New combination of thermodynamic and kinetic promoters to enhance carbon dioxide hydrate formation under static conditions

Nesterov, A. N.; Reshetnikov, A. M.

doi:10.1016/j.cej.2019.122165

Cited by 37 publications

(24 citation statements)

References 39 publications

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“…Therefore, from a financial perspective, it is necessary to study methods that can form hydrates under moderate operating conditions. In the existing literature, there are many studies on the formation of hydrate phases by using accelerators under appropriate circumstances, some of which also help to accelerate the hydrate formation process. − …”

Section: Introductionmentioning

confidence: 99%

Capturing Carbon Dioxide on the Wet SBA-15 Mesoporous Molecular Sieves with Different Surfactants

et al. 2020

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SBA-15 mesoporous molecular sieves were used as the adsorption medium to capture carbon dioxide by the gas hydrate method. First, it is confirmed that the synthesized SBA-15 material has a uniform pore size with the 77 K nitrogen adsorption− desorption isotherms and transmission electron microscopy analyses. Second, the effects of the capture of carbon dioxide on the SBA-15 material by adding different amounts of water were investigated. Each adsorption isotherm of the SBA-15 material with different presorbed water has a jump point, and the adsorption capacity of CO 2 increased with the increase of the water−sample ratio (R w , the mass ratio of the preadsorbed water and the dry SBA-15 material). At 2.5 MPa, the adsorption capacity of R w = 2.0 is 20.14 mmol/g and that of the dry material is 3.86 mmol/g. The optimal water−sample ratio was determined to be 2.0. The formation of carbon dioxide hydrate of the jump point on the wet SBA-15 is verified by the enthalpy of capturing carbon dioxide. Finally, the effects on carbon dioxide hydrate formation at the wet SBA-15 material with different surfactants [SDS, sodium dodecyl benzene sulfonate (SDBS), and polysorbate 80 (Tween 80)] were investigated. The results show that the promoting effects of different types of promoters increase first and then decrease with increasing concentration. The optimal concentrations of SDS, SDBS, and Tween 80 are 1000, 1500, and 1000 mg/L, respectively. The wet SBA-15 with 1500 mg/L SDBS has the best promotion effect among the three surface surfactants.

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Section: Introductionmentioning

confidence: 99%

Capturing Carbon Dioxide on the Wet SBA-15 Mesoporous Molecular Sieves with Different Surfactants

et al. 2020

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“…In the presence of NaCl, the hydrate structures with less stability were easier to be destroyed, and sII hydrate was more suitable for stable hydrate forming system. Therefore, the decrease in total CO2 consumption at the initial pressure of 3.0 MPa was not induced by the structural change during hydrate formation, but the competitive occupation of 5 12 6 4 cages between CP and CO2 molecules [34,[37][38][39].…”

Section: Effect Of Initial Pressurementioning

confidence: 95%

“…4a, the Bragg peaks of sII hydrate and hexagonal ice could be clearly seen and no other types of hydrate structures were observed from the samples. It was reported that pure CO2 hydrate could be sI hydrate or the coexistence of sI and sII hydrates under moderate hydrate forming conditions [34,35]. Since the CP mass fraction used for initial pressure tests was 0.2, which was generally in accord with the CP mass fraction in typical CP hydrate, the amount of CP molecules was enough to guarantee all the free water molecules to the host lattice of sII hydrate.…”

Section: Effect Of Initial Pressurementioning

confidence: 96%

“…Since the CP mass fraction used for initial pressure tests was 0.2, which was generally in accord with the CP mass fraction in typical CP hydrate, the amount of CP molecules was enough to guarantee all the free water molecules to the host lattice of sII hydrate. On the other hand, CP molecules were too big to occupy the cages in sI hydrate and the mixed CP-CO 2 hydrate was more thermodynamically stable than pure CO 2 hydrate [15,34,36]. In the presence of NaCl, the hydrate structures with less stability were easier to be destroyed, and sII hydrate was more suitable for stable hydrate forming system.…”

Section: Effect Of Initial Pressurementioning

confidence: 99%

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Formation Kinetics of the Mixed Cyclopentane—Carbon Dioxide Hydrates in Aqueous Sodium Chloride Solutions

et al. 2020

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Hydrate formation from cyclopentane (CP) and carbon dioxide was measured at 281 K by powder X-ray diffraction (PXRD) and macroscopic methods. The effect of initial pressure and CP mass fraction in liquid phase was analyzed. The results showed that hydrate formation was assumed to start with the nucleation of the mixed CP-CO2 hydrate with small fraction of CO2 followed by a large continuous CO2 adsorption. Initial pressure was found to have a positive correlation with the total CO2 consumptions when the initial pressure was below 2.5 MPa. However, the total CO2 consumptions dropped by over a half as the initial pressure was 3.0 MPa. PXRD revealed that all the hydrate samples formed at different initial pressures were structure II. The CO2 consumptions were assumed to be inhibited by the competitive occupation of 51264 cages between CP and CO2 molecules when the initial pressure was above 2.5 MPa. The CO2 consumptions were also found to be reduced as the CP mass fraction was above 0.25. An excess of CP molecules was not assumed to strengthen the formation of the mixed CP-CO2 hydrates at the initial stage, but increased the thickness of liquid CP film at aqueous brine and hydrate particles, which increased the diffusion resistance of CO2 molecules. Therefore, the suitable initial pressure and the CP mass fraction for the mixed CP-CO2 hydrate formation should be around 2.5 MPa and 0.2, respectively.

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“…Promoters include kinetic promoters − and thermodynamic promoters. − Thermodynamic promoters usually improve the equilibrium conditions of hydrate formation by filling hydrate cages and increase the driving force of hydrate formation. Delahaye et al studied the effect of tetrahydrofuran (THF) with a mass concentration of 3.98–15.00 wt % on the equilibrium conditions of CO 2 hydrate.…”

Section: Introductionmentioning

confidence: 99%

Effect of HFE254 or Cyclopentanone on Phase Equilibrium Dissociation Conditions for Carbon Dioxide Hydrate

Song

Sun

et al. 2021

J. Chem. Eng. Data

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Hydrate equilibrium conditions of the CO2 + HFE254 or cyclopentanone + water system are determined by the isometric method. The presence of cyclopentanone promotes CO2 hydrate formation, while HFE254 does not affect the equilibrium pressure of CO2 hydrate. The hydrate dissociation temperature of the CO2 + cyclopentanone system increases as the pressure increases. However, the hydrate equilibrium temperature gradually decreases when pressure is above 3.2 MPa and a mixed hydrate of structure I and structure II forms. It can be seen that cyclopentanone is a thermodynamic accelerator that can promote the formation of CO2 hydrate.

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New combination of thermodynamic and kinetic promoters to enhance carbon dioxide hydrate formation under static conditions

Cited by 37 publications

References 39 publications

Capturing Carbon Dioxide on the Wet SBA-15 Mesoporous Molecular Sieves with Different Surfactants

Capturing Carbon Dioxide on the Wet SBA-15 Mesoporous Molecular Sieves with Different Surfactants

Formation Kinetics of the Mixed Cyclopentane—Carbon Dioxide Hydrates in Aqueous Sodium Chloride Solutions

Effect of HFE254 or Cyclopentanone on Phase Equilibrium Dissociation Conditions for Carbon Dioxide Hydrate

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