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

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
by

1 Answer

Answer :

(B) Flame temperature
by

Related questions

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

Description : 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

Last Answer : (B) Oxygen in the flue gas

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)

Description : 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)

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

Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case ofcomplete combustion of(A) Furnace oil with air(B) Furnace oil with oxygen(C) Blast furnace gas with air(D) Blast furnace gas with oxygen

Description : Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case ofcomplete combustion of (A) Furnace oil with air (B) Furnace oil with oxygen (C) Blast furnace gas with air (D) Blast furnace gas with oxygen

Last Answer : (C) Blast furnace gas with air

Pick out the wrong statement. (A) High concentration of oxygen in flue gas means high stack loss (B) Gaseous fuels require the least % excess air for complete combustion (C) The ratio of fixed carbon to volatile matter percentage in coal is called its 'fuel ratio' (D) Calorific value of natural gas is more than that of LPG

Description : Pick out the wrong statement. (A) High concentration of oxygen in flue gas means high stack loss (B) Gaseous fuels require the least % excess air for complete combustion (C) The ratio of fixed carbon to ... coal is called its 'fuel ratio' (D) Calorific value of natural gas is more than that of LPG

Last Answer : (D) Calorific value of natural gas is more than that of LPG

Fuel economy in furnaces can be achieved by (A) Using oxygen enriched combustion air (B) Preheating the combustion air (C) Reducing the heat loss through furnace openings & doors (D) All (A), (B) and (C

Description : Fuel economy in furnaces can be achieved by (A) Using oxygen enriched combustion air (B) Preheating the combustion air (C) Reducing the heat loss through furnace openings & doors (D) All (A), (B) and (C

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

If oxygen content in the flue gas rises too high, fuel is being wasted by (A) Incomplete combustion (B) Dry gas/stack gas loss (C) Moisture loss (D) None of these

Description : If oxygen content in the flue gas rises too high, fuel is being wasted by (A) Incomplete combustion (B) Dry gas/stack gas loss (C) Moisture loss (D) None of these

Last Answer : (B) Dry gas/stack gas loss

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

Description : 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

Last Answer : (B) Enhanced sensible heat loss in the flue gas

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

Description : 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

Last Answer : (A) Increase in calorific value of the fuel

Fuel economy in an industrial furnace operation cannot be achieved by the use of (A) Stoichiometric combustion air (B) Non-preheated combustion air (C) Combustion air not enriched with oxygen (D) Recuperators

Description : Fuel economy in an industrial furnace operation cannot be achieved by the use of (A) Stoichiometric combustion air (B) Non-preheated combustion air (C) Combustion air not enriched with oxygen (D) Recuperators

Last Answer : (A) Stoichiometric combustion air

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

Description : 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 ... of fuel & air and infiltration of air (D) Use of excessive positive draft in the furnace

Last Answer : (C) Imperfect mixing of fuel & air and infiltration of air

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

Description : 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

Last Answer : (B) Complete combustion

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)

Description : 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 ... release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)

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

Pick out the wrong statement. (A) Theoretical flame temperature is the temperature attained by the products of combustion, when the fuel is burned without loss or gain of heat (B) Burning the fuel with theoretically required amount of pure oxygen results in attainment of maximum adiabatic flame temperature (C) Burning the fuel with excess pure oxygen results in maximum theoretical flame temperature (D) Adiabatic flame temperatures of actual combustions are always less than the maximum values

Description : Pick out the wrong statement. (A) Theoretical flame temperature is the temperature attained by the products of combustion, when the fuel is burned without loss or gain of heat (B) ... flame temperature (D) Adiabatic flame temperatures of actual combustions are always less than the maximum values

Last Answer : (C) Burning the fuel with excess pure oxygen results in maximum theoretical flame temperature

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

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

Last Answer : (A) Increased fuel consumption

Higher furnace temperature cannot be achieved by use of a lean fuel gas in the furnace by (A) Increasing the draft in the furnace (B) Preheating the fuel gas (C) Oxygen enrichment of combustion air (D) Preheating the combustion air

