Illustration of Hydrate-Based Methane Gas Separation in Coal Bed Methane Type Gas Composition at Lower Pressures

Abstract

Coal bed methane is an emerging and prosperous unconventional energy source, encompassing highly variable (10-70%) mole fractions of methane gas along with other higher hydrocarbon and nonhydrocarbon gases. The gas pressure at the source is typically low, posing technical constraints in the gas separation process. In particular, separation of methane gas from this source is a topic of wider scientific interest. The present study demonstrates the ability of hydrate-based technology in trapping methane gas, in nitrogen (N 2 ) + methane (CH 4 ) gas mixture, using tetrahydrofuran (THF)-based hydrate-forming system at lower operating pressures (1.0 MPa). It is observed that the gas trapping is efficient and rapid. All the experiments were conducted at non-stirred condition, which is technically easy to achieve. Mole fraction of CH 4 was increased in proportion with N 2 , and it was found that methane gas uptake capacity in hydrate cages, increased progressively with increasing CH 4 concentration. Gas uptake kinetics was also found to be extremely fast and 90% of the gas consumed in hydrates within 50-60 min from hydrate nucleation.

Enhancing Methane Storage in Clathrate Hydrates Using Leaf Extract Catalysts: Advancing Sustainable Energy Storage

“…Certain thermodynamic additives can influence the dimensions and arrangement of hydrate crystals, directly affecting the storage capacity and stability. Furthermore, they possess the ability to alter the thermodynamic landscape of hydrate formation, enhancing the feasibility of the process across diverse temperature and pressure settings. ,− The exploration of environmentally friendly and biodegradable “green” additives is a focus of ongoing research, in line with sustainable principles. These additives play a pivotal role in fine-tuning the formation, dissociation, and storage attributes of gas hydrates.…”

Raman Spectroscopy Study on Ternary Model Coal Mine Methane Hydrates

“…The THF and gas (CH 4 /N 2 ) molecules are caged in 5 12 6 4 and 5 12 cages, respectively. 21 For the characteristic Raman signatures of CH 4 , N 2 , and CO 2 molecules encased in sI hydrates, the primary material CH 4hydrate is kept in association of other gas molecules at 265 K and 1.0 MPa for about 10−12 h. 22 However, the relationship between the crystalline structure and guest molecule size is not strict, for example, in a CH 4 + C 2 H 6 system, transitions of the gas hydrate structure from sI to sII can be observed 23, 24 Figure 3 shows that the collected Raman spectra of the model CMM hydrates are divided into several individual peaks. Raman bands in the C−H region are very distinct from the bands of the gas phase.…”

“…CH 4 /N 2 crystallizes into sII hydrates with a unit cell composition of 16­(CH 4 /N 2 )­8­(THF)­136H 2 O. The THF and gas (CH 4 /N 2 ) molecules are caged in 5 12 6 4 and 5 12 cages, respectively . For the characteristic Raman signatures of CH 4 , N 2 , and CO 2 molecules encased in sI hydrates, the primary material CH 4 -hydrate is kept in association of other gas molecules at 265 K and 1.0 MPa for about 10–12 h .…”

Enrichment of gas storage in clathrate hydrates by optimizing the molar liquid water–gas ratio

“…8 Natural hydrates are ascertained to be a future energy source if used with feasible technology and will have economic value. 9 The synthetic hydrates provide multifaceted applications such as storage media for greenhouse gases, [10][11][12][13][14][15][16] carbon dioxide capture from fuel gas, 17 methane recovery from coal mine gas, 18,19 desalination, [20][21][22] cold storage, [23][24][25][26][27] and gas transportation. 12,28 Because of their structural properties and selectivity, this process slowly escalates to address various food technology issues.…”