ENERGY ANALYSIS OF REPOWERING STEAM POWER PLANTS BY FEED WATER HEATING

Modern society and economic development are completely dependent on various forms of energy while the ever-increasing demand for energy, in combination with significant environmental topics, has resulted in state-of-the-art ideas and solutions for fulfilling these often-contradictory goals, i.e. increasing efficiency or environmental protection and economic goal. The efficiency of the existing operating units for electricity production based on the usage of low-quality coal does not go hand in hand with the requirements of this new concept. One of the most efficient ways to reduce specific energy consumption is using Combined Heat and Power plants. In comparison to classical, separate heat and power plants, the advantage for CHP plants comes from their high efficiency. The result of higher efficiency is lower primary energy consumption and lower environmental pollution due to low values of CO2 emissions. Several revitalization configurations can be applied in order to fit the existing thermal power plants into combined cycles. The idea is to install, at the existing location, one gas turbine to increase the overall efficiency. This paper analyzes the potential of a combined gas-steam facility in the situation where the gas facility is used for heating feed water, which enters the heat recovery steam generator. A comparison of energy efficiency for various operating regimes, with and without heat production, is performed for this option.