Deficiency of combustion air during combustion of a gaseous fuel (A) Lengthens the flame (B) Causes heat loss of fuel by its partial combustion (C) Both (A) & (B) (D) Shortens the flame

Deficiency of combustion air during combustion of a gaseous fuel
(A) Lengthens the flame
(B) Causes heat loss of fuel by its partial combustion
(C) Both (A) & (B)
(D) Shortens the flame
by

1 Answer

Answer :

(C) Both (A) & (B)
by

Related questions

During combustion of gaseous fuels, deficiency of air (A) Lengthens the flame (B) Tends to shorten the flame (C) Does not affect the flame length (D) Increases the flame temperature

Description : During combustion of gaseous fuels, deficiency of air (A) Lengthens the flame (B) Tends to shorten the flame (C) Does not affect the flame length (D) Increases the flame temperature

Last Answer : (A) Lengthens the flame

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If the specific heat of gaseous products of combustion of a fuel is high, the abiabatic flame temperature will be (A) Low (B) High (C) Very high, if the fuel is of low calorific value (D) None of these

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During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the (A) Incomplete combustion (B) Complete combustion (C) High oxygen in flue gas (D) None of these

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Combustion of fuel in a furnace with oxygen enriched air results in higher (A) Flue gas volume (B) Flame temperature (C) Fuel consumption (D) Stack loss

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Use of excess of combustion air in the combustion of fuels results in (A) Heat losses (B) Long flame (C) Condensation of water vapour from the fuel gas (D) None of these

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Oxygen enrichment of combustion air does not result in increase of the (A) Flame temperature (B) Oxygen in the flue gas (C) Stack loss (D) Heat transfer rate in the furnace

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Coke oven gas is a better fuel than blast furnace gas, because of its higher (A) Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) (B) Adiabatic flame temperature (C) Heat release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)

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Actual flame temperature is always lower than the adiabatic flame temperature, because there is (A) No possibility of obtaining complete combustion at high temperature (B) Always loss of heat from the flame (C) Both (A) and (B) (D) Neither (A) nor (B)

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Preheating of combustion air is done to (A) Increase the adiabatic flame temperature (B) Increase the calorific value of the fuel (C) Complete the combustion of fuel (D) Reduce its requirement for effecting the complete combustion

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The optimum percentage of excess air for combustion depends upon the__________ of the fuel.(A) Type (solid, liquid or gaseous)(B) Calorific value(C) Sulphur content(D) Ignition temperature

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Advantages of use of preheated combustion air are (A) Saving in fuel consumption (B) Reduction in scale losses (C) Increase in flame temperature (D) All (A), (B) and (C)

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Which of the following advantages is not associated with the use of preheated air for combustion of a fuel in the furnace? (A) Increase in calorific value of the fuel (B) Increase in flame temperature (C) Reduction in scale losses (D) Saving in fuel consumption

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For the case of a fuel gas undergoing combustion with air, if the air/fuel ratio is increased, the adiabatic flame temperature will (A) Increase (B) Decrease (C) Increase or decrease depending on the fuel type (D) Not change

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Use of preheated air for combustion of fuel in the furnace, increases the (A) Scale losses of the furnace stock (B) Calorific value of the fuel (C) Flame temperature (D) None of these

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High excess air in combustion of fuels results in (A) Increased fuel consumption (B) Incomplete combustion (C) Smoky flame (D) None of these

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Last Answer : (D) Either (A) or (B) without gain or loss of heat

Preheating of a gaseous fuel results in increased (A) Flame length (B) Flame temperature (C) Quantity of flue gas

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Last Answer : (B) Flame temperature

The main drawback of supplying more excess air in the combustion of fuel is the (A) Excessive power requirement of air blower (B) Enhanced sensible heat loss in the flue gas (C) Intermittent and uncontrolled combustion of the fuel (D) High exit flue gas temperature from the furnace

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Combustion of pulverised coal as compared to that of lump coal (A) Develops a non-luminous flame (B) Develops a low temperature flame (C) Can be done with less excess air (D) Provides a lower rate of heat release

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Presence of nitrogen in combustion air does not reduce the (A) Amount of heat liberated (B) Flame temperature (C) Flue gas temperature (D) Any of the above

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Last Answer : (A) Amount of heat liberated

Combustion of pulverised fuel (A) Requires larger combustion chamber than rich gaseous fuel (B) In a metallurgical furnace does not contaminate the product in the furnace by ash from fuel (C) Suppresses the discharge of fine dust and grit into atmosphere (D) All (A), (B) and (C)

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Combustion of pulverised coal compared to the lumpy coal (A) Provides better control of furnace temperature (B) Facilitates combustion with lower excess air (C) Provides higher thermal efficiency & flame temperature (D) All (A), (B) & (C)

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Last Answer : (D) All (A), (B) & (C)

Size of the combustion chamber of a furnace depends upon the (A) Heat release rate of the fuel (B) Preheat temperature of fuel & air (C) Method of mixing the fuel & air (D) All (A), (B) and (C)

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Adiabatic flame temperature of a fuel is dependent on the initial temperature of (A) Fuel (B) Air (C) Both (A) & (B) (D) Neither (A) nor (B)

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Moisture loss is determined by the (A) Humidity of combustion air (B) Moisture content of fuel (C) Both (A) and (B) (D) The water formed by combustion reaction

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Presence of moisture in fuel oil would (A) Keep the burner tips cool (B) Aid in proper combustion (C) Because sputtering, possibly extinguishing flame (D) Clean the nozzles

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Last Answer : (D) Clean the nozzles

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Last Answer : Internal Combustion Engine

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Last Answer : (D) None of these

Fuel' can be defined as a substance which produces heat by (A) Combustion (B) Nuclear fission (C) Nuclear fusion (D) All (A), (B) & (C)

Description : Fuel' can be defined as a substance which produces heat by (A) Combustion (B) Nuclear fission (C) Nuclear fusion (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C

Too much of excess air in combustion results in high (A) Fuel consumption for the same heat load (B) Stack gas temperature (C) Percentage of oxygen in flue gases (D) All (A), (B) and (C)

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In practical operation of any furnace, zero oxygen percentage or theoretical CO2 percentage in flue gas is rarely achieved, because of (A) Use of non-preheated combustion air (B) Use of pulverised solid fuels (C) Imperfect mixing of fuel & air and infiltration of air (D) Use of excessive positive draft in the furnace

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Last Answer : (D) All (A), (B) & (C)

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Last Answer : (B) Keeping the flue gas exhaust temperature very high

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