Analysis of Flow Field Characteristics of Sand Removal Hydroyclone Applicable to Solid Fluidization Exploitation of Natural Gas Hydrate

Abstract

Abstract With the development of economy and society, the consumption of fossil energy is gradually increasing. In order to solve the current energy dilemma, NGH is considered as an ideal alternative energy. At the same time, the solid fluidization exploitation is an ideal exploit method for NGH at present. However, in the process of solid fluidization exploitation, sand and hydrate ore bodies enter the closed pipeline together, which will block the pipeline and increase the difficulty of exploitation. Therefore, the pre-separation of sand by hydrocyclone plays an important role in solid fluidization exploitation. In this study, the numerical simulation method was used to study the internal flow field characteristics of the hydrocyclone under different conditions, and the effects of different flow rate, different flow ratio, different sand content and different particle diameter on the phase distribution are investigated. The results show that: at the same axial position, the increase of flow rate and sand content makes the sand phase more distributed at the edge of the flow field, while the change of flow ratio has no significant effect on the distribution of sand phase. Under the same working conditions, the sand gradually migrates to the center of the flow field with the increase of the axial distance, while the particle diameter change has no significant effect on the sand distribution. By calculation, it is obtained that under the optimum working condition of the flow rate is 4.83m3/h, the flow ratio is 20%, the sand content is 20%, and sand particle diameter is 80µm, the maximum Es is 22.1% and the minimum is 86.1%. Finally, a comprehensive analysis of the hydrocyclone in this study shows that this type of hydrocyclone is applicable to rough pre-separation of sand in the process of solid fluidization exploitation of NGH, and can not fine separate complex mixture. Through the study of the internal flow field characteristics and phase distribution law of the hydrocyclone, this study provides a reference for the practical engineering application of sand phase pre-separation in the solid fluidization exploitation of NGH.