scholarly journals A theoretical model for coal swelling induced by gas adsorption in the full pressure range

2020 ◽  
Vol 38 (3-4) ◽  
pp. 94-112
Author(s):  
Ping Guo
Keyword(s):  
Theoretical Model ◽  
Pressure Range ◽  
Gas Adsorption ◽  
Coal Bed ◽  
Model Parameters ◽  
Model Errors ◽  
Mixed Gas ◽  
Methane Recovery ◽  
Coal Swelling ◽  
Full Pressure

The phenomenon of coal swelling caused by gas adsorption is well known. For Enhanced Coal Bed Methane Recovery and carbon storage, coal swelling induced by gases adsorption may cause significant reservoir permeability change. In this paper, based on the assumption that the surface energy change caused by adsorption is equal to the change in elastic energy of the coal matrix, a theoretical model is derived to describe coal swelling induced by gas adsorption in the full pressure range. The Langmuir constant, coal density, solid elastic modulus, and Poisson’s ratio are required in this model. These model parameters are easily obtained through laboratory testing. The developed model is verified by available experimental data. The results show that the presented model shows good agreement with the experimental observations of swelling. The model errors are within 14% for pure gas, and within 20% for mixed gas. It is shown that this model is able to describe coal swelling phenomena for full pressure range and different gas type including pure gas and mixed. In addition, it is also shown that the errors of the presented model and the Pan’s model are almost the same, but the presented model is solved more easily.

scholarly journals Changes in Pore Structure of Coal Caused by CS2 Treatment and Its Methane Adsorption Response

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Run Chen ◽  
Yong Qin ◽  
Pengfei Zhang ◽  
Youyang Wang
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Gas Adsorption ◽  
Recovery Process ◽  
Micropore Volume ◽  
Methane Adsorption ◽  
Coal Bed ◽  
Methane Recovery ◽  
Before And After ◽  
Key Issues

The pore structure and gas adsorption are two key issues that affect the coal bed methane recovery process significantly. To change pore structure and gas adsorption, 5 coals with different ranks were treated by CS2 for 3 h using a Soxhlet extractor under ultrasonic oscillation conditions; the evolutions of pore structure and methane adsorption were examined using a high-pressure mercury intrusion porosimeter (MIP) with an AutoPore IV 9310 series mercury instrument. The results show that the cumulative pore volume and specific surface area (SSA) were increased after CS2 treatment, and the incremental micropore volume and SSA were increased and decreased before and after Ro,max=1.3%, respectively; the incremental big pore (greater than 10 nm in diameter) volumes were increased and SSA was decreased for all coals, and pore connectivity was improved. Methane adsorption capacity on coal before and after Ro,max=1.3% also was increased and decreased, respectively. There is a positive correlation between the changes in the micropore SSA and the Langmuir volume. It confirms that the changes in pore structure and methane adsorption capacity due to CS2 treatment are controlled by the rank, and the change in methane adsorption is impacted by the change of micropore SSA and suggests that the changes in pore structure are better for gas migration; the alteration in methane adsorption capacity is worse and better for methane recovery before and after Ro,max=1.3%. A conceptual mechanism of pore structure is proposed to explain methane adsorption capacity on CS2 treated coal around the Ro,max=1.3%.

The Research of Variation Regularity of Coal Bed Methane Production in CO2 Flooding

2013 ◽  
Vol 868 ◽  
pp. 677-681
Author(s):  
Yang Liu ◽  
Di Wu
Keyword(s):  
Methane Production ◽  
Injection Pressure ◽  
Initial Pressure ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Mixed Gas ◽  
Methane Recovery ◽  
Factors Affecting ◽  
Gas Concentration ◽  
Injection Process

