Question

5 m³ of sulphur trioxide is initially at 150 °C and 60 bar undergo an isochoric heating process to a final pressure of 70 bar. Calculated the heat transfer (kJ) for the process. (assume ideal gas)

Answer 1

first calculate the final temperature obtained after the process. using ideal gas equation, PV=nRT

Here, P_i/P_f=T_i/T_f

T_f=423*(70/60)=493.5 K

Q=heat transfer= change in internal energy + work done

work done in the case of isochoric process is zero

so, heat transfer= change in internal energy = n*C_v*(T_f-T_i)

from ideal gas equation, no. of moles can be calculated. n= P*V/(RT)=8530.42 moles

T_f-T_i=493.25-423=70.25 K

Cv=0.5 kJ/Kg-K(assumed )=0.5/(80000) KJ/mol-K (use proper value from table or any correlation )

heat transfer=8530.42*0.5*70.25/80000=3.745 KJ