Use NelsonObert compressibility chart to determine the tempe

Use Nelson-Obert compressibility chart to determine the temperature of Benzene at a pressure of 7.4 MPa and specific volume of 0.00425 m^3/kg.

Solution

Using nelson Obert generalized compressibility chart

Pressure P = 7.4 MPa

Specific Volume v = 0.00425 m³/kg

Benzene Properties - Pcr = 4.89 MPa and Tcr = 562 K (Ref: https://en.wikipedia.org/wiki/Benzene_(data_page) )

P_R = P/Pcr = 7.4/4.89 = 1.513

v_R = (v*Pcr)/(R*Tcr) = (0.00425*4.89*10⁶)/(8.314*562) = 4.45

where R = gas constant = 8.314 JK^-1mol^-1

compressibility factor Z = 1.02 (from Nelson Obert chart 0 <P_R <7 with P_R = 1.51 and v_R = 4.5 appox.)

T = Pv/zR = (7.4*10⁶ *0.00425)/(1.02*8.314) = 3708 K