Question

An 850-MW Rankine cycle operates with turbine inlet steam at 1200 psia and 1000°F and condenser pressure at 1 psia. There are three feedwater heaters placed optimally as follows: (a) the high-pressure heater is of the closed type with drains cascaded backward; (b) the intermediate-pressure heater is of the open type; (c) the low- pressure heater is of the closed type with drains pumped forward. Each of the turbine sections has the same polytropic efficiency of 90 percent. The pumps have polytropic efficiencies of 80 percent. Calculate (a) the mass flow rate at the turbine inlet in pound mass per hour, (b) the mass flow rate to the condenser, (c) the mass flow rate of the condenser cooling water, in pound mass per hour, if it undergoes a 25°F temperature rise, (d) the cycle efficiency, and (e) the cycle heat rate, in Btus per kilowatt hour.

Answer 1