Problem 14.13: Acetaldehyde can be produced from the dehydrogenation of ethanol according to the following reaction:
CH3 CH2 OH(g) = CH3 CHO(g) + H2 (g).
Additional data. The ideal-gas heat capacities of the pure species in this reaction are: ethanol: 118 J/mole K; acetaldehyde: 90 J/mole K; hydrogen: 30 J/mole K.
a) Calculate the equilibrium constant at 25 °C.
b) Calculate the heat of reaction at 25 °C. Is the reaction exothermic or endothermic?
c) Assuming that the heat of reaction does not change much with temperature, calculate the equilibrium constant at 550 °C.
d) Is it an acceptable assumption that the heat of reaction does not change much with temperature? (Answers without justification do not count.)
e) The reactor initially contains one mole of ethanol and nothing else. The reaction is run at 550 °C and 2 bar until equilibrium is reached. What is the mole fraction of species at equilibrium?
f) It is desirable to react 98% of the initial amount of ethanol. If the temperature is to remain at 550 °C, at what pressure should you run the reaction?