Overfire burning in a furnace is a phenomenon characterised by____________________?
(A) Supply of excess fuel
(B) Supply of excess air
(C) Burning carbon monoxide and other incombustible in upper zone of furnace by supplying more air
(D) None of these
Pick out the wrong statement?
(A) Sand & coke is the main raw material for the manufacture of silicon carbide
(B) Carbon refractories cannot be used in the furnaces operating under reducing conditions
(C) Mullite can be obtained by the heating of alusite, kyanite or sillimanite
(D) Silica occurs in nature in all cellular, amorphous or crystalline form
Pick out the wrong statement ?
(A) Refractories used in muffle furnace should have low thermal conductivity
(B) The electrical resistivity of refractories drops rapidly with rise in temperature
(C) For reducing spalling tendency, the refractory should be well fired and its porosity should be more
(D) Refractoriness under load (RUL) of a refractory is always less than its refractoriness
Pick out the wrong statement?
(A) Insulating refractories used in place of regular refractory bricks are usually called light weight refractories, and they have similar composition as heavy bricks
(B) Graphite refractories are also called plumbago refractories
(C) Superduty fireclay bricks correspond to a pyrometric cone equivalent of 26-28
(D) Calcined magnesite is also called dead burnt magnesite
Pick out the wrong statement ?
(A) Surface tension of a liquid is because of the difference in magnitude of adhesive & cohesive forces
(B) A hydrometer used for the determination of specific gravities of liquids works on the principle of buoyant forces
(C) In case of unsteady fluid flow, the velocity at any given point does not change with time
(D) Turbulent fluid flow is characterised by the rapid fluctuation of instantaneous pressure & velocity at a point
Which is a continuous furnace ?
(A) Coke ovens
(B) Annealing furnace
(C) Glass tank furnace
(D) None of these
Turndown ratio of a burner gives an idea of the ______________ in the furnace?
(A) Range of fuel firing rates
(B) Volume of the combustion chamber
(C) Maximum heat input rate only
(D) Minimum heat input rate only
A refractory wall separating the stock and the source of heat is provided in a__________________?
(A) Updraft kiln
(B) Muffle furnace
(C) Continuous furnace
(D) None of these
Ostwald charts are meant for__________________?
(A) Computing the excess/deficiency of combustion air
(B) Calculation of flue gas temperature
(C) Computation of flue gas analysis
(D) None of these