scholarly journals Hydrates for Cold Storage: Formation Characteristics, Stability, and Promoters

2021 ◽  
Vol 11 (21) ◽  
pp. 10470
Author(s):  
Huan Chen ◽  
Bingyue Han ◽  
Chen Lang ◽  
Min Wen ◽  
Baitao Fan ◽  
...  
Keyword(s):  
Cold Storage ◽  
Induction Time ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Process Time ◽  
Ice Cube ◽  
Nucleation Sites ◽  
Multiple Cycle ◽  
The Stability ◽  
Positive Effect

The potential of hydrates formed from R141b (CH3CCl2F), trimethylolethane (TME), and tetra-n-butylammonium bromide/tetra-n-butylammonium chloride (TBAB/TBAC) to be used as working substances for cold storage was investigated to provide a solution for unbalanced energy grids. In this study, the characteristics of hydrate formation, crystal morphology of hydrates, and the stability of hydrate in cyclic formation under 0.1 MPa and at 5 °C were carried out. It found that the ice had a positive effect on the hydrate formation under same conditions. Upon the addition of the ice cube, the induction time of R141b, TME, and TBAB/TBAC hydrates decreased markedly, and significantly high formation rates were obtained. Under magnetic stirring, the rate at which TBAB/TBAC formed hydrates was significantly lower than that when ice was used. In microscopic experiments, it was observed that the TBAB/TBAC mixture formed hydrates with more nucleation sites and compact structures, which may increase the hydrate formation rate. In the multiple cycle formation of TBAB/TBAC hydrates, the induction time gradually decreased with the increasing number of formation cycles and finally stabilized, which indicated the potential of the TBAB/TBAC hydrates for application in cold storage owing to their good durability and short process time for heat absorption and release.

Kinetic analysis of dual impellers on methane hydrate formation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sotirios Nik Longinos ◽  
Mahmut Parlaktuna
Keyword(s):  
Power Consumption ◽  
Kinetic Analysis ◽  
Induction Time ◽  
Methane Hydrate ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Mixed Flow ◽  
Pitched Blade Turbine ◽  
Decline Rate

Abstract This study investigates the effects of types of impellers and baffles on methane hydrate formation. Induction time, water conversion to hydrates (hydrate yield), hydrate formation rate and hydrate productivity are components that were estimated. The initial hydrate formation rate is generally higher with the use of Ruston turbine (RT) with higher values 28.93 × 10−8 mol/s in RT/RT with full baffle (FB) experiment, but the decline rate of hydrate formation was also high compared to up-pumping pitched blade turbine (PBTU). Power consumption is higher also in RT/RT and PBT/RT with higher value 392,000 W in PBT/RT with no baffle (NB) experiment compared to PBT/PBT and RT/PBT experiments respectively. Induction time values are higher in RT/RT experiments compared to PBT/PBT ones. Hydrate yield is always smaller when there is no baffle in all four groups of experiments while the higher values exist in experiments with full baffle. It should be noticed that PBT is the same with PBTU, since all experiments with mixed flow have upward trending.

Effects of Cyclodextrin Solutions on Methane Hydrate Formation

2007 ◽  
Author(s):  
Ryo Nozawa ◽  
Mohammad Ferdows ◽  
Kazuhiko Murakami ◽  
Masahiro Ota
Keyword(s):  
Raman Spectroscopy ◽  
Induction Time ◽  
Methane Hydrate ◽  
Methane Concentration ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Formation Water ◽  
Advanced Method

In this paper, we suggest the advanced method of methane hydrate formation by cyclodextrin solutions. The structures of the methane hydrate were experimentally investigated by Raman spectroscopy. The induction time of the methane hydrate formation becomes by shorter 10–30 times and formation rate become by faster 2–4 times originated in the increased methane concentration of hydrate formation water by adding cyclodextrins. The results by the Raman spectroscopy indicate that the structure I methane hydrate is produced and methane molecules exist in both Large and Small cages.

