The Influence of Feedwater Preheaters on the Power Plant Thermal Efficiency

According to the new statistical reports of world energy, coal-fired energy production still stands over 30% of total energy production worldwide. It is already demonstrated that the use of regenerative preheating leads an increase in the thermal power plant efficiency as a whole. The present paper focuses on the optimal number of regenerative preheaters used and on their location: on the low pressure side or on the high pressure side. The study was conducted on a 300 MW thermal power station equipped with an intermediate super heater, the initial steam parameters at the turbine entrance being: 170 bar pressure and 540°C temperature. Finally, the increase or decrease of the thermal efficiency for each analyzed case is illustrated. The most favorable case and the most unfavorable case are highlighted.