Modeling of the Balance of Plant for 1 kW Solid Oxide Fuel Cells fueling with natural gas

Abstract

As the maritime industry faces increasing pressure to lower greenhouse gas (GHG) emissions, solid oxide fuel cell (SOFC) technology has emerged as a potential option for a clean and efficient onboard power energy solution. This thesis demonstrates the development and performance evaluation of a steady-state 1 kW-class SOFC system model fueled by methane, which was designed using the TIL-Suite simulation environment. The model comprises a key balance of plant (BoP) components, which are reformer, compressor, heat exchanger, and afterburner, which integrate to simulate realistic system behavior and energy distribution.

The effect of key operational variables, including stack current (Istack), fuel utilization (Uf), steam-to-carbon ratio (STCR), and anode gas recirculation ratio (RR), on system performance were examined to evaluate such power output, fuel composition, and efficiency. Under nominal conditions: Istack of 27 A, Uf of 0.8, and STCR of 2, the system generates 1.07 kW of stack power, with a stack efficiency of 49% (LHV) and a net system efficiency of 43% after accounting for parasitic BoP loads. The simulated SOFC stack electrochemical model strongly corresponds with literature data, deviating by less than 5%.

In addition, a local sensitivity analysis was performed to examine the impact of operating parameters on system performance, and it was found that stack current mainly affects power output, while fuel utilization has the highest impact on efficiency.