Design And Analysis Of Multi-Mode Test Platform For Catalytic Conversion Performance Of Ortho-parahydrogen In Wide Temperature Range

Hydrogen energy has a good application prospect.As secondary energy,hydrogen energy needs primary energy to produce.Hydrogen production from nuclear energy takes water as raw material and uses nuclear energy to implement large-scale production of hydrogen.In the future of energy diversification,the complementarity of nuclear and hydrogen will become one of the directions of new energy development.Large-scale utilization of hydrogen energy needs to solve the problems of production,storage,transportation and utilization.Liquid hydrogen storage has the advantage of high hydrogen storage density,which is one of the mainstream ways of hydrogen storage and transportation.In the process of hydrogen liquefaction,to reduce the heat generated by the spontaneous conversion of orthohydrogen to parahydrogen during liquefaction and make the liquid hydrogen evaporate and dissipate,the catalytic conversion of orthohydrogen to parahydrogen must be carried out to obtain stable storage of liquid hydrogen.In this paper,in order to realize the performance analysis of catalytic conversion of ortho-parahydrogen,based on the production process of liquid hydrogen,a multi-mode test platform for catalytic conversion performance of orthoparahydrogen in wide temperature range was designed.The temperature of hydrogen conversion(77 K-20 K)can be controlled by liquid nitrogen precooling and GM cryorefrigerator(Gifford-McMahon cryorefrigerator).The parahydrogen component of the inlet raw material can be controlled by setting the ortho-parahydrogen prereaction;the detachable converter and heat sink were replaced to realize various ortho-parahydrogen conversions(adiabatic transformation mode,isothermal transformation mode,continuous transformation mode).The performance test platform for the catalytic conversion performance of ortho-parahydrogen completed in this paper can provide experimental data for the performance test of the catalyst and the design of the parahydrogen converter.Specific studies are carried out as follows:1)Global analysis of test platform for catalytic conversion performance of ortho-parahydrogen:The design and experiment of the ortho-parahydrogen conversion test platform were investigated,and the operating conditions of the platform were set according to the hydrogen liquefaction process and experimental condition.The test process of catalytic conversion of ortho-parahydrogen was innovated,and the control methods of reaction temperature and reaction mode were proposed.The measurement method based on sound velocity difference was selected,and the physical properties needed were analyzed and the method of physical property selection was determined.2)Major component design of test platform for catalytic conversion performance of ortho-parahydrogen:Based on the study of the relationship between space velocity and parahydrogen component after reaction,the amount of catalyst used in the catalytic converter was calculated,and the size of the converter was designed.The flow model of porous media in catalytic converter was established,and study on pressure loss of hydrogen flowing through converter by FLUENT had been done.The thermal calculation of the heat exchanger was completed,and three kinds of heat exchanger size specifications were designed.After the size design of the internal components was completed,the design of the liquid nitrogen tank and the vacuum Dewar was completed,to achieve compact installation and complete functions.3)Safety design of test platform for catalytic conversion performance of orthoparahydrogen:Considering the potential dangers of asphyxiation and explosion in the experiment,and safety related physical properties used in the study(liquid nitrogen,hydrogen)were analyzed.To ensure the safety of the experiment and the reliability of the platform function,the function and operation characteristics of each system of the platform were analyzed,and the design scheme of the safe experimental site was proposed.According to the relevant national standards of hydrogen energy equipment,the matters needing attention in the installation and integration of the platform were proposed.In this paper,the design and analysis of multi-mode test platform for catalytic conversion performance of ortho-parahydrogen in wide temperature range were completed.According to the functional design of pipeline flow,the functional scheme was given.The design of the main components of the test platform had been completed based on the analysis of the difference in physical properties of orthohydrogen and parahydrogen;Safety design of test platform had been done to ensure safe and reliable operation of the platform.