scholarly journals Nature of dust and smoke generation during gas-oxygen blasting in converter bath

2021 ◽  
Vol 64 (2) ◽  
pp. 112-121
Author(s):  
V. V. Solonenko ◽  
E. V. Protopopov ◽  
M. V. Temlyantsev ◽  
N. F. Yakushevich ◽  
S. O. Safonov
Keyword(s):  
Reaction Zone ◽  
Dust Emission ◽  
Combustion Products ◽  
Metal Films ◽  
Oxygen Flow ◽  
Metal Loss ◽  
Bath Surface ◽  
Converter Bath ◽  
Metal Impurities ◽  
Smoke Generation

The article presents the study of the nature of dust and smoke generation during gas-oxygen blasting of a converter bath. The main reasons causing metal waste have been determined. Influence of the process main parameters on metal loss has been studied during dust removal and evaporation of iron in the reaction zone. The authors have estimated the process of metal pulverization due to CO bubbles floating, determined by the rate of their rise to the bath surface. Specifics of temperature regime of the reaction zone and heat balance have been determined when adding fuel to the oxygen flow. Adding fuel to oxygen makes it possible to increase heat input into the bath, while reducing the rate of decarburization. This enables reduction of dust discharge during rupture and crush of metal films by gas bubbles. The effect of combustion products oxygen use on metal impurities oxidation is considered. By the example of blasting carbon and alloyed steel for mill rolls, it has been shown that the degrees of CO2 and H2O decomposition in the bath are the main qualities of gas-oxygen blasting. These indicators determine the oxidizing and heating properties of the blast. Assessment of change in total, consumed heat and its losses with exhaust gases, depending on degree of the oxygen flow dilution with natural gas (methane), has been carried out. Under these conditions, use of submersible combustion torches with change in their oxidizing ability makes it possible to solve various technological tasks, including provision of an effective way to reduce dust emission in converter process.

Video registration of physicochemical processes in BOF cavity at bath top blowing at application oxygen lances of various designs. Report 1. Facility and methodology of the study

2021 ◽  
Vol 77 (8) ◽  
pp. 969-976
Author(s):  
A. G. Chernyatevich ◽  
L. C. Molchanov ◽  
E. N. Sigarev ◽  
S. A. Dudchenko ◽  
V. V. Vakal’chuk ◽  
...  
Keyword(s):  
High Temperature ◽  
Reaction Zone ◽  
Video Camera ◽  
Bath Surface ◽  
Hot Metal ◽  
Metal Melt ◽  
Physicochemical Processes ◽  
Video Registration ◽  
Foamed Slag ◽  
Practical Information

Interaction of the upper oxygen jets with the BOF bath considerably effects the hot metal refining flow. To optimize the lances designs and methods of BOF bath blowing, information is needed on the actual physical and technical phenomena taking place during top blowing of BOF bath by groups of ultrasonic and sonic oxygen jets. It was shown that obtaining the information is possible at high temperature simulation of the BOF bath blowing by application oxygen lances of various designs and video registration. Results of previous studies by filming of the blowing in a BOF and OHF presented. Description of modern facilities of high temperature simulation within a multi-purpose 160 and 60‒80 kg BOFs, equipped by special manholes for observation and registration by video camera the physicochemical processes taking place on the surface of the bath presented. In particular the manholes made it possible to observe the processes taking place at various methods of top and combined blowing of the BOF bath by application regular, two-circuit and double-flow oxygen lances. A methodology of test heats carrying out presented, which ensured obtaining important practical information on forming and variation of dimensions of the reaction zone. In particular, information was obtained about the interaction of ultrasonic and sonic oxygen jets with the metal melt, development of afterburning, emission out of reaction zone C to CO2 in the subsonic and sonic oxygen jets with forming high temperature flares directed on the BOF bath surface or penetrated in the foamed slag, emissions of slag-metal suspension out the BOF, forming of metal-slag sculls on the lance tube during the blowing with various level of foamed slag-metal emulsion.

