Regularities of Methane and Coal Dust Ignition Caused by Electric Sources in Mine Workings

2021 ◽  
pp. 119-124
Author(s):  
I.E. Kolesnichenko ◽  
E.A. Kolesnichenko ◽  
E.I. Lyubomishchenko ◽  
E.I. Kolesnichenko ◽  
A.A. Evsyukova
Keyword(s):  
High Frequency ◽  
Coal Dust ◽  
Electromagnetic Emission ◽  
Electric Arc ◽  
Underground Mines ◽  
Visible Range ◽  
Electrical Grid ◽  
Electrical Grids ◽  
Failure Regularities ◽  
Breaking Points

Fires and explosions pose the greatest threat in underground mines that use high-voltage electrical grids. The paper presents data on explosions of combustible methane and coal dust mixtures in Russian mines. It is shown that there always exists a high risk of fire resulting from a malfunction in the electrical grid. The research aims at determining the type and parameters of an electric arc, spark or open flame generated at the breaking points of electric conductors which initiate the ignition of a combustible medium. It was found that the commonly known ionic and thermal theories of ignition do not match the present state of knowledge. The methodology consisted in investigating patterns of electric charge generation and transfer up to the point of the mains failure. Regularities of energy processes in the atomic and molecular structure of the conductor material are presented. For the first time ever the concept of transformation of the electromagnetic energy generated in the alternator into photon packets of high-frequency energy is justified. An electron of the conductor atom absorbs a quantum of the generated energy, converts the generated frequency into a high-frequency photon packet and radiates it into the electric grid. It has been found that an electric arc or a spark, acting as a source of ignition for a combustible medium, is an electromagnetic emission of energy in the visible range.

scholarly journals Water-retaining properties of NCZ composite dust suppressant and its wetting ability to hydrophobic coal dust

2021 ◽  
Author(s):  
Jianguo Liu ◽  
Shu Wang ◽  
Longzhe Jin ◽  
Tianyang Wang ◽  
Zihao Zhou ◽  
...  
Keyword(s):  
Least Squares Method ◽  
Coal Dust ◽  
Water Injection ◽  
Synthesis Method ◽  
Underground Mines ◽  
Initial Contact ◽  
Clean Water ◽  
Mining Operations ◽  
Thermal Synthesis ◽  
Wetting Ability

AbstractCoal dust is a primary threat to underground coal miners. The most common approach to control coal dust is hydraulic methods, such as water spray and coal seam water injection. To improve the dust suppressant efficiency of hydraulic methods, a novel chemical composite dust suppressant, called NCZ, was prepared in this study using calcium chloride (CaCl2), magnesium chloride (MgCl2), and nonionic surfactants using a thermal synthesis method. The water-retaining properties of NCZ powder and its solutions were characterized using the water absorption rate (WAR) and evaporation rate (ER), respectively, and the wetting abilities of the NCZ solutions on coal dust were tested using the initial contact angle (ICA) and sink rate (SR). The results indicate that the NCZ solutions have anti-evaporation effects, and the ER of the solution with a 20.0 wt% NCZ is reduced by 11.7% compared with that of clean water. Furthermore, NCZ solutions have remarkable enhancement effects on the wettability of coal dust. The ICA and SR of clean water and the NCZ solution at 20.0 wt% are 141.9° and 0 mg/s, and 29.3° and 1.46 mg/s, respectively. Finally, quantitative relationships between the solution surface tension and the ICA and IR were established using the least squares method. This study provides a new product for dust suppression in underground mines, which is significant for the optimum applied concentration of dust suppressant in mining operations.

scholarly journals Impacts of Distributed Generation in Electrical Grids

2020 ◽  
Author(s):  
Maria Cecilia C. Lima ◽  
Handerson Marques ◽  
Thommas Kevin Sales Flores ◽  
Fabiano Salvadori ◽  
Lucas V. Hartmann ◽  
...  
Keyword(s):  
Distributed Generation ◽  
Power Factor ◽  
Power Grid ◽  
Energy Sources ◽  
Impedance Matrix ◽  
Electrical Grid ◽  
Preliminary Results ◽  
Electrical Grids ◽  
Common Coupling ◽  
The Impact

Unconventional energy sources such as wind, solar and biomass represents more and more an alternative in substitution of conventional energy sources. In effect, many studies still need to be done to clearly identify the impacts that the insertion of distributed generation (DG) sources represent in the power grid. In this paper, an analysis of the impact of the distributed generation (DG) insertion in the electrical grid is realized, based on impedance matrix, grid voltage and power factor (PF). Benchmarks were created to relate the sensibility in a point common coupling (PCC) to the DG insertion. Preliminary results show that sensibility does not change with the load or the PF of the DG.

