A Review of Underground Coal Gasification Field Tests Sponsored by the U.S. Department of Energy

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.

Underground coal gasification: Development of theory, laboratory experimentation, interpretation, and correlation with the Hanna field tests: Final report

10.2172/7042875 ◽

1987 ◽

Cited By ~ 5

Author(s):

R.D. Gunn ◽

W.B. Krantz

Keyword(s):

Coal Gasification ◽

Field Tests ◽

Final Report ◽

Underground Coal Gasification ◽

Laboratory Experimentation

Small Scale Field Tests on Underground Coal Gasification at Surface Coal Mine in Hokkaido

Journal of the Japanese Association for Petroleum Technology ◽

10.3720/japt.77.435 ◽

2012 ◽

Vol 77 (6) ◽

pp. 435-437

Author(s):

Kotaro Ohga ◽

Kenichi Itakura ◽

Gota Deguchi

Keyword(s):

Coal Mine ◽

Coal Gasification ◽

Field Tests ◽

Small Scale ◽

Underground Coal Gasification ◽

Surface Coal Mine ◽

Scale Field

Underground Coal Gasification Research

Journal of Energy Resources Technology ◽

10.1115/1.3230897 ◽

1983 ◽

Vol 105 (2) ◽

pp. 165-169 ◽

Cited By ~ 2

Author(s):

G. J. Harloff

Keyword(s):

Mathematical Modeling ◽

Coal Gasification ◽

Cavity Growth ◽

Field Tests ◽

Resource Recovery ◽

Laboratory Research ◽

Gas Composition ◽

Underground Coal Gasification ◽

Complex Processes ◽

Research Studies

Recent successful field tests of underground coal gasification, UCG, have demonstrated the potential for UCG commercialization. This paper presents results of mathematical modeling and laboratory research studies which have been conducted to improve our understanding of the complex processes involved. These studies include: cavity growth including resource recovery, gas composition, and subsidence. Both single and multi-module results are presented.

Gas Production Strategy of Underground Coal Gasification Based on Multiple Gas Sources

The Scientific World JOURNAL ◽

10.1155/2014/154197 ◽

2014 ◽

Vol 2014 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Duan Tianhong ◽

Wang Zuotang ◽

Zhou Limin ◽

Li Dongdong

Keyword(s):

Power Generation ◽

Blast Furnace ◽

Coal Gasification ◽

Field Tests ◽

Coke Oven ◽

Gas Production ◽

Underground Coal Gasification ◽

Coke Oven Gas ◽

Blast Furnace Gas ◽

Converter Gas

To lower stability requirement of gas production in UCG (underground coal gasification), create better space and opportunities of development for UCG, an emerging sunrise industry, in its initial stage, and reduce the emission of blast furnace gas, converter gas, and coke oven gas, this paper, for the first time, puts forward a new mode of utilization of multiple gas sources mainly including ground gasifier gas, UCG gas, blast furnace gas, converter gas, and coke oven gas and the new mode was demonstrated by field tests. According to the field tests, the existing power generation technology can fully adapt to situation of high hydrogen, low calorific value, and gas output fluctuation in the gas production in UCG in multiple-gas-sources power generation; there are large fluctuations and air can serve as a gasifying agent; the gas production of UCG in the mode of both power and methanol based on multiple gas sources has a strict requirement for stability. It was demonstrated by the field tests that the fluctuations in gas production in UCG can be well monitored through a quality control chart method.

