The Claude liquefaction process is to be applied to methane. Using the schematic of Fig. 5.13 for stream numbering, the key variables depend on the fraction of stream 3 that is liquefied, ṁ₈/ṁ₃, and the fraction of stream 3 that is fed through the expander, ṁ₅/ṁ₃. Create a table listing all streams from low to high stream numbers. Fill in the table as you complete the problem sections. Attach a P-H diagram with your solution.

(a) Write a mass balance for the system boundary encompassing all equipment except the compressor and precooler.

(b) Write an energy balance for the same boundary described in part (a), and show

(c) Stream 3 is to be 300 K and 3 MPa, stream 4 is to be 280 K and 3 MPa, stream 12 is to be 290 K and 0.1 MPa, and the flash drum is to operate at 0.1 MPa. The expander has an efficiency of 91%. The fraction liquefied is to be ṁ₈/ṁ₃ = 0.15. Determine how much flow to direct through the expander, ṁ₅/ṁ₃.

(d) Find the enthalpies of streams 3–12, and the temperatures and pressures.

Transcribed Image Text:

mg M3 (H3-H12)+(m5/m3)WS expander (Hg - H12)