9.44. Hydrogen is produced in the steam reforming of propane: C3H8(g) + 3H2O(v) 3CO(g) +...

 

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9.44. Hydrogen is produced in the steam reforming of propane: C3H8(g) + 3H2O(v) → 3CO(g) + 7H2(g) The water-gas shift reaction also takes place in the reactor, leading to the formation of additional hydrogen: CO(g) + H2O(v) → CO2(g) + H2(g) The reaction is carried out over a nickel catalyst in the tubes of a shell-and-tube reactor. The feed to the reactor contains steam and propane in a 6:1 molar ratio at 125°C, and the products emerge at 800°C. The excess steam in the feed assures essentially complete consumption of the propane. Heat is added to the reaction mixture by passing the exhaust gas from a nearby boiler over the outside of the tubes that contain the catalyst. The gas is fed at 4.94 m³/mol C3H3, entering the unit at 1400°C and 1 atm and leaving at 900°C. The unit may be considered adiabatic. Heating gas 1400°C, 1 atm C3Hg(g) H2O(v) 125°C C,Hg(g) H,O(v) CO(g) H2(g) CO,(g) 800°C Spent heating gas 900°C (a) Calculate the molar composition of the product gas, assuming that the heat capacity of the heating gas is 0.040 kJ/(mol·°C). (b) Is the reaction process exothermic or endothermic? Explain how you know. Then explain how running the reaction in a reactor–heat exchanger improves the process economy. 9.44. Hydrogen is produced in the steam reforming of propane: C3H8(g) + 3H2O(v) → 3CO(g) + 7H2(g) The water-gas shift reaction also takes place in the reactor, leading to the formation of additional hydrogen: CO(g) + H2O(v) → CO2(g) + H2(g) The reaction is carried out over a nickel catalyst in the tubes of a shell-and-tube reactor. The feed to the reactor contains steam and propane in a 6:1 molar ratio at 125°C, and the products emerge at 800°C. The excess steam in the feed assures essentially complete consumption of the propane. Heat is added to the reaction mixture by passing the exhaust gas from a nearby boiler over the outside of the tubes that contain the catalyst. The gas is fed at 4.94 m³/mol C3H3, entering the unit at 1400°C and 1 atm and leaving at 900°C. The unit may be considered adiabatic. Heating gas 1400°C, 1 atm C3Hg(g) H2O(v) 125°C C,Hg(g) H,O(v) CO(g) H2(g) CO,(g) 800°C Spent heating gas 900°C (a) Calculate the molar composition of the product gas, assuming that the heat capacity of the heating gas is 0.040 kJ/(mol·°C). (b) Is the reaction process exothermic or endothermic? Explain how you know. Then explain how running the reaction in a reactor–heat exchanger improves the process economy.