Steam Power Plant Performance Operating at High Temperature and Pressure Conditions

Steam power plants have been used for generating electric power since early 20 century; their cycles have been subjected to extensive studies in order to improve their performance including power output, thermal efficiency and specific steam consumption etc. The aim of this work is to examine several configurations based on Rankin cycle to obtain optimum cycle performance. However, four different configurations have been studied including simple Rankine cycle, Ideal regenerative Rankine cycle, Ideal regenerative-reheat cycle and finally regenerative – reheat cycle with intermediate steam extraction for high pressure turbine. Two cases have beenconsidered in current study; the first case was carried out when the turbine pressure is assumed to be constant at 80 bar and the temperature varies from 300°C to 700°C. The second case was studied when turbine inlet pressure varies from 35 to 120 bars and the temperature of steam entering turbine is kept constant at 480 °C. Regarding to the first case, the obtained results reflects that the configuration of regenerative – reheat with intermediate steam extraction has a better performances which involve high thermal efficiency, low specific steam consumption, and very high work ratio. Results show that thermal efficiency increases nearly by (4.77 %), while the specific steam consumption reduced nearly by (10.22%), and finally work ratio improved nearly by (0.08%) in comparison with simple cycle, when inlet turbine temperature increase from 300 to 700 °C. However, in the second case, the turbine inlet pressure increases from 35 to 120 bar (temperature of superheated steam is 480°C). Results show the thermal efficiency increase nearly by (2.42 %), Specific steam consumption improved nearly by (7.65%), and finally work ratio decreased nearly by (0.12%).