Question

Water is the working fluid in a regenerative Rankine cycle with one open feedwater heater. Steam enters the turbine at 1400 lbf/in^2 and 1000F and expands to 120 lbf/in^2, where some of the steam is extracted and diverted to the open feedwater heater operating at 120 lbf/in^2. The remaining steam expands through the second-stage turbine to the condenser pressure of 2 lbf/in^2. Each turbine stage and both pumps have isentropic efficiencies of 85%. Flow through the condenser, open feedwater heater, and steam generator is at constant pressure. Saturated liquid exits the open feedwater heater at 120 lbf/in^2. The net power output of the cycle is 1 x 10^9 Btu/h. Determine for the cycle

(a) the mass flow rate of steam entering the first stage of the turbine, in lb/h.

(b) the rate of heat transfer, in Btu/h, to the working fluid passing through the steam generator.

(c) the thermal efficiency.

Answer 1

(a)The mass flow rate =

2.297×10^6 lb/HR

(b)the rate of heat transfer =2700.847×10^6Btu/hr

(c)thermal efficiency is 37.025%

Check attachments for calculation