Formation and Dissociation of CH4 and CO2 Hydrates in Presence of a Sediment Composed by Pure Quartz Mixed with Ti23 Particles.

Alberto Maria Gambelli,Andrea Di Schino,Federico Rossi,Giulia Stornelli

doi:10.3390/ma15041470

Alberto Maria Gambelli, Andrea Di Schino + Show 2 more

Open Access

https://doi.org/10.3390/ma15041470

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Journal: Materials	Publication Date: Feb 16, 2022
Citations: 4	License type: CC BY 4.0

Affiliation: University of Perugia, University of Rome Tor Vergata

Abstract

The present research deals with the formation and dissociation of methane and carbon dioxide hydrates in a confined environment (small—size reactor) and in presence of a porous sediment of pure quartz impregnated with Ti23 particles. This research is part of a wider study aimed at verifying the possibility to use metallic powders, produced via gas-atomization for applications in additive manufacturing, as additives during the production/dissociation of gas hydrates. The porous medium was used to ensure the presence of Ti23 particles in the whole volume and not only in the lowest portion of the internal volume. For both the guest compounds considered, two Ti23 concentrations were explored, respectively, 8.68 and 26.04 wt%. Under the thermodynamic point of view, the dissociation process well approximated the phase equilibrium (defined with values collected from literature) for both compounds. In addition, the amount of gas trapped into hydrates, evaluated as a function of the initial amount of gas inserted inside the reactor, did not show relevant changes. Conversely, the presence of Ti23 was found to reduce the induction time for both components, thus allowing to define it as a kinetic promoter for the process. Such tendency was found to increase with the concentration.

Highlights

Gas hydrates are ice-like crystalline compounds which naturally occur in presence of natural gas molecules, which play the role of “guest” and water molecules, capable of forming a solid lattice containing the guest molecules, and commonly defined as “hosts” [1]
Chemical inhibitors permit the shifting of the phase equilibrium curve of hydrates to higher pressures and/or lower temperatures [3]
The simple recovery of natural gas is almost exclusively carried out using chemical inhibitors; several applications may require the use of promoters [17,18], for instance the sea-water desalination via hydrate formation often needs of chemical promoter, to be economically feasible

Summary

Introduction

Gas hydrates are ice-like crystalline compounds which naturally occur in presence of natural gas molecules, which play the role of “guest” and water molecules, capable of forming a solid lattice containing the guest molecules, and commonly defined as “hosts” [1] Since their discovery, the research on natural gas hydrates (NGH) can be distinguished in three different phases [2]. Chemical inhibitors permit the shifting of the phase equilibrium curve of hydrates to higher pressures and/or lower temperatures [3] In this way, the local thermodynamic conditions are not suitable anymore for hydrates stability and their dissociation will inevitably occur [15,16]. The simple recovery of natural gas is almost exclusively carried out using chemical inhibitors; several applications may require the use of promoters [17,18], for instance the sea-water desalination via hydrate formation often needs of chemical promoter, to be economically feasible

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