Flammability properties of fire-retardant timber

2021 ◽  
Vol 30 (2) ◽  
pp. 23-34
Author(s):  
O. N. Korolchenko ◽  
S. G. Tsarichenko ◽  
N. I. Konstantinova
Keyword(s):  
Mass Loss ◽  
Flame Propagation ◽  
Flame Retardants ◽  
Fire Retardant ◽  
Combustion Products ◽  
Timber Structures ◽  
Measurement Instruments ◽  
Pine Tree ◽  
Smoke Generation ◽  
Oak Tree

Introduction. At present, the house-building industry, that produces timber structures, is in the process of sufficiently intensive development; however, high flammability of wood is the factor that restrains widespread use of timber in construction. The purpose of this work is to optimize the conditions of application of fire-retardant timber in the construction industry. The co-authors believe that the following problems are to be solved to attain this objective:● a comparative analysis of the fireproofing efficiency of several fire-proofing agents applied to different species of wood;● determination of the character of influence produced by fire proofing agents on fire retardant properties of wood.Methods of research. The fire proofing efficiency of sample compositions designated for wood was measured in compliance with the benchmark testing method specified in GOST R 53292 (p. 6.2). Experiments were launched pursuant to the methodology and with the help of measurement instruments specified in GOST 30244–94 (Method 2) to study the extent of the pine-tree timber flammability suppression. Critical values of thermal loads that may trigger inflammation and flame propagation in timber structures, that can be described using values of the critical surface density of the heat flow, were determined pursuant to GOST 30402–96 and GOST R 51032–97. The toxicity of combustion products and the smoke generation ability of fire-retardant pine-tree samples was assessed using standard methods and measurement instruments pursuant to GOST 12.1.044–89 (paragraphs 4.18 and 4.20).Research results and discussion. Biological flame retardants, integrated biological flame retardants that also ensure moisture protection, intumescent coatings, lacquers and varnishes that are ready for use and labelled as having group I and II fire-retardant efficiency pursuant to GOST R 53292, were studied in the course of this research project. The co-authors have identified that the mass loss by all fire-retardant compositions is below 9 %, if applied to samples of larch and oak-tree timber, same as if it were applied to standard samples of pine-tree timber.The findings of the experiment conducted to assess the flammability, ignitibility, flame propagation, smoke generation ability and toxicity of combustion products have proven the maximal efficiency of the composition designated for full-cell pressure impregnation of timber that ensures the properties of the material labelled as G1, V1, RP1, T2, D2.Conclusions. Hence, the research results have enabled the co-authors to assess the discrepancy between average mass loss values demonstrated by the samples of different species of timber (alder, linden, pine-tree, larch, and oak-tree).The comprehensive study of flammability properties of timber, treated by compositions that vary in their chemical composition and mode of action of the fire proofing agent, enabled the co-authors to identify the impact produced by versatile fire-proofing agents on different flammability properties of pine-tree timber with regard taken of the fire-safe use of construction materials and constructions of buildings and structures.

The Diffusion Stratification Effect in Bunsen Flames

1974 ◽  
Vol 96 (4) ◽  
pp. 530-535 ◽  
Author(s):  
G. I. Sivashinsky
Keyword(s):  
Reaction Zone ◽  
Reaction Rate ◽  
Lewis Number ◽  
Combustion Products ◽  
Bimolecular Reaction ◽  
Adiabatic Temperature ◽  
Strong Temperature Dependence ◽  
Light Component ◽  
Stratification Effect ◽  
Bunsen Flames

The thermal diffusion flame model for a bimolecular reaction under stoichiometry conditions of the fresh mixture was examined. The structure of the flame tip of the Bunsen cone was studied. A local breakdown in the stoichiometry in the vicinity of the reaction zone was found such that the light component is always insufficient. For Lewis numbers greater than unity, the flame front is continuous. The temperature at the exit from the reaction zone exceeds the adiabatic temperature of the combustion products. For a Lewis number of the light component less than unity, either a flame with a continuous front, the temperature of which is less than the adiabatic temperature, or a flame with an exposed tip is possible. The problem is solved on the assumption of a strong temperature dependence of the reaction rate.

