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

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
by

1 Answer

Answer :

(D) All (A), (B) and (C
by

Related questions

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

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

Higher fuel combustion efficiency cannot be achieved by (A) Preheating of fuel gases & combustion air (B) Reducing sulphur content in the fuel (C) Adopting proper fuel firing technique & fuel preparation (D) Supplying correct amount of combustion air

Description : Higher fuel combustion efficiency cannot be achieved by (A) Preheating of fuel gases & combustion air (B) Reducing sulphur content in the fuel (C) Adopting proper fuel firing technique & fuel preparation (D) Supplying correct amount of combustion air

Last Answer : (B) Reducing sulphur content in the fuel

Ingress of cold air in the furnaces through cracks, charging doors, openings etc(A) Reduces the flue gas temperature and makes the furnace atmosphereoxidising(B) Increases the load on the induced draft fan(C) Reduces the furnace draught(D) All (A), (B) and (C)

Description : Ingress of cold air in the furnaces through cracks, charging doors, openings etc (A) Reduces the flue gas temperature and makes the furnace atmosphere oxidising (B) Increases the load on the induced draft fan (C) Reduces the furnace draught (D) All (A), (B) and (C)

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

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

Description : 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

Last Answer : (B) Flame temperature

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)

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

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

In general, the limit of inflammability/explosion limit of fuel gases is widened by the (A) Increase in gas pressure (B) Increase in temperature (i.e. preheating) (C) Use of pure oxygen for combustion instead of air (D) All (A), (B) & (C)

Description : In general, the limit of inflammability/explosion limit of fuel gases is widened by the (A) Increase in gas pressure (B) Increase in temperature (i.e. preheating) (C) Use of pure oxygen for combustion instead of air (D) All (A), (B) & (C)

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

Economizer is provided to utilize the flue gas heat for ___ a) preheating the boiler feed water b) preheating the stock c) preheating the combustion air d) preheating fuel

Description : Economizer is provided to utilize the flue gas heat for ___ a) preheating the boiler feed water b) preheating the stock c) preheating the combustion air d) preheating fuel

Last Answer : preheating the boiler feed water

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)

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

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

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

Description : 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

Last Answer : (A) Increase the adiabatic flame temperature

Preheating of __________ the flame temperature. (A) The gaseous fuel before combustion decreases (B) Combustion air decreases (C) Either the fuel or the air or both, increases (D) Either the fuel or the air does not affect

Description : Preheating of __________ the flame temperature. (A) The gaseous fuel before combustion decreases (B) Combustion air decreases (C) Either the fuel or the air or both, increases (D) Either the fuel or the air does not affect

Last Answer : (C) Either the fuel or the air or both, increases

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)

Description : 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)

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

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

Major sources of noise in furnace operation arises from air inspirators, combustion, side wall vibrations and fluctuation in the process heat load. A 50% increase in fuel firing rate may increase the furnace noise level by about __________ decibels. (A) 3 (B) 30(C) 7 (D) 70

Description : Major sources of noise in furnace operation arises from air inspirators, combustion, side wall vibrations and fluctuation in the process heat load. A 50% increase in fuel firing rate may increase the furnace noise level by about __________ decibels. (A) 3 (B) 30 (C) 7 (D) 70

Last Answer : (A) 3

The heat recoverable from flue gases of furnaces depends on the (A) Thermal efficiency of furnace (B) Quantity of flue gases (C) Flue gas temperature drop through the furnace (D) All (A), (B) and (C)

Description : The heat recoverable from flue gases of furnaces depends on the (A) Thermal efficiency of furnace (B) Quantity of flue gases (C) Flue gas temperature drop through the furnace (D) All (A), (B) and (C)

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

LSHS is a type of furnace oil, which (A) Is more viscous than high viscosity furnace oil (HVFO) (B) Stands for low sulphur heavy stock (C) Is an ideal fuel for metallurgical furnaces due to its lower sulphur content (< 1%(D) All (A), (B) and (C))