Lawrence Livermore National Laboratory underground coal gasification data base. [US DOE-supported field tests; data]

10.2172/5385426 ◽

1981 ◽

Cited By ~ 7

Author(s):

R. J. Cena ◽

C. B. Thorsness

Keyword(s):

Data Base ◽

Coal Gasification ◽

Lawrence Livermore National Laboratory ◽

National Laboratory ◽

Field Tests ◽

Underground Coal Gasification

Thermal and Structural Response Evaluation for Underground Coal Gasification

Society of Petroleum Engineers Journal ◽

10.2118/6152-pa ◽

1977 ◽

Vol 17 (06) ◽

pp. 413-422 ◽

Cited By ~ 4

Author(s):

Sunder H. Advani ◽

Y.T. Lin ◽

L. Zane Shuck

Keyword(s):

Stress Response ◽

Coal Seam ◽

Coal Gasification ◽

Boundary Value ◽

Research Center ◽

Circular Cavity ◽

Underground Coal Gasification ◽

Energy Research ◽

Roof Collapse ◽

The U.S

Abstract Global and micro/macro structural models simulating the Longwall generator concept for underground coal gasification (UCG) are formulated for several geometric and loading conditions. Dynamic thermal and stress response solutions are computed for axisymmetric boundary value problems represented by a stationary circular cavity model and an expanding radially propagating circular cavity. Static thermoelastic response solutions are presented for circular and elliptical cylindrical presented for circular and elliptical cylindrical cavities in a homogeneous, isotropic medium and layered media. Considerations pertaining to roof collapse and surface subsidence are discussed. The micro/macro modeling investigations include thermorheological representation of Pittsburgh coal at elevated temperature and studies on thermal crack propagation of coal fissures. Finally, the relevance of stress and temperature profiles, fracture permeabilities, and fissure response is discussed in relation to the propagation and stability of the UCG process. Introduction Fossil fuels are currently the main energy resource for the U.S. with coal reserve estimates ranging from 3 to 4 trillion tons. Only one-sixth of this coal can be extracted by state-of-the-art mining techniques. It is anticipated that about one-third of the U.S. total coal energy reserves, particularly thin coal beds and thick-seam deep coal, can be recovered by underground coal gasification (UCG). This process entails ignition of a coal seam and circulation of gas through a controlled path. The resulting chemical reactions produce a gas with calorific value, depending on several process parameters and variables. Their optimization parameters and variables. Their optimization requires sophisticated analytical simulations of the structural, heat transfer, fluid flow, and reaction kinetics aspects along with controlled laboratory experiments and field tests. Descriptions and appraisals of various underground coal pregasification schemes and gasification processes mad a discussion of significant problems, processes mad a discussion of significant problems, such as roof collapse, gas leakage, water control, and surface subsidence, etc., have been given in a detailed report by Arthur D. Little, Inc.. Reports on UCG experiments in the Soviet Union, Great Britian, and other countries have been summarized in excellent monographs. The outlook for UCG in the U.S. was discussed recently at the First Annual UCG Symposium conducted by the Laramie Energy Research Center in Wyo. It appears that several candidate concepts and solutions exist, depending (on the type of coal, coal seam thickness, overburden, and environmental requirements. The concepts currently being investigated by ERDA's research centers and laboratories includethe vertical well to well linking experiments at Hanna, Wyo., for medium seams (Laramie Energy Research Center),the packed-bed concept for thick coal seams (Lawrence Livermore Laboratory), andthe Longwall generator concept for thin seams (Morgantown Energy Research Center). This paper presents results obtained from analytical structural and thermal simulations associated moth the Longwall generator UCG concept. Temperature and stress response solutions are presented for different boundary value problem representations. The results of this study provide fundamental insight to the interpretation of UCG global and micro/macro mechanisms. UCG LONGWALL GENERATOR CONCEPT AND MECHANISMS Morgantown Energy Research Center presently is developing the Longwall generator concept to gasify thin-seam eastern coals (Fig. 1). In this concept, directional holes (6-in. diameter) are drilled from the ground surface with horizontal holes, 500 ft in length, entering through the 6-ft-thick coal seam (1,000-ft overburden) and returning vertically back to the coal surface. The gasification reaction zone propagates horizontally in the coal propagates horizontally in the coal maximum-permeability direction between the parallel horizontal holes drilled approximately in the coal butt-cleat direction. JPT P. 413