Abstract: This paper summarizes the application effect of variable frequency speed control in catalytic cracking units, analyzes the problems encountered during application, and proposes issues and suggestions that should be noted in the actual operation of frequency converters. Keywords: Variable frequency speed control; Application effect; Problem analysis 1 Introduction Fluid machinery, as an important energy conversion device, is the heart of many basic and energy industries. 80% of the electricity consumption in petrochemical enterprises is used for driving pumps and motors. In recent years, with the development of power electronics technology, petrochemical enterprises have achieved significant energy-saving effects and economic benefits by using variable frequency speed control technology for motors. At the same time, with the development of variable frequency technology and control technology, the application of variable frequency speed control in pumps and motors has expanded from simply saving energy to improving product quality and achieving automation, and its application areas are constantly expanding. 2. Application of Variable Frequency Speed ​​Control System in Pump Units The 1.40 Mt/a catalytic cracking unit has nearly 100 rotating equipment of various sizes. During overhauls in 1998 and 2001, variable frequency speed control systems were added to 13 pump units (see Table 1). After the variable frequency system was put into operation, the flow rate was changed from being controlled by regulating valves to being controlled by speed. The opening of the regulating valves increased or fully opened, resulting in a significant reduction in pump outlet pressure and varying degrees of reduction in motor current, leading to significant energy savings. Simultaneously, due to the reduced motor speed, motor noise decreased, and the frequency of pump repairs due to seal and bearing failures decreased significantly, saving material costs and reducing maintenance workload. The following analysis focuses on the effectiveness of the variable frequency system and issues to be aware of during its use. [b][align=center]For detailed information, please click: Analysis of the Application of Variable Frequency Speed ​​Control in Catalytic Cracking Units[/align][/b]