Formation Kinetics and Self-Preservation of CO2 Hydrates in the Presence of Carboxylated Multiwall Carbon Nanotubes

2021 ◽  
Author(s):  
Khalik Mohamad Sabil ◽  
Omar Nashed ◽  
Bhajan Lal ◽  
Khor Siak Foo
Keyword(s):  
Gas Hydrate ◽  
Induction Time ◽  
Completion Time ◽  
Formation Rate ◽  
Sodium Dodecyl ◽  
Hydrate Formation ◽  
Significant Finding ◽  
Formation Kinetic ◽  
Gas Hydrate Formation ◽  
The Impact

Abstract Nanofluids are known of having the capability to increase heat and mass transfer and their suitability to be used as kinetic gas hydrate promoters have been recently investigated. They have favorable properties such as high thermal conductivity, large surface area, recyclable, ecofriendly, and relatively cheap that are favorable for kinetic gas hydrate promoters. However, the nanomaterials face challenges related to their stability in the base fluid. Therefore, it is crucial to investigate the impact of surfactant free nanofluid on hydrate formation and dissociation kinetics. In this work, COOH-MWCNT suspended in water is used to study the effect of surfactant free nanofluid on CO2 hydrates formation kinetic and stability. Kinetic study on CO2 hydrates formation as well as self-preservation are conducted in a stirred tank reactor. The kinetic experiments are carried out at 2.7 MPa and 274.15 K. The induction time, initial gas consumption rate, half-completion time t50, semi completion time t95 are measured to evaluate the effect of COOH-MWCNT. Furthermore, the dissociation rate was calculated to assess the impact of COOH-MWCNT on self-preservation at 271.15 K and atmospheric pressure. The results are compared with that of sodium dodecyl sulphate (SDS). The study of CO2 hydrates formation kinetic shows that the induction time is not affected by COOH-MWCNT. The impact of nanofluid is more pronounced during the hydrate growth. The initial formation rate is the highest at 0.01 wt% of COOH-MWCNT whereas 0.01 and 0.03 wt% shows the same and shortest t50. However, t95 found to be decreased with increasing the concentration. The effect of COOH-MWCNT is attributed to the strong functional group. Self-preservation results shows CO2 hydrates are less stable in the presence of COOH-MWCNT. The result of this work may provide significant finding that can be used to developed kinetic gas hydrate promoter based on nanofluid that work better than SDS to eliminate gas hydrate formation in oil and gas pipeline.

Surfactant Effect of Promoting Research on Hydrate Formation

2015 ◽  
Vol 1092-1093 ◽  
pp. 220-225
Author(s):  
Lei Wang ◽  
Shu Li Wang ◽  
Tian Tian Kang
Keyword(s):  
Gas Hydrates ◽  
Induction Time ◽  
Oil And Gas ◽  
Formation Rate ◽  
Technical Problem ◽  
Hydrate Formation ◽  
Oil And Gas Industry ◽  
Research Direction ◽  
Equal Concentration ◽  
Observation Method

Gas hydrates are a major concern in oil and gas industry, Gas hydrates form in small amounts of water, gas, and the appropriate pressure and temperature conditions. Gas hydrate storage and transportation technology starts a new way for energy storage and transportation industry. The most critically technical problem is how to improve the hydrate formation rate, storage capacity and form continuously. The influences of surfactants on induction time in three types of solution with equal concentration were studied by means of visual hydrate experimental equipment, and generalized induction time was measured by direct observation method. Specific effects of different surfactants on hydrate formation were summarized, as well as the hydrate formation mechanism of surfactants . The lack of research and the research direction of the future were concluded . The further study of surfactant mechanism and build kinetics model containing surfactant have important theoretical value . The result shows that the gas molecules saturated due to the solubilization of surfactant, which promotes the progress of mass transfer in the hydrates. And driving force is provided for the complexation of host molecules and guest molecules during the formation progress of gas hydrates.

scholarly journals Experimental Study on the Influence of Micron SiO2 on the Kinetics of Hydrate Formation

2021 ◽  
Vol 2076 (1) ◽  
pp. 012086
Author(s):  
Shuai Wu ◽  
Mingzhong Li ◽  
Chongrui Zhang ◽  
Chengwei Liu ◽  
Shuai Zhao ◽  
...  
Keyword(s):  
Growth Rate ◽  
Particle Size ◽  
Induction Time ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Kinetic Mechanism ◽  
Experimental Results ◽  
Particle Content ◽  
Obvious Effect ◽  
Average Growth

