A new SPICE behavioral macromodeling method of magnetic components including the self-heating process

2003 ◽  
Author(s):  
A. Maxim ◽  
D. Andreu ◽  
J. Boucher
Keyword(s):  
The Self ◽  
Heating Process ◽  
Self Heating ◽  
Magnetic Components

Numerical modelling of the self-heating process of a wet porous medium

2011 ◽  
Vol 54 (25-26) ◽  
pp. 5200-5206 ◽  
Author(s):  
A. Ejlali ◽  
D.J. Mee ◽  
K. Hooman ◽  
B.B. Beamish
Keyword(s):  
Porous Medium ◽  
Numerical Modelling ◽  
The Self ◽  
Heating Process ◽  
Self Heating

scholarly journals A study of dynamic adsorption of propylene and ethylene emitted from the process of coal self-heating

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Karolina Wojtacha-Rychter ◽  
Adam Smoliński
Keyword(s):  
Underground Mining ◽  
Early Stage ◽  
Coal Dust ◽  
Fixed Bed ◽  
Gaseous Mixture ◽  
The Self ◽  
Coal Bed ◽  
Heating Process ◽  
Constant Flow Rate ◽  
Self Heating

AbstractThe gaseous products emitted in the self-heating process constitute one of the parameters suggested for detecting coal spontaneous combustion in underground mining. The objective of the study is to investigate the changes of ethylene and propylene content in a gaseous mixture which flowed through a fixed bed column filled with bituminous coal of different grain size. The mixtures of fire gases were obtained from laboratory simulated heating of coal at the temperatures of 373 K, 423 K, 473 K and 523 K. Hydrocarbons of various initial concentrations were introduced to the adsorption column at the constant flow rate of 2∙10−7 m3/s. The experimental findings show that decreasing the adsorbent granulation and gases concentration causes an extended breakthrough and coal bed saturation times. In all the tests, the saturation time was gained faster for ethylene than for propylene. Thus, the content of tested hydrocarbons, which are some of the indicators for assessing the degree of the coal self-heating process, in mine air may change in time as a result of the adsorption phenomenon. It occurs particularly at the early stage of the self-heating process and in places where coal dust has been left.

Analysis of the self-heating process of tetrafluoroethylene in a 100-dm3-reactor

2012 ◽  
Vol 25 (6) ◽  
pp. 1010-1017 ◽  
Author(s):  
Fabio Ferrero ◽  
Robert Zeps ◽  
Martin Beckmann-Kluge ◽  
Volkmar Schröder ◽  
Tom Spoormaker
Keyword(s):  
The Self ◽  
Heating Process ◽  
Self Heating

scholarly journals Molecular and Stable Isotope Composition of Pollutants Emitted during Thermal Processes within the Rymer Coal Waste Dump (Upper Silesia, Poland)

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1120
Author(s):  
Dariusz Więcław ◽  
Krzysztof Jurek ◽  
Monika J. Fabiańska ◽  
Elżbieta Bilkiewicz ◽  
Adam Kowalski ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotope Composition ◽  
The Self ◽  
Gas Chromatography Mass Spectrometry ◽  
Heating Process ◽  
Coal Waste ◽  
Waste Dump ◽  
Pyrolysis Gas ◽  
Self Heating ◽  
Gaseous Hydrocarbons

Twenty-seven gases and sixteen rock wastes from the thermal active Rymer coal waste dump were collected. The composition and origin of gaseous, liquid, and solid pollutants emitted during the self-heating process and the development of these processes with time were established. Gases were subjected to determination of molecular and stable isotope (δ13C and δ2H) composition. Rock-Eval pyrolysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were applied for evaluation of the quantity and molecular composition of pyrolysates released during the heating of rocks in temperatures from 100 to 650 °C. The main products of Py-GC-MS are released between 350 and 650 °C, namely alkanes, aromatic hydrocarbons, and aromatic alcohols. These components were also recorded in Py-GC-MS products of samples collected from the dump surface. Besides the high-molecular-weight organic compounds, in emitted gases CO2, CO, gaseous hydrocarbons, and S-compounds were recorded. The stable isotope data indicated that methane was generated mainly during the low-temperature thermogenic process, but a share of the microbial-originated gas was visible. The source of the CO2 was the oxidation of organic matter. The gaseous S-compounds were products of high-temperature decomposition of sulphides and organic S-compounds. The hydrocarbon and CO contents of the emitted gases proved to be good indicators for tracking of the self-heating processes.

scholarly journals Influence of the Volumetric Expenditure of Air Supplied to the Longwall Through the “Y” Ventilation System on the Location of an Area at the Risk of an Endogenic Fire

2020 ◽  
Vol 3 (1) ◽  
pp. 206-215
Author(s):  
Magdalena Tutak
Keyword(s):  
Oxygen Content ◽  
Research Methodology ◽  
Ventilation System ◽  
The Self ◽  
Hard Coal ◽  
Heating Process ◽  
Air Velocity ◽  
Self Heating ◽  
Air Stream ◽  
Endogenous Fire

AbstractIn the case of longwall ventilation, in the underground hard coal mines, a phenomenon related to the migration of a certain amount of the air stream supplied to the longwall deep into goaf zones occurs. One of the wall ventilation systems, in which this phenomenon is quite intense, is the so called “Y” ventilation system. This migration is immensely unfavorable because it can lead to the self-heating process of coal left in a goaf and, consequently, to an endogenous fire. Such a fire is a great threat to both the safety and continuity of operation processes. For this reason, various activities are undertaken to prevent such a fire from occurring in goaf zones. One solution is a method presented in this article. It aims at determining an area in goaf zones, where an endogenous fire may occur. The study focused on the longwall ventilated with the Y system. This area was determined based on two criteria, namely air velocity and oxygen content. The study was carried out for various volumes of air supplied to the longwall. Therefore, the purpose of the study was to develop research methodology and determine the location of an area at the risk of an endogenous fire. The location of this area was determined for three different volume expenditures of air supplied to the longwall ventilated with the Y system.

A Simple Model for the Effective Thermal Conductivity of a Particulate Mixture

2002 ◽  
Author(s):  
Mehrdad Massoudi ◽  
Tran X. Phuoc
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Heat Dissipation ◽  
Accurate Estimate ◽  
The Self ◽  
Control Measures ◽  
Heating Process ◽  
Self Heating ◽  
History Of ◽  
Phenomenological Coefficients

When a coal stockpile is stored in the presence of air, slow oxidation of the carbonaceous materials occurs and heat is released. If the rate of heat generation within the stockpile is greater than the rate of heat dissipation and transportation to the external environment, the self-heating of the coal stockpile ensues. The self-heating of coal stockpiles has a long history of posing significant problems to coal producers because it lowers the quality of coal and may result in hazardous thermal runaway. Precise prediction of the self-heating process is, therefore, necessary in order to identify and evaluate control measures and strategies for safe coal mining, storage and transportation. Such a prediction requires an accurate estimate of the various processes associated with the self-heating which are impossible unless the appropriate phenomenological coefficients are known. This note is to present a simple approach to determine the effective thermal conductivity of a granular porous medium such as a coal stockpile.

scholarly journals Influence of Air Supply Velocity on Temperature Field in the Self Heating Process of Coal

2017 ◽  
Vol 46 (11) ◽  
pp. 2143-2148
Author(s):  
Shuanglin Song ◽  
Shugang Wang ◽  
Yuntao Liang ◽  
Xiaochen Li ◽  
Qi Lin
Keyword(s):  
Temperature Field ◽  
The Self ◽  
Heating Process ◽  
Self Heating ◽  
Air Supply ◽  
Supply Velocity
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