Page 255 - Standard Handbook Of Petroleum & Natural Gas Engineering

226 General Engineering and Science

Qin

&

T yq
condenser
0 0

I
S

(0) (b)
Figure 2-36. (a) Schematic diagram of system. (b) T-S diagram of process.

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The efficiency of power cycles such as the Rankine cycle is given by the ratio of
the net work out to the heat added. Thus from Figure 2-36 the efficiency is

(2-154)

The H-S plot is called a Mollier diagram and is particularly useful in analyzing
throttling devices, steam turbines, and other fluid flow devices. A Mollier diagram
for steam is presented in Figure 2-37 (standard engineering units) and in Figure 2-38
in SI units.
Thermodynamic properties may be presented in various ways, including:
Equations of state (e.g., perfect gas laws, Van der Waals equation, etc.).
Charts or graphs.
tables.
Tables 2-20-2-25 present thermodynamic properties for several pure substances
commonly encountered in petroleum engineering practice.
For further information on this subject, refer to References 15 through 26.

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