Desalination using gas hydrates

The research article 'Desalination using gas hydrates: The role of crystal nucleation, growth and separation' has been published in Elsevier journal Desalination.

Abstract

Seawater desalination using gas hydrates is a potential technique for water treatment. However, limited understanding and control in prior studies on nucleation, growth, and separation have prevented adequate commercialization of hydrate desalination processes.

Hydrate formation and ‘memory’ experiments of C1 + C2 (74.7/25.3 mol%) gaseous mixtures were carried out using a Jerguson high pressure visual cell. The C1-C2 hydrate formation results indicate that formation onset times were three times longer in salt water compared to fresh water. Furthermore, it was observed that induction times decrease with increasing subcooling, and hydrate memory effects are reduced with increasing replenish time, i.e. the time lapse between dissociation and subsequent gas depressurization.

A high-pressure desalination apparatus was also designed and constructed to produce the overflow of hydrates in the inner annulus of a gas bubble column placed inside a dissociation reactor. The working principle for this system is that the overflowing hydrates enter the outer annulus and are then dissociated. The salt removal efficiency was determined by measuring the conductivity of the recovered water.

Experiments to assess the efficiency of the process were performed to determine how the salinity in the recovered water depends on different initial salt contents and subcooling for hydrate formation.

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