Methane Adsorption Data Research Articles

Adsorption equilibrium of methane on activated carbon and typical metal organic frameworks

To develop adsorbents suitable for the storage of natural gas by adsorption, activated carbon SAC-02, HKUST-1 and MIL-101(Cr) were synthesized and characterized in terms of structural morphology observation, nitrogen physisorption at 77.15 K, and methane adsorption at 293.15–313.15 K and 0–4 MPa. The methane adsorption isotherms were comparatively correlated with the Toth, D-A and Ono-Kondo equations and the performances of the adsorbent samples were evaluated in terms of the isosteric adsorption heat and the adsorbed phase density. The results indicate that, in comparison with the D-A and Ono-Kondo equations, the Toth equation displays much smaller relative errors in correlating the methane adsorption data and is more suitable for the adsorption equilibrium analysis on the adsorbed natural gas (ANG) system. MIL-101(Cr) exhibits the largest mean isosteric heat for methane adsorption and the density of the adsorbed phase of methane is smaller than that of the liquid methane but increases with the equilibrium pressure; overall, MIL-101(Cr) with the highest adsorption capacity is more suitable for methane adsorption than activated carbon and HKUST-1.

Deep Learning Models for Predicting Gas Adsorption Capacity of Nanomaterials.

Metal–organic frameworks (MOFs), a class of porous nanomaterials, have been widely used in gas adsorption-based applications due to their high porosities and chemical tunability. To facilitate the discovery of high-performance MOFs for different applications, a variety of machine learning models have been developed to predict the gas adsorption capacities of MOFs. Most of the predictive models are developed using traditional machine learning algorithms. However, the continuously increasing sizes of MOF datasets and the complicated relationships between MOFs and their gas adsorption capacities make deep learning a suitable candidate to handle such big data with increased computational power and accuracy. In this study, we developed models for predicting gas adsorption capacities of MOFs using two deep learning algorithms, multilayer perceptron (MLP) and long short-term memory (LSTM) networks, with a hypothetical set of about 130,000 structures of MOFs with methane and carbon dioxide adsorption data at different pressures. The models were evaluated using 10 iterations of 10-fold cross validations and 100 holdout validations. The MLP and LSTM models performed similarly with high prediction accuracy. The models for predicting gas adsorption at a higher pressure outperformed the models for predicting gas adsorption at a lower pressure. The deep learning models are more accurate than the random forest models reported in the literature, especially for predicting gas adsorption capacities at low pressures. Our results demonstrated that deep learning algorithms have a great potential to generate models that can accurately predict the gas adsorption capacities of MOFs.

Absolute adsorption and adsorbed volume modeling for supercritical methane adsorption on shale

Adsorbed methane significantly affects shale gas reservoir estimates and shale gas transport in shale formations. Hence, a practical model for accurately representing methane adsorption behavior at high-pressure and high-temperature in shale is imperative. In this study, a reliable mathematical framework that estimates the absolute adsorption directly from low-pressure excess adsorption data is applied to describe the excess methane adsorption data in literature. This method provides detailed information on the volume and density of adsorbed methane. The obtained results indicate that the extensively used supercritical Dubinin-Radushkevich model with constant adsorbed phase density underestimates absolute adsorption at high pressure. The adsorbed methane volume increases both the pressure and expands with the temperature. The adsorbed methane density reduces above 10 MPa, and approaches a steady value at high pressure. This study provides a novel method for estimating adsorbed shale gas, which is expected improve the prediction of shale gas in place and gas production.

