Thermal-hydro-chemical-mechanical alteration of coal pores in underground coal gasification

Underground coal gasification (UCG) is being considered an economically and environmentally sustainable clean coal technology which converts coal in-situ into combustible gases. It involves a number of complex physiochemical processes, e.g., drying and evaporation, thermal expansion, pyrolysis, comp...

Full description

Saved in:
Bibliographic Details
Published in:Fuel (Guildford) 2020-02, Vol.262, p.116543, Article 116543
Main Authors: Jiang, Liangliang, Chen, Zhangxin, Farouq Ali, S.M.
Format: Article
Language:English
Subjects:
Clean technology
Coal
Coal combustion
Coal gasification
Combustion
Design optimization
Drying
Evaporation
Flammability
Gases
Gasification
Modelling
Organic chemistry
Permeability
Physiochemistry
Pore variation
Pores
Porosity
Pyrolysis
Shrinkage
Thermal expansion
Three dimensional models
Underground coal gasification
Weight loss
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Underground coal gasification (UCG) is being considered an economically and environmentally sustainable clean coal technology which converts coal in-situ into combustible gases. It involves a number of complex physiochemical processes, e.g., drying and evaporation, thermal expansion, pyrolysis, compressional shrinkage, gasification and combustion. As a result, coal pores constantly undergo drastic changes in the course of UCG. This work aims to shed light upon the complex changes of coal structure in the context of UCG through modelling. A 3-D UCG model was constructed using very fine grids, and several important indicators regarding pore variations were studied, i.e., weight loss of coal, solid concentrations, porosity and permeability. The modelling results were comprehensively compared with experimental data, and a good agreement in trend was achieved. It shows that coal pores alteration is associated with the various phenomena occurred in UCG, and four distinct characteristics can be categorized in the indicator curves. Furthermore, coal pores variation with respect to coal gasification and combustion, not covered in the experimental works, was also revealed. The findings would serve as a helpful guide for process design and optimization.
ISSN:0016-2361
1873-7153
DOI:10.1016/j.fuel.2019.116543