Research On Submarine Gas Hydrate Pumping System

In the 21st century, the energy is still the most important foundation of economic development for every country, and peoples can't live without the energy's development and utilization. The rapid development of economy brought prosperity to every country and made people rich. But, it's accompanied by a large number of traditional energy consumption and accelerated the depletion of traditional energy. The fossil energy will release a large number of harmful gas In the process of combustion and it's a threat to human's survival and development space. And at the same time, the oil industry was not good in recent years. For these reasons, we should to search for new alternative energy and the alternative energy should have the advantages of high efficiency and clean that traditional energy don't have.The gas hydrate is a kind of clean and efficient energy and it have a bright application future. Its total reserves is about 2×1016m3 and 99 percent of it is in the ocean. Most of the marine gas hydrate is deposition in the seabed shallow and without good cover and there is no suitable mining technology solutions for this type of hydrate yet. According to research and analysis, mining the undersea gas hydrate in solid form and pumping through pump will be a safe mining method. As the core of the solid recovery scheme, the pumping technology will be the key that we study in this paper. We made a in-depth study and design in this article for pipeline transportation and transfer pump, and finally we made a numerical simulation for the multiphase flow in the pumping system by CFD software. In this article, we divide the research and analysis for natural hydrate in six parts and the main contents are as follows:First:Introduce the basic situation of natural gas hydrate(such as the structure, properties and characteristics). Analyze the advantages and disadvantages of different mining technology. Make a summary of solid extraction method though the research status of pipeline transportation and transfer pump. Put forward the research purpose and research content.Second:Design feasible pumping system solutions. Determine the parameters of the pumping system such as the volume flow, the inner diameter of pipeline, the system's working depth and the volume concentration of solid phase.Third:Describe the design process of double-channel transfer pump's impeller and volute. Make the hydraulic calculation by using speed coefficient method. Complete the calculate of related parameters. Establish 3D model of the centrifugal pump flow section.Fourth:Analysis the process of how the mathematical model was set up and deduce the two-phase flow control equation.Fifth:Make meshing of pipeline transportation, impeller and volute by using ICEM CFD software. Set the boundary conditions. Make multiphase flow analysis for the pumping system's internal flow field. Collect the analysis and calculation diagram and get the relevant conclusions.Sixth:Give this article's main conclusion, put forward the development and prospect of the research direction in this article, point out the shortages and defects of this article.Summarize the above analysis and research and list the research results that have some practical value and significance as follows:(1) solid mining technology can be used in exploitation of marine gas hydrate, the pumping system we designed can reach the set requirements; (2) the change of volume concentration of solid phase have a greater effect to the velocity distribution inside impeller than to velocity distribution inside volute; (3) with the increase of particle size, the grain accumulation phenomenon is starting to appear at the impeller's working face and the perisporium of volute. This is because the particle size has a great influence to the segregation of solid-liquid two phase; (4) the transport concentration is smaller than the volume concentration of particle inside the vertical tube, and the particle concentration is gradually lower from the entrance to the way out. At the same time, there will be a trend that particles distribution uniformity and particles gathered to the center of pipe.