On Specific Features of Operating Crucibleless Salt-Bath Furnaces

2005 ◽  
Vol 488-489 ◽  
pp. 89-94 ◽  
Author(s):  
I.V. Zabyelin ◽  
Igor M. Komelin ◽  
Ivan A. Barannik ◽  
I.L. Sikorskaya
Keyword(s):  
Service Life ◽  
Salt Bath ◽  
Heating Element ◽  
Furnace Design ◽  
Atmospheric Air ◽  
Gaseous Products ◽  
Salt Melts

This paper covers information on salt melts, used in crucibleless electrical furnaces as a heating element, which interact with atmospheric air to form solid and gaseous products and mostly determine the furnace design, governing furnace maintenance conditions and its service life.

scholarly journals Corrosion of carbon steel and cast iron in gas phase above salt melts used in magnesium industry

2019 ◽  
pp. 34-49
Author(s):  
I. M. Komelin ◽  
A. P. Lysenko ◽  
D. S. Kondrat'eva
Keyword(s):  
Cast Iron ◽  
Carbon Steel ◽  
Chemical Analysis ◽  
Gas Phase ◽  
Gravimetric Method ◽  
Iron Corrosion ◽  
Atmospheric Air ◽  
Corrosion Rates ◽  
Salt Melts ◽  
Salt Melt

Corrosion tests of SCh15 cast iron, Steel 3 and Steel 3 with aluminized coating in some compositions of 10%MgCl2-KCl-NaCl and 10%MgCl2-KCl-Naa-Caa2 salt melts with 10 %, 25 % and 40 % CaCl2 concentrations, and also in 10MgCl2-45%KCl-20%NaCl-25%NaBr melt, and in the gas phase above these melts at 700 °C. A gravimetric method was used to determine corrosion rates of metal samples. Chemical analysis of absorption solutions was used to determine concentrations of halide and hydrogen halide impurities in air blown through the reactor with melts and samples. It was shown that carbon steel aluminizing can reduce the corrosion rate in the gas phase over the salt melt by a factor of 5 to 70. The formation mechanism of gases aggressive in relation to carbon steel and cast iron in atmospheric air in contact with salt chloride melt was considered. Accelerated hydrogen chloride and chlorine formation during the salt melt interaction with atmospheric air under the influence of iron corrosion products was found.

Influence of the Radiation Destruction of Polymeric Insulation on its Ageing in the Impulse Electric Field

2014 ◽  
Vol 880 ◽  
pp. 88-92 ◽  
Author(s):  
Peter N. Bychkov ◽  
Olga V. Solodovnikova
Keyword(s):  
Service Life ◽  
Radiation Resistance ◽  
Molecular Level ◽  
Gas Permeability ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Volume Charge ◽  
Charge Accumulation ◽  
Gaseous Products ◽  
Ionizing Radiations

Sensitivity of the destructive doses of ionizing radiations, specifically radiolysis gaseous products to multipulse electric intensity of low-density polyethylene (LDPE) and a polymethyl-methacrylate (PMMA) was investigated. LDPE and PMMA were found to differ significantly depending on radiation resistance and gas permeability. The service life of the materials was basically determined by the intensity of the destruction processes at the molecular level, the macrodefects were developed at the last ageing stage . It was shown that microseconds impulses did not cause accumulation of volume charge in LDPE and PMMA. It was concluded that the ageing of polymer dielectrics affected by electric microseconds impulses did not relate to volume charge accumulation in the polymers.

Effects of Technological Conditions and Substrate Material on TD Coatings

2014 ◽  
Vol 590 ◽  
pp. 271-275 ◽  
Author(s):  
Yan Jie Zhang ◽  
Hui Chen ◽  
Zhang Yu Gao ◽  
Shi Nan Li ◽  
Hong Mei Yu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Service Life ◽  
Industrial Production ◽  
Vanadium Carbide ◽  
High Hardness ◽  
Salt Bath ◽  
Substrate Material ◽  
Carbide Coating ◽  
Vanadium Carbide Coating

Thermal diffussion (TD) is a method of coating steels to improve the service life of materials and tools. With this process, high hardness of vanadium carbide coating is formed on the surface of materialsso that its wear, bite, corrosion resistance can be greatly improved. Since thereare still several problems remaining to be solved, this technology is still not widely used in our country and that limit the popularity of the salt bath technology. In this paper, these problems and their causes are discussed based on experiments, and several solutions are presented to hopefully provide suggestions for industrial production.

