Basic Aspects Of Productivity Of Underground Coal Gasification Process

2015 ◽  
Vol 60 (2) ◽  
pp. 443-453 ◽  
Author(s):  
Józef Dubiński ◽  
Marian Turek
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Coal Gasification ◽  
Industrial Scale ◽  
Hard Coal ◽  
Underground Coal Gasification ◽  
Coal Seams ◽  
Gasification Process ◽  
Mining Coal ◽  
Gasification Technology

Abstract An analysis of conditions which enable attaining possibly highest productivity of industrial scale underground coal gasification technology is presented. The analysis was prepared basing on results obtained during an experimental gasification process conducted in workings of an active hard coal mine. Basic aspects determining application and productivity of the technology concern both general conditions, referring to the hard coal seam being gasified, and practical issues, which need to be considered in coal mine conditions. To present them, the technology of underground coal gasification and still commonly used classical longwall method of mining coal seams are compared.

Underground Сoal Gasification Efficiency in Areas of High Faulting Frequency

2017 ◽  
Vol 25 ◽  
pp. 118-127
Author(s):  
Vasyl Lozynskyi
Keyword(s):  
Coal Seam ◽  
Coal Gasification ◽  
Analytical Calculation ◽  
Underground Coal Gasification ◽  
Practical Application ◽  
Gasification Efficiency ◽  
Rational Order ◽  
Coal Reserves ◽  
Gasification Technology ◽  
Generator Gas

The purpose of this paper is substantiating of efficiency during application of borehole underground coal gasification technology based on target coal seam geology. Comprehensive methodology that included analytical calculation is implemented in the work. To determine the efficiency of coal seam gasification in faulting areas, an economic calculation method was developed. The obtained conditions of coal seam allow to provide rational order of mine workings. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. The obtained results with sufficient accuracy in practical application will allow consume coal reserves in the faulting zones using environmentally friendly conversion technology to obtain power and chemical generator gas, chemicals and heat.

scholarly journals A Study of the Laws of Abnormal Gas Emissions and the Stability Controls for Coal Mine Walls in Deeply Buried High-Gas Coal Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Anying Yuan ◽  
Hao Hu ◽  
Qiupeng Yuan
Keyword(s):  
Coal Seam ◽  
Water Content ◽  
Coal Mine ◽  
Gas Diffusion ◽  
Hard Coal ◽  
Coal Seams ◽  
Gas Emissions ◽  
Soft Coal ◽  
Pressure Water ◽  
Gas Coal

At the present time, it is considered to be of major significance to study the gas emission law and stability controls of coal bodies in deeply buried high-gas coal seams. For this reason, in view of the specific problems of gas emissions caused by unstable rib spalling in coal mine walls, comprehensive research methods were adopted in this study, in order to conduct an in-depth examination of micropore structure parameters, gas desorption, diffusion laws, and coal stability levels. The results showed that the development degree of the pores above the micropores, as well as the small pores in soft coal seams, was better than those observed in hard coal seams. In addition, the gas outburst phenomenon was found to have more easily formed in the soft coal seams. The coal body of the No. 6 coal seam in the Xieqiao Coal Mine not only provided the conditions for gas adsorption but also provided dominant channels for gas diffusion and migration. The abnormal gas emissions of the No. 6 coal seam were jointly caused by the relatively developed pores above the small holes in the coal body, rib spalling of coal mine walls, and so on. The research results also revealed the evolution law of mechanical characteristics of the No. 6 coal seam under different water content conditions. It was found that the strength levels of the No. 6 coal seam first increased and then decreased with the increase in water content, and the water content level at the maximum strength of the coal seam was determined to be 7.09%. This study put forward a method which combined the water injection technology of long-term static pressure water injections in deep coal mining holes and real-time dynamic pressure water injections in shallower holes. Field experiments were successfully carried out.

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

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5444
Author(s):  
Milan Durdán ◽  
Marta Benková ◽  
Marek Laciak ◽  
Ján Kačur ◽  
Patrik Flegner
Keyword(s):  
Coal Seam ◽  
Regression Model ◽  
Regression Models ◽  
Coal Gasification ◽  
Cavity Growth ◽  
Temperature Data ◽  
Ex Situ ◽  
Underground Coal Gasification ◽  
Gasification Process ◽  
Cavity Growth Rate

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.