ZrBDC-Based Functional Adsorbents for Small-Scale Methane Storage Systems

Metal-organic frameworks (MOF), potentially porous coordination structures, are envisioned for adsorption-based natural gas (ANG) storage, including mobile applications. The factors affecting the performance of the ANG system with a zirconium-based MOF with benzene dicarboxylic acid as a linker (ZrBDC) as an adsorbent were considered: textural properties of the adsorbent and thermal effect arising upon adsorption. The high-density ZrBDC-based pellets were prepared by mechanical compaction of the as-synthesized MOF powder at different pressures from 30 to 240 MPa at 298 K without a binder and mixed with polymer binders: polyvinyl alcohol (PVA) and carboxyl methylcellulose (CMC). The structural investigations revealed that the compaction of ZrBDC with PVA under 30 MPa was optimal to produce the ZrBDC-PVA adsorbent with more than a twofold increase in the packing density and the lowest degradation of the porous structure. The specific total and deliverable volumetric methane storage capacities of the ZrBDC-based adsorbents were evaluated from the experimental data on methane adsorption measured up to 10 MPa and within a temperature range from 253 to 333 K. It was measured experimentally that at 253 K, an 100 mL adsorption tank loaded with the ZrBDC-PVA pellets exhibited the deliverable methane storage capacity of 172 m3(NTP)/m3 when the pressure dropped from 10 to 0.1 MPa. The methane adsorption data for the ZrBDC powder and ZrBDC-PVA pellets were used to calculate the important thermodynamic characteristic of the ZrBDC/CH4 adsorption system—the differential molar isosteric heat of adsorption, which was used to evaluate the state thermodynamic functions: entropy, enthalpy, and heat capacity. The initial heats of methane adsorption in powdered ZrBDC evaluated from the experimental adsorption isosteres were found to be ~19.3 kJ/mol, and then these values in the ZrBDC/CH4 system decreased at different rates during adsorption. In contrast, the heat of methane adsorption onto the ZrBDC-PVA pellets increased from 19.4 kJ/mol to a maximum with a magnitude, width, and position depended on temperature, and then it fell. The behaviors of the thermodynamic state functions of the ZrBDC/CH4 adsorption system were interpreted as a variation in the state of adsorbed molecules determined by a ratio of CH4-CH4 and CH4-ZrBDC interactions. The heat of adsorption was used to calculate the temperature changes of the ANG systems loaded with ZrBDC powder and ZrBDC pellets during methane adsorption under adiabatic conditions; the maximum integrated heat of adsorption was found at 273 K. The maximum temperature changes of the ANG system with the ZrBDC materials during the adsorption (charging) process did not exceed 14 K that are much lower than those reported for the systems loaded with activated carbons. The results obtained are of direct relevance for designing the adsorption-based methane storage systems for the automotive industry, developing new gas-power robotics systems and uncrewed aerial vehicles.

Monte Carlo Simulation and Experimental Studies of CO2, CH4 and Their Mixture Capture in Porous Carbons.

Adsorption of carbon dioxide and methane in porous activated carbon and carbon nanotube was studied experimentally and by Grand Canonical Monte Carlo (GCMC) simulation. A gravimetric analyzer was used to obtain the experimental data, while in the simulation we used graphitic slit pores of various pore size to model activated carbon and a bundle of graphitic cylinders arranged hexagonally to model carbon nanotube. Carbon dioxide was modeled as a 3-center-Lennard-Jones (LJ) molecule with three fixed partial charges, while methane was modeled as a single LJ molecule. We have shown that the behavior of adsorption for both activated carbon and carbon nanotube is sensitive to pore width and the crossing of isotherms is observed because of the molecular packing, which favors commensurate packing for some pore sizes. Using the adsorption data of pure methane or carbon dioxide on activated carbon, we derived its pore size distribution (PSD), which was found to be in good agreement with the PSD obtained from the analysis of nitrogen adsorption data at 77 K. This derived PSD was used to describe isotherms at other temperatures as well as isotherms of mixture of carbon dioxide and methane in activated carbon and carbon nanotube at 273 and 300 K. Good agreement between the computed and experimental isotherm data was observed, thus justifying the use of a simple adsorption model.

Thermodynamic Behaviors of Adsorbed Methane Storage Systems Based on Nanoporous Carbon Adsorbents Prepared from Coconut Shells.

The present work focused on the experimental study of the performance of a scaled system of adsorbed natural gas (ANG) storage and transportation based on carbon adsorbents. For this purpose, three different samples of activated carbons (AC) were prepared by varying the size of coconut shell char granules and steam activation conditions. The parameters of their porous structure, morphology, and chemical composition were determined from the nitrogen adsorption at 77 K, X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and scanning electron microscopy (SEM) measurements. The methane adsorption data measured within the temperature range from 178 to 360 K and at pressures up to 25 MPa enabled us to identify the most efficient adsorbent among the studied materials: AC-90S. The differential heats of methane adsorption on AC-90S were determined in order to simulate the gas charge/discharge processes in the ANG system using a mathematical model with consideration for thermal effects. The results of simulating the charge/discharge processes under two different conditions of heat exchange are consistent with the experimentally determined temperature distribution over a scaled ANG storage tank filled with the compacted AC-90S adsorbent and equipped with temperature sensors and heat-exchanger devices. The amounts of methane delivered from the ANG storage system employing AC-90S as an adsorbent differ from the model predictions by 4–6%. Both the experiments and mathematical modeling showed that the thermal regulation of the ANG storage tank ensured the higher rates of charge/discharge processes compared to the thermal insulation.

