Development And Flow Field Simulation Of Alkaline Electrolyzer For Hydrogen Production

Hydrogen energy has the advantages of wide sources,high combustion calorific value,high energy density,storable,renewable,electric and combustible,and is known as the ultimate energy in the 21st century.Hydrogen production by water electrolysis is one of the best ways to obtain high purity hydrogen without pollution.Alkaline hydrogen production by water electrolysis has the largest market in the field of hydrogen production by water electrolysis because of its advantages of low equipment cost and mature technology.Electrolyzer is the core equipment of alkaline hydrolysis hydrogen production system,but the traditional electrolyzer has the disadvantages of low current density and low energy conversion rate.Therefore,this paper adopts the method of combining simulation and experiment to improve the electrolyzer from the aspects of plate structure,diaphragm material and electrolytic material.The main work and research conclusions are as follows:(1)A 60Nm~3/h electrolyzer platform for hydrogen production was built and trial run was carried out.The results show that the start-up time can be reduced by 50%when the lye heater is used in the start-up process.The installation of hydrogen flowmeter in the system will make it impossible to accurately measure hydrogen flow rate because of the instability of pressure and temperature in the system.The pneumatic diaphragm regulating valve of the system is easily damaged when the designed gas production of the system differs greatly from the actual gas production of the electrolyzer.(2)Simulation research of flow field characteristics in electrolyzer based on Fluent.The simulation results show that in the traditional electrolyzer with circular plate,the proportion of the area above the average outlet temperature is39.3%.By replacing the circular plate with a square plate,increasing the number of lye inlet and adding a spoiling area in the lye inlet area,the proportion of the area higher than the average outlet temperature in the flow field can be reduced to 6.3%,so as to provide a more uniform temperature field for the electrolyzer.(3)The micro-electrolyzer was designed and assembled,and the properties of different plate,diaphragm and electrode materials were tested.The results show that the assembly mode of hydraulic fastening can save a lot of disassembly time of electrolyzer.The direct use of 304 stainless steel plate material will form a large amount of precipitation in the hydrogen chamber blocking the flow channel;Because the surface of nickel mesh electrode is not smooth enough,it is easy to cause local ablation of composite membrane,so it is not suitable to be used with composite membrane.Taking the current density as the index,when the unipolar cell voltage is 1.9V,the current density of nickel felt electrode combined with composite film is 56%higher than that of traditional PPS diaphragm combined with nickel mesh electrode,and 9%higher than that of foam nickel electrode combined with composite film.