Description : Higher furnace temperature cannot be achieved by use of a lean fuel gas in the furnace by (A) Increasing the draft in the furnace (B) Preheating the fuel gas (C) Oxygen enrichment of combustion air (D) Preheating the combustion air

Last Answer : (A) Increasing the draft in the furnace

To reduce the stack loss, heat recovery from flue gas can be done by (A) Preheating of cold stock (B) Preheating of combustion air (C) Steam generation in waste heat boilers (D) All (A), (B) and (C)

Description : To reduce the stack loss, heat recovery from flue gas can be done by (A) Preheating of cold stock (B) Preheating of combustion air (C) Steam generation in waste heat boilers (D) All (A), (B) and (C)

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

Which among the following has the highest flue gas loss on combustion due to Hydrogen in the fuel? a) natural gas b) furnace oil c) coal d) light diesel oil

Description : Which among the following has the highest flue gas loss on combustion due to Hydrogen in the fuel? a) natural gas b) furnace oil c) coal d) light diesel oil

Last Answer : a) natural gas

Higher efficiency in the combustion of solid fuel cannot be achieved by (A) Proper fuel preparation (B) Keeping the flue gas exhaust temperature very high (C) Adopting efficient-fuel firing technique & equipment (D) Supplying correct quantity of combustion air

Description : Higher efficiency in the combustion of solid fuel cannot be achieved by (A) Proper fuel preparation (B) Keeping the flue gas exhaust temperature very high (C) Adopting efficient-fuel firing technique & equipment (D) Supplying correct quantity of combustion air

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

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

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

Last Answer : (B) Flame temperature

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

Description : 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

Last Answer : (C) Flame temperature

Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature? (A) Calorific value of the fuel (B) Flame temperature achieved (C) Speed of combustion of fuel (D) Heat transfer rate to the stock in the furnace

Description : Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature? (A) Calorific value of the fuel (B) Flame temperature achieved (C) Speed of combustion of fuel (D) Heat transfer rate to the stock in the furnace

Last Answer : (A) Calorific value of the fuel

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

Description : 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

Last Answer : (A) Amount of heat liberated

Air filtration in a furnace (A) Reduces its thermal efficiency (B) Is indicated by flame sting out (C) Increases the flue gas temperature (D) None of these

Description : Air filtration in a furnace (A) Reduces its thermal efficiency (B) Is indicated by flame sting out (C) Increases the flue gas temperature (D) None of these

Last Answer : (A) Reduces its thermal efficiency

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)

Description : 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)

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

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)

Description : 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)

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

A carbonaceous fuel (containing no H2 or hydrocarbons) is burnt and the resulting flue gas contains 21% CO2 . It means that (A) 21% excess air has been used for combustion (B) 21% excess oxygen has been used for combustion (C) Complete combustion of fuel has taken place (D) No excess air has been used for combustion

Description : A carbonaceous fuel (containing no H2 or hydrocarbons) is burnt and the resulting flue gas contains 21% CO2 . It means that (A) 21% excess air has been used for combustion (B) 21% excess oxygen has ... (C) Complete combustion of fuel has taken place (D) No excess air has been used for combustion

Last Answer : (C) Complete combustion of fuel has taken place

Volumetric composition of flue gas analysed with the Orsat apparatus is : CO2 = 12%, O2 = 8%, CO = nil, N2 = 80%. This flue gas composition indicates that (A) Pure oxygen has been used for combustion (B) Nitrogen percentage in the fuel is very high (C) Excess air has been used for combustion (D) Hydrogen is not present in the fuel

Description : Volumetric composition of flue gas analysed with the Orsat apparatus is : CO2 = 12%, O2 = 8%, CO = nil, N2 = 80%. This flue gas composition indicates that (A) Pure oxygen has been used for combustion ... very high (C) Excess air has been used for combustion (D) Hydrogen is not present in the fuel