High-frequency water-content meter for coal dust

1976 ◽  
Vol 19 (7) ◽  
pp. 1048-1049
Author(s):  
V. G. Valeev ◽  
A. F. Avdeeva
Keyword(s):  
Water Content ◽  
High Frequency ◽  
Coal Dust

scholarly journals Evaluation of the safety parameters for a permitted explosive type emulsion

2021 ◽  
Vol 342 ◽  
pp. 01002
Author(s):  
Ilie-Ciprian Jitea ◽  
Daniela Carmen Rus ◽  
Cristian Rădeanu ◽  
Dragoş Gabriel Vasilescu
Keyword(s):  
Coal Dust ◽  
Underground Mines ◽  
Open Pit ◽  
Explosion Hazard ◽  
Blasting Operation ◽  
Handling Characteristics ◽  
Safety And Health ◽  
Efficient Performance ◽  
Safety Parameters ◽  
Low Sensitivity

When preparing a permitted explosive recipe an energy or an explosive heat is considered, which should ensure the detonability of the system and at the same time a power that satisfies the purpose for which it will be used, under the conditions of firedamp hazardous mines. The safety parameters for the explosive charges used in the firedamp hazardous mines are decisive, in order to ensure the safety and health requirements at work together with the efficient performance of the blasting operation. The permitted explosive type emulsion is recommended to be used in underground mines, open pit mines as a special methane explosive and can be used where a coal dust and/or methane explosion hazard exists can be loaded into dry and wet blasting holes and it can be used for mechanical loading. The permitted explosive type emulsion is a Detonator-sensitive explosives that can be reliably initiated in an unconfined state by a No. 8 strength detonator it have safety handling characteristics because of the relatively low sensitivity to friction, shock and impact. Technological changes due to the change of suppliers of certified explosives for civil use for underground use in the firedamp hazardous mines, involve reassessing the safety and efficiency of the loads made with these products, which have not been tested and evaluated for the conditions from the Jiu Valley mines.

scholarly journals Principles of electrical grid configuration management and tasks of their implementation

2021 ◽  
Vol 23 (3) ◽  
pp. 34-46
Author(s):  
A. V. Vinogradov ◽  
A. V. Vinogradova ◽  
A. Yu. Seyfullin ◽  
A. V. Bukreev ◽  
V. E. Bolshev
Keyword(s):  
Power Supply ◽  
System Analysis ◽  
Configuration Management ◽  
Quality Parameters ◽  
Management Tools ◽  
Electrical Grid ◽  
Operating Modes ◽  
Electrical Grids ◽  
Nominal Voltage ◽  
Supply Interruptions

THE PURPOSE. To consider and analyze the definitions of the concepts "configuration of the electrical grid", "control of the configuration of the electrical grid ", "parameters of the configuration of the electrical grid ". To justify the need to manage the configuration of electrical grid, describe the principles and methods of managing the configuration of the electrical grid. To demonstrate the implementation of the principles of managing the configuration of the electrical grid on the example of an electrical grid with a nominal voltage of 0.4 kV with the use of proprietary technical configuration management tools. METHODS. Based on the literature review, the study identified the wording of key concepts, such as" configuration of the electrical grid"," management of the electrical grid configuration", "parameters of the electrical grid configuration". Methods of managing the configuration of the electrical grid are shown. The principles of electrical grid configuration management proposed by the authors are considered, which include observability, manageability, segmentability, flexibility of the electrical grid configuration, equipment intellectualization, and integration into the economy. The essence of each of the management principles is revealed and the effects of their implementation are shown. The effects of implementing the configuration management principles are to reduce the number of power supply interruptions and reduce the time of power supply interruptions to consumers, mismatch the quality parameters of the electricity supplied to them, as well as to increase the availability of electricity infrastructure. The rationale for the need to manage the configuration of electrical grid is given. Within the framework of the conducted research, the method of system analysis, methods of comparisons and analogies, and expert assessments were used. RESULTS. On the example of the scheme of power supply to consumers at a voltage of 0.4 kV, the implementation of the principles of control of the configuration of electrical grid with the use of proprietary technical means – multi-contact switching systems, input-accounting-distribution devices integrated into the monitoring systems of the parameters of the operating modes of electrical grid and other devices is illustrated. CONCLUSION. The implementation of the principles of configuration management of electrical grid allows to increase the efficiency of power supply systems for consumers and at the same time causes the need to develop new technical means of automation and monitoring of parameters of operating modes of electrical grids.

