FEEDWATER HEATING METHODS Steam-Plant Feedwater-Heating cycle Analysis Direct-Contact Feedwater Heater Analysis Closed Feedwater Heater Analysis and Selection Power-Plant Heater Extraction-Cycle Analysis Feedwater Heating with Diesel-Engine Repowering of a Steam Plant | Source HANDBOOK OF MECHANICAL ENGINEERING CALCULATIONS SECTION 5 FEEDWATER HEATING METHODS Steam-Plant Feedwater-Heating cycle Analysis Direct-Contact Feedwater Heater Analysis Closed Feedwater Heater Analysis and Selection Power-Plant Heater Extraction-Cycle Analysis Feedwater Heating with Diesel-Engine Repowering of a Steam Plant STEAM-PLANT FEEDWATER-HEATING CYCLE ANALYSIS The high-pressure cylinder of a turbogenerator unit receives 1 000 000 lb per h 454 000 kg h of steam at initial conditions of 1800 psia 12 402 kPa and 1050 F C . At exit from the cylinder the steam has a pressure of 500 psia 3445 kPa and a temperature of 740 F C . A portion of this 500-psia 3445-kPa steam is used in a closed feedwater heater to increase the temperature of 1 000 000 lb per h 454 000 kg h of 2000-psia 13 780-kPa feedwater from 350 F C to 430 F C the remainder passes through a reheater in the steam generator and is admitted to the intermediate-pressure cylinder of the turbine at a pressure of 450 psia 3101 kPa and a temperature of 1000 F C . The intermediate cylinder operates nonextraction. Steam leaves this cylinder at 200 psia 1378 kPa and 500 F 260 C . Find a flow rate to the feedwater heater assuming no subcooling b work done in kW by the high-pressure cylinder c work done in kW by the intermediate-pressure cylinder d heat added by the reheater. Calculation Procedure 1. Find the flow rate to the feedwater heater a Construct the flow diagram Fig. 1. Enter the pressure temperature and enthalpy values using the data given and the steam tables. Write an equation for flow across the feedwater heater or H2 - H7 water H6 - H5 . Substituting using the enthalpy data from the flow diagram flow to heater 1 x 106 409 - - lb h 41 kg h . 2. Determine the work done by the high-pressure cylinder b The work done steam flow rate lb h H1 - H2 3413 1 x 106 - 3414 38 kW. Downloaded from .
