Mechanism of action of heat treatment on the adsorption of polymorphic gases from raw coal

ABSTRACT

The adsorption properties of coal determine the economic benefits of coalbed methane (CBM) extraction. To investigate the gas adsorption behavior of raw coal after heating, gas adsorption tests and pore characterization tests were conducted. Meanwhile, the influence of high temperature on coal pore structure and polymorphic gas adsorption was analyzed. The results showed that the gas adsorption gradually increased with the increase of coal grade at the same temperature. For the same coal grade coals, the adsorbed gas content decreased 5.96%-21.53% and the non-adsorbed gas content increased 51.25%-95.47% with the increase of temperature. The high temperature has a dilating effect on coal pores, causing the proportion of tiny pores to decrease and the adsorbed gas storage capacity to become weaker, and the proportion of medium and large pores to increase and the non-adsorbed gas storage capacity to become stronger. This study can provide data support for coalbed methane heat injection extraction.

KEYWORDS:

• Polymorphic gas
• raw coal
• adsorption process
• pore structure
• high-temperature

Disclosure statement

No potential conflict of interest was reported by the authors.

CrediT authorship contribution statement

Lei Liu: Formal analysis, Visualization, Writing – original draft.

Ming Yang: Formal analysis, Visualization, Funding acquisition.

Additional information

Funding

This research was funded by the National Natural Science Foundation of China [grant number 51704099]