Theoretical Study on Premixed Flames of Nano Aluminum Particles and Water Mixture

2013 ◽  
Vol 284-287 ◽  
pp. 567-571
Author(s):  
Jun Su Shin ◽  
Hong Gye Sung
Keyword(s):  
Reaction Zone ◽  
Aluminum Particle ◽  
Particle Diameter ◽  
Initial Pressure ◽  
Combustion Products ◽  
Flame Speed ◽  
Computational Domain ◽  
Water Mixture ◽  
Aluminum Particles ◽  
Preheat Zone

A theoretical model is proposed to investigate premixed combustion characteristics of Nano aluminum particles - water mixture. The effects of particle size, initial pressure, and temperature were considered as well. Computational domain is divided into 3 regions; preheat zone 1, preheat zone 2, and reaction zone. No reaction occurs in either of the preheat zones. Reaction zone, consisting of nano aluminum particles–steam mixture and the combustion products, is the region where reaction and heat-release occurs. Energy conservation is considered separately at each zones. The flame speed and temperature distribution are derived by solving the energy equation in each regime and matching the temperature and heat flux at the interfacial boundaries. Combustion time correlation of nano aluminum particle is also considered to imply complex aluminum combustion kinetics. Normalized flame speed is calculated as a function of pressure, initial particle diameter, and equivalence ratio and compared with experimental data.

scholarly journals Experimental Study on Smoke Production and Smoke Generation in Thermoplastic Resins Based on PP, PMMA, and PVC

2020 ◽  
Vol 34 (3) ◽  
pp. 1-7
Author(s):  
Euy-Hong Hwang ◽  
Don-Mook Choi
Keyword(s):  
Human Life ◽  
Combustion Products ◽  
Test Standards ◽  
Smoke Production ◽  
Large Size ◽  
Smoke Generation ◽  
Smoke Measurement ◽  
Plastic Resin ◽  
Thermoplastic Resins ◽  
Related Test

Due to the complexity and large size of buildings, plastic resin is widely used as a building material. Accordingly, the occurrence of fires caused by plastics is increasing. Due to the nature of plastic resin fires, the amount of damage to properties and human life caused by combustion products such as smoke are large, and these damages are related to smoke production and smoke generation. Therefore, this study reviews smoke measurement methods and laws on domestic buildings and fire services. Experiments were conducted based on three smoke-related test standards (ISO 5660-1, ISO 12136, ASTM E 662). The experiment results indicate a total smoke production and generation by PP, PVC, and PMMA of 43.27, 32.83, and 12.33 m2, and 27.855, 9.599, and 6.975 g, respectively.

scholarly journals Fire-Side Corrosion: A Case Study of Failed Tubes of a Fossil Fuel Boiler

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Majid Asnavandi ◽  
Mohaddeseh Kahram ◽  
Milad Rezaei ◽  
Davar Rezakhani
Keyword(s):  
Power Plant ◽  
Critical Points ◽  
Fossil Fuel ◽  
Corrosion Behaviour ◽  
Combustion Products ◽  
Metal Loss ◽  
Corrosion Monitoring ◽  
Boiler Tubes ◽  
Conventional Models

The failures of superheater and reheater boiler tubes operating in a power plant utilizing natural gas or mazut as a fuel have been analysed and the fire-side corrosion has been suggested as the main reason for the failure in boiler tubes. The tubes have been provided by a fossil fuel power plant in Iran and optical and electron microscopy investigations have been performed on the tubes as well as the corrosion products on their surfaces. The results showed that the thickness of the failed tubes is not uniform which suggests that fire-side corrosion has happened on the tubes. Fire-side corrosion is caused by the reaction of combustion products with oxide layers on the tube surface resulting in metal loss and consequently tubes fracture. However, the tubes corrosion behaviour did not follow the conventional models of the fire-side corrosion. Given that, using the corrosion monitoring techniques for these boiler tubes seems essential. As a result, the thickness of the boiler tubes in different parts of the boiler has been recorded and critical points are selected accordingly. Such critical points are selected for installation of corrosion monitoring probes.

