Effect of Spiral Inlet Geometric Parameters on the Performance of Hydrocyclones Used for In Situ Desanding and Natural Gas Hydrate Recovery in the Subsea

Abstract

The inlet structure of hydrocyclones has great impact on performance. In this paper, the effects of spiral inlet geometric parameters on the flow field characteristics and separation performance were investigated by CFD. Numerical results show that the pitch has the largest influence, followed by the heads, the turns, and the steady flow cone. With the increase of the steady flow cone angle, the turbulence intensity increases. The efficiency, pressure drop, tangential velocity, sand volume fraction at the spigot, and natural gas hydrate (NGH) volume fraction at the vortex finder decrease, when the pitch increases. With the increase of the number of heads and turns, the efficiency, pressure drop, tangential velocity, the NGH volume fraction at the vortex finder, and the sand volume fraction at the spigot increase. The efficiency and pressure drop of hydrocyclones with the optimal parameters are 90% and 0.05 MPa, respectively. Therefore, the performance of the NGH hydrocyclone can be improved by increasing the inlet pitch and the number of spiral heads and inlet spiral turns. The results provide theoretical guidance for the engineering design of NGH in situ separators.

Effect of Structural Parameters on the Performance of Axial-Flow Inlet Hydrocyclones for In Situ Desanding from Natural Gas Hydrate Mixed Slurry

“…Therefore, key and important parameters are selected when carrying out specific impact law analysis. However, the specific impact of the structural parameters of the spiral inlet on separation performance has been revealed in previously published papers . In this paper, the specific parameters selected do not duplicate the spiral inlet parameters.…”

“…Wang − et al combined the test mining parameters and considered the effect of phase transition, and used the numerical simulation method to reveal the particle motion trajectory, phase distribution, and separation efficiency in the classical tangential inlet hydrocyclone and spiral separator. The effect of spiral inlet geometric parameters on the performance of the NGH axial-flow inlet hydrocyclone was investigated, and the influence laws were obtained among the published articles by the author . However, all structural parameter configuration plays a decisive role in the performance of specific NGH hydrocyclones.…”

“…One of the key components of the method is to remove sand from the broken NGH-mixed slurry in situ and put the sand back on the seafloor. The principle of mining and sand removal is shown in Figure . The new method can prevent wellbore and reservoir blockage while maintaining productivity and even effectively reduce the risk of subsea reservoir collapse.…”

“…The effect of spiral inlet geometric parameters on the performance of the NGH axial-flow inlet hydrocyclone was investigated, and the influence laws were obtained among the published articles by the author. 14 However, all structural parameter configuration plays a decisive role in the performance of specific NGH hydrocyclones. Therefore, the purpose of this paper is to reveal the influence of structural parameters on separation performance.…”

“…The principle of mining and sand removal is shown in Figure 1 . 14 The new method can prevent wellbore and reservoir blockage while maintaining productivity and even effectively reduce the risk of subsea reservoir collapse.…”