Numerical Study on Convection Diffusion for Gasification Agent in Underground Coal Gasification (UCG). Part II: Determination of Model Parameters and Results Analysis

2009 ◽  
Vol 31 (4) ◽  
pp. 318-324
Author(s):  
L. H. Yang ◽  
Y. M. Ding
Keyword(s):  
Coal Gasification ◽  
Numerical Study ◽  
Model Parameters ◽  
Underground Coal Gasification ◽  
Convection Diffusion

Determination of random pore model parameters for underground coal gasification simulation

Energy ◽  
2019 ◽  
Vol 166 ◽  
pp. 972-978 ◽  
Author(s):  
Sebastian Iwaszenko ◽  
Natalia Howaniec ◽  
Adam Smoliński
Keyword(s):  
Coal Gasification ◽  
Model Parameters ◽  
Underground Coal Gasification ◽  
Pore Model ◽  
Random Pore Model

The Effect of Moisture on the Structural Stability of a Coal Cavity

1986 ◽  
Vol 108 (3) ◽  
pp. 246-253 ◽  
Author(s):  
H. R. Mortazavi ◽  
A. F. Emery ◽  
R. C. Corlett ◽  
W. R. Lockwood
Keyword(s):  
Coal Gasification ◽  
Failure Modes ◽  
Crack Formation ◽  
Western United States ◽  
Internal Cavity ◽  
Underground Coal Gasification ◽  
Structural Failure ◽  
Convection Diffusion ◽  
Cavity Collapse ◽  
Internal Convection

The drying of coal and the associated thermal and moisture-induced stresses are examined with a numerical model to estimate the rate of surface regression in underground coal gasification. The model includes internal convection, diffusion, conduction and flow of liquid, vapor and gas. The structural failure is modeled by three different mechanisms based upon a strength reduction due to heating, drying, or crack formation. Using properties and boundary conditions appropriate to Western United States coal, the model predicts a regression rate which is in qualitative agreement with measured results. Using the model, it is possible to examine different thermal and failure modes and to gain an understanding of some of the mechanisms which may control the surface regression of coal during gasification. These results may be applicable to the formation of rubble during gasification and to internal cavity collapse.

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

1983 ◽  
Vol 105 (2) ◽  
pp. 145-155 ◽  
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.

scholarly journals Determination of the Technological Parameters of Borehole Underground Coal Gasification for Thin Coal Seams

2013 ◽  
Vol 12 (3) ◽  
pp. 8-16 ◽  
Author(s):  
Volodymyr S. Falshtynskyi ◽  
Roman O. Dychkovskyi ◽  
Vasyl G. Lozynskyi ◽  
Pavlo B. Saik
Keyword(s):  
Coal Gasification ◽  
Underground Coal Gasification ◽  
Technological Parameters ◽  
Coal Seams

scholarly journals Determination of Ammonium Concentration in Post-Process Waters from Underground Coal Gasification

2016 ◽  
Vol 21 (1-2) ◽  
pp. 107-116
Author(s):  
Malwina Cykowska ◽  
Małgorzata Bebek ◽  
Aleksandra Strugała-Wilczek
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Coal Gasification ◽  
Ammonium Concentration ◽  
Hard Coal ◽  
Underground Coal Gasification ◽  
Permeable Membrane ◽  
Indicator Solution ◽  
Validation Parameters

AbstractA flow injection analysis method for spectrophotometric determination of ammonium in waters produced during underground coal gasification (UCG) of lignite and hard coal was described. The analysis of UCG water samples is very difficult because of their very complicated matrix and colour. Due to a huge content of organic and inorganic substances and intensive colour of samples (sometimes yellow, quite often dark brown or even black), most analytical methods are not suitable for practical application. Flow injection analysis (FIA) is based on diffusion of ammonia through a hydrophobic gas permeable membrane from an alkaline solution stream into an acid-base indicator solution stream. Diffused ammonia causes a colour change of indicator solution, and ammonia is subsequently quantified spectrophotometrically at 590 nm wavelength. The reliability of the results provided by applied method was evaluated by checking validation parameters like accuracy and precision. Accuracy was evaluated by recovery studies using multiple standard addition method. Precision as repeatability was expressed as a coefficient of variation (CV).

scholarly journals Determination of the Technological Parameters of Borehole Underground Coal Gasification for Thin Coal Seams

2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Volodymyr S. Falshtynskyi ◽  
Roman O. Dychkovskyi ◽  
Vasyl G. Lozynskyi ◽  
Pavlo B. Saik
Keyword(s):  
Coal Gasification ◽  
Underground Coal Gasification ◽  
Technological Parameters ◽  
Coal Seams
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