ME 5110: Fuel Cell
How many numbers of moles of electron transfer per one mole of oxygen reacted in hydrogen oxygen fuel cell
4
What fuel cell type is used in Apollo space shuttle?
AFC
Which statement is true about the AFC?
ALL OF THE ABOVE: Electrode reaction rates are faster than those at proton exchange membrane electrode (PEMFC); Ionic conductivity in alkaline electrolyte is higher than that of proton exchange membrane electrolytes; Ni can be used as anode catalysts.
Which of the following chemical reaction types can be used in fuel processing for fuel cell systems?
ALL OF THE ABOVE: Selective oxidation, water gas shift reaction; steam reforming.
Which statement is true about the CO_2 intolerance in AFC?
Anion ion exchange membranes can be used to eliminate CO_2 effects.
Which electrode of hydrogen oxygen fuel cells require lower catalyst loading. Why?
Anode because the hydrogen oxidation rate is much faster than oxygen reduction which results in lower activation polarization
Which is true about direct carbon fuel cells?
Can be combined with a gas turbine for CHP
Activation
Charge Transfer
What is a fuel cell
Chemical energy to electrical energy
Which fuel cell has the highest volumetric energy content (Wh/L)?
Coal
Ohmic
Conductive ion transfer
Which fuel cell type is most suitable for low power transportation applications?
DMFC
Fuel cells generally designated according to the type of electrolytes. Provide the names of two fuel cell types which go against this
DMFC MFC DEFC
Mass Transport
Diffusion
List four components of PEMFC stack
Electro catalytic layers, electrolyte bipolar plates and end plates
DFC 300, DFC 1500 systems from FuelCell Energy are based on SOFC technology
F
T or F: Activation losses are higher in high temperature fuel cells.
F
T or F: Chemical reactions with positive Gibbs free energy changes (delta G>0) can be used in fuel cells to get electrical energy.
F
T or F: Fuel cells generally exhibit peak power and maximum efficiency under the same operating conditions.
F
The operating principle of Breathalyzers is based on enzymatic fuel cells
F
List four sub systems of a natural gas fueled SOFC for CHP applications
Fuel reformers, desulfurizers, heat engines, power conditioners
Fuel Crossover
Fuel transfer
Overall chemical reaction of hydrogen to oxygen fuel cell operating at 120 deg C and 1 atm pressure.
H_2+0.5O_2->H_2O
Which fuel cell has the highest gravimetric energy content (Wh/kg)?
Hydrogen at 2000 psi
Which statement is true about Toyota MIrai FCV?
Hydrogen storage capacity is about 5 kg.
Provide four chemicals which can be used as fuels in fuel cells to harvest energy
Hydrogen, Carbon, Methane, Methanol, Ethanol, Glucose
What increases the rate of heat generation of a fuel cell?
Increased work load
Which one of the following is not a major issue for PEMFC?
Intermittent operations
The practical efficiency's of modern energy conversion/storage systems are
Li-Ion batteries>Fuel Cells>Internal Combustion Engines>Solar Cells
Which fuel cell type requires CO_2 in one of the reactant feeds? At which electrode CO_2 reacts in this fuel cell type?
MCFC Cathode
What is true about PAFC?
Medium temperature (~200 deg C) hydrogen fuel cell; sulfur containing compounds reduce the anode electro catalytic activity; catalytic activity decay due to particle agglomeration is an issue.
Which is true about the thermo-neutral voltage (E_tn) of a hydrogen fuel cell.
NONE OF THE ABOVE: Higher if the kinetics are faster; decreases with increasing current density; it is independence of the temperature.
Which is not true about PAFC?
Operational cell voltage depends on the relative concentrations of CO_2 at anode and cathode sides
Although the cathodic reactions and the catalyst types of PEMFC and DMFC are same, the activation overvoltage of DMFC cathode is significantly higher than that of PEM cathode. Why.
Oxidation of crossed-over methanol at cathode, poisoning of cathode catalyst by methanol oxidation by products.
Which statement is true about direct methanol (Methanol-Oxygen) fuel cells?
Oxygen reduced at the cathode.
Which statement is true about metal-air, battery-fuel cell hybrid systems?
Oxygen reduction reaction takes place at the cathode.
Provide two fuel cell types that require platinum group metal catalyst
PEMFC DMFC
What is the most widely used electrocatalyst for PEM fuel cells
PT
Which is true about methanol cross over in DMFC?
Reduces the practical efficiency
Provide two fuel cell types which can be used for stationary, high power applications
SOFC MCFC
Desulfurization is required for natural gas fueled PAFC
T
Michigan holds more US patents for fuel cell technologies than any other states
T
T or F: Fuel cell power is determined by fuel cell size. Fuel energy capacity is determined by fuel reservoir size.
T
T or F: Thermodynamic fuel cell generally decreases as temperature increases.
T
There is no dedicated humidifier in Toyota Mirai fuel cell stack
T
Which statement is true about voltage losses of fuel cells?
To increase exchange current density, fuel cell catalyst-electrodes are designed to maximize the number of reaction sites per unit area.
Which is true about different water movements within MEA of a hydrogen PEMFC?
Water will be dragged from anode to cathode side by protons moving through the electrolyte.
Which is true about SOFC?
Y_2O_3 stabilized ZrO_2 serve as the electrolyte
Reduction
e on L
Oxidation
e on R