TO-98-04-4 -- Improving Cogeneration Plant Performance Through Effective Maintenance Strategies PDF

Gas-fired cogeneration plants supplying power and thermal energy make up an increasing percentage of new fossil generation capacity additions, both in the U.S. and overseas. These plants are popular, not only because they cost less to build, but also because they are highly efficient and their operation and maintenance costs are lower than plants using the traditional coal-based Rankine cycle. One of the methods being used to contain the initial cost of building cogeneration plants is to minimize redundancy both in the quantity of spare equipment specified for the various systems in the plants and in the design capacity of individual components. The overall effect of such a strategy may lead to reduced reliability and availability of the cogeneration plant in the long term.

Operating cogeneration plants present a variety of technologies, equipment, and operating practices. While newer cogeneration plants routinely operate at a reliability of 90% or higher, older plants may not be able to achieve such performance due to excessive equipment breakdowns or inadequate maintenance strategies. By not having the appropriate maintenance programs in place, even newer cogeneration plants are vulnerable to deteriorating reliability and availability in the long term. This paper describes mechanisms for directing maintenance resources toward reducing current maintenance costs while maintaining high availability without sacrificing long-term reliability. The maintenance strategies discussed are those that can provide the maximum benefits for improving cogeneration plant reliability, availability, capacity, cost control, and safety.

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