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Liquefaction: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

Example Problem 1

For N2 gas fed at 300 K and 1.0-bar pressure to a Linde liquefaction cycle, calculate the fraction of the flow entering the Joule-Thomson expansion at 200 bar and 165 K that is converted to liquid. The values in the table below were obtained from the Peng Robinson equation of state.

table for example problem for Liquefaction module on LearnChemE.com
Example Problem 2

For N2 gas fed at 300 K and 1.0-bar pressure to a Linde liquefaction cycle, the gas enters the J-T expansion at 200 bar and 165 K. How much compressor work is required per kg of liquid N2 formed? The feed gas is compressed in 3 stages with cooling to 300 K after each stage. The outlet pressures from the three compressors are 5.0 bar, 25 bar, and 200 bar. The values in the table below were obtained from the Peng-Robinson equation of state.

table for example problem for Liquefaction module on LearnChemE.com