Question

Help solve this problem with step by step work solve using the Peng-Robinson equation

7.35 A well-insulated gas cylinder, containing ethylene at 85 bar and 25°C, is exhausted until the pressure drops to 10 bar. This process occurs fast enough that no heat transfer occurs between the gas and the cylinder walls, but not so rapidly perature gradients within the cylinder. a. Calculate the final temperature of the ethylene in the cylinder. b. What fraction of the ethylene remaining in the cylinder is present as a as to produce large velocity or tem- liquid?

Answer 1

Part a.

Formula: P1/T1 = P2/T2

Where 'P1' is the initial pressure of ethylene = 85 bar

'T1' is the initial temperature = 25+273.15 = 298.15 K

'P2' is the final pressure of ethylene = 10 bar

'T2' is the final temperature

i.e. 85 bar/298.15 K = 10 bar/T2

Therefore, T2 = 35 K = 35-273 = -238 °C

Part b.

The fraction of ethylene that is present as liquid = (10/85)×100 = 11.765%