Hierarchical porous carbon converted from scrap rubber for methane storage and supercapacitor electrodes

This paper presented an effective method that utilized scrap rubber as the precursor to prepare porous activated carbons by the pyrolysis and KOH activation processes. Adjusting the activation temperature can tailor the textural characteristics of the resulting activated carbon, thus tuning the energy storage performance of the activated carbon, including methane storage behavior and electrochemical performance. The as-obtained carbon materials possessed hierarchical porous structure, and the methane adsorption data were analyzed by Langmuir, Langmuir-Freundlich and D-A models, respectively, among which the D-A model fitted the data best. The greatest storage capacity (110.39 mg/g, D-A model) was obtained for the sample AC-750 due to its highest SSA and abundant micropores. Furthermore, the hierarchical porous activated carbon electrode exhibited good rate performance (capacitance retention rate at above 86% as the charge/discharge current density increased by 40 times).

Adsorption equilibrium and the effect of honeycomb heat exchanging device on charge/discharge characteristic of methane on MIL-101(Cr) and activated carbon

Experiments were conducted for developing suitable ANG adsorbents for vehicular applications. MIL-101 and activated carbon samples were respectively prepared by hydrothermal and chemical activation methods. Two samples were undergone structure analysis on adsorption data of nitrogen at 77.15 K, and adsorption data of methane were then volumetrically measured within temperature–pressure range 293.15 K–313.15 K and 0–8 MPa. A conformable vessel in volume 2.5 L was employed for charge/discharge tests under the flow rate 10–30 L·min−1. It shows that limit isostreic heat of methane adsorption is respectively about 25.15 kJ·mol−1 and 22.94 kJ·mol−1 on the activated carbon and the MIL-101, and isosteric heat within the experimental condition is 14–19.5 kJ·mol−1; employing a smaller charge/discharge flow rate can weaken the temperature fluctuation of the adsorbent bed and increase the charge/discharge amount; employing honeycomb heat exchanging device enhance the thermal conductivity of the adsorbent bed by consuming a negligible part of volume of the vessel. It suggests that a smaller flow rate for charge/discharge should be employed, and MOFs together with the honeycomb heat exchanging device are promising for practical applications.

Modeling High-Pressure Methane Adsorption on Shales with a Simplified Local Density Model.

Shale gas has attracted increasing attention as a potential alternative gas in recent years. Because a large fraction of gas in shale formation is in an adsorbed state, knowledge of the supercritical methane adsorption behavior on shales is fundamental for gas-in-place predictions and optimum gas recovery. A practical model with rigorous physical significance is necessary to describe the methane adsorption behavior at high pressures and high temperatures on shales. In this study, methane adsorption experiments were carried out on three Lower Silurian Longmaxi shale samples from the Sichuan Basin, South China, at pressures of up to 30 MPa and temperatures of 40, 60, 80, and 100 °C. The simplified local density/Elliott–Suresh–Donohue model was adopted to fit the experimental data in this study and the published methane adsorption data. The results demonstrate that this model is suitable to represent the adsorption data from the experiments and literature for a wide range of temperatures and pressures, and the average absolute deviation is within 10%. The methane adsorption capacity of the Longmaxi shale exhibited a strong linear positive correlation with the total organic carbon content and a linear negative correlation with increasing temperature. The rate of decrease in the methane adsorption capacity with swing temperature increased with the total organic carbon content, indicating that the organic matter is sensitive to temperature.

Natural gas storage properties of adsorbents synthesised from three different coal waste in South Africa

Adsorbed natural gas (ANG) storage has been identified as the most promising low-pressure alternative to storing natural gas. However, in addition to the thermal management of the system, successful implementation of this technology is largely constrained by the cost of adsorbents. The usefulness and cost of suitable adsorbent such as activated carbon are essential to ANG technology's productivity. In this study, activated carbons were prepared from three South Africa coal waste samples (run-of-mine fines, discard and flotation slurry) by KOH activation. The adsorption isotherm of methane on the synthesized activated carbons revealed that the activated carbon synthesized from run of mine fines (ACR) has the highest adsorbed amount compared to activated carbons synthesized from coal discard (ACD) and slurry (ACS). The maximum adsorbed amount of methane was attained at an average pressure of 37 bar with ACR having the largest volume of methane adsorbed at 162.71 cm3/g followed by ACD (157.58 cm3/g) and ACS (106.69 cm3/g) respectively. This sequence is consistent with the BET surface areas of the activated carbons; ACR (1925.34 m2/g) > ACD (1826.41 m2/g) > ACS (1484.96 m2/g). The methane adsorption data were validated with Langmuir, Toth, and D-A isotherm models for the three activated carbons. It was found that, for all three activated carbons, the D-A model was the best fit. Based on the requirements of suitable porous materials for ANG application, the study indicated that the produced activated carbons from South Africa coal wastes could well be used for natural gas storage.

