Thermodynamic and Kinetic Promoters for Gas Hydrate Technological Applications

Abstract

In recent years, there has been growing interest in gas hydrates as technological applications, such as for energy (methane and hydrogen) storage and transportation, separation (gas and desalination), and carbon capture. However, there are several challenges that deter large-scale applications and commercialization of these hydrate-based technologies. One of the main challenges is the long induction time and slow growth of hydrate particles, which can increase the overall operating costs of these technologies. It has been reported that the addition of additives (known as hydrate promoters) can help improve the nucleation and growth rate of hydrates. In general, there are two types of hydrate promoters: thermodynamic hydrate promoters and kinetic hydrate promoters. Thermodynamic hydrate promoters shift the hydrate equilibrium curve to milder conditions (i.e., lower pressures and higher temperatures), while kinetic hydrate promoters reduce the induction time for hydrate formation and increase the growth rate. In this review, we provide a comprehensive review of the two types of hydrate promoters (thermodynamic and kinetic) and their effects on hydrate phase equilibria, induction time, and growth rate.

Minireview of Hydrate-Based CO2 Separation from a CO2/CH4 Gas Mixture: Progress and Outlook

“…Surfactant molecules contain hydrophobic and hydrophilic groups and can be characterized as cationic, anionic, and nonionic . The anionic surfactant performs better in improving the hydrate conversion rate compared to cationic and nonionic surfactants .…”

Nucleation Behavior of Single-Gas Hydrates in the Batch-type Stirred Reactor and Their Promotion Effect with Ultrafine Bubbles: A Mini Review and Perspectives

“…THPs are clathrate-forming molecules themselves at relatively moderate conditions. As summarized in Majid et al, THF − and hydrocarbons, such as cyclopentane , and propane, are in this category. Guest molecules that form structure-H clathrates , and semiclathrates are also THPs for hydrates with smaller guest gases (such as CH 4 ).…”

“…As summarized in Majid et al, THF − and hydrocarbons, such as cyclopentane , and propane, are in this category. Guest molecules that form structure-H clathrates , and semiclathrates are also THPs for hydrates with smaller guest gases (such as CH 4 ). For example, neohexane , can act as a THP for CH 4 hydrate, allowing it to form under more moderate conditions than that for pure CH 4 hydrate.…”

“…Solid additives can also exhibit this formationpromoting effect. Solid types include nanoparticles of metal and silica, 62,86,87 porous media such as zeolitic imidazolate framework, 62,80−85 carbon materials such as carbon nanotubes (CNT) and graphene. 88−93 Although these additives may be used alone, they are often used in combination with surfactants.…”

“…KHPs have been extensively studied since Karaaslan et al reported that the addition of surfactants promoted hydrate formation. ,, Typically, sodium dodecyl sulfate (SDS) and other surfactants are used, but amino acids, , starches, , and biosurfactants are also thought to have similar effects. These are thought to promote the crystal growth process, primarily by promoting the mass transport of gas into the water.…”