Abstract In order to explore the kinetic mechanism of hydrate formation in a system containing micron-sized SiO2 particles, this paper uses a high-pressure reactor device with stirring function to record changes in pressure, temperature and torque during the growth of hydrates through a data acquisition system, based on the conservation of mass in the system The principle and gas equation of state calculate the kinetic parameters of hydrate formation such as gas consumption in the reactor, hydrate formation rate and induction time, and analyze the influence of particle size and particle concentration on the kinetic characteristics of hydrate formation based on the experimental results. The experimental results show that the particle content has no obvious effect on the average growth rate of hydrate in the range of 1%-7%, but increasing the particle content can effectively reduce the hydration induction time; when the particle size is in the range of 2.5-85 μm, the larger the particle size, the shorter the hydrate induction time and the greater the hydrate growth rate.

scholarly journals Effect of three representative surfactants on methane hydrate formation rate and induction time

2017 ◽  
Vol 26 (2) ◽  
pp. 331-339 ◽  
Author(s):  
Mostafa keshavarz Moraveji ◽  
Ahmadreza Ghaffarkhah ◽  
Arash Sadeghi
Keyword(s):  
Induction Time ◽  
Methane Hydrate ◽  
Formation Rate ◽  
Hydrate Formation

scholarly journals Experimental Study on the Effect of Combination of Thermodynamic Inhibitors’ and Kinetic Inhibitors’ Hydrate Inhibition

2021 ◽  
Vol 9 ◽  
Author(s):  
Yonghai Gao ◽  
Yanlong Wang ◽  
Guizhen Xin ◽  
Xiangdong Wang ◽  
Cheng Yue ◽  
...  
Keyword(s):  
Induction Time ◽  
Low Dose ◽  
Formation Rate ◽  
Hydrate Formation ◽  
Well Testing ◽  
Gas Well ◽  
Cooling Method ◽  
Mixed Use ◽  
Wellbore Temperature ◽  
Temperature And Pressure

In deepwater gas well testing, the high-pressure and low-temperature environment in the wellbore provides conditions for hydrate formation. When the thermodynamic inhibitor is used, it needs a large amount and is difficult to inject. Low-dose hydrate inhibitors such as kinetic inhibitors are rarely used in high supercooling and natural gas–dominated environments. The mixed use of thermodynamic inhibitors and kinetic inhibitors provides a new way. By simulating the wellbore temperature and pressure conditions during the deepwater gas well testing, the inhibiting effect of the mixtures of PVCap and methanol with various concentrations was experimentally tested by using rocking cells with a step-cooling method at 21MPa. The effect of PVCap and its mixture with methanol on hydrate plugging was evaluated by monitoring the movement of slider in the rocking cell. The results showed that 5 wt%, 16 wt%, and 20 wt% methanol mixed with 0.5 wt% PVCap could prolong the induction time, and the higher the methanol concentration, the longer the hydrate induction time. Among them, the best combination of 20wt% methanol and 0.5wt% PVCap can inhibit the hydrate for 379 min. The hydrate was formed but did not block the rocking cell, indicating that the combination of PVCap and methanol could not only prolong the hydrate formation time but also avoid the blockage after hydrate formation. The hydrate formation rate with various inhibitor concentrations was calculated; it may provide some guidance for making a shut-in plan for on-site wells.

scholarly journals Influence of THF and THF/SDS on the Kinetics of CO2 Hydrate Formation Under Stirring

2021 ◽  
Vol 9 ◽  
Author(s):  
Hongliang Wang ◽  
Qiang Wu ◽  
Baoyong Zhang
Keyword(s):  
Induction Time ◽  
Pure Water ◽  
Formation Rate ◽  
Sodium Dodecyl ◽  
Hydrate Formation ◽  
Gas Absorption ◽  
Obvious Effect ◽  
Gas Uptake ◽  
Gas Consumption ◽  
And Control

Hydrate-based gas separation is a potential technology for CO2 recovery and storage, and its products can be used for fire prevention and control in mines. Promoters are often employed to accelerate or moderate hydrate formation. In this study, experiments were performed to examine the effects of different concentrations of the thermodynamic promoter tetrahydrofuran (THF) and kinetic promoter sodium dodecyl sulphate (SDS) on CO2 hydrate formation under stirring. The results showed that THF significantly shortens the induction time of CO2 hydrates; however, because THF occupies a large cavity in the hydrate structure, it also reduces the gas absorption and hydrate formation rate. SDS has no obvious effect on the induction time of hydrates, but it can increase the gas storage density and hydrate formation rate. Using THF and SDS together consumed more CO2 than using THF alone or pure water. The peak gas consumption rate was 2.3 times that of the THF system. The hydrate formation efficiency was improved by including both THF and SDS, which maximized both the hydrate formation rate and total gas uptake.