Selective Corrosion of brazed joint between BNi-2 filler metal and stainless steel 316

1996 ◽  
Vol 54 ◽  
pp. 218-219
Author(s):  
H. S. Kim ◽  
R. U. Lee
Keyword(s):  
Stainless Steel ◽  
Filler Metal ◽  
Surface Preparation ◽  
Optical Microscope ◽  
Heating Element ◽  
Incomplete Fusion ◽  
Atmospheric Conditions ◽  
Leak Test ◽  
High Temperature Side ◽  
Inconel 600

A heating element/electrical conduit assembly used in the Orbiter Maneuvering System failed a leak test during a routine refurbishment inspection. The conduit, approximately 100 mm in length and 12 mm in diameter, was fabricated from two tubes and braze-joined with a sleeve. The tube on the high temperature side (heating element side) and the sleeve were made of Inconel 600 and the other tube was stainless steel (SS) 316. For the filler metal, a Ni-Cr-B brazing alloy per AWS BNi-2, was used. A Helium leak test spotted the leak located at the joint between the sleeve and SS 316 tubing. This joint was dissected, mounted in a plastic mold, polished, and examined with an optical microscope. Debonding of the brazed surfaces was noticed, more pronounced toward the sleeve end which was exposed to uncontrolled atmospheric conditions intermittently. Initially, lack of wetting was suspected, presumably caused by inadequate surface preparation or incomplete fusion of the filler metal. However, this postulation was later discarded based upon the following observations: (1) The angle of wetting between the fillet and tube was small, an indication of adequate wetting, (2) the fillet did not exhibit a globular microstructure which would be an indication of insufficient melting of the filler metal, and (3) debonding was intermittent toward the midsection of the sleeve.

Study of the Kinetics of Thermal Destruction of Crossed Polyethylene

2019 ◽  
Vol 5 (12) ◽  
pp. 37-46
Author(s):  
K. Chalov ◽  
Yu. Lugovoy ◽  
Yu. Kosivtsov ◽  
E. Sulman
Keyword(s):  
Total Yield ◽  
Calorific Value ◽  
High Heat ◽  
Process Temperature ◽  
Optimum Process ◽  
Quantitative Composition ◽  
Pyrolysis Gas ◽  
Gaseous Products ◽  
Liquid Products ◽  
Kinetics Of

This paper presents a study of the process of thermal degradation of crosslinked polyethylene. The kinetics of polymer decomposition was studied by thermogravimetry. Crosslinked polyethylene showed high heat resistance to temperatures of 400 °C. The temperature range of 430–500 °C was determined for the loss of the bulk of the sample. According to thermogravimetric data, the decomposition process proceeds in a single stage and includes a large number of fracture, cyclization, dehydrogenation, and other reactions. The process of pyrolysis of a crosslinked polymer in a stationary-bed metal reactor was investigated. The influence of the process temperature on the yield of solid, liquid, and gaseous pyrolysis products was investigated. The optimum process temperature was 500 °C. At this temperature, the yield of liquid and gaseous products was 85.0 and 12.5% (mass.), Respectively. Samples of crosslinked polyester decomposed almost completely. The amount of carbon–containing residue was 3.5% by weight of the feedstock. With increasing temperature, the yield of liquid products decreased slightly and the yield of gaseous products increased, but their total yield did not increase. For gaseous products, a qualitative and quantitative composition was determined. The main components of the pyrolysis gas were hydrocarbons C1–C4. The calorific value of pyrolysis gas obtained at a temperature of 500 °C was 17 MJ/m3. Thus, the pyrolysis process can be used to process crosslinked polyethylene wastes to produce liquid hydrocarbons and combustible gases.

MANUFACTURING GASEOUS PRODUCTS BY PYROLYSIS MICROALGAE BIOMASS

2019 ◽  
pp. 23-34
Author(s):  
N. I. Chernova ◽  
S. V. Kiseleva ◽  
O. M. Larina ◽  
G. A. Sytchev
Keyword(s):  
Raw Materials ◽  
Renewable Energy Sources ◽  
High Energy ◽  
Initial Mass ◽  
Solid Residue ◽  
Algae Biomass ◽  
Gaseous Products ◽  
Microalgae Biomass ◽  
Pyrolysis Liquid ◽  
Pyrolysis Gases