Experimental evaluation of activated carbon derived from South Africa discard coal for natural gas storage

Lacking in literature is the use of discard coal to produce activated carbon and in its subsequent use in the storage of natural gas. In this study, the characterization and gas storage evaluation of a largely porous activated carbon with large surface area synthesized from discard coal were investigated. Discard coals are waste material generated from coal beneficiation process. In developing the activated carbon, chemical activation route with the use of KOH reagent was applied. The effects of KOH/discard coal weight ratio (1:1, 2.5:1, 4:1), temperature (400–800 °C) and particle size (0.15–0.25 mm, 0.25–0.5 mm, 0.5–1 mm) on the adsorptive properties of the activated carbon were methodically evaluated and optimized using response surface methodology. The synthesized activated carbon was characterized using BET, SEM/EDS, and XRD. The results showed that for each activation process, the surface area and pore volume of the resulting activated carbon increased with increased temperature and KOH/discard coal weight ratio. The maximum surface area of 1826.41 m2/g, pore volume of 1.252 cm3/g and pore size of 2.77 nm were obtained at carbonization temperature of 800 °C and KOH/discard coal weight ratio of 4:1. Methane and nitrogen adsorption data at high pressure were fitted to Toth isotherm model with a predictive accuracy of about 99%. Adsorption parameters using the Toth model provides useful information in the design of adsorbed natural gas storage system. According to the requirements of adsorbent desired for natural gas storage, it could be stated that the synthesized activated carbon could well be applied for natural gas storage.

Applicability of various adsorption isotherm models on adsorption of methane and CO2 on Indian shales

To produce natural gas (methane) and simultaneously sequester CO2 in unconventional geologic reservoirs such as gas shale, coalbeds and so on, it is necessary to understand the adsorption behavior of methane and CO2 in these reservoir formations. In this article, adsorption behavior of methane and CO2 on shale samples from Gondwana Basin and KG Basin of India are studied. Adsorption experiments are conducted on as‐received shale samples from these basins at a temperature of 313 K to a maximum equilibrium pressure of approximately 9 MPa for methane and 6 MPa for CO2. The methane and CO2 adsorption data are applied to test the applicability of Langmuir, Dubinin‐Polanyi, BET, and Ono‐Kondo models. A comparison of these models is performed using linear and nonlinear Chi‐squared methods. It was observed that Dubinin‐Astakhov equation was the most accurate adsorption isotherm model for adsorption of methane and CO2 on tested shales. Further, the better fitting by Dubinin‐Polanyi equation over BET, Langmuir, and Ono‐Kondo models suggest that the mechanism of volume filling may be applicable during the adsorption of methane and CO2 on shales. The preferential adsorption of methane and carbon dioxide on Pakur, KG, and Salanpur shales were investigated. The Pakur shale had CO2:CH4 adsorption ratio ~1. © 2019 American Institute of Chemical Engineers Environ Prog, 38: 13222, 2019

A modified supercritical Dubinin–Radushkevich model for the accurate estimation of high pressure methane adsorption on shales

Knowledge of supercritical methane adsorption behavior in shales is crucial for evaluations of total shale gas-in-place (GIP) resources in deep formations. The primary object of this study is to establish an optimized model for the adsorption of supercritical methane in shale. An adaptive L-SDR model, which is a modification of the supercritical Dubinin–Radushkevich (SDR) model in combination with the Langmuir model, was introduced to interpret the measured absolute adsorption isotherms. A series of shale gas high pressure methane adsorption isotherms were measured at 303.15 K for Mesozoic shale collected in the Kuqa Depression of the Tarim Basin. In addition, published methane adsorption data on Posidonia shales were also investigated. The absolute adsorption results were fitted using the Langmuir, SDR and L-SDR models, and the accuracy of each model was analyzed and compared using an average relative error analysis. It was found that the L-SDR model can improve predictions of supercritical methane adsorption compared with predictions from the Langmuir and SDR models at both low and high temperatures, and the results indicate that this model can effectively model supercritical methane adsorption on shale. The individual contributions of the Langmuir and SDR models to the overall adsorption capacity were investigated at multiple temperatures, and the results showed that the contribution of the Langmuir model became more significant with increasing temperatures.

