Experimental study of using CuO nanoparticles as a methane hydrate promoter

Synergistic effect of combination of surfactant and oxide powder on enhancement of gas hydrates nucleation

“…The reason may be either summation of the rates of hydrate nucleation connected with the presence of a surfactant and Al 2 О 3 powder in the system, or modification of the surface of Al 2 О 3 powder by surfactant molecules adsorbed on this surface; the joint action of these factors may also be a possible reason. Possible sorption of surfactants on the surface of particles added into the system, and the effect of these processes on nucleation is confirmed by the results reported in [55,57] . On the other hand, substantial excess of the oxide powder over the amount of surfactant in the system causes an increase in the induction period [55] , most probably due to surfactant transfer from solution into the adsorption layer and maybe due to agglomeration of the oxide particles with the surface modified by the adsorption layer.…”

“…It should be noted that this behavior could not be predicted unambiguously from the data available from literature. For example, in the studies of methane hydrate nucleation from the solutions containing CuO nanopowder and SDS [55,56] , any information about the own effect of CuO powder on hydrate formation was absent. In [46] , the induction period was close to 1 min in all the cases, while the additives only caused an increase in the degree of water transformation into hydrate.…”

Effect of hydrophilic silica nanoparticles on hydrate formation: Insight from the experimental study

“…The reason to choose 5.0 °C as the hydrate formation temperature is that the average temperature of drilling fluid in deep water drilling is close to this value [32] . In order to compare to other results and provide a reference for further research [21,23,26] , 5.0 MPa is chosen as the experimental pressure. When the system temperature was stable at 5.0 °C, the valve of gas inlet was opened to supply http://engine.scichina.com/doi/10.1016/j.jechem.2018.02.021 methane from the buffer vessel to the autoclave until its pressure increased to ∼5.0 MPa (The phase-equilibrium pressure P eq corresponding to the temperature 5.0 °C is predicted by CSMHYD, a phase-equilibrium calculation program [33] , to be 4.23 MPa.…”

“…However, the addition of nanoparticles may also introduce new risk, as studies indicated; the addition of solid particles, especially nanoparticles, can facilitate hydrate formation and growth [20,21] . Nanoparticles can become the "seeds" for hydrate nucleation and also increase the thermal conductivity of the drilling fluid [21][22][23][24] , which induces shallow gases or gases from the dissociation of gas hydrates to easily form hydrates in drilling fluid, which causes blockage of circulation channels and borehole accidents. Thus, reducing the invasion level of drilling fluid while preventing large-scale formation and aggregation of gas hydrates in boreholes is a critical issue to be resolved for the application of nano-based hydrate drilling fluid.…”

“…Most studies have indicated that hydrophobic nanoparticles in water system facilitate the formation of gas hydrates [25][26][27] , but they inhibit hydrate growth if they locate at the water/oil interface [28] , while other results also showed that nanoparticles facilitate the formation of hydrates at low concentrations [21,23] . However, the researchers did not elucidate the nanoparticle in their experiments is hydrophilic or hydrophobic [21,23] . In addition, the effect of grain size and high concentration of hydrophilic nanoparticles on hydrate formation and its mechanism has yet to be revealed.…”