Hydrate Formation in Water-in-Oil Emulsions in the Presence of Resins

2020 ◽  
Author(s):  
Dongxu Zhang ◽  
Qiyu Huang ◽  
Rongbin Li ◽  
Danfu Cao ◽  
Huiyuan Li
Keyword(s):  
Induction Time ◽  
Hydrate Formation ◽  
Droplet Surface ◽  
Resin Content ◽  
Flow Assurance ◽  
Common Component ◽  
Nucleation Sites ◽  
Oil Emulsions ◽  
Water Cut ◽  
Delay Phenomenon

Abstract Gas hydrate is one of the main concerns in the flow assurance issues for under water multiphase pipelines. Hydrate nucleation and growth in the water-in-oil emulsions have not been completely understood due to the complex factors, such as the composition of crude oils. Resins, as a common component in crude oil, can pose great effects on hydrate formation, which is still lack of investigation. This paper aims to bridge this gap with a custom-designed high pressure autoclave. Different with other hydrate investigation apparatus, an online viscometer was equipped for the real time viscosity measurement. Resins were separated from the Venezuelan residue for the purpose, following the saturates, aromatics, resins, and asphaltenes fractionation method. A series of experiments of hydrate formation were carried out in the emulsions with the presence of different resin contents, under the condition of 2.7 °C, 2.6 MPa, and 40 vol. % water cut. It was observed that resins hindered hydrate formation in water-in-oil emulsions. The induction time increased with the increasing of resin content. The induction time in the emulsion with the presence of 1.0 wt. % resin content was almost 200 min longer than that in the emulsion without resins. It was found that an increase in resin concentration led to the significant reduction in temperature peak. In addition, a time delay phenomenon of temperature and pressure in the growth onset was found in the system with 0.5 or 1.0 wt. % resin content, by virtue of the online viscometer. It demonstrated the impeding effect of resins on hydrate growth. Moreover, the microphotographs of water-in-oil emulsions were obtained. It was observed that the resins can be adsorbed on the water droplet surface, and hence occupied the hydrate nucleation sites and formed a barrier for the further penetration of gas molecules. The adsorption phenomenon can preliminarily account for the inhibiting effect of resins on hydrate formation. It provides a scientific understanding for the effect of resins on hydrate formation in water-in-oil emulsions, excluding the interference of wax and other components. It would be useful to an appropriate flow assurance strategy designing for the under-water multiphase pipelines.

scholarly journals Improved Formation Kinetics of Carbon Dioxide Hydrate in Brine Induced by Sodium Dodecyl Sulfate

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2094
Author(s):  
Lu Liu ◽  
Yuanxin Yao ◽  
Xuebing Zhou ◽  
Yanan Zhang ◽  
Deqing Liang
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Induction Time ◽  
Conversion Rate ◽  
High Efficiency ◽  
Low Cost ◽  
Formation Rate ◽  
Sodium Dodecyl ◽  
Hydrate Formation ◽  
Sem Images ◽  
Dodecyl Sulfate

Due to high efficiency and low cost, hydrate-based desalination is investigated as a pretreatment method for seawater desalination. To improve the formation rate of hydrates, the effect of sodium dodecyl sulfate (SDS) on CO2 hydrate formation from a 3.5 wt.% NaCl solution was measured at 275 K and 3 MPa. X-ray diffraction (XRD) and cryo-scanning electron microscopy (cryo-SEM) were used to measure the crystal structure and micromorphology of the formed hydrates. The results showed that the induction time of CO2 hydrate formation reduced from 32 to 2 min when SDS concentration increased from 0.01 to 0.05%, the hydrate conversion rate increased from 12.06 to 23.32%, and the remaining NaCl concentration increased from 3.997 to 4.515 wt.%. However, as the SDS concentration surpassed 0.05 wt.%, the induction time increased accompanied by a decrease in the hydrate conversion rate. XRD showed that the CO2 hydrate was a structure I hydrate, and SDS had no influence on the hydrate structure. However, cryo-SEM images revealed that SDS promoted the formation of hydrates by increasing the specific surface area of the formed hydrates and folds; rods and clusters could be found on the surface of the CO2 hydrate. Thus, the best SDS concentration for promoting CO2 hydrate formation was approximately 0.05 wt.%; desalination was most efficient at this concentration.

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