Shale gas is reshaping petrochemicals. A big change is the generation of on purpose propylene (OPP) plants. These OPP plants in most cases are based on propane dehydration (PDH). The reason for OPP plants is the change of mixtures being fed to crackers produces less propylene. In PDH plants, propane are converted to propylene but not quantitatively (e.g. 85% yield) so there is a need to improve propylene to polymer grade (99%) propylene. This can be done with an expensive distillation process or a more economical hybrid membrane/distillation process. This program will focus on (1) developing enhanced catalysts and (2) using either a membrane process or a hybrid membrane distillation process. The membranes developed in this process will enhance not only OPP processes but many other olefin-paraffin pinch points at the petrochemical plant. More of these pinch points will have developed with the shifting of feedstock to more ethane and related shale gas. This program proposes to develop an enhanced CMS custom amorphous fluoropolymer (CAF) membrane system for enhancing the OPP process by replacing downstream distillation with a CMS CAF membrane system for purifying the propylene. In developing this enhanced OPP membrane purification system we will not only reduce the cost of OPP but we will be providing a valuable tool for enhancing the broader debottlenecking need of the shifting petrochemical industry. To date, CMS has developed CAF facilitated transport membranes (FTM) containing Ag+ sites which have shown superior flux, selectivity, and long term stability when tested with ethylene/ethane and propylene/propane. Phase I will further customize these CMS membranes and overall systems with a goal of 30+% improvement in performance by developing and evaluating higher temperature CAF membranes. Engineering + economic evaluation will show payback times of less than 18 months and/or internal rate of return greater than 50% related to use of CMS membranes for making polymer grade propylene at OPP plant. Phase I will also show long term stable performance in presence of hydrogen poisons. Ethylene and propylene are two of the three major building blocks of the petrochemical industry (benzene is third). Therefore membrane processes that can cost effectively enhance olefin-paraffin (e.g. ethylene from ethane) separations provides potential for energy savings approaching 100 Trillion BTU/yr.