Description : LSHS is a type of furnace oil, which (A) Is more viscous than high viscosity furnace oil (HVFO) (B) Stands for low sulphur heavy stock (C) Is an ideal fuel for metallurgical furnaces due to its lower sulphur content (< 1%) (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

Smoke is produced due to (A) Insufficient supply of combustion air and insufficient time for combustion (B) Poor quality of fuel and improper mixing of fuel & combustion air (C) Poor design & overloading of furnace (D) All (A), (B) and (C)

Description : Smoke is produced due to (A) Insufficient supply of combustion air and insufficient time for combustion (B) Poor quality of fuel and improper mixing of fuel & combustion air (C) Poor design & overloading of furnace (D) All (A), (B) and (C)

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

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)

are portable devices capable of estimating the combusting efficiency of furnaces, boilers, or other fossil fuel burning machines. a) Sound analyzer. c) Combustion analyzer. b) Light analyzer. d)Temperature analyzer

Description : are portable devices capable of estimating the combusting efficiency of furnaces, boilers, or other fossil fuel burning machines. a) Sound analyzer. c) Combustion analyzer. b) Light analyzer. d)Temperature analyzer

Last Answer : Combustion analyzer. 

are portable devices capable of estimating the combusting efficiency of furnaces, boilers, or other fossil fuel burning machines. a) Sound analyzer. b) Light analyzer. c) Combustion analyzer. d) Temperature analyzer.

Description : are portable devices capable of estimating the combusting efficiency of furnaces, boilers, or other fossil fuel burning machines. a) Sound analyzer. b) Light analyzer. c) Combustion analyzer. d) Temperature analyzer.

Last Answer : Combustion analyzer.

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

Thickness of stock does not affect the fuel economy of furnaces, if thematerial to be heated is of(A) Low emissivity(B) High thermal conductivity(C) Both (A) and (B)(D) Neither (A) nor (B)

Description : Thickness of stock does not affect the fuel economy of furnaces, if thematerial to be heated is of (A) Low emissivity (B) High thermal conductivity (C) Both (A) and (B) (D) Neither (A) nor (B)

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

Thermal efficiency of furnaces can be improved by (A) Waste heat recovery from flue gas (B) Minimising heat losses from furnace walls(C) Maintaining proper draught(D) All (A), (B) and (C

Description : Thermal efficiency of furnaces can be improved by (A) Waste heat recovery from flue gas (B) Minimising heat losses from furnace walls (C) Maintaining proper draught (D) All (A), (B) and (C

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

Maximum heat transfer in high temperature furnaces is by (A) Conduction (B) Convection (C) Radiation (D) Either (A), (B) or (C); depends on the type of furnace

Description : Maximum heat transfer in high temperature furnaces is by (A) Conduction (B) Convection (C) Radiation (D) Either (A), (B) or (C); depends on the type of furnace

Last Answer : (C) Radiation

Forced recirculation of furnace gases is practised (A) To increase heat transfer by convection (B) To ensure uniform temperature (C) In furnaces, operating below 750°C (D) All (A), (B) and (C)

Description : Forced recirculation of furnace gases is practised (A) To increase heat transfer by convection (B) To ensure uniform temperature (C) In furnaces, operating below 750°C (D) All (A), (B) and (C)

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

Turndown ratio of a burner gives an idea of the __________ in the furnace. (A) Range of fuel firing rates (B) Volume of the combustion chamber (C) Maximum heat input rate only (D) Minimum heat input rate only

Description : Turndown ratio of a burner gives an idea of the __________ in the furnace. (A) Range of fuel firing rates (B) Volume of the combustion chamber (C) Maximum heat input rate only (D) Minimum heat input rate only

Last Answer : (A) Range of fuel firing rates

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) 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

Which of the following is the most suitable for preheating combustion air above 650°C? (A) Regenerator (B) Metallic recuperator (C) Ceramic recuperator (D) None of these

