Design And Implementation Of A Mechanical Seal Improvement Program At An Oil Refinery
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A mechanical seal improvement program was initiated at a major oil refinery. The program was intended to improve seal reliability, reduce emissions, improve safety, and reduce costs. A partnership agreement was reached between the refinery and a major mechanical seal manufacturer. In preparation for the program, extensive research was conducted to ensure that all relevant information was readily available. A computer database was set up to organize the information and document changes as they were implemented. A document was generated detailing preferred seal designs and piping plans for various classifications of operating conditions, based on past experience and established engineering principle. The actual program focused on several areas. All mechanical seal failures were closely investigated in order to determine the root cause of failure and to make recommendations for changes that would improve seal reliability. Additionally, a list was generated of the pumps with the worst history of seal reliability. At least two of these “worst seals” were addressed each month in an attempt to identify and correct the cause of premature failure. Pumps that were determined to be current or future environmental emissions problem were addressed at the rate of at least two per month in a similar fashion. As much as possible, all seal designs were standardized such that each seal was capable of being installed in the greatest number of pumps possible. In conjunction with this standardization, an attempt was made to identify and eliminate obsolete warehouse stock items. Additional training was provided to mechanics and unit operators to ensure that seals were being installed and operated properly. Over the course of 32 months, 191 pumps out of a population of over 12000 were converted to cartridges. During the same period of time, the seal mean time between failures for the entire population increased by 54 percent, and the average monthly maintenance cost associated with mechanical seal failures decreased by 17 percent. In addition, due to standardization and consolidation efforts, the net value of warehouse stock of seals and seal parts was reduced by 11 percent and the number of warehouse stock items was reduced by 34 percent. Several important conclusions were reached as a result of the success of the program. Cartridge seals, when properly applied, have an inherent advantage over noncartridge designs in terms of reliability and ease of installation. In order to be successful, any seal improvement program must incorporate additional training and support for mechanics and unit operators. Lastly, it is possible to reduce overall costs associated with seal failures, while fully complying with increasingly stringent environmental regulations and significantly improving safety.
Pellin, Johnny J.; McCollough, William J. (1995). Design And Implementation Of A Mechanical Seal Improvement Program At An Oil Refinery. Turbomachinery Laboratories, Department of Mechanical Engineering, Texas A&M University. Available electronically from