Bulk Separations by tt-Complexation

Bulk separation/recoveiy of CO from synthesis gas by TT-complexation has already been conunercialized worldwide since 1989. TT-Complexation is highly promising for other bulk separations such as olefin/paraffin and aromatic/ahphatic separations, either in vapor phase by PSA or in liquid phase by simulated moving bed processes. Before discussing these processes, problems of deactivation or stability of the jr-complexation sorbents will be first addressed. 

The deactivation behaviors of various TT-complexation sorbents have been studied. Cu+ salts such as CuCl and Cu(l) zeolites are oxidized quickly into Cu + state upon exposure to ambient air. Moismre is known to accelerate the oxidation process. Ag+ salts and Ag+-zeolites, on the other hand, are quite stable in ambient air with minimized light exposure (Hutson, 2000). 

The behavior of AgY zeolite in H2S was studied by Takahashi et al. (2001b). At 25 to 120 °C, H2S chemisorbed on AgY, while reaction with H2S with continual weight gain was observed at 180 °C. XPS analysis showed the formation of Ag2S. However, the adsorption capacities for 1-butene and 1,3-butadiene were only slightly lowered, indicating the r-complexation capability of Ag2S. 

The effects of H2 and H2S on Cu(I)Y were studied by Takahashi et al. (2001a). Unlike AgY, exposnre to H2 and H2S at 120 °C showed no effect on CuY, demonstrating its excellent poison resistance toward H2 and H2S. 

Since 1989, CO separation/recovery by PSA using supported CuCl has been commercialized worldwide. PSA separation results are available in the literature (Kansai Coke Chemicals Co., 1989 Chen et al., 1997 Golden et al., 1998). 

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