The function of secondary combustion air is to (A) Pneumatically convey the pulverised coal (B) Completely burn the volatile matter (C) Burn the lumpy coal (D) None of these

The function of secondary combustion air is to
(A) Pneumatically convey the pulverised coal
(B) Completely burn the volatile matter
(C) Burn the lumpy coal
(D) None of these
by

1 Answer

Answer :

(B) Completely burn the volatile matter
by

Related questions

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)

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 function of primary air in pulverised coal fired burner is to (A) Burn CO to CO2 (B) Dry and transport the coal (C) Have proper combustion by supplying it around the burner (D) Preheat the tertiary air used for complete combustion of CO to CO2

Description : The main function of primary air in pulverised coal fired burner is to (A) Burn CO to CO2 (B) Dry and transport the coal (C) Have proper combustion by supplying it around the burner (D) Preheat the tertiary air used for complete combustion of CO to CO2

Last Answer : (B) Dry and transport the coal

A coal having high ratio of volatile matter to fixed carbon as compared to a coal having low ratio of volatile matter to fixed carbon (A) Is less liable to spontaneous combustion on storage (B) Is more difficult to ignite and produces a shorter flame (C) Requires smaller combustion space and less secondary air (D) None of these

Description : A coal having high ratio of volatile matter to fixed carbon as compared to a coal having low ratio of volatile matter to fixed carbon (A) Is less liable to spontaneous combustion on storage (B) ... a shorter flame (C) Requires smaller combustion space and less secondary air (D) None of these

Last Answer : (D) None of these

Which of the following would require least amount of secondary air for combustion? (A) Coke breeze containing 25% ash and 2% volatile matter (B) Anthracite containing 10% volatile matter and 8% ash(C) Bituminous coal containing 20% ash and 25% volatile matter(D) Semi-bituminous coal containing 25% ash and 20% volatile matter

Description : Which of the following would require least amount of secondary air for combustion? (A) Coke breeze containing 25% ash and 2% volatile matter (B) Anthracite containing 10% volatile matter and 8% ash ... ash and 25% volatile matter (D) Semi-bituminous coal containing 25% ash and 20% volatile matter

Last Answer : (A) Coke breeze containing 25% ash and 2% volatile matter

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

The function of an economiser in a boiler is to preheat the (A) Feedwater (B) Combustion air (C) Pulverised coal (D) Furnace oil

Description : The function of an economiser in a boiler is to preheat the (A) Feedwater (B) Combustion air (C) Pulverised coal (D) Furnace oil

Last Answer : (A) Feedwater

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

Function of secondary air in pulverised coal firing is to (A) Transport the coal to the burner (B) Dry the coal (C) Ensure efficient burning of coal around the burner (D) Reduce primary air requirement

Description : Function of secondary air in pulverised coal firing is to (A) Transport the coal to the burner (B) Dry the coal (C) Ensure efficient burning of coal around the burner (D) Reduce primary air requirement

Last Answer : (C) Ensure efficient burning of coal around the burner

Ratio of primary air to secondary air increases with increase in the rank of coal, because the (A) High rank coals have higher amount of volatile matter (B) Ratio of fixed carbon to volatile matter increases (C) Oxygen content progressively decreases (D) Calorific value of the coal increases

Description : Ratio of primary air to secondary air increases with increase in the rank of coal, because the (A) High rank coals have higher amount of volatile matter (B) Ratio of fixed carbon to volatile matter increases (C) Oxygen content progressively decreases (D) Calorific value of the coal increases

Last Answer : (B) Ratio of fixed carbon to volatile matter increases

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

Description : 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

Last Answer : (C) Can be done with less excess ai

Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the (A) Requirement of large volume combustion chamber (B) Risk of explosion (C) Chances of clinker formation (D) Incomplete combustion of coal

Description : Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the (A) ... chamber (B) Risk of explosion (C) Chances of clinker formation (D) Incomplete combustion of coal

