Pre-combustion carbon dioxide capture is the separation of carbon dioxide from the feed from the water-gas shift reaction, which mainly contains carbon dioxide and hydrogen gas. Due to their relatively easy application, membranes are widely used in gas separation apparatuses. For pre-combustion capture, membranes must be highly stable due to the harsher conditions, as compared to post-combustion carbon dioxide capture. Minor gases in the feed gas influence both the performance and stability of membranes; however, few studies have examined the effects of these minor gases.  PEBAX (Poly (ether block amide)), by itself or mixed with other chemical compounds, is one of the most common polymers used for carbon dioxide capture membranes. Hydrogen sulfide is reported as a factor that affects membrane performance and, at the same time, is a general minor gas in the feed of pre-combustion carbon dioxide capture.  For the experiments, feed gas with 60mol% of hydrogen gas and 40mol% of carbon dioxide and trace levels of hydrogen sulfide, which varied by concentration from 5ppm to 200ppm, was used. The permeability test was conducted with and without hydrogen sulfide in different concentrations to identify the impact of hydrogen sulfide on membrane permeability and selectivity. Then, the membrane that was exposed to the feed gas was analyzed using various methods, such as SEM, AFM, and FT-IR, to identify changes of membrane stability and morphology, such as swelling. Each test varied by concentration, time, and temperature. The interaction of hydrogen sulfide and the PEBAX membrane and a relevant mechanism is expected to be clarified throughout a series of experiments.

Effects of hydrogen sulfide on the PEBAX 2533 polymeric membrane for carbon dioxide/hydrogen separation

256th National Meeting (2018)

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