Abstract: A refinery has built a catalytic cracking (FCC) unit with a processing capacity of 4.8 Mt/a, planning to utilize the by-product C₄ components to construct an industrial facility for the carbonylation of mixed C₄ to produce high-carbon alcohols. However, the high methanol content in the C₄ components adversely affects downstream chemical production. To address the issue of excessive methanol content in the C₄ components, a systematic analysis of the process flow from the FCC unit to the C₄ separation column was conducted, identifying the causes of methanol generation. It was found that methanol primarily originates from FCC side reactions. In response, strategies were proposed to suppress methanol production, introduce a trace methanol removal process, and regulate the mixed C₄ feedstock. These measures provide technical references for reducing methanol content in C₄ and ensuring stable operation of the downstream high-carbon alcohol unit.

Key words: fluid catalytic cracking, ethanol, mixed C₄, higher aliphatic alcohol