Abstract: In recent years, the number of failures such as sudden rise of bearing temperature and jamming of slide valve occurred during the operation of the equipment has been increasing. However, during the disassembly and inspection process, no major equipment problems were found and only some coking materials and carbon laydown were found. After simple cleaning and putting into operation for some time, the same failure would occur again. The problem was studied and the cause of the failure was found to be varnish. This paper expounds the formation principles of varnish, the hazards of varnish, and lubricating oil detection. It introduces several commonly used equipment for varnish removal. At the same time, it compares and analyzes the data before and after the practical application of two varnish removal equipment. The results show that the application of varnish removal equipment reduces the MPC. In addition, conventional lubricating oil detection cannot meet current production requirements, and targeted detection programs need to be developed based on actual lubricating oil application scenarios.

Key words: varnish, MPC, lubricating oil detection