Application of RCM for safety considerations in a steel plant

Abstract

Abstract Any operation or process done on machine or its parts to enhance the efficiency of machine before or after the breakdown is called maintenance. A concern may be said to be successful over the years, when it runs non-interrupted, maintains a smooth production flow consistently and at optimum productivity levels. Plant can achieve productivity up to a satisfactory level by proper maintenance work. The maintenance system may be categorized as either ‘Planned’ or ‘Unplanned‘. The classic maintenance problems in modern industries are insufficient pro-active maintenance, frequent problem repetition, erroneous maintenance work, sound maintenance practices not institutionalized, unnecessary and conservative PM, sketchy rationale for PM actions, lack of traceability/visibility for maintenance program, blind acceptance of OEM inputs, PM variability between like/similar units, paucity of predictive maintenance applications. Hence it was necessary to develop an appropriate methodology to develop strategies and programmatic approach to deal with such problems. The reliability centered maintenance offers the most systematic and efficient process to address an overall programmatic approach to the optimization of plant and equipment maintenance In this paper, the concept of RCM has been applied to process of vacuum degassing/vacuum oxygen decarburising (VD/VOD) in steel melting shop of a medium scale steel industry. Safety consideration is the significant aspect for selection of the system. By systematically applying the RCM methodology, failures, failure modes are analyzed. To preserve the system function, preventive maintenance tasks such as inspection/checking, lubrication, cleaning, adjustment, replacement, are allotted for various failure modes. RCM based preventive maintenance schedule for the system is formulated and compared with the company's existing preventive maintenance schedule. For subsystems such as ejectors, water-ring pumps and the RLC/ladle car/furnace, existing maintenance schedule is conservative. For oxygen lance and cooling pumps, maintenance frequency is to be increased to quarterly from yearly in the present schedule. For condensers bimonthly schedule is recommended as compared to none, whereas for cooling pumps the schedule remains unchanged. This reveals that RCM based tasks need not necessarily increase the frequency but can, retain or even decrease the frequency of maintenance based on functional priorities. RCM can also recommend the additional maintenance tasks. Application of RCM based PM schedule requires use of age exploration technique and attitudinal changes.