The heat recoverable from flue gases of furnaces depends on the

Thermal conductivity based continuous flue gas analyser makes use of varying thermal conductivity of the constituents of flue gases. Which of the following constituents of flue gases has the maximum thermal conductivity?

A

CO₂

B

N₂

C

O₂

D

CO

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?

A

H = 23.28m

B

H = 18.56m

C

H = 32.77m

D

H = 41.92m

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

A

True

B

False

The ratio of the energy required to produce the artificial draught (expressed in meters head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as

A

Efficiency of the boiler

B

Efficiency of the chimney

C

Efficiency of the fan

D

Power of the boiler

In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the

A

Rate of firing and emissivity of flame

B

Thermal conductivity of the charge & structural materials of furnace

C

Nature of process ; whether batch, continuous or intermittant

D

All of the above

In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the

A

Rate of firing and emissivity of flame

B

Thermal conductivity of the charge & structural materials of furnace

C

Nature of process ; whether batch, continuous or intermittant

D

All of the above

All the forms of matter except gases emit electromagnetic radiation continuously. The gases which electrically or thermally excited emit a certain wavelength only, then which of the following is/are true about the process (i) The spacing between the atoms in the other forms of matter is high than in gas (ii) The spacing between the atoms in gases is high than the other forms of matter (iii) The energy of the emitted radiation depends on the spacing between the atoms (iv) The wavelength of the emitted radiation depends on the spacing between the atoms

A

only i and iv

B

only i, iii & iv only

C

iv only

D

All the above

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?

A

22.66m

B

23.84m

C

24.52m

D

25.16m

A bioremedial solution to reduce oxides of nitrogen and carbon in flue gases is to integrate flue gas emission to

A

Microalgal culture

B

Fish culture

C

Mushroom culture

D

Sericulture

Crucible furnaces are economical for melting metal, but heat loss is the major problem in the crucible furnaces.

A

True

B

False

The heat recoverable from flue gases of furnaces depends on the

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