Last Answer : (C) Excess air has been used for combustion

Incomplete combustion of a fuel is characterised by the high __________ in the flue gas. (A) Smoke (B) Temperature (C) Oxygen (D) Carbon monoxide

Description : Incomplete combustion of a fuel is characterised by the high __________ in the flue gas. (A) Smoke (B) Temperature (C) Oxygen (D) Carbon monoxide

Last Answer : (D) Carbon monoxide

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

Description : 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

Last Answer : (A) Heat losses

Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by (A) Preheating the combustion air (B) Oxygen enrichment of combustion air (C) Preheating the fuel gas (D) All (A), (B) & (C)

Description : Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by (A) Preheating the combustion air (B) Oxygen enrichment of combustion air (C) Preheating the fuel gas (D) All (A), (B) & (C)

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

Stack heat losses can be minimised by (A) Controlling the excess air (B) Oxygen enrichment of combustion air (C) Using low c.v. fuels (D) Maintaining proper draft in the furnace

Description : Stack heat losses can be minimised by (A) Controlling the excess air (B) Oxygen enrichment of combustion air (C) Using low c.v. fuels (D) Maintaining proper draft in the furnace

Last Answer : (A) Controlling the excess air

Oxygen trim control strategy __ a. continuously measures the oxygen content in the flue gas b. adjusts the combustion air flow c. Continually tuning the air-fuel mixture. d. All of above

Description : Oxygen trim control strategy __ a. continuously measures the oxygen content in the flue gas b. adjusts the combustion air flow c. Continually tuning the air-fuel mixture. d. All of above

Last Answer : d. All of above

measures oxygen and temperature of the flue gas. a) Fuel efficiency monitor. b) Combustion analyzer. c) Contact thermometer. d) Infrared thermometer.

Description : measures oxygen and temperature of the flue gas. a) Fuel efficiency monitor. b) Combustion analyzer. c) Contact thermometer. d) Infrared thermometer.

Last Answer : Combustion analyzer

Incomplete combustion of fuel in the furnace is judged by high __________ of the flue gases. (A) CO content (B) Dew point (C) CO2 content (D) O2 content

Description : Incomplete combustion of fuel in the furnace is judged by high __________ of the flue gases. (A) CO content (B) Dew point (C) CO2 content (D) O2 content

Last Answer : (A) CO content

Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its (A) Emissivity factor is higher (B) Sulphur content is lower (C) Flue gas has lower dew point thereby facilitating more waste heat recovery (D) All (A), (B) and (C)

Description : Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its (A) Emissivity factor is higher (B) Sulphur content is lower (C) Flue gas has lower dew point thereby facilitating more waste heat recovery (D) All (A), (B) and (C)

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

Advantages of fluidised bed combustion are (A) Reduced NOx formation in flue gas (B) Lower furnace operating temperature (C) High heat transfer rate (D) All (A), (B) & (C)

Description : Advantages of fluidised bed combustion are (A) Reduced NOx formation in flue gas (B) Lower furnace operating temperature (C) High heat transfer rate (D) All (A), (B) & (C)

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

Pick out the wrong statement. (A) A slight haze at the top of chimney indicates good combustion in the furnace (B) A bag filter incurs very small pressure drop and is very efficient for removal of submicronic dust particles from flue gases at very high temperature (C) Electrostatic precipitator is the most efficient dust collection equipment for removal of submicronic dust particles present in flue gas (D) None of these

Description : Pick out the wrong statement. (A) A slight haze at the top of chimney indicates good combustion in the furnace (B) A bag filter incurs very small pressure drop and is very efficient for ... dust collection equipment for removal of submicronic dust particles present in flue gas (D) None of these

Last Answer : (B) A bag filter incurs very small pressure drop and is very efficient for removal of submicronic dust particles from flue gases at very high temperature

Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about __________ percent. (A) < 2 (B) < 5 (C) < 8 (D) < 10

Description : Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about __________ percent. (A) < 2 (B) < 5 (C) < 8 (D) < 10

Last Answer : (A) < 2

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

Description : 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

Last Answer : (B) Decrease

Find false statement about effect of sulphur in fuel? (A) It has heating value (B) It helps in electrostatic precipitation of ash in flue gases (C) It leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low (D) It erodes furnace walls

Description : Find false statement about effect of sulphur in fuel? (A) It has heating value (B) It helps in electrostatic precipitation of ash in flue gases (C) It leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low (D) It erodes furnace walls

Last Answer : (D) It erodes furnace walls

Fuel combustion is never cent per cent efficient due to (A) Incomplete combustion (B) Dry gas/stack gas loss (C) Moisture loss (D) All (A), (B) and (C)

Description : Fuel combustion is never cent per cent efficient due to (A) Incomplete combustion (B) Dry gas/stack gas loss (C) Moisture loss (D) All (A), (B) and (C)

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

The maximum adiabatic flame temperature in air as compared to that in pure oxygen is (A) Much lower (B) Much higher (C) Same (D) Either lower or higher, depends on the type of fuel

Description : The maximum adiabatic flame temperature in air as compared to that in pure oxygen is (A) Much lower (B) Much higher (C) Same (D) Either lower or higher, depends on the type of fuel

Last Answer : (A) Much lower

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

Description : 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

Last Answer : (C) Both (A) & (B)

Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about __________ °C. (A) 80 (B) 130 (C) 180 (D) 250

Description : Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about __________ °C. (A) 80 (B) 130 (C) 180 (D) 250

Last Answer : (B) 130

Efficiency of the combustion of a fuel is judged by the __________ the flue gas. (A) % of CO2 in (B) % of O2 in (C) Temperature of (D) Colour of

Description : Efficiency of the combustion of a fuel is judged by the __________ the flue gas. (A) % of CO2 in (B) % of O2 in (C) Temperature of (D) Colour of

Last Answer : (B) % of O2 in

Theoretical flame temperature of a fuel is that temperature which is attained, when the fuel is completely burnt 'using theoretical amount of air in (A) Air (B) Oxygen (C) Either (A) or (B) (D) Either (A) or (B) without gain or loss of heat

Description : Theoretical flame temperature of a fuel is that temperature which is attained, when the fuel is completely burnt 'using theoretical amount of air in (A) Air (B) Oxygen (C) Either (A) or (B) (D) Either (A) or (B) without gain or loss of heat

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

Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around __________ percent. (A) 4 (B) 96 (C) 20 (D) 40

Description : Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around __________ percent. (A) 4 (B) 96 (C) 20 (D) 40

Last Answer : (C) 20

Which of the following will generate maximum volume of product of complete combustion (Nm3 /Nm3 of fuel)? (A) Carburetted water gas (B) Blast furnace gas(C) Natural gas(D) Producers' gas

Description : Which of the following will generate maximum volume of product of complete combustion (Nm3 /Nm3 of fuel)? (A) Carburetted water gas (B) Blast furnace gas (C) Natural gas (D) Producers' gas

Last Answer : (C) Natural gas

Which of the following accounts for maximum energy loss in a boiler? (A) Flue gases (B) Ash content in the fuel (C) Incomplete combustion (D) Unburnt carbon in flue gases

Description : Which of the following accounts for maximum energy loss in a boiler? (A) Flue gases (B) Ash content in the fuel (C) Incomplete combustion (D) Unburnt carbon in flue gases

Last Answer : (A) Flue gases

Furnace aerodynamics is related to the __________ in the furnace. (A) Movement of gases (B) Measurement of flue gas volume (C) Temperature control

Description : Furnace aerodynamics is related to the __________ in the furnace. (A) Movement of gases (B) Measurement of flue gas volume (C) Temperature control

Last Answer : (A) Movement of gases