Introduction

Coalbed methane is a worthwhile potential energy source, because methane gas is eco-friendly and a huge amount of coalbed methane has been buried in the United States, China, Australia, etc. This paper introduces a new simulation model of a vacuum pressure swing adsorption process that has been widely used to purify unconventional gases such as coalbed methane and landfill gas. The developed mathematical model includes a novel interstitial gas velocity equation derived by using a mole balance concept and an overall mass balance equation. The model is verified by comparing with three sets of laboratory-scale (about 0.5 Nm3h–1) experimental data and one set of pilot-scale (100 Nm3h–1) design data. Because the differences between the simulation results and the data are reasonably small, one can conclude that the 200 times scale-up design through the new simulation model is successful.

Section: Introductionmentioning

confidence: 99%

Development of a Simulation Model for the Vacuum Pressure Swing Adsorption Process To Sequester Carbon Dioxide from Coalbed Methane

2016

“…Because the adsorbents are regenerated by lowering the operating pressure instead of heating, the energy intensity of PSA technology is low. In addition, the PSA units can be easily downsized to be mounted as modules on a skid, which is appropriate for the transportation and exploitation of small gas reservoirs, for example, unconventional gas reservoirs such as coalbed methane (CBM), which has recently been accepted as an important economic energy resource …”

Section: Introductionmentioning

confidence: 99%

Optimization of Vacuum Pressure Swing Adsorption Processes To Sequester Carbon Dioxide from Coalbed Methane

2016

This paper introduces an efficient scale-up design technology based on mathematical modeling and optimization approach. The target process is a vacuum pressure swing adsorption process which is preferred in purifying unconventional gas such as coalbed methane or landfill gas by sequestering carbon dioxide. The optimization results are validated very well from a pilot scale (10 N m 3 /h) to a large commercial scale (5000 N m 3 /h). The simulation and optimization model for the scale up design is established in gPROMS custom modeling tool. Judging from the reasonably very small differences between the optimization results and the vendor suggested data, it can be concluded that the scale-up design is very successful not by depending on the experimental and real plant experiences but by using a mathematical optimization modeling approach.

Toward a Fundamental Understanding of Geological Hydrogen Storage

Aftab

Hassanpouryouzband

Xie

et al. 2022

152

Geological H 2 storage plays a central role to enable the successful transition to the renewable H 2 economy and achieve net-zero emission in the atmosphere. Depleted oil and gas reservoirs are already explored with extensive reservoir and operational data. However, residual hydrocarbons can mix with injected H 2 in the reservoirs. Furthermore, low density and high diffusivity of H 2 may establish H 2 leakage from the reservoirs via fault pathways. Interestingly, H 2 can be consumed by microorganisms, which results in pore-network precipitation, plugging, and partial permeability impairment. Therefore, stored H 2 may be lost in the formations if the storage scenario is not planned cautiously. While salt caverns are safe and commercially proven geo-rock for H 2 storage, they have low-storage capacity compared to depleted gas reservoirs. Moreover, salt structures (e.g., domel, bedded) and microorganisms activities in the salt cavern are limiting factors, which can influence the storage process. Accordingly, we discuss challenges and future perspectives of hydrogen storage in different geological settings. We also highlight geographical limitations with diverse microbial communities and theoretical understanding of abiotic transformation (in terms of rock's minerals, i.e., mica and calcite) for geological H 2 storage. Regarding the fundamental behavior of H 2 in the geological settings, it is less soluble in formation water; therefore, it may achieve less solubility trapping compared to CO 2 and CH 4 . Furthermore, H 2 gas could attain higher capillary entrance pressures in porous media over CH 4 and CO 2 due to higher interfacial tension. Additionally, the low viscosity of H 2 may facilitate its injection and production but H 2 may establish the secondary trapping and viscous fingering. Thus, this review documents a blend of key information for the amendment of subsurface H 2 storage at the industrial scale.