Dynamic Model Implementation for a Multi-Purpose 1-D Planar SOFC

Dynamic Model Implementation for a Multi-Purpose 1-D Planar SOFC: Gaining Insight Behaviour into an Intermediate Temperature SOFC

Azzopardi, M.

van Biert, L. (mentor)

Mechanical, Maritime and Materials Engineering

Marine and Transport Technology

2017-03-27

There appears to be something of a perfect storm on the horizon with a sense of drive and changing demand from consumers. The urge to act now mainly revolts around resilience to adapt well in the face of adversity. Fuel cells are a revolutionary technology which can be used as energy conversion devices for distributed combined heat and power generation which can be used as auxiliary power units on board maritime ships alongside the main prime mover, normally provided by internal combustion engines. In this thesis, the principle of operation of fuel cells as well as their technical advantages and limitations are covered. Thereafter, a broad overview of the fuel cells being developed is given as well as in-depth review of how solid oxide fuel cells are categorised. The study mainly focuses on the intermediate temperature operation of solid oxide fuel cells which could prove to break the deadlock in the maritime market. Of all potential technologies for small cogeneration plants (1-10 MW), solid oxide fuel cell systems offer the highest efficiency, highest end-user cost/benefit ratio and the lowest pollutant emissions. In this research, a dynamic model is developed by the finite volume method for co-flow planar solid oxide fuel cells, which can be used for both steady-state and transient performance analysis. The spatial distributions of current densities, pressures, temperatures and gas compositions in the solid oxide fuel cell are dealt with by discretising the cell into small units along the flow direction in the model. For each unit, the partial pressure of each species in the gas flow and the temperature of each solid layer and gas channel are assumed to be homogeneous, and therefore the dynamics are derived as a lumped parameter system. The model is applicable for various fuel inlet compositions and compatible with direct internal reforming. Flow velocities are approximated by applying linear orifice equation instead of solving momentum balance dynamics while a two-temperature layer is enough to capture the dynamics of solid oxide fuel cells, thus mitigating computation intensity. The model developed in this thesis is compared with the “Baseline” model of (Handa Xi and Jing Sun, 2008) which taken as the reference model published in the peer-reviewed Journal of Fuel Cell Science and Technology, (renamed to the Journal of Electrochemical Energy Conversion and Storage, in 2016). The comparison between the two sets of models is made using the same choice of operating parameters made in (Handa Xi and Jing Sun, 2008) on steady-state and dynamic performance. In retrospect, this thesis will attempt to provide a solid oxide fuel cell diagnostic tool to be able to tackle the last bottleneck mentioned in the introduction chapter which was associated with maritime breakthrough problems. Ultimately, the model developed will be convenient and effective for achieving the larger goal in future ship system integration projects for simulating advanced energy systems based on solid oxide fuel cells.

Intermediate Temperature
Anode Supported
Planar SOFC
1-D Dynamic Model

http://resolver.tudelft.nl/uuid:2a4683ac-f345-464c-97ce-b11bc3631ed2

Student theses

master thesis

(c) 2017 Azzopardi, M.