What safety problems are associated with molten carbonate fuel cells?
The proton exchange membrane is one of the most advanced fuel cell designs. Hydrogen gas under pressure is forced through a catalyst, typically made of platinum, on the anode (negative) side of the fuel cell. At this catalyst, electrons are stripped from the hydrogen atoms and carried by an external electric circuit to the cathode (positive) side. The positively charged hydrogen ions (protons) then pass through the proton exchange membrane to the catalyst on the cathode side, where they react with oxygen and the electrons from the electric circuit to form water vapour (H2O) and heat. The electric circuit is used to do work, such as power a motor.
Molten carbonate fuel cells (MCFCs) present specific safety challenges primarily due to their operating environment and the materials involved. Key safety concerns include:
- High Operating Temperatures: These cells operate at approximately 650 °C (1,200 °F). This extreme heat creates significant engineering challenges for the long-term integrity of system components and joints, particularly when the cells undergo frequent heating and cooling cycles.1
- Toxic Fuel: The use of fuel mixtures containing carbon monoxide introduces toxicity risks that require careful management during commercial operation, engineering design, and testing.1
- Containment and Pressure Control: As with other fuel cell systems, maintaining stable operation is critical. If fuel breaks through to the electrolyte side of the electrode, the compartment can fill with gas or vapor. This creates an explosion risk if the fuel gas enters the oxidizing gas compartment or if the oxidizing gas reaches the electrolyte compartment.2
Consequently, ensuring power plant safety requires rigorous design, construction, and precise pressure control to manage these high-temperature and chemical hazards effectively.12