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 and H2O at 10 atm and 23^oC, what are the total degrees of freedom?

(a) 10

(b) 12

(c) 15

(d) 17

I have been asked this question in semester exam.

The origin of the question is Degrees of Freedom Analysis 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 option is (c) 15

Easy explanation: Total species = 1 + 1 + 2 = 4, total stream flows = 3, stream pressures = 3, stream temperatures = 3, heat released = 1, and extent of reaction = 1, => degrees of freedom = 4 + 3 + 3 + 3 + 1 + 1 = 15.