Description : Which of the following is the most suitable for preheating combustion air above 650°C? (A) Regenerator (B) Metallic recuperator (C) Ceramic recuperator (D) None of these

Last Answer : (C) Ceramic recuperator

Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above __________ °C. (A) 250 (B) 650 (C) 850 (D) 1000

Description : Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above __________ °C. (A) 250 (B) 650 (C) 850 (D) 1000

Last Answer : (B) 650

In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of (A) Transportation of coal (B) Drying of coal (C) Combustion of coal by supplying it around the burner (D) Preheating the primary air

Description : In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of (A) Transportation of coal (B) Drying of coal (C) Combustion of coal by supplying it around the burner (D) Preheating the primary air

Last Answer : (C) Combustion of coal by supplying it around the burner

In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of (A) Transportation of coal (B) Drying of coal (C) Combustion of coal by supplying it around the burner (D) Preheating the primary air

Description : In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of (A) Transportation of coal (B) Drying of coal (C) Combustion of coal by supplying it around the burner (D) Preheating the primary air

Last Answer : (C) Combustion of coal by supplying it around the burner

Means for giving direction to the circulation of gases in furnaces are (A) Fans (B) Arrangement of heating stock in the furnaces (C) Location of outlet ports and heating & combustion devices (D) All (A), (B) and (C)

Description : Means for giving direction to the circulation of gases in furnaces are (A) Fans (B) Arrangement of heating stock in the furnaces (C) Location of outlet ports and heating & combustion devices (D) All (A), (B) and (C)

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

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)

Preheating temperature of medium viscosity furnace oil for better atomisation through burner is about __________ °C. (A) 50 (B) 70 (C) 90 (D) 140

Description : Preheating temperature of medium viscosity furnace oil for better atomisation through burner is about __________ °C. (A) 50 (B) 70 (C) 90 (D) 140

Last Answer : (C) 90

Which of the following does not require preheating during storage in the storage tank as well as during atomisation through burners? (A) PCM (B) Tar (C) Light diesel oil (D) Low viscosity furnace oil

Description : Which of the following does not require preheating during storage in the storage tank as well as during atomisation through burners? (A) PCM (B) Tar (C) Light diesel oil (D) Low viscosity furnace oil

Last Answer : (C) Light diesel oil

Pick out the wrong statement. (A) Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal (B) Low grade coal can be used, but generally high volatile matter coals are more suitable for making pulverised fuel (C) Regulation of furnace temperature and atmosphere (oxidising or reducing) is easily possible with pulverised fuel firing (D) None of these

Description : Pick out the wrong statement. (A) Pulverised fuel can be completely burnt with less percentage of excess air compared to lump coal (B) Low grade coal can be used, but generally high volatile ... and atmosphere (oxidising or reducing) is easily possible with pulverised fuel firing (D) None of these

Last Answer : (D) None of these

The main advantage of forced draft over natural draft is that (A) Combustion of fuel is complete (B) Smaller height chimney can be used (C) Furnace control is easier (D) All (A), (B) & (C)

Description : The main advantage of forced draft over natural draft is that (A) Combustion of fuel is complete (B) Smaller height chimney can be used (C) Furnace control is easier (D) All (A), (B) & (C)

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

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

Which of the following fuel gases will require maximum amount of air for combustion of 1 Nm3 gas? (A) Blast furnace gas (B) Natural gas (C) Producer gas (D) Water gas

Description : Which of the following fuel gases will require maximum amount of air for combustion of 1 Nm3 gas? (A) Blast furnace gas (B) Natural gas (C) Producer gas (D) Water gas

Last Answer : (B) Natural gas

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

Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace. (A) Low amount of excess combustion air (B) Large quantity of excess combustion air(C) Hydrocarbon fuel(D) Pulverised coal as fuel

Description : Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace. (A) Low amount of excess combustion air (B) Large quantity of excess combustion air (C) Hydrocarbon fuel (D) Pulverised coal as fuel

Last Answer : (A) Low amount of excess combustion air