Typically technical lifetimes of major thermal (coal fired) power plants are in the order 30 to 40 years; however, in order to actually obtain such a long lifetime a major renewal of central highly stressed parts after 15 to 20 years is a prerequisite. For a particular power plant this paper will describe the background for the decision, the planning and the execution as well as the challenges met and the results achieved following an extensive project aimed at extending the lifetime of the plant. The plant is an approx. 350 MWe unit with the ability of coproducing up to approx. 450 MJ/s heat for the district heating (DH) network of a city in Denmark. Since the unit is vital for the DH supply of the city, the lifetime extension was essential to ensure a continued and reliable supply of heat. The lifetime extension project became the first step in securing the future of the power plant. The unit was commissioned in the 1980’s, and over time updated with co-firing of bio-fuel, and additional flue gas emission equipment, i.e. Flue Gas Desulphurisation (FGD) and DeNOx (SCR). After 185,000 operating hours the owner launched a comprehensive project with the aim of a complete refurbishment of the unit to extend the life of the plant with 15 years until 2030. In this project Ramboll acted as Owners Engineer and was responsible for: - Technical assessment of the complete plant. CAPEX budget. Planning of execution. Tendering / contracting. Supervision and commissioning. Hand-over and documentation. This paper will address the methodology utilised when performing the technical assessment and when choosing which components to upgrade / exchange. Plant components requiring special attention in ageing power plants will be discussed. In addition the paper will address two specific issues handled in the project concerning components subject to creep / fatigue and uneven temperature distribution in super heaters.
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