scholarly journals Influence of N2 on Formation Conditions and Guest Distribution of Mixed CO2 + CH4 Gas Hydrates

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3336 ◽  
Author(s):  
Vladimir Belosludov ◽  
Yulia Bozhko ◽  
Oleg Subbotin ◽  
Rodion Belosludov ◽  
Ravil Zhdanov ◽  
...  
Keyword(s):  
Gas Phase ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Lattice Relaxation ◽  
Host Lattice ◽  
Clathrate Hydrate ◽  
Formation Pressure ◽  
Co2 Gas ◽  
Formation Conditions

In this contribution, a method based on a solid solution theory of clathrate hydrate for multiple cage occupancy, host lattice relaxation, and guest-guest interactions is presented to estimate hydrate formation conditions of binary and ternary gas mixtures. We performed molecular modeling of the structure, guest distribution, and hydrate formation conditions for the CO2 + CH4 and CO2 + CH4 + N2 gas hydrates. In all considered systems with and without N2, at high and medium content of CO2 in the gas phase, we found that CO2 was more favorable in occupying clathrate hydrate cavities than CH4 or N2. The addition of N2 to the gas phase increased the ratio concentration of CO2 in comparison with the concentration of CH4 in clathrate hydrates and made gas replacement more effective. The mole fraction of CO2 in the CO2 + CH4 + N2 gas hydrate rapidly increased with the growth of its content in the gas phase, and the formation pressure of the CO2 + CH4 + N2 gas hydrate rose in comparison to the formation pressure of the CO2 + CH4 gas hydrate. The obtained results agreed with the known experimental data for simple CH4 and CO2 gas hydrates and the mixed CO2 + CH4 gas hydrate.

scholarly journals Influence of Nitrogen on Structure, Guest Distribution and Hydrate Formation Conditions of the Mixed CO2–CH4 and CO2–CH4–N2 Gas Hydrates

2018 ◽  
Author(s):  
Vladimir R. Belosludov ◽  
Yulia Yu. Bozhko ◽  
Oleg S. Subbotin ◽  
Rodion V. Belosludov ◽  
Ravil К. Zhdanov ◽  
...  
Keyword(s):  
Gas Phase ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Lattice Relaxation ◽  
Host Lattice ◽  
Clathrate Hydrate ◽  
Formation Pressure ◽  
Co2 Gas ◽  
Formation Conditions

In this contribution, a method based on a solid solution theory of clathrate hydrate for multiple cage occupancy, host lattice relaxation and guest-guest interactions has been presented to estimate hydrate formation conditions of binary and ternary gas mixtures. We have performed molecular modeling of structure, guest distribution, and hydrate formation conditions for the CO2 + CH4, and CO2 + CH4 + N2 gas hydrates. In all considered systems with and without N2, at high and medium content of CO2 in the gas phase we have found that CO2 is more favorable to occupy clathrate hydrate cavities than CH4 or N2. Addition of N2 to the gas phase increases ratio concentration CO2 in compressing with concentration CH4 in clathrate hydrates and makes gas replacement more effective. The mole fractions of CO2 in CO2 + CH4 + N2 gas hydrate rapidly increases with the growth of its content in the gas phase. And the formation pressure of CO2 + CH4 + N2 gas hydrate rises in comparison with the formation pressure of CO2 + CH4 gas hydrate. Obtained results agree with the known experimental data for simple CH4, CO2 gas hydrates and mixed CO2 + CH4 gas hydrate.

Selective trapping of CO2 gas and cage occupancy in CO2–N2 and CO2–CO mixed gas hydrates

2018 ◽  
Vol 54 (34) ◽  
pp. 4290-4293 ◽  
Author(s):  
Claire Petuya ◽  
Françoise Damay ◽  
Sarah Desplanche ◽  
David Talaga ◽  
Arnaud Desmedt
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Gas Hydrates ◽  
Hydrate Formation ◽  
Gas Mixtures ◽  
Clathrate Hydrate ◽  
Mixed Gas ◽  
Co2 Gas ◽  
Carbon Dioxide Separation

New carbon dioxide separation and capture technology, thanks to clathrate hydrate formation from pressurized ice with (carbon monoxide and nitrogen containing) gas mixtures.

