Processing And Performance Of 3D Printed Methane Catalytic Reformer

Hydrogen energy,usually refers to hydrogen gas,is an abundant,recyclable and clean energy source that possesses high energy density.The traditional methods of producing hydrogen mainly include water electrolysis and industrial by-production of hydrogen.However,the cost of water electrolysis is high.Methane is one type of high quality and clean gas with high hydrogen content.Therefore,methane is very suitable for catalytic reforming process to produce hydrogen gas and catalytic reforming reaction with methane water vapor to produce hydrogen is also considered as a promising technology for hydrogen production.Currently,the traditional ways of assembling catalytic reformers are complicated and expensive.It is urgent to develop a new technology for preparing catalytic reformer.Selective laser melting（SLM）exhibits the advantage of precisely integrated manufacturing,which can prototype net-shape samples with complex structures and functions of the catalytic reformer.In other words,the selective laser melted（SLMed）parts can be directly used in the catalytic reforming reaction.However,literature reviews on metal-based integrated catalytic reactors manufactured via the SLM technique is scarce.Therefore,in the present thesis,the processing of SLMed Inconel625（In625）,one type of Ni-based superalloys,bulk samples were firstly studied.The effects of processing on density,surface quality,mechanical properties and corrosion resistance of the samples were investigated and the optimal parameters were obtained.A series of reformers were designed and the corresponding catalytic reformer was prepared by SLM.The experimental platform of methane steam catalytic reforming was built before the experiment of hydrogen production was conducted.The effects of catalytic reformer structure and the reaction temperature on the efficiency of methane steam catalytic reforming were studied.The state of catalyst after reacting was also investigated.The results showed that the density of the SLMed bulk In625 increased with the decrease of laser power and the optimum processing parameters were selected as:laser power of 300 W,scanning rate of 800 mm/s and scanning distance of 0.11 mm,respectively.The SLMed sample exhibited the best performance with tensile strength,yield strength and breaking potential of 954 MPa,621 MPa and 1.0133×10^-6A/cm².In addition,it can be summarized that the structure of the methane steam catalytic reformer exhibited a significant effect on its catalytic reforming efficiency.The aperture of the reformer had a certain relationship with the hydrogen conversion efficiency,while the wall thickness of the reformer had no significant effect on the hydrogen conversion efficiency.When the pore size was appropriate,the hydrogen concentration increased with the increase of the specific surface area of the reformer.The balance between the pore size and the specific surface area of the porous structure was important for structural design.When the wall thickness was fixed,the H₂concentration had the highest value of 80.62%at900℃with an aperture of 3 mm.When the aperture was the same,the wall thickness was0.4 mm and H₂concentration reached the highest 78.86%at 900℃.Besides,the reaction temperature also exhibited a significant effect on the catalytic reforming efficiency.Ni-based catalyst exhibited a extraordinary catalytic effect at high temperature.A stable reaction could only take place when the temperature reached 700℃.Rate of hydrogen conversion reached the highest when the temperature was 900℃ under the same structure.