Study of adsorption behavior in shale reservoirs under high pressure

Understanding adsorption behavior is of critical importance for the development of shale reservoirs. However, most extant adsorption models cannot properly describe isothermal adsorption when the pressure exceeds a specific value at which the Langmuir volume is obtained. In this study, a modified bi-adsorbent simplified local density/Peng-Robinson model (SLD-PR) was developed in which adsorption in both organic and inorganic components of shale was considered at the same time, and a new modification was imposed on the covolume parameter in equation of state. The model was demonstrated on high pressure methane isothermal adsorption tests of terrestrial shale samples and the high pressure methane adsorption data for marine shales available in the literature samples. It is found that the proposed model can fit isothermal adsorption well for both terrestrial and marine shales with different shapes of adsorption curves, especially in the high pressure range. With the application of the model, it was determined that the methane adsorption capacity of Yanchang Formation terrestrial shale exhibits a positive correlation with its TOC content. Other factors, such as specific surface area, clay content and temperature, also significantly affect adsorption capacity. Furthermore, in the calculation of in-situ gas storage in shale reservoirs, the proposed model produces more reliable results generally when compared with the original SLD-PR model and the Langmuir model.

A comparative study of several microporous materials to store methane by adsorption

Methane adsorption was studied in microporous materials with differences in their pore geometry and surface chemistry in order to evaluate the characteristics that enhance methane storage in porous materials. The studied materials included metal-organic frameworks (Cu-BTC, MIL-53 and ZIF-8), zeolites (5A and 13X) and an activated carbon (Maxsorb). Textural properties such as pore volume and specific surface area were studied by nitrogen adsorption–desorption isotherms. Methane adsorption was analyzed by means of measurements at low and high pressures (0–5000 kPa) at various temperatures (278–323 K). The effect of the adsorbate–adsorbent interaction was evaluated by the determination of the Henry constant using the adsorption data of methane at low pressures and 298 K. In addition, the isosteric enthalpy of adsorption using data of adsorption at several temperatures was obtained. A linear trend was observed between the Henry constant, the enthalpy of adsorption and the pore size, indicating that the latter is the most influential factor in the interaction of a microporous adsorbent and methane at room temperature. Also, it was found that the textural properties (i.e. specific surface and micropore volume) are directly related with the methane storage capacity at 298 K and 3.5 MPa. However, we obtained a deviation of this behavior for ZIF-8 that is related to its geometry and pore size.

Characteristics of Pore Volume Distribution and Methane Adsorption on Shales

Shale pore structure has an important effect upon shale-gas adsorption. In order to quantify their contribution to the total amount of adsorbed gas, we investigate the pore volume distribution on shale, coal, isolated kerogen, and clay samples using low pressure nitrogen and carbon dioxide adsorption method. And a series of methane adsorption isotherms on the samples was measured by a volumetric approach at 20 °C, 30 °C and 40 °C under pressures up to 10 MPa. Results indicate that a strong correlation exists between TOC and micropore volume of shale, but to verify the correlations between BET surface area and TOC, or micropore volume and Ro are still difficult. Certain isotherms on shales differ from Type I IUPAC (International Union of Pure and Applied Chemistry) isotherm. The unusual shape may be attributed to shale pore structure or composition. Finally, the modified D-A-Langmuir model including pore distribution parameters can provide a precise representation of the methane adsorption data on shales. ...

Critical Factors Driving the High Volumetric Uptake of Methane in Cu₃(btc)₂.

