Draught System MCQ

Test your knowledge with important Draught System MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30 + more Draught System MCQs at Bissoy

• Which of these is not a type of drive of variable speed control?
  ক

  variable speed turbine

  খ

  hydraulic coupling

  গ

  multiple speed ac motor

  ঘ

  electronically adjustable turbine drive
• Which of the following types of the fans has the highest cost?
  ক

  centrifugal fans

  খ

  axial fans

  গ

  primary fans

  ঘ

  gas recirculation fans
• In a furnace employing forced draught compared to induced draught __________
  ক

  the fan operates hot and hence blades are liable to corrosion and erosion

  খ

  positive pressure exists in the furnace

  গ

  air is sucked in, so air leaks are more and hence furnace efficiency is reduced

  ঘ

  none of the mentioned
• Natural draught produced by a chimney depends upon __________
  ক

  density of chimney gases

  খ

  height of chimney

  গ

  both ‘density of chimney gases’ and ‘height of chimney’

  ঘ

  none of the mentioned
• Which of these accentuates clinkering trouble on furnace grate burning coal?
  ক

  low reactivity of carbonised residue containing high proportions of iron and sulphur

  খ

  low forced draught and low fuel bed temperature

  গ

  thick fire bed and preheated primary air

  ঘ

  all of the mentioned
• Stack heat losses can be minimised by __________
  ক

  using low c.v. fuels

  খ

  controlling the excess air

  গ

  oxygen enrichment of combustion air

  ঘ

  maintaining proper draft in the furnace
• Which of these is not a type of mechanical draft system for a furnace?
  ক

  balanced draft

  খ

  induced draft

  গ

  forced draft

  ঘ

  actuated draft
• The draught or pressure difference for a chimney of height of H metres is given by?
  ক

  Δp = gH(ρa-ρg) c) Δp = gHρg d) Δp = gH(ρa+ρg) View Answer]

  খ

  Δp = gH(ρg-ρa)

  গ

  Δp = gHρg

  ঘ

  Δp = gH(ρa+ρg)
• Which of these terms defines the pressure difference in the furnace?
  ক

  draught

  খ

  duct

  গ

  stack

  ঘ

  chimney
• Using which of the given formula the chimney height is calculated to get the answer of 67.4m when the coal burnt is 18.8TPH and considering 0.5% of sulfur content in coal?
  ক

  H = 12(Q)13

  খ

  H = 17(Q)13

  গ

  H = 14(Q)13

  ঘ

  H = 22(Q)13
• A 15kg of air is supplied per kg of fuel burnt to the combustion chamber of a boiler using fuel 600kg/hr. the temperature of flue gases and ambient air are 273°C and 32°C. If the minimum draught required to start the flue is 9.5mm of water, find out the minimum height of the chimney?
  ক

  22.66m

  খ

  23.84m

  গ

  24.52m

  ঘ

  25.16m
• Determine the height of the chimney to get net draught of 12mm if the total losses are 4mm. the temperature of air is 25oC and the temperature of chimney gases is 300oC. The mass of air used per kg of fuel used is 18kg. One kg of air occupies a volume of 0.7734m3 at normal temperature?
  ক

  26.84

  খ

  20.22

  গ

  29.93

  ঘ

  18.09
• The flue gases of natural draught are at higher temperature when compared to flue gases in artificial gas.
  ক

  True

  খ

  False
• Determine the height of the chimney to produce a static draught of 22mm of water if the mean flue gas temperature in chimney is 290oC and ambient temperature in boiler house is 20oC. The gas constant for air is 29.26Kgm/Kgk and for chimney flue gas is 26.2 Kgfm/Kgk. Assume reading as 760mm of mercury?
  ক

