CO2 hydrate heat cycle using a carbon fiber supported catalyst for gas hydrate formation processes

Kawasaki, Toshiyuki; Obara, Shin’ya

doi:10.1016/j.apenergy.2020.115125

Cited by 18 publications

(8 citation statements)

References 18 publications

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Section: Introductionmentioning

confidence: 99%

“…In contrast, in the chemical method, the formation of hydrates is enhanced by adding accelerators, which allow the use of milder reaction conditions and increase the amount of dissolved gas. − Concerning energy consumption and cost, physical methods are less favorable than chemical methods, so chemical methods have proven to be popular. Common accelerators include thermodynamic accelerators, kinetic accelerators, nanofluids, ionic accelerators, biosurfactants, and others. , Among them, surfactants and kinetic accelerators have attracted the most attention because they show the best enhancement of hydrate formation. − …”

Section: Introductionmentioning

confidence: 99%

“…Common accelerators include thermodynamic accelerators, 17 kinetic accelerators, 18 nanofluids, 19 ionic accelerators, 20 biosurfactants, and others. 21,22 Among them, surfactants and kinetic accelerators have attracted the most attention because they show the best enhancement of hydrate formation. 23−25 For example, Ye et al 26 found that the addition of tetra-nbutylammonium bromide (TBAB) in mass fractions of 0.1 and 0.05 accelerates the rate of formation of carbon dioxide hydrates, and the addition of 0.05 wt % TBAB was optimal.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Composite Accelerators on the Formation of Carbon Dioxide Hydrates

et al. 2022

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To improve the rate of formation of carbon dioxide hydrates, tetra- n -butylammonium bromide (TBAB) was compounded with different concentrations of sodium dodecyl sulfate (SDS) and nanographite, and the effects of these mixtures on carbon dioxide hydrate formation were studied. The addition of TBAB alone, as well as mixtures of TBAB and SDS or nanographite, shortened the induced nucleation time, and the induction times of the TBAB–2.5 g/L nanographite and TBAB–0.24 g/L SDS systems were the shortest and longest, respectively. Further, on mixing TBAB and SDS, the induced nucleation time first increased and then decreased with the increase in the SDS concentration. When TBAB and nanographite were mixed together, the induced nucleation time first decreased, then increased, and again decreased with the increase in the nanographite concentration. In addition, the hydrate formation rate and conversion were highest for the TBAB–0.48 g/L SDS system and lowest for the TBAB–0.06 g/L SDS system; in the first 35 min, from the end of gas charging, the TBAB–10 g/L nanographite and TBAB–5 g/L nanographite systems yielded the highest and lowest hydrate formation rates and conversions, respectively. For the composite systems, obvious effects were observed in the initial stages of reaction, but the effects varied over the course of the reaction. Overall, the use of different accelerators resulted in little differences in the total production, conversion, and formation rate of carbon dioxide hydrates over the course of the reaction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Composite Accelerators on the Formation of Carbon Dioxide Hydrates

et al. 2022

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“…Number of publications on different hydrate formers from 2019 to 2020 − based on search results from Google Scholar using keywords “refrigerant” + “hydrate” on 23 February 2021.…”

Section: Methodsmentioning

confidence: 99%

Conceptual Design of a Sustainable Hybrid Desalination Process Using Liquefied Natural Gas Cold Energy

Lee

Lim

et al. 2021

ACS Sustainable Chem. Eng.

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To counter growing shortages in water supply and the energy crisis, a sustainable hybrid desalination process using liquefied natural gas (LNG) cold energy is proposed in this study. The newly proposed dual-expander organic Rankine cycle-hydrate-based desalination (dual-expander ORC-HBD) process with a reverse osmosis (RO) system consists of two expanders to utilize LNG cold energy and pressure energy simultaneously and can cogenerate electricity and pure water. To analyze the feasibility of the proposed dual-expander ORC-HBD process, computational modeling was performed using liquid-phase and gas-phase hydrate formers (propane, R125A, R141B, and cyclopentane). Thereafter, optimization, energy, and sensitivity analyses were also conducted. The dual-expander ORC-HBD process using propane resulted in a negative product cost to yield a profit of up to 0.521 $/ton of pure water while producing 82.5 tons/h of pure water and electricity (25.4 kWh/ton of pure water). These profits could be further increased to 3.095 $/ton of pure water with free external heat. These values are superior to many RO technologies in terms of energy, exergy, and economics. Therefore, the dual-expander ORC-HBD process with the RO system has a strong potential for resolving the water shortage and electricity generation crises simultaneously.

