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.

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.

scholarly journals Spatial and Temporal Distribution of Temperature, Relative Humidity and Air Velocity in a Parallel Milking Parlour During Summer Period

2015 ◽  
Vol 15 (2) ◽  
pp. 517-526 ◽  
Author(s):  
Piotr Herbut ◽  
Sabina Angrecka ◽  
Grzegorz Nawalany ◽  
Krzysztof Adamczyk
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Ventilation System ◽  
Temporal Distribution ◽  
Operating Conditions ◽  
Air Velocity ◽  
Summer Period ◽  
Air Movement ◽  
Air Stream ◽  
Relative Air Humidity

Abstract The research aimed at determining the most significant parameters affecting the microclimate of milking parlours, such as temperature, relative humidity and air movement in a parallel milking parlour in real operating conditions. The research was conducted in the summer period, when the risk of heat stress in cattle is higher. To check welfare of cows during milking, days with air temperature >25°C and days with temperature equal or lower than 25°C were analysed. Observation and analysis were performed for air flow in milking parlour, range of supplied air stream and how air movement affects cattle. It was observed that the irregular distribution of air movement led to the development of diverse air velocity in different zones of the milking parlour (0.2-9.0 m∙s-1). As a consequence, the conditions inside the barn were not homogenous for all the cattle. A significant effect of the cows and external air temperature (which depends indirectly on orientation of the milking parlour relative to cardinal directions) on temperature increase (approx 6°C) was concluded, with relative air humidity at the level of 85-90%, during the milking, which led to systematic decrease of microclimatic comfort for cattle. Based on the conducted research, it was concluded that the design of ventilation systems in parallel milking parlours should be preceded by increased research not only on ventilation system efficiency but also on the distribution of flow ventilated air.

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 Analysis of Dustiness State in a Driven Underground Dog Heading Ventilating by Auxiliary Air-Duct

2020 ◽  
Vol 28 (2) ◽  
pp. 73-77
Author(s):  
Jarosław Brodny ◽  
Magdalena Tutak
Keyword(s):  
Rock Mass ◽  
Research Methodology ◽  
Transport Process ◽  
Coal Dust ◽  
Ventilation System ◽  
Dust Grains ◽  
Movement Trajectories ◽  
Air Stream ◽  
Electrical Devices

AbstractDustiness of the mine atmosphere during carrying out exploitation is one of the most hazardous factors threaten to health and life of employees. Also it is large hazard for all type of mechanical and electrical devices operating in mining headings. Coal dust is also very dangerous due to its possibility of explosion. Currently applied technologies of rock mass mining process, entire transport process of output and applied ventilation system cause that rock and coal dust is presented practically in each of the mining heading. Practically, is impossible to eliminate dust from mining headings. However, one can determine its parameters and potential ways its displacement. In the paper there is presented modeling research methodology of dustiness state in a driven dog heading. Developed model is the basis for this methodology, including the diphase flow of mixture of air and dust in the mining heading. Analysis was performed for real driven dog heading. Based on performed analyses, distributions of particular fraction and movement trajectories of selected dust grains were determined. Developed methodology gives a lot of opportunities for analysis of dustiness state in mining headings and in other compartments. It enables to determine parameters of particular grains and their impact on ventilation parameters of the air stream in the tested headings. Obtained results can also be used to reduce dust hazard.

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 Determination of the Zone Endangered by Methane Explosion in Goaf with Caving of Longwalls Ventilated on „Y“ System

2016 ◽  
Vol 24 (4) ◽  
pp. 247-251 ◽  
Author(s):  
Jarosław Brodny ◽  
Magdalena Tutak
Keyword(s):  
Oxygen Concentration ◽  
Underground Mining ◽  
Ventilation System ◽  
Hard Coal ◽  
Methane Drainage ◽  
Endogenous Fire ◽  
Flow Through ◽  
Selection Of ◽  
Sufficient Oxygen

Abstract One of the most dangerous and most commonly present risks in hard coal mines is methane hazard. During exploitation by longwall system with caving, methane is emitted to mine heading from the mined coal and coal left in a pile. A large amount of methane also flows from neighboring seams through cracks and fissures formed in rock mass. In a case of accumulation of explosive methane concentration in goaf zone and with appropriate oxygen concentration and occurrence of initials (e.g. spark or endogenous fire), it may come to the explosion of this gas. In the paper there are presented results of numerical analysis of mixture of air and methane streams flow through the real heading system of a mine, characterized by high methane hazard. The aim of the studies was to analyze the ventilation system of considered heading system and determination of braking zones in goaf zone, in which dangerous and explosive concertation of methane can occur with sufficient oxygen concentration equal to at least 12%. Determination of position of these zones is necessary for the selection of appropriate parameters of the ventilation system to ensure safety of the crew. Analysis of the scale of methane hazard allows to select such a ventilation system of exploitation and neighboring headings that ensures chemical composition of mining atmosphere required by regulation, and required efficiency of methane drainage. The obtained results clearly show that numerical methods, combined with the results of tests in real conditions can be successfully used for the analysis of variants of processes related to ventilation of underground mining, and also in the analysis of emergency states.

Sign in / Sign up

Export Citation Format

Share Document