  38.42m

  খ

  42.55m

  গ

  45.84m

  ঘ

  44.03m
• A draught of 15mm of water is produced by using a chimney of height 30m. The ambient air and flue gases are at 27oC and 300oC respectively. The coal burned on the grate contains 81% carbon, 5% moisture and remaining ash. Neglect the losses and assume values of burnt products equivalent to the volume of air supplied and for the complete combustion of fuel, find the percentage of excess of air supplied?
  ক

  14.56%

  খ

  52.89%

  গ

  8.13%

  ঘ

  20.002%
• Determine the height of chimney above grate level. Where diameter of chimney is 1.75m and produces a draught of 1.8cms of water. Temperature of flue gases is 290oC. The flue gases formed per kg of fuel burnt are 23kg. Neglect the losses and assume atmospheric temperature as 20oC?
  ক

  H = 23.28m

  খ

  H = 18.56m

  গ

  H = 32.77m

  ঘ

  H = 41.92m
• The portion of flue gases carried away to produce draught could be utilized to _______
  ক

  Heat the air entering furnace

  খ

  Blow out the combustion products such as soot and ash

  গ

  Heat the fuel in ash chamber

  ঘ

  Support the combustion
• Which is the equation used to find chimney diameter?
  ক

  D = 1.128\(\sqrt{\frac{Mg}{ρg V}}\)

  খ

  D = 5.48\(\sqrt{\frac{ρg V}{Mg}}\)

  গ

  D = 5.48\(\sqrt{\frac{Mg}{ρg V}}\)

  ঘ

  D = 1.128\(\sqrt{\frac{ρg V}{Mg}}\)
• Which is the net pressure equation used to find chimney height?
  ক

  P = H (Wa-Wg) d) P = H (\(\frac{W_a}{W_g}\)) View Answer]

  খ

  P = H (Wa+Wg)

  গ

  P = H (Wg-Wa)

  ঘ

  P = H (\(\frac{W_a}{W_g}\))
• Which draught system is used as conjunction with chimney draught?
  ক

  Forced steam draught

  খ

  Forced draught

  গ

  Induced draught

  ঘ

  Balanced draught
• Which draught system is also known as turbine draught?
  ক

  Forced steam draught

  খ

  Induced steam draught

  গ

  Natural draught

  ঘ

  Fan draught
• Which type of draught system is used in the locomotives?
  ক

  Natural draught system

  খ

  Balanced draught system

  গ

  Forced draught system

  ঘ

  Induced Steam draught system
• How pressure in the furnace is maintained below atmospheric pressure in balanced draught system?
  ক

  By forced draught fan

  খ

  By induced fan

  গ

  Depends on the height of chimney

  ঘ

  By installing Natural draught
• Which is most preferred type of draught system?
  ক

  Chimney draught

  খ

  Fan draught

  গ

  Force draught

  ঘ

  Balanced draught
• How can exhaust gas be recovered in the induced draught?
  ক

  By installing the forced draught fan at the starting point

  খ

  By extending the chimney’s height

  গ

  By inletting high amount of air from multiple air ducts

  ঘ

  By installing air preheater and economizer along the gas path
• Where is blower installed in induced draught system?
  ক

  Near the boiler

  খ

  Base of the chimney

  গ

  Above the boiler

  ঘ

  Between economizer and air preheater
• What is installed to transfer air into furnace in forced draught system?
  ক

  Air blower

  খ

  Tuyeres

  গ

  Draft gauges

  ঘ

  Cyclone separator
• Artificial draught is also called as _______
  ক

  Force draught

  খ

  Induced draught

  গ

  Balanced draught

  ঘ

  Mechanical draught
• When is artificial draught preferred?
  ক

  When quick evacuation of flue gases is required

  খ

  When we choose large power plant systems

  গ

  When draught produced by chimney is not sufficient

  ঘ

  When there are many components inside the boiler
• Which of the following given below as the affect on amount natural draught?
  ক

  Boiler operation

  খ

  Size of the furnace

  গ

  Grade of the fuel

  ঘ

  Dust content in the fuel is used