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2024
Meeting Abstract
Title
Investigation of the Effect of Ammonia As Ambient Air Contaminant on PEM Fuel Cell Stack Performance and Degradation Using EIS, Thda and Different Gas Analysis Methods
Abstract
The negative effects of airborne contaminants on polymer electrolyte membrane fuel cell (PEMFC) have already been shown in several publications. [1] Among these contaminants, ammonia (NH3) with its multistep reversible and irreversible effects is particularly significant. Recent studies on air quality in urban areas have revealed a notable increase in ammonia levels within a span of two years. [2] This rapid increase can be attributed to the growing prevalence of EURO-6 diesel vehicles equipped with selective catalytic reduction (SCR) cats, which results in ammonia slip during the nitrogen oxide reduction process in diesel engines. [2]
Ambient air is the most common used oxidant gas in mobile and stationary PEM fuel cell systems. The performance of fuel cell can suffer beyond the oxygen gain from airborne contaminants, which also have the potential to accelerate degradation. To prevent that airborne contaminants reach the fuel cell cathode, air filter systems consisting of particle filter and specially for fuel cell requirements developed filter are installed at the cathode inlet. Despite the installation of an air filter system, airborne contaminants can still reach the fuel cell cathode.
The focus of this investigation is on the effects of ammonia in PEM fuel cell stacks. In contrast to single cell operation, stack operation can introduce additional effects such as cell-to-cell inhomogeneities and varying degrees of ammonia-induced degradation among cells. For the investigation, experiments with a PEMFC stack are going to be done on a fuel cell testbed equipped with an impedance analyzer. Ammonia is going to be mixed into the cathode air in the ppb range. Its effects on PEMFC stack performance are going to be investigated with electrochemical impedance spectroscopy (EIS) and total harmonic distortion analysis (THDA). The cathode exhaust gas is also going to be analyzed by gas analyzers such as FTIR gas analyzer and mass spectrometry.
It is planned to test the PEMFC stack under different operating conditions like temperature, relative humidity and pressure of inlet gases, with various parameters and different cathode gas mix ratios while monitoring possible conversion of impurities via FTIR and the stack state of health using THDA and conventional technologies to understand the link between the effect of ammonia on fuel cell stack performance, on its lifetime and to determine possible early indicators.
Ambient air is the most common used oxidant gas in mobile and stationary PEM fuel cell systems. The performance of fuel cell can suffer beyond the oxygen gain from airborne contaminants, which also have the potential to accelerate degradation. To prevent that airborne contaminants reach the fuel cell cathode, air filter systems consisting of particle filter and specially for fuel cell requirements developed filter are installed at the cathode inlet. Despite the installation of an air filter system, airborne contaminants can still reach the fuel cell cathode.
The focus of this investigation is on the effects of ammonia in PEM fuel cell stacks. In contrast to single cell operation, stack operation can introduce additional effects such as cell-to-cell inhomogeneities and varying degrees of ammonia-induced degradation among cells. For the investigation, experiments with a PEMFC stack are going to be done on a fuel cell testbed equipped with an impedance analyzer. Ammonia is going to be mixed into the cathode air in the ppb range. Its effects on PEMFC stack performance are going to be investigated with electrochemical impedance spectroscopy (EIS) and total harmonic distortion analysis (THDA). The cathode exhaust gas is also going to be analyzed by gas analyzers such as FTIR gas analyzer and mass spectrometry.
It is planned to test the PEMFC stack under different operating conditions like temperature, relative humidity and pressure of inlet gases, with various parameters and different cathode gas mix ratios while monitoring possible conversion of impurities via FTIR and the stack state of health using THDA and conventional technologies to understand the link between the effect of ammonia on fuel cell stack performance, on its lifetime and to determine possible early indicators.
