). The conducted research compared the promising methods of chemical analysis of gaseous products of thermal decomposition and combustion of synthetic and natural materials that carry a fire load in residential and public spaces. Data on the quantitative and qualitative composition of combustion products of wood, textile and interior design items were obtained. Toxicity indices of combustion product components were calculated. The data presented in the tables and diagrams for the smoke aerosol component yield in the thermal decomposition and combustion of materials can be used to determine gas hazards from combustion products in an area and to solve other applied problems. These findings are fundamental for predicting the toxic substance concentrations, developing fire safety measures and planning the evacuation paths. It is instructive to use these findings as the basis for developing the physical and mathematical models of heat and mass transfer, phase transformations and chemical reactions to determine the patterns of propagation of gaseous components of thermal decomposition and combustion in spaces with different geometries and dimensions.

Влияние фосфорсодержащих антипиренов на показатели пожарной опасности газонаполненных полимеров на основе реакционноспособных олигомеров

Introduc tion. The reduction of flammability of gas-filled polymers prone to carbonization is based on the use of phosphorus- and boron-containing compounds that reduce the formation of combustible volatile pyrolysis products and increase the yield of coke residue. This reduces the rate of heat release, heat and mass transfer between the material and the flame. In the scientific literature the data about the influence of phosphorus-containing flame retardants on thermal stability, combustibility and smokeability of foams are given, but there are no data about the influence of phosphorus concentration on fire danger indicators of foams. The aim of this paper is the development of effective methods of production of casting foams based on reactive oligomers with low fire hazard and high-performance. Objectives: to reveal the influence of phosphorus concentration on the technological and physical-mechanical characteristics, thermal resistance and fire hazard indices of foams and to develop fire-proof thermal insulation materials possessing high performance. Methods. Physical-mechanical properties and fire hazard indices of gas-filled polymers were determined according to current GOST. Thermal properties and composition of combustion products of foams have been studied with thermoanalytical complex DuPONT-9900 and chromatography-mass spectrometry. Results and discussion. The concentration of phosphorus in the synthesis of rigid polyurethane foams with reduced flammability and high performance should exceed 2.1 % wt. The low-combustible urea foams have been obtained at a phosphorus concentration of 0.2–0.3 % wt. For the production of non-flammable, low-­flammable resin foams, the phosphorus concentration is 0.6–0.7 % wt. At the same time, organophosphorus flame retardants containing reactive groups are highly effective. Conclusion s. As a result of experimental studies the influence of phosphorus concentration and content of organophosphorus-containing flame retardants on physical-mechanical properties, thermal stability and fire hazard of foams based on reactive oligomers was revealed, the pouring foams with lowered fire hazard and high performance were developed.

Combustion Synthesis of Magnesium-Aluminum Oxynitride MgAlON with Tunable Composition.

Magnesium-aluminum oxynitride MgAlON has garnered significant attention in recent years due to its unique properties and potential applications. Herein, we report a systematic study on the synthesis of MgAlON with tunable composition by employing the combustion method. The Al/Al2O3/MgO mixture was combusted in nitrogen gas, and the effects of Al nitriding and oxidation by Mg(ClO4)2 on the exothermicity of the mixture, combustion kinetics, and phase composition of combustion products were investigated. Our results demonstrate that the MgAlON lattice parameter can be controlled by varying the AlON/MgAl2O4 ratio in the mixture, which corresponds to the MgO content in the combustion products. This work provides a new pathway for tailoring the properties of MgAlON, which may have significant implications in various technological applications. In particular, we reveal the dependence of the MgAlON lattice parameter on the AlON/MgAl2O4 ratio. The limitation of the combustion temperature by 1650 °C resulted in obtaining submicron powders with a specific surface area of about 3.8 m/g2.

FACTORS OF USING WASTE AS FUEL IN THERMAL ENERGY SYSTEMSOF PART 1. STUDY OF SHW COMBUSTION PROCESSES

The reason for the ambiguous assessment of the feasibility of using boiler systems of centralized heat supply for burning solid household waste (SHW) is the specific composition of SHW and the peculiarities of their combustion process. The experience of waste incineration plants shows the need to use for this purpose special incineration equipment and complex systems for cleaning combustion products. The purpose of the study is to determine the conditions for the implementation of solid waste incineration systems that would meet the requirements of environmental and economic efficiency. The article presents the results of experimental studies of the SHW burning process and recommendations for the safe and effective organization of such a process. The main factors of negative impact on the environment are identified, which are directly related to the organization of the combustion process and the composition of combustion products, in particular, the high content of sulfur and chlorine in solid waste. The research results confirm that the use of waste as fuel requires specific conditions for the organization of the combustion process, the operation of combustion plants and the arrangement of systems for cleaning combustion products. It is shown that the composition of solid waste and their combustible characteristics differ significantly from known types of solid and alternative fuels. This leads to the need to reconstruct existing solid fuel heating boilers