Algae biomass is considered as an alternative raw material for the production of biofuels. The search for new types of raw materials, including high-energy types of microalgae, remains relevant, since the share of motor fuels in the structure of the global fuel and energy balance remains consistently high (about 35%), and the price of oil is characterized by high volatility. The authors have considered the advantages of microalgae as sources of raw materials for fuel production. Biochemical and thermochemical conversion are proposed as technologies for their processing. This paper presents the results of the study of the pyrolysis of the biomass of clonal culture of blue-green microalgae / cyanobacteriumArthrospira platensis rsemsu 1/02-Pfrom the collection of the Research Laboratory of Renewable Energy Sources of the Lomonosov Moscow State University. An experiment to study the process of pyrolysis of microalgae biomass was carried out at the experimental facility of the Institute of High Temperatures RAS in pure nitrogen grade 6.0 to create an oxygen-free environment with a linear heating rate of 10 ºС / min from room temperature to 1000 ºС. The whole process of pyrolysis proceeded in the field of endothermy. The specific amounts of solid residue, pyrolysis liquid and gaseous products were experimentally determined. As a result of the pyrolysis of microalgae biomass weighing 15 g, the following products were obtained: 1) coal has the mass of the solid residue is 2.68 g, or 17.7% of the initial mass of the microalgae (while 9.3% of the initial mass of the microalgae remained in the reactor); 2) pyrolysis liquid – weight 3.3 g, or 21.9% of the initial weight; 3) non-condensable pyrolysis gases – weight 1.15 l. The specific volumetric gas yield (the amount of gas released from 1 kg of the starting material) was 0.076 Nm3/ kg. The analysis of the composition and specific volume yield of non-condensable pyrolysis gases formed in the process of pyrolysis, depending on temperature. It is shown that with increasing temperature, the proportion of highcalorie components of the gas mixture (hydrogen, methane and carbon monoxide) increases. The calorific value of the mixture of these gases has been estimated.

WET BURNING – THE MODERN TREND IN ENVIRONMENTAL BENIGN FUEL COMBUSTION AND IN SOLUTION TO THE PROBLEM OF SUSTAINABLE DEVELOPMENT OF THE POWER GENERATION

2018 ◽  
pp. 96-117 ◽  
Author(s):  
B. S. Soroka
Keyword(s):  
Numerical Simulation ◽  
Nitrogen Oxides ◽  
Chemical Kinetics ◽  
Fuel Combustion ◽  
Transport Processes ◽  
Cfd Modeling ◽  
Furnace Chamber ◽  
Modern Trend ◽  
Atmospheric Air ◽  
No Formation

The article considers the role and place of water and water vapor in combustion processes with the purpose of reduction the effluents of nitrogen oxides and carbon oxide. We have carried out the complex of theoretical and computational researches on reduction of harmful nitrogen and carbon oxides by gas fuel combustion in dependence on humidity of atmospheric air by two approaches: CFD modeling with attraction of DRM 19 chemical kinetics mechanism of combustion for 19 components along with Bowman’s mechanism used as “postprocessor” to determine the [NO] concentration; different thermodynamic models of predicting the nitrogen oxides NO formation. The numerical simulation of the transport processes for momentum, mass and heat being solved simultaneously in the united equations’ system with the chemical kinetics equations in frame of GRI methane combustion mechanism and NO formation calculated afterwards as “postprocessor” allow calculating the absolute actual [CO] and [NO] concentrations in dependence on combustion operative conditions and on design of furnace facilities. Prediction in frame of thermodynamic equilibrium state for combustion products ensures only evaluation of the relative value of [NO] concentration by wet combustion the gas with humid air regarding that in case of dry air – oxidant. We have developed the methodology and have revealed the results of numerical simulation of impact of the relative humidity of atmospheric air on harmful gases formation. Range of relative air humidity under calculations of atmospheric air under impact on [NO] and [CO] concentrations at the furnace chamber exit makes φ = 0 – 100%. The results of CFD modeling have been verified both by author’s experimental data and due comparing with the trends stated in world literature. We have carried out the complex of the experimental investigations regarding atmospheric air humidification impact on flame structure and environmental characteristics at natural gas combustion with premixed flame formation in open air. The article also proposes the methodology for evaluation of the nitrogen oxides formation in dependence on moisture content of burning mixture. The results of measurements have been used for verification the calculation data. Coincidence of relative change the NO (NOx) yield due humidification the combustion air revealed by means of CFD prediction has confirmed the qualitative and the quantitative correspondence of physical and chemical kinetics mechanisms and the CFD modeling procedures with the processes to be studied. A sharp, more than an order of reduction in NO emissions and simultaneously approximately a two-fold decrease in the CO concentration during combustion of the methane-air mixture under conditions of humidification of the combustion air to a saturation state at a temperature of 325 K.

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