Make a thermodynamic analysis of the process described in Ex. 9.3. T = 295 K. Ex.

Make a thermodynamic analysis of the process described in Ex. 9.3. T_σ = 295 K.

Ex. 9.3

Natural gas, assumed here to be pure methane, is liquefied in a Claude process. Compression is to 60 bar and precooling is to 300 K. The expander and throttle exhaust to a pressure of 1 bar. Recycle methane at this pressure leaves the exchanger system (point 15, Fig. 9.7) at 295 K. Assume no heat leaks into the system from the surroundings, an expander efficiency of 75%, and an expander exhaust of saturated vapor. For a draw-off to the expander of 25% of the methane entering the exchanger system (x = 0.25), what fraction z of the methane is liquefied, and what is the temperature of the high-pressure stream entering the throttle valve?

Fig. 9.7

Transcribed Image Text:

Cooler Exchangers 4 5 14 11 15 Win W. out 13 8 12 10 Gas feed 9. Liquid Figure 9.7: Claude liquefaction process. 00 3.