scholarly journals Influence of asphaltene polarity on hydrate behaviors in water-in-oil emulsions

2020 ◽  
Author(s):  
Dongxu Zhang ◽  
Qiyu Huang ◽  
Wei Wang ◽  
Rongbin Li ◽  
Huiyuan Li ◽  
...  
Keyword(s):  
Growth Rate ◽  
Nucleation Rate ◽  
Induction Time ◽  
Hydrate Formation ◽  
Polar Fraction ◽  
Side Chain ◽  
Alkyl Side Chain ◽  
Asphaltene Fraction ◽  
Oil Emulsions ◽  
Self Aggregation

Asphaltene was fractionated into four subfractions with different polarities, and used to conduct the hydrate formation and dissociation experiments. It was observed that the more polar fraction could result in a higher tendency of self-aggregation and fewer asphaltenes adsorbing at the water-oil interface mainly due to the larger C/H ratio, higher aromaticity, and shorter length of the alkyl side chain. The nucleation rate decreased with the presence of asphaltenes, and the induction time increased with a reduction in asphaltene polarity in water-in-oil emulsions. The results showed that the formed amount of hydrates were reduced by the addition of asphaltenes. For the asphaltene containing emulsions, less hydrate was formed with the presence of a more polar asphaltene fraction. The presence of asphaltenes was also found to affect the growth rate of hydrate, which varies with the polarity. Meanwhile, all four asphaltene fractions were found to promote the dissociation of hydrate.

Research Progress on the Driving Force of Gas Hydrate Formation

2012 ◽  
Vol 616-618 ◽  
pp. 902-906 ◽  
Author(s):  
Chun Long Wang ◽  
Xue Min Zhang ◽  
Jin Ping Li ◽  
Lin Jun Wang ◽  
Liang Jiao
Keyword(s):  
Growth Rate ◽  
Gas Hydrate ◽  
Induction Time ◽  
Driving Force ◽  
Hydrate Formation ◽  
Research Direction ◽  
Research Progress ◽  
Force Model ◽  
Hydration Reaction ◽  
Gas Hydrate Formation

Predicting the driving force accurately is the key process to hydrate nucleating and growing of hydration reaction. The nucleating and growing process of hydrate is relevant to temperature, pressure and component of reactant, and the property of reaction tank and intermiscibility of reactant have notable effect on the formation process of hydrate with its nucleating position, the induction time, growth rate and hydration rate. However, the present driving force model of hydrate cannot predict nucleating area, induction time, growth rate and the reaction limit, and also can't explain the influence of some factors such as cooling rate, temperature disturbance and inlet way on the hydration reaction, it is uncertain of the process to gas hydrate nucleation. We introduced some driving force models, analyzed their merits and demerits, and looked into the distance of research direction to driving force in the future.

Induction Time of Hydrate Formation in Water-in-Oil Emulsions

2017 ◽  
Vol 56 (29) ◽  
pp. 8330-8339 ◽  
Author(s):  
Haimin Zheng ◽  
Qiyu Huang ◽  
Wei Wang ◽  
Zhen Long ◽  
Peter G. Kusalik
Keyword(s):  
Induction Time ◽  
Hydrate Formation ◽  
Oil Emulsions

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 INFLUENCE OF THE TIME STORAGE OF ICE POWDER ON KINETICS OF FORMATION AND GROWTH OF FREON-12 GAS HYDRATE

2018 ◽  
pp. 77-83
Author(s):  
M. Sh. Madygulov ◽  
A. G. Zavodovsky ◽  
V. P. Shchipanov
Keyword(s):  
Growth Rate ◽  
Gas Hydrate ◽  
Induction Time ◽  
Storage Time ◽  
Hydrate Formation ◽  
Induction Effect ◽  
Long Term Storage ◽  
Process Formation ◽  
Modified Ice ◽  
Ice Powder

The article explores the influence a storage time on the samples of pure ice powder and mod-ified ice powder with polyvinylpyrrolidone on process formation and growth of the gas hydrate by used P-V-T measurements. It has been established that increased storage time of the pure ice powder leads to a decrease the rate of growth of gas hydrate. Fresh modified ice powder has induction time of hydrate formation which increased in a polyvinylpyrrolidone concentration. At long-term storage of modified ice powder with a polyvinylpyrrolidone concentration less 0,3 % the induction time don’t registrate and growth rate of gas hydrate likes zero. In the samples of modified ice powder with a polyvinylpyrrolidone concentration more 0,75 % after 10 days a storage were retained growth rate of gas hydrate likes fresh modified ice powder. There is no induction effect.

