Promotion of hydrate formation by multi‐walled carbon nanotubes in ultrasonic compounding system

Abstract

Multi‐walled carbon nanotubes (MWCNTs) are an excellent hydrate promoter, with their own Brownian motion of nanoparticles effectively shortening hydrate nucleation and accelerating hydrate formation. In this work, the properties of methane hydrate formation in a complex system of MWCNTs, sodium dodecyl sulphate (SDS) and NaCl were investigated. It was shown that the compounding system effectively enhanced the kinetics of methane hydrate formation, and the gas consumption of the reaction reached 0.38 MPa at 100 ppm MWCNTs, an increase of 865.8% compared to the pure water system, effectively promoting methane hydrate. In the complexed system, NaCl significantly enhanced the dispersion of MWCNTs, with 1000 ppm NaCl showing the best kinetic promotion effect. SDS not only increases the gas–liquid contact area through the wall attachment effect, but also enhances the dispersion of MWCNTs by adsorbing on the surface of carbon nanotubes and forming an electronic layer with NaCl. MWCNTs not only improve the mass transfer of the system through Brownian motion, but their large heat transfer coefficients can also effectively conduct the heat generated by the system. However, MWCNTs become agglomerated with increasing concentration, making the kinetic promotion effect weaker and the solution less stable, resulting in shorter shelf life. This study confirmed the effective promotion of hydrate formation by MWCNTs under the ultrasonic compounding system, and also provided a reference for related studies on the compounding of MWCNTs with NaCl.