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Principal Modernization Solutions for a 300 MW Power Unit to be Converted to Operate at Ultra-Supercritical Steam Parameters

This paper analyses the state of power engineering in Ukraine and the main trends in the development of the world market in the field of converting high-capacity powerful power units of thermal power plants into ultra-supercritical (USC) ones. It is shown that the energy sector of Ukraine requires special attention and the introduction of new modern technical solutions. Worldwide trends indicate that the emphasis is now on increasing the steam parameters before a turbine to ultra-supercritical ones. This allows one both to increase the efficiency of power units and to reduce thermal emissions, fighting the global environmental problem of climate warming. The implementation of this approach is proposed taking into account the realities of the Ukrainian economy and the available technical capabilities of the power engineering industry. This paper presents the results of variational computational studies of the thermal scheme of the 300 MW power unit of the K-300-23.5 turbine to be converted into a USC one. The problem was solved under the condition of maximizing the preservation of the thermal scheme, increasing the efficiency of the power unit and minimizing capital investments during the modernization of the turbine. It was chosen to preserve the regeneration system, as well as the medium-pressure (MP) and low-pressure (LP) cylinders. Considered and calculated were variants with the addition to the existing turbine of a USC cylinder and the creation of a new high-pressure cylinder (HPC) with insignificant changes in its overall characteristics. The results of computational studies showed that the most rational variant for modernizing the 300 MW turbine plant is the creation of a new HPC designed for operation at USC steam parameters as well as the addition to the IPC of a new cylinder with the purpose of increasing the reheat steam parameters while preserving the regeneration system.