Analysis of the Efficiency of Technologies for Extraction Carbon Dioxide from Combustion Products

The main purpose of the article is to compare and analyze existing technologies for extracting carbon dioxide from combustion products in relation to mini-CHP plants operating on local fuels. The article presents a brief overview of the main technical features of the implementation of carbon dioxide extraction technologies from gas mixtures. The specific features and limitations for each of the methods are shown. Mathematical modeling of technological processes of adsorption, physical and chemical absorption is carried out on the basis of Aspen Hysys and Aspen Adsorption software packages. When modeling absorption processes, the composition of combustion products characteristic of the actual operating conditions of an energy source on wood chips was considered, while for the adsorption process, the composition of combustion products was simulated by a binary mixture of carbon dioxide and nitrogen with a molar content of 11 and 89 %, respectively. The results of numerical research that were obtained have shown that the highest degree of carbon dioxide extraction from combustion products is 97 %, and it is achieved in the optimal mode of implementation of chemical absorption technology. With the same method, the highest degree of purity of the resulting carbon dioxide is observed, viz. 86 % taking into account water vapor and 99 % if it is dry. The least effective technology for extracting carbon dioxide was the method of physical absorption in a fixed bed, in which the degree of purity of the resulting dry carbon dioxide was 79 %. Therefore, for practical use in the deep utilization of combustion products of mini-CHP plants operating on local fuels, to obtain carbon dioxide with a low content of impurities, it is necessary to apply the method of chemical absorption. The use of physical absorption technology in a fixed bed can be used to reduce energy source emissions or in cases where the degree of purity of carbon dioxide does not matter.

Predicting composition of combustion products of the pyrotechnic based on Magnesium‐Teflon‐Viton

AbstractDetermining the equilibrium composition of combustion products is important in studying high‐energetic materials such as explosives, propellants, and pyrotechnics. This paper presents a theoretical method and computer program named CAL to predict the composition of combustion products of pyrotechnic mixture based on Magnesium‐Teflon‐Viton by the Gibbs free energy minimization principle. Computer program CAL was developed using the fmincon tool in MATLAB. The reliability of CAL was confirmed when comparing its calculation results with ones obtained by other software and experimental data.

Thermodynamic Analysis of Compositions of Combustion Products of Radioactive Graphite in Water Vapor or Air

Thermodynamic Analysis of Compositions of Combustion Products of Radioactive Graphite in Water Vapor or Air

Design of a system for diagnosing the technical condition of a gas pumping unit based on the analysis of existing methods of processing vibroacoustic signals

The gas transportation system of Ukraine provides transportation of natural gas from deposits to consumers located both on the territory of Ukraine and outside its borders. One of the key elements of the gas transportation system of Ukraine are compressor stations, the task of which is to maintain the specified pressure in the system for uninterrupted transportation of natural gas. The main element of the compressor station is the gas pumping unit (GPU). It is a complex mechanical system consisting of many nodes. In the process of functioning of the gas pumping unit, in its nodes and units, the process of wear of parts occurs, which, subsequently, can lead to an accident. To avoid such situations, current and capital repairs of the system are periodically carried out. A number of non-destructive technical condition control methods have been developed to monitor the technical condition of the GPU between repairs, to optimize the periodicity of their carrying out and to provide early warning of the GPU leaving the nominal state. Such methods are divided into parametric methods, based on the analysis of the operating parameters of the system (temperature and pressure at various GPU nodes, turbine rotation frequency, chemical composition of combustion products), and vibroacoustic, based on the analysis of vibration and acoustic oscillations generated by the GPU nodes. The current state of vibroacoustic signal processing methods, such as Fourier transform, wavelet transform, artificial neural networks, discrete cosine transform, and autocorrelation functions are considered in the work. Based on the analysis, a system for diagnosing the technical state of the GPU based on the Fourier transform in combination with the wavelet transformation and an artificial neural network with two hidden layers is proposed, the task of which is to recognize the technical condition of the GPU, based on the result of the wavelet transformation, divided into separate images in primary colors.

Thermodynamic Analysis of Compositions of Combustion products of Radioactive Graphite in Water Vapor or Air

Thermodynamic Analysis of Compositions of Combustion products of Radioactive Graphite in Water Vapor or Air

Assessment of threat arising by closed - volume explosions of fuel - air mixtures

The method of estimation of maximal parameters of combustion of gaseous mixtures in closed space is presented. Estimation of chemical composition of combustion products is based on simplified rules of decomposition of reactive medium. Exemplary calculations of temperature, pressure, heat of combustion of hydrocarbon/air mixtures are presented. The accuracy of presented method was validated by comparison with calculations performed by thermodynamic numerical code that include wide list of chemical substances present in combustion products. The obtained results confirm applicability of the proposed method to predict closed space combustion parameters of gaseous mixtures. Semi-empirical methods of estimation of flammability limits are briefly referred

