Exercise 7.1 Compression and expansion of an ideal gas 50 mol/s of an ideal gas at 300 K and 1 bar (flow 1) is compressed to 10 bar (flow 2). The compression takes place adiabatically, the adiabatic efficiency is 80%. Stream 2 is expanded in a valve down to 1 bar (stream 3) and then cooled to 300 K (stream 4). A constant heat capacity Cp= 30 J/mol*K is assumed. a) Make a table showing temperature, pressure, enthalpy [J/mol] and entropy [J/mol*K] for the four streams. Choose 298 K and 1 bar as the reference state. b)Calculate added heat and work [J] in the process. c)Calculate the total entropy increase [J/mol*K] for each of the three process steps (compression, pressure relaxation and cooling) (ie the entropy change in the process plus the ambient; the ambient is assumed to be at 1 bar and 289 K).
Exercise 7.1 Compression and expansion of an ideal gas
50 mol/s of an ideal gas at 300 K and 1 bar (flow 1) is compressed to 10 bar (flow 2). The compression takes place adiabatically, the adiabatic efficiency is 80%. Stream 2 is expanded in a valve down to 1 bar (stream 3) and then cooled to 300 K (stream 4). A constant heat capacity Cp= 30 J/mol*K is assumed.
a) Make a table showing temperature, pressure, enthalpy [J/mol] and entropy [J/mol*K] for the four streams. Choose 298 K and 1 bar as the reference state.
b)Calculate added heat and work [J] in the process.
c)Calculate the total entropy increase [J/mol*K] for each of the three process steps (compression, pressure relaxation and cooling) (ie the entropy change in the process plus the ambient; the ambient is assumed to be at 1 bar and 289 K).
Given:
To find:
a) Make a table showing temperature, pressure, enthalpy [J/mol] and entropy [J/mol*K] for the four streams. Choose 298 K and 1 bar as the reference state.
b)Calculate added heat and work [J] in the process.
c)Calculate the total entropy increase [J/mol*K] for each of the three process steps (compression, pressure relaxation and cooling) (ie the entropy change in the process plus the ambient; the ambient is assumed to be at 1 bar and 289 K).
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