Dissociation Conditions and Raman Spectra of CO2 + SO2 and CO2 + H2S Hydrates

Chen, Litao; Lu, Hailong; Ripmeester, John A.

doi:10.1021/acs.iecr.5b00350

Cited by 19 publications

(7 citation statements)

References 25 publications

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“…An example is given in Figure 3 F I G U R E 1 Calculated pressure temperature hydrate stability limits for CH4 (dash dot), CO2 (solid), CO2 mixture with 1 mole % H2S (dash). * are experimental data for pure CH4 from Tumba et al 29 ; o are experimental data for pure CO2 from Herri et al 30 ; x are experimental data for CO2 mixture with 1 mole % H2S from Chen et al 31 F I G U R E 2 Calculated free energies for pure CH 4 hydrate (dash dot), pure CO 2 hydrate (solid), and a mixture with 1 mole % H 2 S in CO 2 (dash)…”

Section: Homogeneous Hydrate Formationmentioning

confidence: 99%

Thermodynamics of hydrate systems using a uniform reference state

Kvamme

Zhao

Li³

et al. 2021

Asia-Pacific J Chem Eng

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Formation of natural gas hydrates during processing and transport of natural gas has historically been a significant motivator for hydrate research. The last three decades have also seen the focus increasingly shifting towards CH 4 hydrates as a potential energy source. And in the context of climate changes, the impact of hydrate-related processes is coming more to the forefront as well. This interest is not only limited to leakage fluxes of CH 4 from natural gas hydrates but also flux from conventional hydrocarbon systems entering the seafloor at temperature and pressure allowing for hydrate formation. Alternative

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Section: Homogeneous Hydrate Formationmentioning

confidence: 99%

Thermodynamics of hydrate systems using a uniform reference state

Kvamme

Zhao

Li³

et al. 2021

Asia-Pacific J Chem Eng

View full text Add to dashboard Cite

show abstract

“…Figure3. Estimated and experimental hydrate equilibrium curve for a system of 90% CO 2 and 10 mol % H 2 S. Solid line, our estimate; asterisk, experimental data from Chen et al29 …”

mentioning

confidence: 93%

Effect of H₂S Content on Thermodynamic Stability of Hydrate Formed from CO₂/N₂ Mixtures

et al. 2017

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Huge resources of energy in the form of natural gas hydrates are widely distributed worldwide in permafrost sediments as well as in offshore sediments. A novel technology for combined production of these resources and safe long-term storage of carbon dioxide is based on the injection of carbon dioxide injection into in situ methane hydrate-filled sediments. This will lead to an exchange of the in situ methane hydrate over to carbon dioxide-dominated hydrate and a simultaneous release of methane gas. Recent theoretical and experimental results indicate that the conversion from natural gas hydrate to carbon dioxide hydrate and mixed carbon dioxide/methane hydrate follows two primary mechanisms. Direct solid state transformation is possible, but very slow. The dominating mechanism involves formation of a new hydrate from injected carbon dioxide and associated dissociation of the in situ natural gas hydrate by the released heat. Nitrogen is frequently added in order to increase gas permeability and to reduce blocking due to new hydrate formation, and will as such also reduce the relative impact of the fast mechanism on the conversion rates. In addition to carbon dioxide also other sour gases, such as hydrogen sulfide, may follow the carbon dioxide from the sour gas removal process. Hydrogen sulfide is a very aggressive hydrate former. It is abundant in various amounts in thermogenic hydrocarbon systems. In this work we investigate the sensitivity of possible additions of hydrogen sulfide in carbon dioxide/nitrogen mixtures, and how the ability to form new hydrate changes with the additions of hydrogen sulfide. This analysis is applied to four case studies: (1) Bjørnøya gas hydrate basin, (2) the Nankai field in Japan, (3) the Hikurangi Margin in New Zealand, and (4) a gas hydrate basin in South-West Taiwan. The hydrate saturations found in these fields vary over a range from 25−80%. Pressures range from 4−22.6 MPa and temperatures from 275.15−292.77 K. For all these ranges of conditions, even 1% H 2 S will substantially increase the ability to form new hydrate from an injected CO 2 /N 2 mixture containing H 2 S. Except for the most shallow of the reservoirs (Bjørnøya) 1% H 2 S results in formation of a new hydrate for all concentrations of CO 2 in N 2 above 1%. Implementation of results from this work into a reservoir simulator is a natural follow-up which can shed light on the macroscopic consequences in term of possible local blocking of the flow due to content of H 2 S. The mass transport, mass balances, and energy balances in a reservoir simulator are also needed for a more detailed evaluation on how the content of H 2 S and CO 2 changes over time and location in the reservoir due to various processes in addition to hydrate formation. H 2 S and CO 2 dissolves significantly in pore water, and also adsorbs well on various sediment minerals.

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“…On the other hand, the PVTSim calculations are favourable for measurements with NaCl solutions containing MeOH. The study of Chen et al (2015) showed that Multiflash TM is more accurate when compared with CSMGem for hydrate modelling; hence its usage in this study. Dehaghani (2017) applied 3 equations of state to model hydrate equilibria conditions of a real natural gas sample.…”

Section: Introductionmentioning

confidence: 99%