The effects of steaming and hydrogen reduction of ZnH-ZSM-5, concerning catalytic activity in aromatization of n-hexane were examined to evaluate the stability of ZnH-ZSM-5 in commercial operating condions, in comparison with H-ZSM-5. Steaming at high temperature resulted in greater drop in the yield of aromatics over H-ZSM 5 than that over ZnH-ZSM-5. Hydrogen reduction had little effect on the yield of aromatics over H-ZSM-5, while a remarkable drop in the yield of aromatics was observed over ZnH-ZSm-5. It was found that zinc oxide in ZaH-ZSM-5 was reduced with hydrogen to give metallic zinc, which was then vaporized from the catalyst. This vaporization led to an irreversible decline in the activity for aromatization. Pre-sulfiding of ZnH-ZSM-5 was found to be effective in preventing the vaporization of zinc, by conducting thermogravimetric measurement of vaporized zinc from the catalyst. ZnH-ZSM-5 was pre-sulfided, using thiophene, dimethylsulfide, and disulfidecarbonate, as sulfiding agents, which reduced not only the vaporization of zinc, but also the cracking activity to yield light gases, such as CH4 and C2H6.
|Number of pages||8|
|Journal||Sekiyu Gakkaishi (Journal of the Japan Petroleum Institute)|
|Publication status||Published - Jan 1 1998|
All Science Journal Classification (ASJC) codes
- Fuel Technology
- Energy Engineering and Power Technology