Improving circulating fluidized bed dehydrogenation technology through optimization of fluidization
Mayank Kashyapa,*, Malleswara Rao Tadiboyinab, Christian Okolob, Sami Al-Mutairic
The dehydrogenation of light alkanes to corresponding light olefins is an important industrial process. The present work involved the assessment of a commercial alkane dehydrogenation circulating fluidized bed (CFB) reactor unit that had been underperforming and exhibiting higher than expected catalyst losses over a long period of time. Several aspects of this unit related to fluidization, catalysis, and process engineering were investigated to understand and resolve these issues. The primary focus was on the fluidization aspects of the process, along with a comparison of equipment design and operating conditions to accepted best practices in the industry. The designs of key equipment in the reactor and regenerator, including feed distributors, fuel gas distributors, cyclones, baffles, strippers, transfer lines, risers, riser terminations, and refractories, were studied in detail. The attrition rates of different types of catalysts used in the unit were also examined. Several recommendations and improvement opportunities were proposed to significantly increase light olefins production and reduce catalyst losses, and were accepted and implemented. This study provides insights into means of improving fluidization behavior and highlights the viability of employing a systematic approach to determine the underlying root causes of issues in a commercial CFB reactor unit.
Fluidization; Circulating fluidized bed; Dehydrogenation; Light olefin; Catalyst loss