CO2flooding can increase coal bed methane production rate, enhance coal bed methane recovery and store CO2into underground. It has good application prospect for CBM development. This paper analyzes the adsorption-desorption law of mixed gas in the coal during the CO2injection process, as well as the diffusion and seepage law of gas in the coal seam. The sensitivity of factors affecting coal bed methane production is studied and then the coal bed methane production under different conditions is simulated numerically. The results show that methane concentration and coals permeability are the two key factors affecting the output of coal bed gas and their influence on productivity are even more significant than injection pressure and initial pressure. The higher injection pressure, coals permeability and gas concentration, the greater amount of methane the coal reservoirs will yield. When the coals permeability and the gas concentration in coal reservoirs increase, the growth rate of methane production accelerates accordingly.

scholarly journals NUMERICAL MODELLING AND SIMULATION OF CO2 –ENHANCED COAL-BED METHANE RECOVERY (CO2-ECBMR): THE EFFECT OF COAL SWELLING ON GAS PRODUCTION PERFORMANCE

2015 ◽  
Vol 7 (2) ◽  
pp. 102
Author(s):  
Ferian Anggara ◽  
Kyuro Sasaki ◽  
Yuichi Sugai
Keyword(s):  
Gas Production ◽  
Production Performance ◽  
Coal Bed ◽  
Methane Recovery ◽  
Coal Matrix ◽  
Ch4 Production ◽  
Coal Swelling ◽  
Production Ratio ◽  
Permeability Changes ◽  
Production Wells

This presents study investigate the effect of swelling on gas production performances at coal reservoirs during CO2-ECBMR processes. The stressdependent permeability-models to express effect of coal matrix shrinkage/swelling using Palmer and Mansoori (P&M) and Shi and Durucan (S&D) models were constructed based on present experimental results for typical coal reservoirs with the distance of 400 to 800 m between injection and production wells. By applying the P&M and S&D models, the numerical simulation results showed that CH4 production rate was decreasing and peak production time was delayed due to effect of stress and permeability changes caused by coal matrix swelling. The total CH4 production ratio of swelling effect/no-swelling was simulated as 0.18 to 0.95 for permeability 1 to 100 mD, respectively. It has been cleared that swelling affects gas production at permeability 1 to 15 mD, however, it can be negligible at permeability over 15 mD.

Interaction between Supercritical CO2 and Coal Petrography

2012 ◽  
Vol 616-618 ◽  
pp. 306-309 ◽  
Author(s):  
Run Chen
Keyword(s):  
Pore Structure ◽  
Supercritical Fluid ◽  
Gas Adsorption ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Organic Matters ◽  
Coal Swelling ◽  
Coal Petrography

CO2enhanced CBM recovery(CO2-ECBM) is an important way for reducing CO2emission into atmosphere and enhancing coal-bed methane (CBM) recovery. The interaction between supercritical CO2and coal petrography has been investigated since the 1990s. Advances in the interaction between supercritical CO2and coal petrography are reviewed in light of certain aspects, such as the competitive multi-component gas adsorption, sorption-induced coal swelling/shrinkage and the fluid-solid coupling between fluids(such as gas, liquid and supercritical fluid) and coal petrography. It is suggested that a comprehensive feasibility demonstration is necessary for a successful application of the technology for CO2-ECBM. At the same time, it also indicated that there are some questions must be discussed in future, such as the influences on pore structure, coal adsorptivity and permeability of the reaction of ScCO2-H2O and rock and small organic matters are extracted by supercritical CO2.

scholarly journals Adsorption Factors in Enhanced Coal Bed Methane Recovery: A Review

Gases ◽  
2022 ◽  
Vol 2 (1) ◽  
pp. 1-21
Author(s):  
Theodora Noely Tambaria ◽  
Yuichi Sugai ◽  
Ronald Nguele
Keyword(s):  
Density Functional ◽  
Gas Adsorption ◽  
Experimental Studies ◽  
Analytical Techniques ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Resonance Spectroscopy ◽  
Methane Recovery ◽  
13C Nuclear Magnetic Resonance ◽  
Adsorption Of Co2