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 Pectin as an Extraordinary Natural Kinetic Hydrate Inhibitor

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Shurui Xu ◽  
Shuanshi Fan ◽  
Songtian Fang ◽  
Xuemei Lang ◽  
Yanhong Wang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Induction Time ◽  
Methane Hydrate ◽  
Hydrate Formation ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Inhibition Activity ◽  
Hydrate Crystal ◽  
Crystal Growth Inhibition

Abstract Pectin as a novel natural kinetic hydrate inhibitor, expected to be eco-friendly and sufficiently biodegradable, was studied in this paper. The novel crystal growth inhibition (CGI) and standard induction time methods were used to evaluate its effect as hydrate inhibitor. It could successfully inhibit methane hydrate formation at subcooling temperature up to 12.5 °C and dramatically slowed the hydrate crystal growth. The dosage of pectin decreased by 66% and effective time extended 10 times than typical kinetic inhibitor. Besides, its maximum growth rate was no more than 2.0%/h, which was far less than 5.5%/h of growth rate for PVCap at the same dosage. The most prominent feature was that it totally inhibited methane hydrate crystal rapid growth when hydrate crystalline occurred. Moreover, in terms of typical natural inhibitors, the inhibition activity of pectin increased 10.0-fold in induction time and 2.5-fold in subcooling temperature. The extraordinary inhibition activity is closely related to its hydrogen bonding interaction with water molecules and the hydrophilic structure. Finally, the biodegradability and economical efficiency of pectin were also taken into consideration. The results showed the biodegradability improved 75.0% and the cost reduced by more than 73.3% compared to typical commercial kinetic inhibitors.

Kinetic effect of single MgCl2 and NaCl aqueous solutions on ethane hydrate formation

2015 ◽  
Vol 93 (8) ◽  
pp. 891-896 ◽  
Author(s):  
Zhen Long ◽  
Deqing Liang ◽  
Dongliang Li
Keyword(s):  
Growth Rate ◽  
Induction Time ◽  
Storage Capacity ◽  
Pure Water ◽  
Hydrate Formation ◽  
Initial Pressure ◽  
Solution Concentration ◽  
Diffusion Reaction ◽  
Gas Consumption ◽  
And Storage

Experimental data on the kinetics of C2H6 hydrate formation in the presence of pure water and two aqueous single solutions, MgCl2 and NaCl, are presented in this study. The measurements of experimental hydrate formation process were performed in a high pressure reactor at 276.15 K, at initial pressure range of 2.0–2.4 MPa, and solution concentration range of 2.34–10 wt%. The effect of solution concentration and initial pressure on the induction time, gas consumption, conversion, and storage capacity and growth rate was examined. It was observed that with the increase of the solution concentration, the induction time increased, while the storage capacity and the number of moles of C2H6 consumed decreased. A diffusion-reaction kinetics model was employed to predict the hydrate growth rate at the beginning of hydrate formation. The results showed that the addition of MgCl2 and NaCl decreased the apparent rate constant, and MgCl2 had a greater effect than NaCl in inhibiting the hydrate growth.

Precipitation Kinetics of the Titanium Isopropoxide Hydrolysis Reaction

1986 ◽  
Vol 73 ◽  
Author(s):  
R. W. Hartel ◽  
K. A. Berglund
Keyword(s):  
Growth Rate ◽  
Nucleation Rate ◽  
Induction Time ◽  
Particle Production ◽  
Inverse Function ◽  
Titanium Isopropoxide ◽  
Correlation Spectroscopy ◽  
Hydrolysis Reaction ◽  
Average Growth ◽  
Absorbance Peak

ABSTRACTThe precipitation product of the titanium isopropoxide (TiPT) hydrolysis reaction was followed using photon correlation spectroscopy. This technique followed the mean size of the precipitate as the reaction progressed, as well as giving an indication of the number of particles being produced. From this analysis, the induction time for the onset of nucleation, nucleation rate (or the rate of particle production) and mean growth rate were correlated with reactant concentrations. In the concentration ranges studied, it was found that the induction time was a very strong inverse function of the reactant concentrations. Both nucleation rate and average growth rate were found to increase very rapidly as reactant concentration increased, with the TiPT concentration being more important. This reaction was also followed using absorbance spectrophotometry in the 500 to 320 nm range. After mixing of the reactants, an absorbance peak was seen between 330 and 335 nm, depending on the conditions. This peak increased slowly during the induction period and then increased rapidly after the onset of nucleation due to the increasing turbidity.

An isomerized alkyl side chain enables efficient nonfullerene organic photovoltaics with good tolerance to pre/post-treatments

2021 ◽  
Vol 5 (7) ◽  
pp. 3050-3060 ◽  
Author(s):  
Chenyu Han ◽  
Huanxiang Jiang ◽  
Pengchao Wang ◽  
Lu Yu ◽  
Jianxiao Wang ◽  
...  
Keyword(s):  
Organic Photovoltaics ◽  
Side Chain ◽  
Alkyl Side Chain ◽  
Good Tolerance

An alkyl isomerization strategy is reported to finely modulate the crystallinity of nonfullerene acceptors as well as their photovoltaic responses to post-treatments.

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