Title: Coal sorption characteristics and coal surface tension

Authors: Lei Zhang; Ting Ren; Naj Aziz; Shihao Tu

Addresses: School of Mines, China University of Mining and Technology, Xuzhou 221116, China; Key Laboratory of Deep Coal Resource Mining, Ministry of Education of China, Xuzhou 221116, China ' School of Civil, Mining and Environmental Engineering, Faculty of Engineering and Information Sciences, University of Wollongong, NSW 2522, Australia ' School of Civil, Mining and Environmental Engineering, Faculty of Engineering and Information Sciences, University of Wollongong, NSW 2522, Australia ' School of Mines, China University of Mining and Technology, Xuzhou 221116, China; Key Laboratory of Deep Coal Resource Mining, Ministry of Education of China, Xuzhou 221116, China

Abstract: Underground coal mining in the Bulli Seam of Sydney Basin, Australia encounters the problems of coal and gas outburst as the coal contains high concentration of CO₂, where certain parts of the seam have been found to be especially hard-to-drain. In order to better understand these problems, the influence of temperature and moisture on sorption capacity of bituminous coal was investigated at 3°C, 45°C and 55°C and at pressure up to 4 MPa. Based on the principle of surface chemistry, the reduced value of surface tension (RVST) was calculated and analysed. The theory of coal surface free energy was found to be capable of explaining coal sorption characteristics. These findings provide the basic knowledge for a better understanding of coal sorption characteristics associated with coal seam gas drainage, which will benefit ventilation and degasification design and hence help to prevent coal mine operations from gas outburst disaster. [Received: December 1, 2013; Accepted: April 10, 2014].

Keywords: coal sorption; coal surface tension; isotherm; surface free energy; underground coal mining; Australia; gas outburst; CO2; carbon dioxide; temperature; moisture; sorption capacity; bituminous coal; surface chemistry; coal seam gas drainage; ventilation; degasification.

DOI: 10.1504/IJOGCT.2014.065833

International Journal of Oil, Gas and Coal Technology, 2014 Vol.8 No.3, pp.336 - 352

Received: 09 Dec 2013
Accepted: 10 Apr 2014
Published online: 29 Nov 2014 *

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