text 2017 07 11

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INDUSTRIAL ORGANIC CHEMISTRY- July 11th, 2017 SURNAME: __________________ NAME: __________________ ID NUMBER: ________________ A possible way to exploit hydrogen produced by water hydrolysis is the production of methane according to the Sabatier reacti on (CO2 + 4 H2 → CH4 + 2 H2O). A simplified process layout consists of a heat exchanger (HE), where the fresh feed at 500 K is heated up using the reactor effluents, and of a reactor where a conversion of 95% of CO2 is achieved when operated at 8 atm . The formation of CO is also experienced in the reactor. By assuming that: • The reacting mixture is an ideal mixture of ideal gases • The thermodynamic equilibrium is reached at the outlet of the reactor (species present at equilibrium: CO2, H2, CH4, H2O, CO) • The heat exchanger is ideal and the heat losses are negligible • The reactor is designed to remove 7000 cal/mol of charge • The fresh feed is at 500 K and the molar ratio between CO2 and H2 is 1: 4 • The pressure drop is negligible 1. Evaluate the composition and the temperature of the stream leaving the reactor H2O H2 CH4 CO CO2 Temperature 2. Evaluate the temperature of the stream entering the reactor (Tin) Temperature 3. Evaluate the temperature of the stream leaving the heat exchanger (Tsc) Temperature Thermodynamic data: Sabatier reaction: 𝐾𝑒𝑞(𝑇) = exp ( 1 1.987 (56000 𝑇2 + 34633 𝑇 − 16.4 ln 𝑇 + 0.00557 𝑇) + 33.165) where T in [K] Water gas shift reaction:   TTGWGS  71.785140 [cal/mol] where T in [K] Reference state: ideal gas at 1 atm H0F(298K) [cal/mol] Cp [cal/mol] H2 0 2207 CO -26420 2253 CO2 -94050 3284 CH4 -17890 3438 H2O -57800 2662 Heat capacity can be assumed constant in the range of temperature of interest.