Hydrate Formation Conditions of Natural Gas with Different Content of Carbon Dioxide and Inhibitors Screening Studies

2013 ◽  
Vol 781-784 ◽  
pp. 141-146
Author(s):  
Ping Guo ◽  
Xiu Yue Shen ◽  
Jian Fen Du ◽  
Zhou Hua Wang
Keyword(s):  
Natural Gas ◽  
Ethylene Glycol ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Natural Gas Hydrate ◽  
Test Device ◽  
Co2 Gas ◽  
Pressure Region ◽  
Formation Conditions ◽  
Different Content

In order to study the formation conditions of CO2-gas hydrate and screen appropriate inhibitors, DBR hydrate test device was put into use .Under 0~15MPa and -10~38°C ,the production conditions of natural gas hydrate was measured when the content of CO2 in the system was 10%,30%,50%,70%,90% respectively .According to prior work ,methanol and ethylene glycol was selected to be the inhibitors .Different concentrations of inhibitors were taken into test to gain the generation conditions of the hydrate .The results of the expriment show that the generation temperature of hydrate increase along with the raise of CO2 content .As an inhibitor ,21.8% of the ethylene glycol could lower the generation temperature about 6°C while 43.6% of it could reduce by 7-10°C .By contrast ,16.5% of methanol could lower the generation temperature about 10-16°C in the low-pressure region ,while 34.6% of it could reduced the generation temperature in all pressure region .It can be drawn that Methanol shows its better character ,but toxicity .The effects of ethylene glycol were relatively poor ,however ,little pollution .Therefore ,supposing the well-developed clearance recovery technology ,methanol was recommended .

Thermodynamic Modelling of Gas Hydrate Formation in the Presence of Inhibitors and the Consideration of their Effect

2014 ◽  
Vol 14 (1) ◽  
pp. 45
Author(s):  
Peyman Sabzi ◽  
Saheb Noroozi
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Low Temperatures ◽  
Hydrate Formation ◽  
Transportation Systems ◽  
Flow Lines ◽  
Main Approach ◽  
Efficient Inhibitor ◽  
System A ◽  
Gas Hydrate Formation

Gas hydrates formation is considered as one the greatest obstacles in gas transportation systems. Problems related to gas hydrate formation is more severe when dealing with transportation at low temperatures of deep water. In order to avoid formation of Gas hydrates, different inhibitors are used. Methanol is one of the most common and economically efficient inhibitor. Adding methanol to the flow lines, changes the thermodynamic equilibrium situation of the system. In order to predict these changes in thermodynamic behavior of the system, a series of modelings are performed using Matlab software in this paper. The main approach in this modeling is on the basis of Van der Waals and Plateau's thermodynamic approach. The obtained results of a system containing water, Methane and Methanol showed that hydrate formation pressure increases due to the increase of inhibitor amount in constant temperature and this increase is more in higher temperatures. Furthermore, these results were in harmony with the available empirical data.Keywords: Gas hydrates, thermodynamic inhibitor, modelling, pipeline blockage

scholarly journals Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3615
Author(s):  
Florian Filarsky ◽  
Julian Wieser ◽  
Heyko Juergen Schultz
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Synthetic Natural Gas ◽  
Operation Conditions ◽  
Gas Hydrate Formation ◽  
Gas Conditioning ◽  
And Storage ◽  
Economic Considerations ◽  
High Storage

