Temperature and hydrogen flow rate controls of diesel autothermal reformer for 3.6 kW PEM fuel cell system with autoignition delay time analysis

• Published in: International journal of hydrogen energy Vol. 45; no. 53; pp. 29345 - 29355
• Main Authors: Malik, Fawad Rahim, Tieqing, Zhang, Kim, Young-Bae
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30.10.2020
• Subjects: Autothermal reforming; Hydrogen production; Proton exchange membrane fuel cell; Reformer catalyst temperature; Proton exchange membrane fuel cell; Reformer catalyst temperature; Hydrogen production; Autothermal reforming
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.07.208

In this paper catalyst temperature and hydrogen flow rate controls are an area of interest for autothermal reforming (ATR) of diesel fuel to provide continuous and necessary hydrogen flow to the on-board fuel cell vehicle system. ATR control system design is important to ensure proper and stable performance of fuel processor and fuel cell stack. Fast system response is required for varying load changes in the on-board fuel cell system. To cope with control objectives, a combination of PI and PID controllers are proposed to keep the controlled variables on their setpoints. ATR catalyst temperature is controlled with feedback PID controller through variable OCR (oxygen to carbon ratio) manipulation and kept to the setpoint value of 900 °C. Additionally diesel auto-ignition delay time is implemented through fuel flow rate delay to avoid complete oxidation of fuel. Hydrogen flow rate to the fuel cell stack is kept to setpoint of required hydrogen flow rate according to fuel cell load current using PI controller. An integrated dynamic model of fuel processor and fuel cell stack is also developed to check the fuel cell voltage. Product gas composition of 35, 18 and 4% is achieved for hydrogen, nitrogen, and carbon dioxide, respectively. The results show fast response capabilities of fuel processor following the fuel cell load change and successfully fulfills the control objectives. •Catalyst temperature and hydrogen flow rate controls are used for reforming.•PI and PID controllers are implemented to keep the operating points near setpoints.•Diesel auto-ignition is avoided in the control model by implementing delay time to fuel flow rate.•Catalyst temperature was controlled at 900 °C and for achieving desired hydrogen flow rate.