Fuel economy in an industrial furnace operation cannot be achieved by
the use of
(A) Stoichiometric combustion air
(B) Non-preheated combustion air
(C) Combustion air not enriched with oxygen
(D) Recuperators
the use of
(A) Stoichiometric combustion air
(B) Non-preheated combustion air
(C) Combustion air not enriched with oxygen
(D) Recuperators