Page 93 - Handbook of Energy Engineering Calculations
P. 93
FIGURE 18 Bleed regenerative steam cycle.
Calculation Procedure:
1. Determine the enthalpy of the steam at the inlet of each heater and the
condenser
From a superheated-steam table, find the throttle enthalpy H = 1474.5 Btu/lb
2
2
(3429.7 kJ/kg) at 2000 lb/in (abs) (13,790.0 kPa) and 1000°F (537.8°C).
Next, find the throttle entropy S = 1.5603 Btu/(lb · °F) [6.5 kJ/(kg · °C)], at
2
the same conditions in the superheated-steam table.
Plot the throttle steam conditions on a Mollier chart, Fig. 19. Assume that
the steam expands from the throttle conditions at constant entropy = constant
S to the inlet of the first feedwater heater 1, Fig. 18. Plot this constant S
expansion by drawing the straight vertical line 2-3 on the Mollier chart, Fig.
19, between the throttle condition and the heater inlet pressure of 750 lb/in 2
(abs) (5171.3 kPa).
