Development of a biogas production and purification process using promoted gas hydrate formation — A feasibility study

Filarsky, Florian; Schmuck, Carsten; Schultz, H. J.

doi:10.1016/j.cherd.2018.04.009

Cited by 28 publications

(11 citation statements)

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“…Although in some areas of gas hydrate research, necessary fundamentals and mechanisms are still being successfully researched and published [23,24], nowadays, the focus is shifting towards technical hydrate application possibilities in the areas of gas storage and transport [25,26], gas separation [27,28], desalination [29,30], phase transfer materials [31,32] and even electricity supply [33].…”

Section: Introductionmentioning

confidence: 99%

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

Filarsky¹,

Wieser²,

Schultz³

2021

Molecules

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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.

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Section: Introductionmentioning

confidence: 99%

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

Filarsky¹,

Wieser²,

Schultz³

2021

Molecules

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“…A low-cost approach for the transportation of methane and sour gases (like CO 2 ) as solid hydrates would be an economically viable route. Thus, natural gas containing a high CO 2 concentration was studied from two prospective applications: separation of CO 2 from natural gas and biogas 14,15 and storage and transportation of high CO 2containing natural gas. 16 There are two major challenges to be faced by any gas hydrates formation process: 5 (i) Hydrate nucleation is a stochastic phenomenon and (ii) sluggish hydrate formation kinetics due to mass transfer limitation of multiphase systems.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

CO₂–CH₄ Hydrate Formation Using l-Tryptophan and Cyclooctane Employing a Conventional Stirred Tank Reactor

et al. 2021

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The present study investigates the effect of L-tryptophan on the kinetics of CO 2 −CH 4 (50:50 mol %) hydrate formation in a gas−water system by employing a stirred tank reactor. The concentration of tryptophan was varied in the range from 0.01 to 1 wt %, and its impact on the kinetics of CO 2 −CH 4 (50:50 mol %) hydrate formation was investigated at 5.0 MPa and 274.15 K. The time required for 90% completion of hydrate formation was reduced from 100.89 ± 11.03 min to 19.11 ± 1.68 min when the tryptophan concentration increased from 0.01 wt % to 1 wt %. The gas uptake achieved using 1 wt % tryptophan (0.1045 ± 0.0023 mol per mol) was approximately 5 times higher than that of 0.01 wt % tryptophan (0.0227 ± 0.0017 mol per mol). Thus, the addition of tryptophan resulted in rapid and extensive hydrate formation. The hydrate formation kinetics were assessed based on gas uptake of hydrate growth, t 90 time, and rate of gas uptake of hydrate growth, and 1 wt % tryptophan concentration was found to be the optimum concentration in the gas−water system. Further, experiments were performed to understand the kinetics of CO 2 − CH 4 (50:50 mol %) hydrate formation by inducing sH hydrate using 2.86 mol % cyclooctane (Cyclo-O), a thermodynamic promoter in a gas−liquid hydrocarbon (LHC)−water system at 5.0 MPa and 274.15 K. After that, the synergistic effect using Cyclo-O with 0.1 and 1 wt % tryptophan separately was evaluated. Application of 1 wt % tryptophan helps in crossing the resistance of immiscible Cyclo-O phase, resulting in higher gas uptake of hydrate growth compared to 0.1 wt % tryptophan with Cyclo-O. Visual macroscopic morphology observations coupled with kinetic experiments were also performed for gas−water and gas−LHC−water systems. Visual observations showed that the hydrate could form and grow below the gas−liquid interface for experiments conducted with (i) pure water, (ii) water and 0.01 wt % tryptophan, and (iii) water and 2.86 mol % Cyclo-O, whereas the experiments with tryptophan concentration > 0.01 wt % in the gas−water system and with tryptophan concentration ≥ 0.1 wt % with Cyclo-O in gas− LHC−water resulted in hydrate formation above the gas−liquid interface. Thus, the capability of tryptophan in forming hydrates above the interface was attributed to different hydrate morphology; an altered morphology resulted in a capillary effect through which the mass transfer of hydrate-forming components improved.

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“…Previous gas hydrate research has focused on the exploitation of natural gas hydrate reservoirs − and on the field of flow assurance. Here, unintentional gas hydrate formation in pipelines results in unsafe operating conditions, defects, and annual economic costs in the range of millions of dollars. − Nowadays, new application possibilities, where targeted formation is favored, have been introduced in the fields of gas storage and transport, , carbon dioxide sequestration, , gas separation, − desalination, , biotechnology, , food engineering, , and phase-change materials. , Thus, the use of gas hydrate storage seems to be a very promising approach, as gas hydrate storage is capable of storing approximately 170 N m 3 /m 3 of natural gas but at more moderate conditions compared to compressed or liquefied natural gas while providing low safety risks toward explosions …”

Section: Introductionmentioning

confidence: 99%

Impact of Modified Silica Beads on Methane Hydrate Formation in a Fixed-Bed Reactor

Filarsky

Schmuck

Schultz

2019

Ind. Eng. Chem. Res.

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The work deals with the optimization of methane hydrate storage in fixed-bed reactor systems made up of modified silica beads. Under transient conditions, rapid hydrate growth is achieved at 4 °C. Glass beads are modified via silanization and treated with peroxymonosulfuric acid. It is proven that the fixed-bed surface properties significantly determine the gas hydrate growth and final gas uptake and therefore determine the successful technical design of the system. The capillary pressure is calculated in each bed configuration and is set in relation to the overall gas uptake. A negative capillary pressure leads to a holdback of water in the fixed-bed system. A high water-to-hydrate conversion is obtained for an untreated fixed bed with a positive capillary pressure. In the presence of SDS, the capillary effects are negated by the kinetic promotion effects. An inhibiting behavior is observed when using hydrophilic beads after treatment with peroxymonosulfuric acid.

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Development of a biogas production and purification process using promoted gas hydrate formation — A feasibility study

Cited by 28 publications

References 50 publications

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

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

CO₂–CH₄ Hydrate Formation Using l-Tryptophan and Cyclooctane Employing a Conventional Stirred Tank Reactor

Impact of Modified Silica Beads on Methane Hydrate Formation in a Fixed-Bed Reactor

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Development of a biogas production and purification process using promoted gas hydrate formation — A feasibility study

Cited by 28 publications

References 50 publications

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

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

CO2–CH4 Hydrate Formation Using l-Tryptophan and Cyclooctane Employing a Conventional Stirred Tank Reactor

Impact of Modified Silica Beads on Methane Hydrate Formation in a Fixed-Bed Reactor

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CO₂–CH₄ Hydrate Formation Using l-Tryptophan and Cyclooctane Employing a Conventional Stirred Tank Reactor