Question

Propane (g) is heated from 20°C to 200°C at 2.5 bar. Steam at 200°C and 5.0 bar enters the same heater and exits as a saturated liquid at the same pressure. Taking a basis of 100 mole of propane fed to the exchanger, calculate the values of the specific enthalpies (H) in the following table. The specific volume of propane is 0.0104 m3/mol. Use the gas constant table for conversions if necessary. Species nin Specific nout Specific Enthalpy Enthalpy C3H8 100 mol Ha (kJ/mol) 100 mol H. (kJ/mol) H2O 0.8 kg Hb (kJ/kg) 0.8 kg Ha (kJ/kg)

Answer 1

Solution > Propanc (9) 2006 Propane (9) 20°c Reactor 2.5 bar 2.5 bar H2o 5 bar H2O Sat liquid 2004 ) 5 bar Choose reference State such that Calculation will become easy Reference State : C3H8 (9) (200 & 2.5 bar) ܘܕA (d) (0° of 5 bar) 7 Ha specific enthalpy of propanc inlet at 20°c & 2.5 bar Ha as we same have choosen this state as reference ملا

> He Specific enthalpy of propane outlet at 2000 2.5 bar 200 Hc - f Cp di -5 propane " -8 2 T-1311XLOT + 68.032x1ó? 22.59x10 +3171101273 200 Hc t + 68.032x103 22.59x105T -13.11x108 31.71X102T 1) dT 20 He 16.38 kJ Tho => нь of H₂O at 2000 & Specific enthalpy 5 bar (Steam) Process : Hzo H2o 200% 5 bar 0° 5 bar t (reference)

at P = 5 bar from Superheated steam table & T = 2006 cy we get Ho 2855.8 kg kg = > Ha outlet 5 bar = Specific enthalpy of tho at € saturated liquid Process H2o a) 5 bar H204) o% sbar (reference) and Saturated temp (Tsat { from from Saturated Steam table at P = 5 bar १ Ha = hf & enthalpy of sat liquid hq 640.09 kJ/kg 6h0.09 kJ/kg Ha

Species изо hout Specific Enthalpy Specific Enthalpy 16.59 Ky/mo | 640-44 s/s C, Hg Тоо тој oks/mo | 100 mol H2o os a 28SS• Es/s» os *