Video registration of physicochemical processes in BOF cavity at bath top blowing at application oxygen lances of various designs. Report 3. The picture of bath blowing at application two-level oxygen lances

2021 ◽  
Vol 77 (11) ◽  
pp. 1142-1155
Author(s):  
A. G. Chernyatevich ◽  
L. S. Molchanov ◽  
E. N. Sigarev ◽  
S. A. Dudchenko ◽  
V. V. Vakul'chuk ◽  
...  
Keyword(s):  
Reaction Zone ◽  
Initial Period ◽  
Video Recording ◽  
Slag Formation ◽  
Double Row ◽  
Metal Melt ◽  
Converter Bath ◽  
Foamed Slag ◽  
Aggressive Action ◽  
Laval Nozzles

Further increase of resources- and energy-saving efficiency of BOF processes is unthinkable without development of new methods of blowing and designs of blowing devices. It requires information on the real physicochemical phenomena in the converter cavity accompanying the blowing of the converter bath using new designs of oxygen lances in order to assess the possible risks in the mastering of the proposed developments in industrial conditions. The paper presents the results of video filming of the top blowing of a 80-kg converter bath by groups of multi-pulse supersonic and sonic oxygen jets formed, respectively, by Laval and cylindrical two-level nozzles of two designs equipped with double-row tips with a circular arrangement of Laval nozzles and cylindrical ones and upper block with cylindrical nozzles. Previously unknown information was obtained on the picture of the bath blowing with the formation of a reaction zone of interaction of supersonic and sonic oxygen jets with a metal melt with a flow of carbon monoxide going out the bath and afterburning of CO to CO2 under conditions of a counter-directed double curtain of sonic oxygen jets at different levels of location of the foamed slag-metal emulsions. It was established that in the initial period of blowing during slag formation most of the thermal energy of CO to CO2 combustion flares is transferred to the surface of the bath with lumps of added lime, and the rest is transferred by forced convection to the converter walls and gases escaping from the bath to the neck. In the case of the location of the foamed slag level at the upper tier of the cylindrical nozzles of the lance, heat transfer from high-temperature flares of localized afterburning of CO to CO2 within a limited in size near-lance flow of exhaust gases from the reaction zone is carried out according to the laws of submerged combustion and is completed completely in foamed slag-metal emulsion with the prevention of aggressive action of afterburning flares and volumes of overheated slag on the converter lining. Revealed and recorded by video recording modes of blowing the converter bath, contributing to the development of such undesirable phenomena during smelting as the appearance of intense emissions of slag-metal suspension from the facility, coagulation of the slag with the cessation of dephosphorization of the metal melt, the development of intense dust formation and the removal of small metal particles and slag with the formation of crust on the lance barrel. A variant of the final stage of blowing with a transition to supplying nitrogen instead of oxygen through cylindrical nozzles of two-level lances was experimentally tested, which provides an effective reduction in the level of foamed slag-metal emulsion before the converter turning down. The data obtained were used in the development of an industrial design of a two-level lance with a double-row tip, blowing and slag modes of blowing a converter bath with its use.

Corrosivity Test Methods for Polymeric Materials. Part 4- Cone Corrosimeter Test Method

1994 ◽  
Vol 12 (2) ◽  
pp. 175-195
Author(s):  
James G. Bennett ◽  
Stephen L. Kessel ◽  
Charles E. Rogers
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Corrosion Test ◽  
Polymeric Materials ◽  
Combustion Products ◽  
Test Methods ◽  
Heat Fluxes ◽  
Test Method ◽  
Metal Loss ◽  
Test Protocol

