Design And Manufacture Of Reaction Support With Ordered Porous Microstructure And Its Performance Of Self-thermal Hydrogen Production

Methanol steam reforming microreactor technology for hydrogen production,which uses methanol and water as fuel and performs catalytic reforming reaction under the catalysis of catalyst on the reaction support in the microreactor and the heating effect of external heat source,can realize real-time online hydrogen production.It is regarded as one of the ideal technologies of hydrogen supply for hydrogen fuel cell vehicles.However,existent methanol steam reforming microreactors for hydrogen production have some problems,such as low hydrogen production performance of reaction support and the need for electric heating,which limit their commercial application.In this context,based on structural optimization and simulation research of porous microstructure reaction support,3D printing technology is proposed to manufacture ordered porous microstructure reaction support,and a proactively loading process of catalyst is developed to improve loading effect of the catalyst on the porous microstructure reaction support.In this way,the methanol steam reforming performance of reaction support for hydrogen production is significantly improved.In addition,by optimizing the structure of catalytic combustion reaction support and integrating it with methanol steam reforming module for hydrogen production,the selfsupply of heat of hydrogen production system is realized,solving the problem of large power consumption in the process of hydrogen production via electric heating.The main research works of this paper are as follows.1.Structure optimization of porous microstructure reaction support and its simulation performanceIn view of the problems,such as difficult control of the directional flow of reactants due to the random-porous structure of existent porous microstructure reaction supports,and based on the established mathematical model of catalytic reaction performance of porous microstructure reaction support,the design scheme of ordered pore structure of porous microstructure reaction support is proposed.In addition,an established numerical simulation model of the ordered porous structure is used to study its heat transfer performance,pressure drop and catalytic reaction performance.It is shown that,a design of the ordered porous microstructure reaction support with high specific surface area is the key to improve catalytic performance of porous microstructure reaction support.Compared with porous microstructure reaction support with cylindrical cubic structure,the optimized porous microstructure reaction support with body-centered cubic crystal structure has higher performance of hydrogen production and catalytic combustion due to its larger specific surface area and more reasonable ordered distribution of reactants.2.3D printing manufacture of ordered porous microstructure reaction support of stainless steel and its reaction performanceTo realize the manufacture of ordered porous microstructure reaction support of stainless steel and verify its catalytic reaction performance,based on the analysis of the influence relationship between its structural parameters and 3D printing process parameter,orthogonal experiment table and range analysis method are emphatically used to optimize its 3D printing process parameters.In addition,the catalytic catalytic performance of the reaction support is studied.It is found that,in 3D printing process,controlling the thermal effect of laser beam on the metal powder is the key to manufacture the ordered porous microstructure reaction support.When the optimized 3D printing process parameters are used,size deviation of the manufactured ordered porous microstructure reaction support of stainless steel is 14.9 μm,and its surface roughness is Ra22.27 μm,and its specific surface area is 8.96 mm2/g,and it has better performances of hydrogen production and catalytic combustion compared to reaction supports of 70 PPI copper foam and Pt/γ-Al2O3 catalyst particles,respectively.3.A novel technology for proactively loading catalyst on porous microstructure reaction support and its reaction performanceTo solve existent problem that the low hydrogen production performance of porous microstructure reaction support due to its poor catalyst loading effect,a novel technology for proactively loading catalyst and its equipment are developed,which uses external air with low pressure to drive the catalyst precursor solution to rapidly flow and make it to be distributed evenly inside the porous microstructure reaction support,so as to realize the uniform and efficient loading of catalyst.Compared to traditional loading technology of impregnation,the porous microstructure reaction support,which uses proactively loading technology to load catalyst,can obtain more uniform distribution of catalyst on it.Moreover,reactants can fully flow inside the porous microstructure reaction support.In this way,the more chances of contact between the reactants and catalyst can be gained,and the hydrogen production performance indexes of porous microstructure reaction support,such as methanol conversion,can be improved.4.Structure optimization of catalytic combustion reaction support and its reaction performanceAiming at the problem of the non-uniform heat-supply of traditional catalytic combustion reaction support to hydrogen production reaction support,based on the established mathematical model of temperature distribution of catalytic combustion reaction support,a structural optimization design scheme of catalytic combustion reaction support with second-stage microchannel structure is proposed.Compared with other catalytic combustion reaction supports,the catalytic combustion reaction support with trapezoidal second-stage microchannel structure can realize directional control of the amount of catalyst and the size of specific surface area of structure at its various positions from the two directions of X and Y,obtaining relative equalization between the catalytic combustion reaction and the heat absorption at its various positions.In this way,its coefficient of temperature difference is significantly reduced,which is conducive to realize the uniform heat-supply of catalytic combustion reaction support to hydrogen production reaction support in the process of auto-thermal hydrogen production.5.Integrated design of auto-thermal methanol steam reforming microreactor for hydrogen production and its reaction performanceTo realize the self-supply of heat for hydrogen production system,based on the analysis and optimization of the catalytic combustion reaction support’s structure scheme and number,the relative flow direction between hydrogen production reactant and catalytic combustion reactant,and the performance amplification scheme of microreactor,the integrated design of hydrogen production reaction unit and heating unit of catalytic combustion reaction is performed to develop auto-thermal methanol steam reforming microreactor for hydrogen production.Experiment results show that in the absence of electric heating,when injection rates of methanol-water mixture(fuel of hydrogen production reaction)and methanol(fuel of catalytic combustion reaction)are 48 mL/h and 3.2 mL/min,respectively,methanol conversion,H2 flow rate and CO selectivity of the developed auto-thermal microreactor for hydrogen production are 100%,2.52 mol/h and 4.43%,respectively.