Laboratory studies on combustion cavity growth in lignite coal blocks in the context of underground coal gasification

In order for current laboratory studies of strata performances under high temperature to be applied in Underground Coal Gasification (UCG) technology, the temperature scope (range) of UCG must be studied. Based on the heat conduction differential equation, this paper simulates the transverse section temperature distribution of UCG in the multi-physics coupling field. It demonstrates that the strata properties at a range of two meters are affected by high temperature, and the influence on sandstone is more obvious than that of coal. The temperature curves show a trend of linear to nonlinear as time goes. This paper presents the precedent of using multi-field coupling calculation to simulate UCG.

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A 0-dimensional cavity growth submodel for use in reactor models of underground coal gasification

International Journal of Coal Science & Technology ◽

10.1007/s40789-019-00269-0 ◽

2019 ◽

Vol 6 (3) ◽

pp. 334-353

Author(s):

Greg Perkins

Keyword(s):

Coal Gasification ◽

Cavity Growth ◽

Underground Coal Gasification ◽

Reactor Models

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

Energies ◽

10.3390/en14175444 ◽

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.

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Classification of overburden properties for underground coal gasification: laboratory studies under high temperature and in situ stress conditions

International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts ◽

10.1016/0148-9062(93)92929-k ◽

1993 ◽

Vol 30 (3) ◽

pp. A164

Keyword(s):

High Temperature ◽

Coal Gasification ◽

In Situ Stress ◽

Stress Conditions ◽

Laboratory Studies ◽

Underground Coal Gasification

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A Side Wall Burn Model for Cavity Growth in Underground Coal Gasification

Journal of Energy Resources Technology ◽

10.1115/1.3230894 ◽

1983 ◽

Vol 105 (2) ◽

pp. 145-155 ◽

Cited By ~ 6

Author(s):

T. L. Eddy ◽

S. H. Schwartz

Keyword(s):

Coal Gasification ◽

Cavity Growth ◽

Side Wall ◽

Field Tests ◽

Underground Coal Gasification ◽

Convection Diffusion ◽

Bituminous Coals ◽

Thin Seam ◽

Burn Through ◽

Cavity Width

A mechanistic computer model is presented which predicts the 3-D cavity growth during the gasification phase of underground coal gasification. Developed for swelling bituminous coals, the model also obtains reasonable cavity width and length values for shrinking sub-bituminous coals. The model predicts cavity shape and burn-through times based on the coal properties, seam thickness, water reacting and the interwell distance. Employing a 2-D boundary layer model to determine the convective diffusion rate of oxygen to the reacting walls, it is found that natural convection diffusion must be included. The model includes flow in the injection region, the swirling, mixing effect in the cavity, and transitions from thick to thin seam geometry. Simulations of the Hanna II, Phase 2 and Pricetown I field tests, as well as a parametric study on Pittsburgh seam coal, are presented.

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