Ion-exchange membranes for bulk separation of acid gases

摘要

The field test has continued with PFSA composite membranes. The substrates have been a microporous polypropylene supplied by 3M Co. The membranes have been imbibed with either aqueous solutions of methyldiethanolamine (MDEA) or n-methylpyrrolidone (NMP). Data from five composite membranes have thusfar been obtained and are presented in the following Figure 6. The composite 1 membrane gave erratic performance before it mechanically failed, but most of the observed separation factors were high enough (>35) to be consistent with the initial results from the gel-NE 111 membrane. The separation factor for the other four composites have been consistently low (between 13 and 3). The main difference is that between composite l and the rest we installed an inertial separator to remove excess moisture from the feed stream. This separator may be too efficient and the membranes may be drying out. Another possibility is that the membranes may just not be made well enough and sufficient uncoated pores may exist to subvert the separation efficiency. We tested a membrane which had been removed from the field test rig in our laboratory permeation equipment. Those results are presented in Figures 7 and 8. Again good agreement between the field test and our lab experiments.