The Numerical analysis of an anode-supported high temperature DIRPSOFC operating conditions with considering the maximum allowable temperature difference

پيل هاي سوختي اكسيد جامد از واكنش سوخت گازي با يك اكسيد كننده، الكتريسيته و گرما توليد ميكنند و شامل اجزاي اتصالدهنده و يك ساختار سه لايه )ساختار پن( كه از دو الكترود سراميكي يعني كاتد و آند كه توسط يك الكتروليت سراميكي از هم جدا شدهاند، ميباشند. مدل حاضر براي يك پيل سوختي اكسيد جامد صفحهاي دما بالا با تكيهگاه آندي و با جريان همسو و واكنش اصلاح داخلي مستقيم ارايه گرديده است كه مدلي يك بعدي بوده و شامل معادلات بقاي جرم، بقاي انرژي و معادلات الكتروشيميايي است. گاز متان با 91 درصد پيش اصلاح به عنوان سوخت ورودي و واكنشهاي پيل شامل واكنش اصلاح متان، شيفت آب-گاز و الكتروشيميايي در نظر گرفته شده است. تاثير پارامترهاي مصرف سوخت و نسبت هوا بر توزيع دما و عملكرد پيل بررسي گرديدهاند تا اطمينان حاصل شود كه بر اثر افزايش اختلاف دما، شكست در ساختار پيل رخ ندهد. نتايج نشان ميدهد كه 1 موجب افزايش يافتن بيشينه اختلاف دماي / 1 به 55 / افزايش پارامتر مصرف سوخت از 45 ساختار پن از 919 به 945 درجه كلوين ميشود. در حالي كه با افزايش پارامتر نسبت هوا از 91 اين بيشينه اختلاف دما از 911 به 914 درجه كلوين كاهش مييابد. به منظور / 6/5 به 5 دستيابي به بيشينه چگالي توان با در نظر گرفتن بيشترين اختلاف دماي مجاز در طول 1 و 1 باشد.

In the present study, the operating conditions of an anode-supported high temperature direct internal reforming (DIR) planar solid oxide fuel cell (SOFC) are numerically analyzed. SOFCs are the energy conversion devices that produce electricity and heat directly from a gaseous fuel by the electrochemical combination of that fuel with an oxidant. A planar SOFC consists of an interconnect structure and a three-layer region often referred to as the PEN (Positive electrode/Electrolyte/Negative electrode) composed of two ceramic electrodes, anode and cathode, separated by a dense ceramic electrolyte. A 1D mathematical model based on the species and the energy balances is conducted to investigate the concentration of the gas components in the channels and the cell temperature distribution in both solid structures and gas channels. In addition, the electrochemical model of the cell is applied to determine its performance parameters. A synthesis gas with 10% pre-reformed methane as fuel stream is fed to the cell and the water-gas shift, the methane-steam reforming and the electrochemical reactions are considered as mass and heat sources/sinks. The effects of the air ratio and the fuel utilization factor on the temperature field and the performance of the cell are examined through parametric analysis to determine the optimum operating conditions of the cell. The investigations are performed to ensure no cracking will occur due to cell crucial temperature difference. The results indicate that increasing the fuel utilization factor from 0.45 to 0.85 leads to increase the value of the maximum temperature difference across the PEN layer from 101K to 145K while it decreases from 177K to 124K by increasing the air ratio from 6.5 to 12.5. In order to achieve the maximum power density by considering the maximum allowable temperature difference across the cell, the value of the fuel utilization factor and the air ratio are obtained 0.85 and 9, respectively.