Ammonia is oxidized in a well-insulated continuous reactor.

The feed stream enters at 200°C and the products leave at temperature T_out(°C). The inlet–outlet enthalpy table for the reactor appears as follows.

(a) Draw and label a process flowchart and calculate the molar amounts of the product stream components and the extent of reaction, ξ. Fill in the values of n₃, n₄, and n₅ in the enthalpy table.

(b) The energy balance for this reactor reduces to ΔH_ 0. Summarize the assumptions that must be made to obtain this result.

(c) Calculate the values of H₁ and H₂ and write expressions for H₃, H₄, and H₅ in terms of the outlet temperature, Tout, and the heat capacity formulas in Table B.2. Then calculate Tout from the energy balance, using a spreadsheet.

(d) A design engineer obtained a preliminary estimate of the reactor outlet temperature using only the first terms of the heat capacity formulas in Table B.2. [For example, (C_p)_NH3 ≈ 0.03515 kJ/(mol °C).] What value did she calculate? Taking the result of Part (c) to be correct, determine the percentage error in Tout that results from using the one-term heat capacity formulas.

(e) The preliminary estimate of Part (d) of Tout was mistakenly used as the basis of the design and construction of the reactor. Was this a potentially dangerous error from the standpoint of reactor safety or did it in fact lower the hazard potential? Explain.

Transcribed Image Text:

4NH3(g) + 502(g) → 4NO(g) + 6H2O(v): AH, = -904.7 kJ References: NH3(g), O2(g), NO(g), H,0(v) at 25°C, 1 atm Ĥin nout (kJ/mol) (mol/s) Hin Substance (mol/s) (kJ/mol) NH3(g) н 4.00 Нз На O2(g) 6.00 йз NO(g) йа H20(v) ns Ĥ5