Flue gases pass through the following boiler accessories in a high pressure natural circulation boiler.
A. Induced draft fan
B. Economiser
C. Air preheater
D. Steam superheater Which of the following gives the correct sequence of flow of the flue gases through the above mentioned boiler accessories?
A, C, B, D
D, B, C, A
D, C, B, A
D, A, B, C
Correct Answer :
B. D, B, C, A
Related Questions
Hydro-cyclone is a
Crusher
wet classifier
Dry classifier
Magnetic separator
The size of the tetrahedral void in the closest packing of atoms is __________ that of the octahedral void.
Equal to
Greater than
Less than
Either (A), (B) or (C); depends on the size of atom
The main constituent of bones is
CaF2
Ca3(PO4)2
CaCO3
CaCl2
__________ glass is used in the mercury in glass thermometer meant for measuring a temperature of 500°C.
Borosilicate
High silica
Supermax
Lead
__________ is the hardest oxide and is hence used where high wear resistance at high temperature is required.
Beryllium
Zirconia
Alumina
Magnesia
Maximum amount of thermal radiation is emitted at all wavelengths at any specified temperature by a/an __________ body.
Grey
Black
Opaque
White
In the X-ray radiography technique, the tube voltage for thicker plates as compared to thin plates, should be
Higher, as it gives higher wavelength
Lower, as it gives higher wavelength
Higher, as it gives shorter wavelength
Lower, as it gives shorter wavelength
__________ has the highest melting point out of the following.
Tungsten
Zirconium
Molybdenum
Tantalum
A solution which resists change in its pH value on addition of acid/alkali is called the __________ solution.
Neutral
Ideal
Buffer
Zero pH
For a spontaneous natural process at constant temperature and pressure, the free energy of the system always
Increases
Decreases
Remain constant
Increases to a maximum before decreasing
Factor of safety in machine design is defined as the ratio of ultimate stress to __________ stress.
Working
Bearing
Yield
None of these
Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs?
Enthalpy
Relative humidity
Wet bulb temperature
Dew point temperature
Austempering of steel requires it to be heated to 875°C followed by sudden cooling to 250-525°C, thereby changing austenite to
Sorbite
Bainite
Martensite
Troostite
A steam pipe is intended to be insulated with two layers of insulating materials of different thermal conductivities. For minimum heat transfer to take place
The better insulation material should be put just next to pipe (i.e., inside)
The better insulating material should be put outside
Either of the insulating material could be put on either side
Steam temperature is considered before deciding as to which insulating material is to be put inside (i.e., just next to the pipe)
On being hit with a hammer, __________ will readily fracture.
Brass
Mild steel
Cast iron
Lead
__________ cannot increase the fatigue strength of a material.
Grain refining
Grain coarsening
Surface hardening
Shot peening
Cold working of a material results in increase in hardness, which is termed as the __________ hardening.
Cold
Work
Age
Induction
Annealing of white cast iron produces __________ iron.
Grey
Nodular
Malleable
Spheroidal
Large diameter reinforced cement concrete (RCC) pipes are generally joined by __________ joint.
Flanged iron
Collar
Flexible
Expansion
Most of the phosphorous present in the blast furnace burden enters into
Hot metal
Flue gases
Slag
Refractory lining
Glycerine is used as a coolant in cooling of some engines instead of water, because
Its higher boiling point (290°C) increases its heat carrying capacity
Comparatively less weight of coolant is required
Smaller radiator can be used
All a, b & c
Nusselt number is related to the Reynolds number (Re) in turbulent & laminar flow respectively as
Re0.5, Re0.8
Re0.8, Re-0.5
Re0.8, Re0.5
Re-0.8, Re0.5
Chromium molybdenum steel cannot be welded using __________ welding.
Thermit
Electrical resistance
Oxy-acetylene
Any of these
Wrought iron is never shaped by
Casting
Cold working
Forging
Welding
Exposure to __________ accelerates the degradation of plastics.
Ultraviolet radiation
High atmospheric temperature
High ambient temperature
Damp atmosphere
Satellites burn off during re-entry to earth's atmosphere, because of the
Combustion with air
Gravitational pull by earth
Friction with earth's atmosphere
Loss in weight of the satellite
Fatigue resistance of a material is measured by the
Elastic limit
Ultimate tensile strength
Young's modulus
Endurance limit
Machinability of hard alloys and tool steels is improved by
Spheroidising
Annealing
Tempering
Normalising
Shampoos are commercially not available in the form of
Powder
Gaseous mixture
Solution
Emulsion
'Flare tower' used in industry is meant for
Venting off (after burning) the excess inflammable/toxic gases at high pressure
Absorbing the pollutant gases from the furnace exhaust
Cooling of furnace exhaust gases
None of these