Question

Coal bed methane is methane gas adsorbed in coal seams. To desorb the methane from the coal seam it should be exposed to CO\(_2\) and/or N\(_2\). Which ONE of the following is an appropriate reason to enhance the desorption process?

• A. N\(_2\) is used because it has low kinetic energy compared to CH\(_4\)
• B. CO\(_2\) is used as it has high kinetic energy compared to CH\(_4\)
• C. CO\(_2\) is used as it strongly binds with coal compared to CH\(_4\)
• D. N\(_2\) is used as it strongly binds with coal compared to CH\(_4\)

Hint:

In enhanced desorption processes, CO\(_2\) is preferred over N\(_2\) because it forms stronger bonds with coal, improving methane release.

Answer 1

The Correct Option is C

Coal bed methane (CBM) is methane that has been adsorbed onto the coal matrix, and to release it (desorb it), different methods can be employed. One common method is to use CO\(_2\) or N\(_2\) to enhance desorption.
- CO\(_2\) is preferred because it strongly binds with coal, more so than methane (CH\(_4\)). This increases the efficiency of desorption by displacing methane from the coal's surface. - N\(_2\), on the other hand, has a low kinetic energy and does not bind as strongly with the coal. This makes it less effective than CO\(_2\) for enhancing desorption. Thus, option (C) is the correct answer. CO\(_2\) is used because it binds more strongly with coal than methane, facilitating the desorption process.