Research On The Structure And Liquefaction Law Of LNG Ejector

With the improvement of people's living standards,the development of industrial production has become more and more rapid.Compared with petroleum,water gas and other substances,natural gas,as a traditional primary energy source,has the advantages of high energy grade,wide application range,and clean combustion products without pollution.Nowadays,in China,there is still room for development of natural gas extraction and transportation technology.LNG liquefaction technology is to process underground gaseous natural gas into high-purity liquid natural gas,and prepare for subsequent further transportation and storage.As the primary link in natural gas extraction and transportation,LNG liquefaction technology commonly used today requires a large amount of energy to drive compressors,cryogenic refrigeration units and other equipment.The energy cost per unit volume of natural gas collection is high,and the liquefaction process is complicated.To this end,this paper proposes an ejector(also known as jet pump)that replaces cryogenic compressors and throttle valves in LNG liquefaction cycles.Through a reasonable design of the ejector structure,high-pressure gaseous natural gas is used to eject liquid natural gas,and The natural gas liquefaction process is carried out in the ejector.Through the design and modeling of the ejector structure and the use of fluid calculation dynamic simulation software,the influence of different working conditions and different structures on the working parameters such as liquefaction rate and entrainment rate is obtained,and the reasonable structure size range and working conditions of the ejector are analyzed.Provide reference and basis for the future use of ejector in LNG liquefaction cycleAccording to the simulation results,it can be found that under different working conditions,the optimal structure of the ejector can maximize the entrainment rate and liquefaction of the ejector,and as the pressure of the working fluid increases,the entrainment rate shows a secondary The increasing trend of the curve.At the same time,supercritical methane begins to liquefy after entering the ejector.As the working pressure increases,the degree of liquefaction is higher;and the inlet temperature of the working fluid and the ejector fluid will not affect the entrainment performance of the ejector.And liquefaction;under the influence of the outlet back pressure,the ejector will appear in two modes.In the subcritical mode,the outlet back pressure has no effect on the entrainment rate,but in the critical mode,the greater the outlet back pressure,the greater the volume The lower the absorption rate.