Question

In a reactor two stream are entering, one with CO2 at 10 atm and 27^oC, and another with H2O at 10 atm and 0^oC, producing CH4, CO2, H2O, and O2 at 10 atm and 23^oC, what are the total degrees of freedom?

(a) 10

(b) 15

(c) 17

(d) 21

I have been asked this question during an interview for a job.

I'm obligated to ask this question of Degrees of Freedom Analysis topic in chapter Energy Balances that Include the Effects of Chemical Reaction, Ideal Processes, Efficiency and the Mechanical Energy Balance and Heats of Solution and Mixing of Basic Chemical Engineering

Answer 1

Correct answer is (c) 17

To explain I would say: Total species = 1 + 1 + 4 = 6, total stream flows = 3, stream pressures = 3, stream temperatures = 3, heat released = 1, and extent of reaction = 1, => degrees of freedom = 6 + 3 + 3 + 3 + 1 + 1 = 17.