The Study on Roadway Layout in Coordination of Mining Coal Seams Base on Failure of Floor Strata

2014 ◽  
Vol 889-890 ◽  
pp. 1362-1374 ◽  
Author(s):  
Yong Zhang ◽  
Chun Lei Zhang ◽  
Chun Chen Wei ◽  
Ya Dong Liu ◽  
Shi Qing Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Coal Seam ◽  
Coal Mining ◽  
Coal Mine ◽  
Simulation Software ◽  
Coal Seams ◽  
Group Coordination ◽  
Mining Coal ◽  
Two Sides

In order to make sure the reasonable roadway layout in lower seam of close coal mining group coordination in Lijiahao coal mine, firstly, applying the theoretical analysis and geological radar detection to get the influence depth of mining from the up coal seam 2-2 to the floor is about 20m, the results show that the thickness of complete strata is about 15m, then determining to use the outward alternate entries in lower seam roadway by using theoretical analysis. At last, determining the distance of outward alternate entries is 12-14m by using FLAC3D numerical simulation software to simulate the change of stress and displacement in roof floor and two sides of roadway.

scholarly journals An ex Situ Underground Coal Gasification Experiment with a Siderite Interlayer. Course of the Process, Production Gas, Temperatures and Energy Efficiency

2020 ◽  
Author(s):  
Marian Wiatowski ◽  
Krzysztof Kapusta ◽  
Jacek Nowak ◽  
Marcin Szyja ◽  
Wioleta Basa
Keyword(s):  
Energy Efficiency ◽  
High Temperature ◽  
Flow Rate ◽  
Coal Gasification ◽  
High Energy ◽  
Ex Situ ◽  
Hard Coal ◽  
Underground Coal Gasification ◽  
Gasification Process ◽  
Process Gas

Abstract A 72-hour ex situ hard coal gasification test in one large block of coal was carried out. The gasifying agent was oxygen with a constant flow rate of 4.5 Nm3/h. The surroundings of coal were simulated with wet sand with 11% moisture content. A 2-cm interlayer of siderite was placed in the horizontal cut of the coal block. As a result of this process, gas with an average flow rate of 12.46 Nm3/h was produced. No direct influence of siderite on the gasification process was observed; however, measurements of CO2 content in the siderite interlayer before and after the process allowed to determine the location of high-temperature zones in the reactor. The greatest influence on the efficiency of the gasification process was exerted by water contained in wet sand. At the high temperature that prevailed in the reactor, this water evaporated and reacted with the incandescent coal, producing hydrogen and carbon monoxide. This reaction contributed to the relatively high calorific value of the resulting process gas, averaging 9.41 MJ/kmol, and to the high energy efficiency of the whole gasification process, which amounted to approximately 70%.

scholarly journals Underground coal gasification - the Velenje Coal Mine energy and economic calculations

2017 ◽  
Vol 23 (2) ◽  
pp. 269-277 ◽  
Author(s):  
Damjan Konovsek ◽  
Zdravko Praunseis ◽  
Jurij Avsec ◽  
Gorazd Bercic ◽  
Andrej Pohar ◽  
...  
Keyword(s):  
Coal Mine ◽  
Coal Gasification ◽  
Economic Assessment ◽  
Operating Mode ◽  
Primary Energy ◽  
Underground Coal Gasification ◽  
Gasification Process ◽  
Coal Deposits ◽  
Demonstration Experiment ◽  
Past Experiences

Underground coal gasification (UCG) is a viable possibility for the exploitation of vast coal deposits that are unreachable by conventional mining and can meet the energy, economic and environmental demands of the 21st century. Due to the complexity of the process, and the site-specific coal and seam properties, it is important to acknowledge all the available data and past experiences, in order to conduct a successful UCG operation. Slovenia has huge unmined reserves of coal, and therefore offers the possibility of an alternative use of this domestic primary energy source. According to the available underground coal gasification technology, the energy and economic assessment for the exploitation of coal to generate electricity and heat was made. A new procedure for the estimation of the energy efficiency of the coal gasification process, which is also used to compare the energy analyses for different examples of coal exploitation, was proposed, as well as the technological schemes and plant operating mode in Velenje, and the use of produced synthetic coal gas (syngas). The proposed location for the pilot demonstration experiment in Velenje Coal Mine was reviewed and the viability of the underground coal gasification project in Velenje was determined.

