2D Simulation for CH4 Internal Reforming-SOFCs: An Approach to Study Performance Degradation and Optimization

Abstract

Solid oxide fuel cells (SOFCs) are a well-developed technology, mainly used for combined heat and power production. High operating temperatures and anodic Ni-based materials allow for direct reforming reactions of CH4 and other light hydrocarbons inside the cell. This feature favors a wider use of SOFCs that otherwise would be limited by the absence of a proper H2 distribution network. This also permits the simplification of plant design avoiding additional units for upstream syngas production. In this context, control and knowledge of how variables such as temperature and gas composition are distributed on the cell surface are important to ensure good long-lasting performance. The aim of this work is to present a 2D modeling tool able to simulate SOFC performance working with direct internal CH4 reforming. Initially thermodynamic and kinetic approaches are compared in order to tune the model assuming a biogas as feed. Thanks to the introduction of a matrix of coefficients to represent the local distribution of reforming active sites, the model considers degradation/poisoning phenomena. The same approach is also used to identify an optimized catalyst distribution that allows reducing critical working conditions in terms of temperature gradient, thus facilitating long-term applications.

Electrochemical Characterization and Modelling of Anode and Electrolyte Supported Solid Oxide Fuel Cells

“…Nevertheless, large temperature gradients on the cell plane and carbon deposition can significantly worsen the performance. For the first point, an optimised catalyst distribution decreases the mismatch between the heat required by endothermic reforming and the heat produced by the exothermic electrochemical reaction (Audasso and Bianchi, 2020). Alternatively, a pre-reformer can be used.…”

Test and Modelling of Solid Oxide Fuel Cell Durability: A Focus on Interconnect Role on Global Degradation

“…Its core consists of a detailed kinetics formulation, which considers reforming and electrochemical processes in an anionic conductive-based cell. For the first point, it assumes that Steam Reforming (SR) and Water Gas Shift (WGS) reach the thermodynamic equilibrium condition [34], expressing the equilibrium constant, K eq , in terms of reactant partial pressure, p, and temperature, T, according to a semi-empirical approach for SR (Equation (1)) [35] and the Van't Hoff formulation for WGS (Equation ( 2)) [36].…”

Operating Principles, Performance and Technology Readiness Level of Reversible Solid Oxide Cells

“…These limits have been partially solved through the introduction of high-temperature PEMFC working at 393 K, which allows for reducing CO adsorption on active sites and therefore simplifies the requested gas pretreatments [70]. Whereas, this issue is not present in SOFC configuration, which is usually fed continuously by common available fuels such as natural gas or liquid petroleum gas, exploiting internal reforming reactions possible by high working temperatures [71]. The stacks are connected steadily to the grid in order to guarantee a regular operation and avoid thermal cycles, which are causes of degradation.…”