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Underground coal gasification is an alternative method for mining coal from thin and ultra-thin seams, which enables conversion of solid fossil fuels into combustible gases at the site of coal occurrence. At the same time, in the case when the coal seam thickness is critically small for the effective course of thermochemical reactions, it is necessary to intensify the gasification process. This paper studies one of the possible methods to intensify the process of underground coal gasification due to the influence of magnetic fields on the injected blast supplied into the gas generator gasification channel. Research tests conducted on a bench setup confirm the effectiveness of injected blast activation in a magnetic field by creating magnetic field inhomogeneity by placing permanent magnets and a discrete solid magnetized phase in a special device. For the first time, the dependence of changing growth of carbon participation during the solid fuel gasification process on changing magnetic field strength in the range of 0-600 E has been determined. It has been proven that the injected blast magnetization can significantly intensify the underground gasification process by increasing the carbon participation share in the fuel, which may be of practical importance for increasing the yield of combustible components.

No abstract

Determination of the repulsive force of an electromagnet to provide the necessary clearance from the skip along the entire length of guides of electromagnetic lifting installation The finite element method was chosen as the method of modeling physical fields in electric machines. As the method of modeling physical fields in electric machines a finite element method was chosen. In the article a formula to express an imbalance between the energy stored in a magnetic field and the energy provided by the supplied electric current in this field, under given boundary conditions is used. It has been established that the experiment, planned by the Plakett-Berman matrices, makes it possible to obtain a multifactorial polynomial model of the «lifting vessel-conductor» system, which establishes a relationship between the values of static loads in this system and the operating conditions of the mine lifting systems. The proposed finite element method of considering a permanent magnet as a nonlinear source of a field makes it possible to abandon additional iterations when searching for working points of a magnet. The developed mathematical apparatus takes into account the distribution of magnetization over the cross section of a permanent magnet and identifies non-identical operating points of different magnet elements, which allows to calculate the fields created by the joint action of several current windings and permanent magnets with different orientations in nonlinear and anisotropic media with regard to their mutual influence.

Abstract-This work is directed to the development of the management system of electromagnetic lifting installation. To develop such control system it is necessary to create automatic system of switching the poles. The experiment model of levitation system is developed for carrying out prior experiments. The Arduino UNO platform on the basis of the Atmega328 microcontroller is chosen. In the work the description of L293D driver is presented and the principle of driver operation which is a part of the circuit is considered. IndexTerms-Electromagnetic lifting installation, microcontroller, Arduino Uno, L293D circuit driver, pulse width modulation.