Normal heptane is dehydrocyclicized to toluene and hydrogen in a continuous vapor-phase reaction:

Pure heptane at 400°C is fed to the reactor. The reactor operates isothermally at 400°C and the reaction goes to completion. Data: The average heat capacity of n-heptane between 25°C and 400°C is 0.2427 kJ/(mol °C).

(a) Taking a basis of 1 mol of heptane fed, draw and label a flowchart.

(b) Taking elemental species [C(s), H₂(g)] at 25°C as references, prepare and fill in an inlet outlet enthalpy table.

(c) Calculate the required heat transfer to or from the reactor (state which it is) in kJ.

(d) What is the heat of the heptane dehydrocyclization reaction (ΔH_r) at 400°C and 1 atm?

(e) The calculation of Part (c) would clearly have been much simpler if you had just looked up the heat of reaction at 400°C instead of calculating it after the fact. Briefly explain why you probably could not have done it that way.

Transcribed Image Text:

C;H16 → C6H5CH3 + 4H2