Development of cost effective manufacturing technologies for key components of fuel cell micro combined heat and power (CHP) system

In a fuel cell system for micro-Combined Heat and Power the Cathode Air Preheater (CAPH) functions as a heat exchanger, recovering heat from the exhaust gas to heat air before it enters the fuel cell. The latest generation of the CAPH design uses an advanced alloy containing Cr to provide improved oxidation resistance under isothermal and cyclic conditions and provide good high temperature strength.
However, a major environmental and fuel cell life concern is evaporation of Cr at high temperatures. This contaminates the fuel cell on the air side and the condensate on the exhaust side leading to cathode poisoning and fuel cell degradation. Therefore, it is required to reduce Cr scale growth and Cr evaporation from the CAPH, thereby minimising Cr poisoning and improving the durability of SOFC stack and system.
The overall objective of the project is to develop an advanced material for the CAPH and SOFC stacks with high performance and robustness to satisfy end user requirements. We will evaluate a series of alloys as the CAPH materials for high temperature oxidation (corrosion), Cr evaporation and physical strength. For this, the PhD candidate will set up a number of analytical tests to assess the evaporation from a number of high temperature stable Cr containing alloys by means of mass spectrometry or gas chromatography and a scale growth (corrosion) using transmission electron microscopy (TEM) or secondary electron microscopy (SEM). A high temperature creep test will be carried out using the proposed materials to assess the mechanical properties. Moreover, modelling of the chemical behaviour of CAPH components will be performed using MATLAB or COMSOL Multiphysics to predict corrosion, chromium evaporation, element diffusion, and reaction of elements.