Preparation and performance of activated carbon-supported zinc ferrite absorbent for hot-gas cleaning

摘要

An efficient absorbent of hydrogen sulfide for hot-gas cleaning was developed. In order to increase the efficiency of the absorbent, activated carbon-supported ferrite was prepared and the absorption behavior of the absorbent was examined using a fixed bed reactor and a thermogravimetric balance. Activated carbon-supported ferrites could be prepared at a much lower calcination temperature (400 °C) than the typical preparation temperature of ca. 1000 °C for a dry process. These ferrites have high surface areas up to 663 m~2/g. Breakthrough behavior was obtained with a fixed-bed flow reactor, with almost complete absorption of hydrogen sulfide from 5000 ppm to nearly zero level being achieved at an absorption temperature of 400 °C. Utilization of Zn and Fe reached nearly 100 %, but ferrite prepared without activated carbon in a similar manner, afforded metal utilization efficiency of about 50 %. The results obtained with a thermogravimetric balance indicated that the initial hydrogen sulfide absorption rate of the activated carbon-supported ferrite was about ten times higher than that of the ferrite prepared by the dry process. Regeneration of activated carbon-supported zinc ferrite can successfully achieve.