Gas hydrates show great potential with regard to various technical applications, such as gas conditioning, separation and storage. Hence, there has been an increased interest in applied gas hydrate research worldwide in recent years. This paper describes the development of an energetically promising, highly attractive rapid gas hydrate production process that enables the instantaneous conditioning and storage of gases in the form of solid hydrates, as an alternative to costly established processes, such as, for example, cryogenic demethanization. In the first step of the investigations, three different reactor concepts for rapid hydrate formation were evaluated. It could be shown that coupled spraying with stirring provided the fastest hydrate formation and highest gas uptakes in the hydrate phase. In the second step, extensive experimental series were executed, using various different gas compositions on the example of synthetic natural gas mixtures containing methane, ethane and propane. Methane is eliminated from the gas phase and stored in gas hydrates. The experiments were conducted under moderate conditions (8 bar(g), 9–14 °C), using tetrahydrofuran as a thermodynamic promoter in a stoichiometric concentration of 5.56 mole%. High storage capacities, formation rates and separation efficiencies were achieved at moderate operation conditions supported by rough economic considerations, successfully showing the feasibility of this innovative concept. An adapted McCabe-Thiele diagram was created to approximately determine the necessary theoretical separation stage numbers for high purity gas separation requirements.

scholarly journals Integrating Support Vector Regression with Genetic Algorithm for Hydrate Formation Condition Prediction

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 519
Author(s):  
Jie Cao ◽  
Shijie Zhu ◽  
Chao Li ◽  
Bing Han
Keyword(s):  
Genetic Algorithm ◽  
Natural Gas ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Support Vector ◽  
Gas Hydrate Formation ◽  
Svm Model ◽  
Data Points ◽  
Formation Conditions ◽  
Relative Molecular Weight

To predict the natural gas hydrate formation conditions quickly and accurately, a novel hybrid genetic algorithm–support vector machine (GA-SVM) model was developed. The input variables of the model are the relative molecular weight of the natural gas (M) and the hydrate formation pressure (P). The output variable is the hydrate formation temperature (T). Among 10 gas samples, 457 of 688 data points were used for training to identify the optimal support vector machine (SVM) model structure. The remaining 231 data points were used to evaluate the generalisation capability of the best trained SVM model. Comparisons with nine other models and analysis of the outlier detection revealed that the GA-SVM model had the smallest average absolute relative deviation (0.04%). Additionally, the proposed GA-SVM model had the smallest amount of outlier data and the best stability in predicting the gas hydrate formation conditions in the gas relative molecular weight range of 15.64–28.97 g/mol and the natural gas pressure range of 367.65–33,948.90 kPa. The present study provides a new approach for accurately predicting the gas hydrate formation conditions.

scholarly journals Investigation on Gas Hydrates Formation and Dissociation in Multiphase Gas Dominant Transmission Pipelines

2020 ◽  
Vol 10 (15) ◽  
pp. 5052 ◽  
Author(s):  
Sayani Jai Krishna Sahith ◽  
Srinivasa Rao Pedapati ◽  
Bhajan Lal
Keyword(s):  
Crude Oil ◽  
Phase Behavior ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Formation Rate ◽  
Water System ◽  
Hydrate Formation ◽  
Multiphase System ◽  
Gas Hydrate Formation ◽  
Water Cut

In this work, a gas hydrate formation and dissociation study was performed on two multiphase pipeline systems containing gasoline, CO2, water, and crude oil, CO2, water, in the pressure range of 2.5–3.5 MPa with fixed water cut as 15% using gas hydrate rocking cell equipment. The system has 10, 15 and 20 wt.% concentrations of gasoline and crude oil, respectively. From the obtained hydrate-liquid-vapor-equilibrium (HLVE) data, the phase diagrams for the system are constructed and analyzed to represent the phase behavior in the multiphase pipelines. Similarly, induction time and rate of gas hydrate formation studies were performed for gasoline, CO2, and water, and crude oil, CO2, water system. From the evaluation of phase behavior based on the HLVE curve, the multiphase system with gasoline exhibits an inhibition in gas hydrates formation, as the HLVE curve shifts towards the lower temperature and higher-pressure region. The multiphase system containing the crude oil system shows a promotion of gas hydrates formation, as the HLVE curve shifted towards the higher temperature and lower pressure. Similarly, the kinetics of hydrate formation of gas hydrates in the gasoline system is slow. At the same time, crude oil has a rapid gas hydrate formation rate.

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