Experimental Studies of the Effect of Design and Technological Solutions on the Intensification of an Underground Coal Gasification Process

Bazaluk, Oleg; Lozynskyi, Vasyl; Falshtynskyi, Volodymyr; Saik, Pavlo; Dychkovskyi, Roman; Cabana, Edgar Cáceres

doi:10.3390/en14144369

Cited by 24 publications

(16 citation statements)

References 104 publications

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“…The methodology of the UCG process physical modeling in experimental equipment is widely used by researchers (e.g., in [34,35]). For this reason, an experimental gasifier was designed and constructed to realize the UCG process experimental measurements.…”

Section: Experiments Methodologymentioning

confidence: 99%

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Durdán¹,

Benková²,

Laciak³

et al. 2021

Energies

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The underground coal gasification represents a technology capable of obtaining synthetic coal gas from hard-reached coal deposits and coal beds with tectonic faults. This technology is also less expensive than conventional coal mining. The cavity is formed in the coal seam by converting coal to synthetic gas during the underground coal gasification process. The cavity growth rate and the gasification queue’s moving velocity are affected by controllable variables, i.e., the operation pressure, the gasification agent, and the laboratory coal seam geometry. These variables can be continuously measured by standard measuring devices and techniques as opposed to the underground temperature. This paper researches the possibility of the regression models utilization for temperature data prediction for this reason. Several regression models were proposed that were differed in their structures, i.e., the number and type of selected controllable variables as independent variables. The goal was to find such a regression model structure, where the underground temperature is predicted with the greatest possible accuracy. The regression model structures’ proposal was realized on data obtained from two laboratory measurements realized in the ex situ reactor. The obtained temperature data can be used for visualization of the cavity growth in the gasified coal seam.

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Section: Experiments Methodologymentioning

confidence: 99%

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Durdán¹,

Benková²,

Laciak³

et al. 2021

Energies

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“…In the work [34], a mathematical model of filtration and heat transfer in the roof rocks of an underground gas generator has been developed and tested, which makes it possible to assess the convection and conduction components of the heat flow. At the same time, the underground gasification process takes place in the underground space and is characterized by a variety of factors depending on the thermophysical and geometrical dimensions of both the reaction channel and the underground gas generator [35], [36].…”

Section: Feasibility Of Conducting Research On This Issuementioning

confidence: 99%

Mathematical model and methods for solving heat-transfer problem during underground coal gasification

Saik¹,

Berdnyk²

2022

Min. miner. depos.

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Purpose. A mathematical model development for heat transfer during underground coal gasification based on the transcendental equation solution by the Newton-Raphson method. Methods. The heat-transfer model development is based on the research into a temperature field with a variable size of the gasification zone when passing through the phase transformation boundary, which changes abruptly. The research on the coal seam T(x, t) temperature field and the displacement length of the phase transition boundary S(t) is based on the integration of the differential heat-transfer equation with the fulfillment of one-phase Stefan problem conditions. The proportionality factor (β), characterizing the ratio of the displacement length of the “generator gas – coal” phase transition boundary to the time of coal seam gasification, is determined by substituting the Boltzmann equation and using the Newton-Raphson method based on solving the obtained transcendental equation. Findings. The main problems related to laboratory research on the coal gasification process have been identified. A mathematical model of heat transfer during underground coal gasification for a closed georeactor system has been developed, taking into account the effective change in its active zones. Originality. A mathematical model of heat transfer during underground coal gasification at the phase transition boundary has been developed, under which the one-phase Stefan problem conditions are fulfilled. Dependences of the change in the underground gas generator temperature, taking into account the change in the active zones of chemical reactions along the length of the combustion face and the gasification column, have been revealed. In addition, the dependences of the change in the phase transition boundary of a “generator gas – coal” heterogeneous system have been determined, which characterize the displacement length of the phase transition boundary on time and reveal the relationship between the thermal conductivity coefficient, specific heat capacity, as well as bulk density of coal and its calorific value. Practical implications. A method has been developed to determine the displacement length of the phase transition boundary of a “generator gas – coal” heterogeneous system and its relationship between the time and temperature of gasification process. This makes it possible to predict in the future the change in the active zones of the underground gas generator along the length of the gasification column.

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“…For surface hardening of parts of elite models of downhole ejection systems, chromium plating in a flowing electrolyte is used, as well as functionally gradient coatings of required parts of surfaces [74][75][76]. New technological schemes for hydrocarbon development from used wells to use additionally non-commercial and closed deposits and extend mining enterprise operation are presented in [77][78][79][80].…”

Section: State Of the Current Development Of The Problem And Formulating A Research Taskmentioning

confidence: 99%

Strategy of Compatible Use of Jet and Plunger Pump with Chrome Parts in Oil Well

et al. 2021

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During oil fields operation, gas is extracted along with oil. In this article it is suggested to use jet pumps for utilization of the associated oil gas, burning of which causes environmental degradation and poses a potential threat to the human body. In order to determine the possibility of simultaneous application of a sucker-rod pump, which is driven by a rocking machine, and a jet pump (ejector) in the oil well, it is necessary to estimate the distribution of pressure along the borehole from the bottomhole to the mouth for two cases: when the well is operated only be the sucker-rod pump and while additional installation of the oil-gas jet pump above its dynamic level. For this purpose, commonly known methods of Poettman-Carpenter and Baksendel were used. In addition, the equations of high-pressure and low-pressure oil-gas jet pumps were obtained for the case, when the working stream of the jet pump is a gas-oil production mixture and the injected stream is a gas from the annulus of the well. The values which are included in the resulting equations are interrelated and can only be found in a certain sequence. Therefore, a special methodology has been developed for the practical usage of these equations in order to calculate the working parameters of a jet pump based on the given independent working parameters of the oil well. Using this methodology, which was implemented in computer programs, many operating parameters were calculated both for the well and for the jet pump itself (pressures, densities of working, injected and mixed flows, flow velocities and other parameters in control sections). According to the results of calculations, graphs were built that indicate a number of regularities during the oil well operation with such a jet pump. The main result of the performed research is a recommendation list on the choice of the oil-gas jet pump location inside the selected oil well and generalization of the principles for choosing the perfect location of such ejectors for other wells. The novelty of the proposed study lays in a systematic approach to rod pump and our patented ejector pump operation in the oil and chrome plating of pump parts. The result of scientific research is a sound method of determining the rational location of the ejector in the oil well and the calculation of its geometry, which will provide a complete selection of petroleum gas released into the annulus of the oil well. To ensure reliable operation of jet and plunger pumps in oil wells, it is proposed to use reinforcement of parts (bushings, plungers, rods, etc.) by electrochemical chromium plating in a flowing electrolyte. This has significantly increased the wear resistance and corrosion resistance of the operational surfaces of these parts and, accordingly, the service life of the pumps. Such measures will contribute to oil production intensification from wells and improve the environmental condition of oil fields.

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Experimental Studies of the Effect of Design and Technological Solutions on the Intensification of an Underground Coal Gasification Process

Cited by 24 publications

References 104 publications

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Regression Models Utilization to the Underground Temperature Determination at Coal Energy Conversion

Mathematical model and methods for solving heat-transfer problem during underground coal gasification

Strategy of Compatible Use of Jet and Plunger Pump with Chrome Parts in Oil Well

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