scholarly journals Interaction of high-frequency electromagnetic emission with layered cylinder

ScienceRise ◽  
2015 ◽  
Vol 12 (2 (17)) ◽  
pp. 67
Author(s):  
Леонид Борисович Лерман
Keyword(s):  
High Frequency ◽  
Electromagnetic Emission ◽  
Layered Cylinder

scholarly journals Тhe study of electronic generation effect on statical aperiodic stability of electrical power system

2020 ◽  
Vol 22 (2) ◽  
pp. 51-64
Author(s):  
A. G. Fishov ◽  
I. S. Murashkina ◽  
A. I. Marchenko ◽  
E. Erdenebat ◽  
Y. S. Ivkin
Keyword(s):  
Power Systems ◽  
Power System ◽  
Renewable Energy Sources ◽  
Electrical Power ◽  
Power Grids ◽  
Small Scale ◽  
Electrical Power System ◽  
Electrical Grid ◽  
Electrical Grids ◽  
Key Aspects

One of the key aspects in the development of power engineering all over the world is the use of distributed small-scale generation. This is both based on fuel carbon resources with a synchronized connection between sources when they are connected to the electric power grids and renewable energy sources operated in the electrical grid via frequency converters (electronic generation). The latter brings an inevitable broad use of inverters in available AC power systems. The objectives of this paper are numerous. First is the desire to study the effect of electronic generation on modes and stability of current electrical grids and electrical power systems. Another objective is to establish requirements for electronic generation control that lets us minimize actions on relay protection coordination and automation upon the integration of electronic generation in power grids. A final objective is to increase the reliability of general electrical modes. This article shows the outcomes of the study on the statical aperiodic stability of the electrical power system upon the integration of electronic generation, requirements for its statical characteristics, and the control when operated within the electrical power system.

Electric arc source for high‐frequency seismic measurement

2000 ◽  
Vol 107 (5) ◽  
pp. 2897-2897
Author(s):  
James S. Martin ◽  
Gregg D. Larson ◽  
Peter H. Rogers ◽  
Waymond R. Scott
Keyword(s):  
High Frequency ◽  
Electric Arc ◽  
Seismic Measurement

INFLUENCE OF MODE AND GEOMETRIC CHRATERISTICS ON HIGHT-FREQUENCY INDUCTIVE PLASMA TORCH WITH REVERSE VORTEX FLOW

2019 ◽  
pp. 77-82
Author(s):  
Sergey Serbin ◽  
Аnna Mostipanenko
Keyword(s):  
High Frequency ◽  
Plasma Torch ◽  
Vortex Flow ◽  
Coal Dust ◽  
Air Plasma ◽  
Plasma Torches ◽  
Structure Of Flow ◽  
Wide Range ◽  
High Frequency Electromagnetic Field ◽  
Numerical Simulation Methods

The analysis of aerodynamic and heat structure of flow in high-frequency inductive plasma torch has been carried out. The range of plasma torch power is measured in dozens of kilowatts. The numerical simulation methods of the turbulent flow in the plasma torch affected by high frequency electromagnetic field without considering the chemical kinetics are used during the research. The data of temperature field and induced current density in the plasma torch depending on current amperage and frequency are obtained. Also, these data are obtained depending on the flow scheme in the operated on argon and air plasma torches. The inductive plasma torches can be applied to solve a wide range of tasks such as activation of coal-dust mixture with its further gasification, coating process for the stabilization of combustion processes as well as for the recycling processes at the mobile seaport recycling complexes. The calculations demonstrated convincingly the advantage of the operation of plasma torches with reverse vortex flow over plasma torches with “direct” vortex flow. Moreover the obtained data allow executing the assessment of thermal efficiency of inductive plasma jet and obtaining its optimal operational modes.

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