Last Answer : (B) Risk of explosion

Which of the following would require maximum amount of % excess air for complete combustion? (A) Coke oven gas (B) Furnace oil (C) Pulverised coal (D) Lump coal (fixed on chain grate)

Description : Which of the following would require maximum amount of % excess air for complete combustion? (A) Coke oven gas (B) Furnace oil (C) Pulverised coal (D) Lump coal (fixed on chain grate)

Last Answer : (D) Lump coal (fixed on chain grate)

Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of (A) Less air for combustion (B) Correct amount of air for combustion (C) Too much air for combustion (D) Pulverised coal in boilers

Description : Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of (A) Less air for combustion (B) Correct amount of air for combustion (C) Too much air for combustion (D) Pulverised coal in boilers

Last Answer : (C) Too much air for combustion

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

The excess air required for the combustion of pulverised coal is of the order of about __________ percent. (A) 5 (B) 15 (C) 30 (D) 45

Description : The excess air required for the combustion of pulverised coal is of the order of about __________ percent. (A) 5 (B) 15 (C) 30 (D) 45

Last Answer : (B) 15

A coal having high amount of volatile matter (A) Would require smaller combustion chamber (B) Produces very little of tar and gas on carbonisation (C) Ignites easily and burns with long smoky flame (D) All (A), (B) and (C)

Description : A coal having high amount of volatile matter (A) Would require smaller combustion chamber (B) Produces very little of tar and gas on carbonisation (C) Ignites easily and burns with long smoky flame (D) All (A), (B) and (C)

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

A coal having high amount of volatile matter (A) Would require smaller combustion chamber (B) Produces very little of tar and gas on carbonisation(C) Ignites easily and burns with long smoky flame(D) All (A), (B) and (C)

Description : A coal having high amount of volatile matter (A) Would require smaller combustion chamber (B) Produces very little of tar and gas on carbonisation (C) Ignites easily and burns with long smoky flame (D) All (A), (B) and (C)

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

Fixed carbon in coal is defined as (A) That present in volatile matters (B) The total quantity of carbon present in the coal (C) Hundred minus the percentage of volatile matter, ash and moisture (D) The one which is present in the residue after combustion

Description : Fixed carbon in coal is defined as (A) That present in volatile matters (B) The total quantity of carbon present in the coal (C) Hundred minus the percentage of volatile matter, ash and moisture (D) The one which is present in the residue after combustion

Last Answer : (C) Hundred minus the percentage of volatile matter, ash and moisture

Low temperature oxidation and spontaneous combustion of freshly mined coal is accentuated, if (A) It contains large amount of volatile matter (B) It is stored in tall heaps (C) Smaller fines are stored in large quantity (D) All (A), (B) and (C)

Description : Low temperature oxidation and spontaneous combustion of freshly mined coal is accentuated, if (A) It contains large amount of volatile matter (B) It is stored in tall heaps (C) Smaller fines are stored in large quantity (D) All (A), (B) and (C)

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

Use of pulverised coal in boilers provides (A) Higher calorific value (B) Better combustion (C) Smokeless burning (D) Less erosion on furnace wall

Description : Use of pulverised coal in boilers provides (A) Higher calorific value (B) Better combustion (C) Smokeless burning (D) Less erosion on furnace wall

Last Answer : (B) Better combustion

Use of pulverised coal in boiler furnace provides (A) High calorific value (B) Better combustion (C) Smokeless burning (D) Less erosion on furnace walls

Description : Use of pulverised coal in boiler furnace provides (A) High calorific value (B) Better combustion (C) Smokeless burning (D) Less erosion on furnace walls

Last Answer : (B) Better combustion

The advantage of firing pulverised coal in the furnace lies in the fact, that it (A) Permits the use of high ash content coal (B) Permits the use of low fusion point ash coal(C) Accelerates the burning rate and economises on fuel combustion(D) All (A), (B) and (C)

Description : The advantage of firing pulverised coal in the furnace lies in the fact, that it (A) Permits the use of high ash content coal (B) Permits the use of low fusion point ash coal (C) Accelerates the burning rate and economises on fuel combustion (D) All (A), (B) and (C)