Enhanced coal bed methane recovery using gas injection can provide increased methane extraction depending on the characteristics of the coal and the gas that is used. Accurate prediction of the extent of gas adsorption by coal are therefore important. Both experimental methods and modeling have been used to assess gas adsorption and its effects, including volumetric and gravimetric techniques, as well as the Ono–Kondo model and other numerical simulations. Thermodynamic parameters may be used to model adsorption on coal surfaces while adsorption isotherms can be used to predict adsorption on coal pores. In addition, density functional theory and grand canonical Monte Carlo methods may be employed. Complementary analytical techniques include Fourier transform infrared, Raman spectroscopy, XR diffraction, and 13C nuclear magnetic resonance spectroscopy. This review summarizes the cutting-edge research concerning the adsorption of CO2, N2, or mixture gas onto coal surfaces and into coal pores based on both experimental studies and simulations.

scholarly journals Simulation of CO2-geosequestration enhanced coal bed methane recovery with a deformation-flow coupled model

2009 ◽  
Vol 1 (1) ◽  
pp. 81-89 ◽  
Author(s):  
Wang Zuo-tang ◽  
Wang Guo-xiong ◽  
Rudolph V. ◽  
Diniz da Costa J. C. ◽  
Huang Pei-ming ◽  
...  
Keyword(s):  
Coupled Model ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Methane Recovery

scholarly journals Isosteric Heat of Single Gas Adsorption on an Energetically Homogeneous Adsorbent Surface

1996 ◽  
Vol 13 (2) ◽  
pp. 105-114 ◽  
Author(s):  
J.K. Garbacz ◽  
A. Kopkowfki ◽  
A. Dabrowski
Keyword(s):  
Gas Adsorption ◽  
Isosteric Heat ◽  
Model Parameters ◽  
Experimental Systems ◽  
Adsorbent Surface ◽  
Monolayer Adsorption

An expression for the isosteric heat of the partially mobile monolayer adsorption of a single gas on a homogeneous adsorbent surface has been derived. Optimization of the model parameters has been performed for selected experimental systems.

Cyclotetrabenzoin Acetate: A Macrocyclic Porous Molecular Crystal for CO2 Separations by Pressure Swing Adsorption

2021 ◽  
Author(s):  
Yao-Ting Wang ◽  
Corie M. McHale ◽  
Xiqu Wang ◽  
Chung-Kai Chang ◽  
Yu-Chun Chuang ◽  
...  
Keyword(s):  
Molecular Crystal ◽  
Pressure Swing Adsorption ◽  
Gas Adsorption ◽  
Close Packing ◽  
Separation Performance ◽  
Mixed Gas ◽  
Water Tolerance ◽  
Pressure Swing ◽  
Breakthrough Experiments ◽  
Group Play

A porous molecular crystal (PMC) assembled by close-packing of macrocyclic cyclotetrabenzoin acetate is an efficient adsorbent for selective CO<sub>2</sub> capture. The 7.1´7.1 Å square pore of PMC and its ester C=O group play important roles in improving its affinity for CO<sub>2</sub> molecules. Thermodynamically, the benzene walls of macrocycle strongly promote CO<sub>2</sub> adsorption via [p···p] interactions at low pressure. In addition, the polar carbonyl groups pointing inward the square channels reduce the size of aperture to a 5.0´5.0 Å square, which offers kinetic selectivity for CO<sub>2</sub> capture. The PMC features water tolerance and high structural stability under vacuum and various gas adsorption conditions, which are rare among intrinsically porous organic molecules. In mixed-gas breakthrough experiments, it exhibits efficient CO<sub>2</sub>/N<sub>2</sub> and CO<sub>2</sub>/CH<sub>4</sub> separations under kinetic flow conditions. Most importantly, the moderate adsorbate–adsorbent interaction allows the PMC to be readily regenerated, and therefore applied to pressure swing adsorption (PSA) processes. The eluted N<sub>2</sub> and CH<sub>4</sub> are obtained with over 99.9% and 99.8% purity, respectively, and the separation performance is stable for 30 cycles. Coupled with its easy synthesis, these properties make cyclotetrabenzoin acetate a promising adsorbent for CO<sub>2</sub> separations from flue and natural gases.

Sign in / Sign up

Export Citation Format

Share Document