Question

Which type of valve is used to prevent air being drawn into the digester?

(a) Non return valve

(b) Poppet vale

(c) Return valve

(d) Check valve

I had been asked this question in an interview.

Question is taken from Anaerobic Fermentation topic in division Biomass Energy of Energy Engineering

Answer 1

Correct option is (a) Non return valve

Easiest explanation: A non return valve is a valuable investment to prevent air being drawn into digester, which would destroy the activity of bacteria and provided a potentially explosive mixture inside the drum. Larger plants may need counterweights of some sort to ensure that the explosive mixture inside the drum.