Detection of ppb level SO 2 in H 2 by an adsorption–desorption gas chromatography method

Abstract

Some H 2 impurities (e.g., SO 2), even at 10–100 ppb level, can greatly reduce the working life of the proton exchange membrane (PEM) fuel cells. Sulfur compounds such as SO 2 is a typical impurity existing in the coal gas derived H 2 fuel. As a result, detection of near ppb level SO 2 in H 2 for fuel cells has been a focus of many recent studies. In this study, we present a gas chromatography (GC) method integrated with an in-house built adsorption–desorption device that can detect SO 2 at near ppb level. The technique is as follows: sample gas is collected by a SO 2 absorbent at room (or low) temperature, followed by desorption at an elevated temperature prior to gas sampling with GC. Operating conditions are optimized through testing on the absorbent material, adsorption and desorption temperature. Under an optimal condition, a sample gas of 10–20 ppb SO 2 was detected within an hour.