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“…Physical methods mainly use bubbling, stirring, or spraying to induce physical disturbance to the gas and liquid system, thereby enlarging the gas−liquid contact area and enhancing the heat and mass transfer capacities. 4,10−13 Meanwhile, chemical methods primarily reduce the phase equilibrium conditions of the reaction through the addition of accelerators (thermodynamic, 14 kinetic, 15 nanofluid, 16 ionic, 17 biosurfactant, and other accelerators 18,19 ), which promote the formation of hydrates under elevated pressures and low temperatures or increase liquid surface tension. 20−22 Compared with physical methods, chemical methods offer the advantages of low energy consumption and low cost.…”

Section: ■ Introductionmentioning

confidence: 99%

Effects of the Presence of Promoters Sodium Dodecyl Sulfate, Nanographite, and Tetra-n-butylammonium Bromide on the Formation of CO₂ Hydrates

et al. 2022

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Carbon dioxide hydrates have attracted considerable attention because of their high gas storage capacity and low-cost carbon capture, but their low formation rate limits their application. Currently, the formation rate of hydrates is mainly improved via physical and chemical methods. Chemical methods promote hydrate formation through the addition of accelerators, which entail low cost and energy. To improve the formation rate of CO2 hydrates, 0.244 g/L sodium dodecyl sulfate (SDS), 0.288 g/L tetra-n-butylammonium bromide (TBAB), and 0.33 g/L nanographite were used, and the effects of different accelerator systems on CO2 hydrate formation were observed. The results show that the single and combined use of promoters SDS, TBAB, and nanographite can shorten the induced CO2 hydrate nucleation time. The combinations of nanographite–TBAB and SDS–TBAB shortened the induced nucleation time better than the single SDS, TBAB, and nanographite systems, while the single SDS and nanographite systems showed better promoting effect compared to the SDS–nanographite system. Thus, the combined accelerators do not necessarily promote the formation of hydrates. Among all accelerator systems, SDS–TBAB showed the shortest induced nucleation time, followed by the other three combinations. Among the single acceleration systems, TBAB showed the largest formation amount, formation rate, and conversion rate in the first 35 min from inflation stoppage. Meanwhile, among the compound systems, SDS–TBAB exhibited the best promoting effect. A comparison of all experiments shows that the accelerator significantly affects the formation amount, conversion, and formation rate of hydrates 35 min before the start of inflation; furthermore, a different effect is observed in the subsequent period. The total production, conversion, and saturation of CO2 hydrates in different accelerator systems show a minimal difference. By providing reference for the rapid formation of CO2 hydrates in a short time, this study promotes the industrial application of hydrate technology.

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CO2 hydrate heat cycle using a carbon fiber supported catalyst for gas hydrate formation processes

Cited by 18 publications

References 18 publications

Effects of Composite Accelerators on the Formation of Carbon Dioxide Hydrates

Effects of Composite Accelerators on the Formation of Carbon Dioxide Hydrates

Conceptual Design of a Sustainable Hybrid Desalination Process Using Liquefied Natural Gas Cold Energy

Effects of the Presence of Promoters Sodium Dodecyl Sulfate, Nanographite, and Tetra-n-butylammonium Bromide on the Formation of CO₂ Hydrates

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CO2 hydrate heat cycle using a carbon fiber supported catalyst for gas hydrate formation processes

Cited by 18 publications

References 18 publications

Effects of Composite Accelerators on the Formation of Carbon Dioxide Hydrates

Effects of Composite Accelerators on the Formation of Carbon Dioxide Hydrates

Conceptual Design of a Sustainable Hybrid Desalination Process Using Liquefied Natural Gas Cold Energy

Effects of the Presence of Promoters Sodium Dodecyl Sulfate, Nanographite, and Tetra-n-butylammonium Bromide on the Formation of CO2 Hydrates

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Effects of the Presence of Promoters Sodium Dodecyl Sulfate, Nanographite, and Tetra-n-butylammonium Bromide on the Formation of CO₂ Hydrates