A thorough experimental and computational study has been carried out to elucidate the mechanistic reasons for the high volumetric uptake of methane in the metal-organic framework Cu3(btc)2 (btc(3-) = 1,3,5-benzenetricarboxylate; HKUST-1). Methane adsorption data measured at several temperatures for Cu3(btc)2, and its isostructural analogue Cr3(btc)2, show that there is little difference in volumetric adsorption capacity when the metal center is changed. In situ neutron powder diffraction data obtained for both materials were used to locate four CD4 adsorption sites that fill sequentially. This data unequivocally shows that primary adsorption sites around, and within, the small octahedral cage in the structure are favored over the exposed Cu(2+) or Cr(2+) cations. These results are supported by an exhaustive parallel computational study, and contradict results recently reported using a time-resolved diffraction structure envelope (TRDSE) method. Moreover, the computational study reveals that strong methane binding at the open metal sites is largely due to methane-methane interactions with adjacent molecules adsorbed at the primary sites instead of an electronic interaction with the metal center. Simulated methane adsorption isotherms for Cu3(btc)2 are shown to exhibit excellent agreement with experimental isotherms, allowing for additional simulations that show that modifications to the metal center, ligand, or even tuning the overall binding enthalpy would not improve the working capacity for methane storage over that measured for Cu3(btc)2 itself.

Methane dual-site adsorption in organic-rich shale-gas and coalbed systems

Herein, we report on a novel dual-site adsorption model to determine state of methane in shale formations and coalbeds. By considering two surface energy terms, the model distinguishes methane adsorption in the intrinsic micropore volume of the organic matter from that of the inorganic structure. One energy term describes methane adsorption in micropores (<2nm) whereas the other one concerns with meso-macropores. This study showed that at storage conditions, 150bar and 50.4°C, where methane is in supercritical state, the surface energy plays the major role to influence methane adsorption capacity whereas the effect of lateral forces between adsorbed molecules has a minor influence on overall adsorption capacity. We applied the model on experimental methane adsorption data in three organic-rich samples including Woodford shale, Woodford isolated kerogen and Cameo coal to quantify their methane storage state. Textural properties of shale and coal samples were analyzed by N2 porosimetry at −196°C. The samples had a weak micropore peak followed by a broader peak stretched over meso and macropore regions up to nearly 120nm. Fitting the dual-site model to experimental methane adsorption data revealed that, among all, the coal sample, with the average heat of adsorption of 24.5kJ/mol, had the highest interaction energies with both micro- and mesopore sites. Further, we find that 37%, 81% and 83% of methane was stored in the organic matter of Woodford shale, Woodford isolated kerogen and Cameo coal, respectively. Considering low maturity, and hence low micropore volume of the samples, and based on significant methane storage in the organic content we estimated that more than 50% of methane gas is being dissolved into the organic matter rather than just being adsorbed into the micropore volume.

Methane adsorption and pore characterization of Indian shale samples

Understanding adsorption behavior of methane in shale is important for predicting the gas reserve and evaluating reservoir potential. This paper presents the methane adsorption behavior of three gas shale samples of Gondwana and KG basin of India. Adsorption experiments are conducted on as-received samples at a temperature of 40°C to a maximum equilibrium pressure of approximately 9.5MPa. The methane adsorption data are applied to test the applicability of Langmuir isotherm model. It was observed that the experimental adsorption data for Parbatpur and KG shale samples did not follow the Langmuir isotherm model, with deviation from the model value more than 10%. Although the experimental adsorption data of Salanpur sample broadly followed the Langmuir model, the deviation from the model value was more than 5%, implying the Langmuir model is not very accurate. Pore characterization study was also carried out to understand the pore structure of the shale samples. The pore characterization suggested that porosity of Indian gas shales are dominated by meso- and macro-pores.

Experimental studies of storage by adsorption of domestically used natural gas on activated carbon

Experiments were designed for developing domestically used natural gas storage vessels. Adsorption data of methane on the activated carbon having SBET = 2074 m2/g was volumetrically measured. Storage vessels in net volume 1.5 L and filled with 700 g activated carbon were employed for dynamic characteristic tests. It shows that a relative error from Toth equation prediction is less than 0.07%. At the flow rate 15 L/min, by circulating water around the central of storage vessels and charging/discharging the gas through a perforated tube, the maximum fluctuation of temperature can be respectively reduced to 15 °C and 10 °C, and the charged/discharged amount can correspondingly be increased about 14.2% and 4.4%. However, the highest temperature in the center is independent of the temperature of the cooling water within the range 10°C–30 °C. Discharged amounts accumulated at 15 L/min increase in the temperature of the heating water from 30 °C to 70 °C, but the total discharged amounts nearly remain the same. It suggests that domestically used ANG vessels can utilize running water as a coolant or the supplemental heat to manage the thermal effect. Optimization of the arrangement of heat exchanging pipes and the charge/discharge ports is required to have a successful design of a storage vessel.