Развитие средств термодинамического расчета характеристик ракетного двигателя с использованием языка программирования Julia

The experience in developing an algorithm and a program for the thermal-chemical calculation of the characteristics of a rocket engine is presented. The program is written in Julia. To calculate the equilibrium composition of combustion products the freely distributed library Ipopt is used. The program is interfaced to the database on thermodynamic properties of individual substances IVTANTERMO. For the convenience of processing, the information on thermodynamic properties is stored in two text files of a special form. The program has been developed using the simplest working process model according to which the flow is one-dimensional, the product flow is adiabatic, there are no friction losses, the product flow is equilibrium, and the speed of condensed particles is equal to the gas flow speed. Ratios for calculating the derivatives of composition, as well as equilibrium values of heat capacity and sound velocity are given. The text of the program can be used in the study process and can easily be adapted to more complex models of the rocket engine workflow. The calculation results obtained using the developed program are in good agreement with the results of TERRA calculations. The execution time of one calculation for a four-element fuel, which includes the determination of the combustion products characteristics in the chamber, the critical cross section and at the nozzle cross section, varies in the range of 3--5 s

Comparative thermodynamic analysis of LNG, LPG, methanol, ethanol, biodiesel and hydrogen as alternative fuels in HCCI engines

Aiming to mitigate the problem of harmful emissions arising from the use of conventional fossil fuels, the performances of alternative fuels, namely LNG, LPG, biodiesel, ethanol, methanol, and hydrogen in an HCCI engine have been analyzed. Thus, a thermodynamic model that considers the gas composition of combustion products and the specific heat temperature dependency of the working fluid has been developed. It allows examining the influence of key engine parameters such as the compressor pressure ratio, ambient temperature, equivalence ratio, engine speed, and the compressor isentropic efficiency on the performance of the HCCI engine. The reliability of the model has been successfully verified against various theoretical and experimental data from the literature. Results showed that LNG performs the best in terms of brake efficiency, exergy efficiency, and placed second in terms of brake specific fuel consumption. With the exception of the latter, although it is associated with a higher energy value, hydrogen produces lower performance compared to the other fuels assessed. For all fuels, the largest exergy destruction rates occur in the HCCI engine. It ranges between 78.4 and 87.8 % of the total exergy destruction rate according to the fuel used. The order of exergy destruction rates within the other components differs from one fuel to the other.

Experimental Investigation on Combustion Characteristics and Agglomeration of Al/NEPE Propellants

AbstractIn order to understand the ignition and combustion characteristics of NEPE propellants under different pressure conditions and the agglomeration behavior of aluminum particles on the burning surface, the Al/NEPE propellant was tested on a sealed high‐pressure laser ignition platform. Laser ignition experiments show that both ignition delay time and combustion time are inversely proportional to ambient pressure. With the increase of pressure, the reduction of ignition delay time and self‐sustaining combustion time is reduced. The impact of pressure on ignition and combustion is very complex. We then analyze the effect of pressure on ignition delay time using a theoretical mechanism. High‐speed microscopic images display the agglomeration of aluminum particles in propellants mainly through the following three processes: accumulation, aggregation, and agglomeration. It is also found that many aluminum particles are agglomerated on the surface, the aluminum droplet agglomerates formed on the combustion surface are separated from the combustion surface, and the agglomerates rupture and flow out of the liquid alumina during the combustion process. The phenomenon of secondary agglomeration is also observed. The microstructure and elemental composition of combustion products of aluminum particles in NEPE propellant were obtained by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The detection results confirmed some agglomeration phenomena. At 3.0 MPa, the combustion of the propellant sample is sufficient, and the aluminum particles are smooth spherical alumina particles. At 1.0 MPa, the combustion of the propellant sample is insufficient, and the aluminum particles are rough. The particle size under different pressure was analyzed by a laser particle size analyzer. The results show that increasing the pressure can reduce the average agglomeration size of aluminum particles and improve combustion efficiency. The number of large particle aggregates is more at 3 MPa. From the perspective of overall particle size results, within the same diameter interval, the percentage of particle number does not increase or decrease significantly with the increase of pressure.

Chemically activated combustion synthesis of AlON under high nitrogen pressure

This work explores the synthesis of aluminum oxynitride (AlON) by combustion of Al/Al2O3 mixtures under a high-pressure nitrogen atmosphere. The effect of nitrogen pressure and addition of Mg(ClO4)2 and excess Al on the exothermicity of the mixture, kinetics of the combustion process, and phase composition of combustion products is studied. In particular, we reveal the dependence of the AlON lattice parameter on nitrogen pressure (and, correspondingly, nitrogen content in the combustion products). Finally, we demonstrate the possibility of the fabrication of transparent Y2O3-doped AlON ceramics from the combustion products.