Assistant Professor, Faculty of Mechanical Engineering , K. N. Toosi University of Technology, Tehran, Iran
The growth of the electrical energy consumption form one side and the bounded available fossil fuel and other limitations from the other side, makes the thermal power plants upgrading as a main demand in the world. Decreasing the internal energy consumption, increasing the performance and the output power with the minimum costs are the important targets of the power plants retrofitting. Nowadays power plant repowering with the help of gas turbine that includes two manners (Full Repowering and Para-Repowering) is one of the best methods for the power plants progress. Different repowering methods according to their costs, amount of the output power increase and the power plant situation could be various solutions for the retrofitting. Choosing each of these methods can be done just by analyzing the related parameters. Technical and economic comparisons between different repowering methods needs an investigation of several technical and economic parameters and the characteristics of the electrical networks development as well. Combined cycling/cycles as a repowering method usually is used for low capacity units and for the bigger units para repowering could be more suitable. Feasibility study for repowering a power plant and choosing the best method should be done through a case study for that specific power plant. In this paper using different para-repowering methods has been studied for the Lowshan power plant. The results show that feed water heating repowering is the best method based on the cost of electrical energy generation in this case.