Air is liquefied using a modified Linde cycle with two consecutive compression stages, the first one from 1 to 20 atm, and the second one from 20 to 150 atm (see Fig. P3.8). The compressed air is cooled down with nonliquefied fractions. The cold air is expanded from 150 atm to 20 atm, and after being used to cool down compressed air, recycled before the second compression stage. The mixture of both streams is at 25C. The liquid air at 20 atm is expanded to 1 atm.

Determine the liquid fraction and the work required at each stage per kg of initial air.

Transcribed Image Text:

Air 298K 1 atm 3 50 2 00 5' 6 7 Liquid