Title : Experimental analysis of delivering various liquid fuels to Molten Carbonate Fuel Cell (MCFC)
During presentation, results of experiments of fuelling Molten Carbonate Fuel Cell with low molecular liquid fuels (methanol, ethanol, propanol isomers, butanol and glycerol) will be presented. As MCFC temperature during operation reaches 650°C and anode is made of nickel, which is a typical catalyst in steam reforming reactors for hydrocarbons, this creates perfect conditions for steam reforming of proposed fuels to take place. In standard conditions, MCFC requires hydrogen as fuel – but hydrogen is a difficult fuel to transport, distribute and store. One of solutions to avoid problems with pure hydrogen is to use liquid fuels (ex. alcohols) as hydrogen carriers. Those fuels can be easily transported and stored in already existing technologies (containers, tanks, pipes etc.) in liquid state at standard conditions. Also most of them are a product of natural phenomena that can be found in everyday life, such as alcohol fermentation, where most of the analysed compounds are created as a product of reaction performed by yeast.
The results of experiments that will be presented contains data on electric power that could be achieved when fuelling MCFC with various fuels at various water:fuel compositions in comparison to pure hydrogen used as fuel. Stoicchiometric steam:carbon compositions of the fuels have been analysed in ratios 2:1, 3:1, and 4:1 for each of 6 used fuels: methanol, ethanol, propan-1-ol, propan-2-ol, butan-2-ol and glycerol fuel. Results were compared with fuel cell powered by pure hydrogen, showing little decrease in performance, but still delivering positive heat balance. Strengths and weaknesses of proposed solutions have been presented. Results of experiments prove that liquid fuels can be used for fuelling molten carbonate fuel cells, thanks to composition of fuel electrode (porous nickel anode) and temperature of operation of fuel cell, which act as a catalyst for the process. In the anode channel and mainly on the anode surface, steam reforming process of hydrocarbons occurs, resulting in creation of hydrogen elements, which take place in the electrochemical process of fuel cell operation right after creation. This allows fuel cell to consume hydrogen generated by steam reforming and power fuel cell directly. In this examination only internal steam reforming was analysed (without external steam reformer). Results of this study shows that problems concerning hydrogen fuel can be easily avoided by utilising liquid fuels, with little decrease of fuel cell performance.