Thermodynamics Model And System Analysis Of Proton Exchange Membrane Electrolysis Cell And Stack System

After our society enters the 21st century,the economy and industry are developing rapidly,and the energy demand has increased.However,the use of fossil energy causes environmental pollution and the greenhouse effect.Therefore,meeting energy supply and reducing environmental pollution are the primary goals of human development.Hydrogen has a high combustion value and does not cause environmental pollution when used.It is an environment-friendly alternative to fossil energy.Compared with photocatalytic hydrogen production and thermochemical cycle hydrogen production,hydrogen production from water electrolysis has higher hydrogen production efficiency and faster hydrogen production rate,so it is very suitable for large-scale production.Hydrogen production using proton exchange membrane(PEM)electrolyzer is a new technology that has attracted much attention in recent years.The hydrogen production process is environmentally friendly and pollution-free,the system device has a compact structure,strong maintainability,and high hydrogen production efficiency,so is being studied and applied more and more.From the perspective of purpose,optimization of PEM electrolyzer can be divided into efficiency optimization,economic optimization,device stability optimization,operation safety optimization,etc.From the perspective of method,optimization of PEM electrolyzer can be divided into structural parameter optimization,operating state parameter optimization,overall optimization of the system.The circulating water flow of the electrolysis cell affects the heat transfer between the entire PEMEC and the outside world,changes the operating temperature of the electrolytic cell,and affects the electrolytic performance of the PEMEC.Therefore,it is of great significance to study the relationship between the performance of the electrolysis cell and the circulating water flow of the electrolysis cell.This article first takes a single PEM electrolysis stack as the research object,and establishes a mathematical model of the electrochemical,and material transport of the electrolytic cell.The purpose is to study the heat transfer,energy transport,and performance of the electrolytic cell in actual operation through the model.By comparing with the results of experimental research on PEMEC in previous literatures,it is proved that the established model is consistent with the experimental results and has the ability to simulate and analyze the operation of actual PEMEC or PEM electrolysis stack.Then this article quantitatively analyzes the impact of the circulating water flow on the system.When the inlet water temperature is determined,the circulating water flow has a very large effect on the temperature of the PEMEC during operation.The increase of circulating water flow will significantly reduce the temperature of the reactor during operation,and the change in the circulating water flow will also affect the operating efficiency of the entire system.Based on the stack model,this article expands the research dimension to the whole proton exchange membrane electrolysis water system level,integrates the electrical stack,circulation pump,inlet water heat exchanger,gas/liquid separator,hydrogen and oxygen storage devices,and adds external heat input.Through the system model,the effects of external heat input and inlet water temperature control were studied.First,the operation simulation of the system when there is no external heat source,that is,when the system generates heat through the inlet water heat exchanger assembly reaction,the results show that the addition of an external heat source or maintaining the inlet water at a certain temperature is critical to the system efficiency The important influence is that the system can only guarantee the ideal temperature of the electrolysis based on the reaction heat only.As a result,the operating efficiency of system is very low,either is the hydrogen production rate.Secondly,the effect of changes of external heat input to the efficiency of the entire electrolysis water system is analyzed.Finally,this paper designs and sets up a proton exchange membrane electrolyzed water experimental bench,and conducts preliminary experimental research on the proton exchange membrane electrolyzed water to produce hydrogen.