Auxiliary equipment for lubrication and sealing of high speed rotating machines plays vital role in working life and down time of machinery. Prior in history, auxiliary equipments were major cause of unscheduled down time of critical machine and even sometime failure. Although designers have eliminated the need of sealing supports system by improving reliability of design and introducing new technologies of bearings and seals but still equipments that are designed earlier in 1970s with old technologies are facing lot of problems.

Examples are there to retrofit these old technologies but that is not economically practical, cost to retrofit is much higher when compared with maintenance and overhauling of the existing technology. Shaft sealing is provided to restrict the escape of hazardous process gases to environment. Environmental legislation bounds us not to put these gases in environment unless we make them harmless to any life in environment. To fulfill requirement of environmental legislation, different types of sealing mechanisms are employed depending upon the process fluid properties that is to be sealed.

Here is a case study of Ammonia plant where in ammonia synthesis loop synthesis gas is compressed in vertical split type centrifugal compressors. These compressors are working with floating ring type oil seals to prevent the leakage of pressurized synthesis gas from compressor into environment. They are facing lot of problems regarding oil seals/seal oil system on synthesis gas compressor since commissioning of the plant. Oil consumption was increasing day by day due to oil carry over with synthesis gas and causing problem in downstream chillers system, every time chiller and ammonia convertor disturbed with disturbance in seal oil system. Recently in 2014 they faced two explosions on lube oil and seal oil reservoir which caused serious damage to Reservoir and connecting lines, this time plant had to shut down and inspection was carried out. Oil seals were found problematic which were passing gas to seal oil reservoir through return lines. This incident was the result of improper working of oil seals and oil seal support equipments. Afterwards taking corrective measures further investigation was carried out which revealed the root cause of the explosion and solution implementation was don.