This is the fourth in a series of papers to investigate corrosivity test methods published by the Polyolefins Fire Performance Council, an operating unit of The Society of the Plastics Industry, Inc. In the first paper, 24 polymeric materials were evaluated for smoke corro sivity following the test method proposed by ASTM E05.21.70 which uses a ra diant combustion/exposure apparatus. The second paper discussed the evalua tion of the same materials using the CNET corrosion test method under consideration by ISO TC61/SC4/WG2 and IEC TC89/WG3 and compared the CNET results with the ASTM E05.21.70 results. In the third paper, the 24 poly meric materials were evaluated using a modified DIN acid gas test method and the results were compared to both the previous ASTM E05.21.70 and CNET results. These commercially available polymeric materials cover a broad range of compositions used for wire and cable insulation and jacketing. In this paper, the same polymeric materials were evaluated following the "Fire Response Standard for Determining the Corrosive Effect of Combustion Products Using a Cone Corrosimeter" proposed by ASTM D09.21.04. In this test method, a specimen is subjected to radiant heat at the recommended heat flux using a spark igniter to ignite combustible vapors. A portion of the pro ducts of decomposition or combustion are channeled in a dynamic mode through an exposure chamber in which corrosion targets are placed until the specimen has lost 70% of its total available mass loss. The mass loss is deter mined from previous experiments at the recommended heat flux. When the specimen has lost 70% of its mass loss, the exposure chamber is sealed and iso lated. The corrosion of the target is determined by exposing the target to the now static combustion products for one hour measured from the start of the test. The target is then placed in an environmental chamber at 75% relative humidity at 23°C for 24 hours. The test method measures the increase in elec trical resistance of a metallic circuit. This increase is related to the decrease in conductive cross-sectional area resulting from metal loss due to corrosion. The increase in electrical resistance of each target is determined throughout the test and correlated to its metal loss. The 24 hour corrosion value is reported as metal loss in angstroms. In this study, heat fluxes of 25 and 50 kW/m2 were used to simulate two dif ferent fire scenarios. All of the materials were run at 50 kW/m2 and 12 materials were run at 25 kW/m 2. Two targets, one with a span of 2,500 Å and the second with a span of 45,000 A were used during each test at each heat flux. The results of this study indicate that the measured corrosivity of materials: (1) does not correlate consistent with the expectations based upon the known chemis try of their compositions (2) varies numerically with the heat flux under which the tests are run and on the target used to obtain the corrosion data and (3) although numerically different, loosely ranks the corrosive potentials of the materials in a consistent manner at both heat fluxes and with both targets. The test protocol does not specify either the heat flux or the targets to be used recommending both in the appendix. As corrosion values are numerically de pendent on the conditions and target used to obtain the data, it is questionable how this test method can be used as a standard for determining and comparing the corrosion potentials of materials without requiring that both the specific heat flux and the target be specified in the test protocol as well as be reported with the results. To complete the review of corrosion test methods, a comparison of the corro sive potentials of the 24 materials using the four test methods will be made and one test method recommended for use as a global standard.

scholarly journals Mathematical Modeling of Postcombustion in an Electric Arc Furnace (EAF)

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 547
Author(s):  
Niloofar Arzpeyma ◽  
Mikael Ersson ◽  
Pär G. Jönsson
Keyword(s):  
Mathematical Modeling ◽  
Flow Rate ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
Bath Surface ◽  
Arc Furnace ◽  
Molten Bath ◽  
Flow Rates

Numerical modeling was used to study the capability of postcombustion in an electric arc furnace (EAF) equipped with virtual lance burners. The CO flow rate at the molten bath surface was estimated using the off-gas data obtained close to the outlet of an EAF. Then, the effect of the secondary oxygen flow rate on postcombustion was studied. The results show a CO flow rate of 0.6 kg·s−1 and 0.8 kg·s−1 for operation modes of burner and burner + lancing. Increase of the secondary oxygen flow rates of 60% and 70% result in 17% and 7% increase in the postcombustion ratio (PCR) for the burner and burner lancing modes, respectively.

IMPACT OF PAINTS, VARNISHES AND SMOKE-GENERATION ABILITY AND TOXICITY OF COMBUSTION PRODUCTS OF WOOD

2014 ◽  
Vol 23 (3) ◽  
pp. 23-29
Author(s):  
M. M. ALMENBAEV ◽  
◽  
R. M. ASEEVA ◽  
B. B. SERKOV ◽  
A. B. SIVENKOV ◽  
...  
Keyword(s):  
Combustion Products ◽  
Smoke Generation
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