Finite Element Analysis of the Subsidence of Cap Rocks during Underground Coal Gasification Process

2013 ◽  
Vol 859 ◽  
pp. 91-94
Author(s):  
Xiao Xiong Zha ◽  
Hai Yang Wang ◽  
Shan Shan Cheng
Keyword(s):  
Finite Element ◽  
Coal Seam ◽  
Coal Gasification ◽  
Feasibility Studies ◽  
Element Model ◽  
Numerical Results ◽  
Surface Subsidence ◽  
Underground Coal Gasification ◽  
Element Analysis ◽  
Gasification Process

This paper discusses the possible surface subsidence and deformation of the overlying rock during the underground coal gasification (UCG) process, which is an important part of feasibility studies for UCG operations. First coal seam roof movement and surface subsidence in the shallow UCG process were simulated by a finite element model coupled with heat transfer module in COMSOL. Numerical results from this model were compared with and in good agreement to the existing studies. This was followed by the development of model for deeper coal seam cases. The comparison of the numerical results from two models shows that surface uneven settlement in deep underground coal gasification is only 7% of that in shallow underground coal gasification.

Technological aspects for underground coal gasification in steeply inclined thin coal seams at Zhongliangshan coal mine in China

Fuel ◽  
2017 ◽  
Vol 191 ◽  
pp. 486-494 ◽  
Author(s):  
Lin Xin ◽  
Zuo-tang Wang ◽  
Gang Wang ◽  
Wen Nie ◽  
Gang Zhou ◽  
...  
Keyword(s):  
Coal Mine ◽  
Coal Gasification ◽  
Underground Coal Gasification ◽  
Coal Seams

Hydrogeological testing associated with underground coal gasification

1979 ◽  
Vol 16 (1) ◽  
pp. 59-68 ◽  
Author(s):  
R. I. J. Vogwill
Keyword(s):  
Hydraulic Conductivity ◽  
Coal Seam ◽  
Coal Gasification ◽  
Major Axis ◽  
Underground Coal Gasification ◽  
Coal Seams ◽  
Aquifer Parameters ◽  
Underground Gasification ◽  
Aquifer Test ◽  
A Site

Four aquifer tests were completed at a site near Forestburg, Alberta, in order to determine aquifer parameters of a coal seam and thus aid in the evaluation of an underground gasification experiment and assess the effects of gasification on the groundwater regime.Analysis of the two pre-gasification aquifer tests indicated that the coal seam was a confined aquifer with small aquifer parameters and a strongly anisotropic hydraulic conductivity that appeared unrelated to known regional fracturing directions. The effect of this anisotropy on controlling directions of gasification was not established.The first post-gasification aquifer test indicated that the groundwater regime of the coal seam had been changed in various ways. Regionally, a general increase in hydraulic conductivity and a more pronounced anisotropy were observed. On a smaller scale, storage coefficients in the gasified block were greatly increased due to a change in the physical character of the coal. Subsequent excavation that exposed the gasified block confirmed these observations.The second post-gasification aquifer test indicated that fracturing in the coal seam was not consistent and that in undisturbed coal seams the direction of regional major fracturing and the major axis of anisotropy do, in fact, coincide.

scholarly journals Large-scale Experimental Investigations to Evaluate the Feasibility of Producing Methane-Rich Gas (SNG) through Underground Coal Gasification Process. Effect of Coal Rank and Gasification Pressure

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1334 ◽  
Author(s):  
Krzysztof Kapusta ◽  
Marian Wiatowski ◽  
Krzysztof Stańczyk ◽  
Renato Zagorščak ◽  
Hywel Rhys Thomas
Keyword(s):  
Energy Efficiency ◽  
Large Scale ◽  
Coal Gasification ◽  
Maximum Energy ◽  
Experimental Investigations ◽  
Hard Coal ◽  
Coal Rank ◽  
Underground Coal Gasification ◽  
Gasification Process ◽  
Pressure Regime

An experimental campaign on the methane-oriented underground coal gasification (UCG) process was carried out in a large-scale laboratory installation. Two different types of coal were used for the oxygen/steam blown experiments, i.e., “Six Feet” semi-anthracite (Wales) and “Wesoła” hard coal (Poland). Four multi-day gasification tests (96 h continuous processes) were conducted in artificially created coal seams under two distinct pressure regimes-20 and 40 bar. The experiments demonstrated that the methane yields are significantly dependent on both the properties of coal (coal rank) and the pressure regime. The average CH4 concentration for “Six Feet” semi-anthracite was 15.8%vol. at 20 bar and 19.1%vol. at 40 bar. During the gasification of “Wesoła” coal, the methane concentrations were 10.9%vol. and 14.8%vol. at 20 and 40 bar, respectively. The “Six Feet” coal gasification was characterized by much higher energy efficiency than gasification of the “Wesoła” coal and for both tested coals, the efficiency increased with gasification pressure. The maximum energy efficiency of 71.6% was obtained for “Six Feet” coal at 40 bar. A positive effect of the increase in gasification pressure on the stabilization of the quantitative parameters of UCG gas was demonstrated.

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