Abstract
This research tests a membrane reactor, equipped with a molecular-sieve carbon membrane, using isobutane dehydrogenation on a chromia alumina catalyst as a model reaction. Most pores of the carbon membrane employed are 6-8 A in size and previous independent transport studies show that the permeability ratio of hydrogen to isobutene is larger than 100. These features make the membrane an excellent highly selective low-cost candidate for application in a membrane reactor. The novelty of this study is in the proposed application at relatively high temperatures (450°C and 500°C); only a few studies have tested carbon membrane reactors. Two types of operation modes were studied, using either nitrogen as a sweeping gas in counter current flow or using vacuum as a driving force for membrane transport. As expected, higher conversions were achieved with decreasing feed flow rate. The conversion achieved in the counter-current flow operation method was higher than in all other modes achieving a maximum of 85% at 500°C. While this result is much higher than in the corresponding PFR, the obtained improvement is a result of nitrogen transport and dilution. The conversions obtained in the vacuum mode show modest gains above the ones received in the PFR (40% vs. 30% at 500°C). These results were compared with simulations that used the experimentally determined transport parameters.
| Original language | English |
|---|---|
| Pages (from-to) | 2013-2021 |
| Number of pages | 9 |
| Journal | Chemical Engineering Science |
| Volume | 59 |
| Issue number | 10 |
| DOIs | |
| State | Published - May 2004 |
| Externally published | Yes |
Keywords
- Carbon membrane
- Chromia catalyst
- Isobutane dehydrogenation
- Membrane reactor