Question

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

(a) 12

(b) 16

(c) 18

(d) 20

I have been asked this question in a job interview.

My question is from Degrees of Freedom Analysis in portion 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 choice is (c) 18

Explanation: Total species = 1 + 1 + 4 = 6, total stream flows = 3, stream pressures = 3, stream temperatures = 3, heat released = 1, and extent of reaction = 2, => degrees of freedom = 6 + 3 + 3 + 3 + 1 + 2 = 18.