Last Answer : (C) Accelerates the burning rate and economises on fuel combustion

Coal is pulverised before burning in large capacity boiler furnaces mainly to (A) Ensure its complete combustion (B) Facilitate easy ash removal (C) Enhance its calorific value (D) Provide trouble free operation

Description : Coal is pulverised before burning in large capacity boiler furnaces mainly to (A) Ensure its complete combustion (B) Facilitate easy ash removal (C) Enhance its calorific value (D) Provide trouble free operation

Last Answer : (A) Ensure its complete combustion

Coal is heated in absence of air for 7 minutes at a temperature of about __________ °C, during its volatile matter determination for proximateanalysis.(A) 550(B) 750(C) 950(D) 1150

Description : Coal is heated in absence of air for 7 minutes at a temperature of about __________ °C, during its volatile matter determination for proximateanalysis. (A) 550 (B) 750 (C) 950 (D) 1150

Last Answer : (C) 950

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

Bucket elevators are not suitable for the vertical lifting of __________ materials. (A) Fine (e.g. - 200 mesh size coal) (B) Sticky (e.g. clay paste) (C) Small lumpy (e.g. grains and sand) (D) Free flowing

Description : Bucket elevators are not suitable for the vertical lifting of __________ materials. (A) Fine (e.g. - 200 mesh size coal) (B) Sticky (e.g. clay paste) (C) Small lumpy (e.g. grains and sand) (D) Free flowing

Last Answer : (B) Sticky (e.g. clay paste

Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about __________ percent. (A) 10-15 (B) 25-30 (C) 45-50 (D) 65-70

Description : Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about __________ percent. (A) 10-15 (B) 25-30 (C) 45-50 (D) 65-70

Last Answer : (B) 25-30

Which of the following is not applicable to fluidised bed combustion of coal? (A) It cannot burn low grade coal (B) It achieves higher fuel combustion efficiency (C) Less heat transfer surface area is required in boilers (D) None of these

Description : Which of the following is not applicable to fluidised bed combustion of coal? (A) It cannot burn low grade coal (B) It achieves higher fuel combustion efficiency (C) Less heat transfer surface area is required in boilers (D) None of these

Last Answer : (A) It cannot burn low grade coal

Pick out the correct statement.(A) Angle of repose is always greater than the angle of slide (B) A hopper is a small bin with a sloping bottom (C) A silo is a short height vessel of very large diameter used for the storage of high volatile matter coal (D) Pine oil is used as a 'modifying agent' (for activating or depressing the adsorption of filming agents) in froth floatation process

Description : Pick out the correct statement. (A) Angle of repose is always greater than the angle of slide (B) A hopper is a small bin with a sloping bottom (C) A silo is a short height ... used as a 'modifying agent' (for activating or depressing the adsorption of filming agents) in froth floatation process

Last Answer : (B) A hopper is a small bin with a sloping bottom

Washability curve based on float and sink test enables an assessment to be made of the possibility of cleaning a coal fraction based on the (A) Density separation (B) Differential wettability (C) Size (D) Volatile matter content

Description : Washability curve based on float and sink test enables an assessment to be made of the possibility of cleaning a coal fraction based on the (A) Density separation (B) Differential wettability (C) Size (D) Volatile matter content

Last Answer : (A) Density separation

The specific gravity of coal depends mainly on its __________ content. (A) Carbon (B) Volatile matter (C) Ash (D) Moisture

Description : The specific gravity of coal depends mainly on its __________ content. (A) Carbon (B) Volatile matter (C) Ash (D) Moisture

Last Answer : (C) Ash

Fussain (A) Is friable, charcoal like substance(B) Has highest fixed carbon and lowest volatile matter content of all the four banded components of coal (C) Is non-coking, but when blended with highly coking coal, controls its swelling and produces high strength coke on carbonisation (D) All (A), (B) and (C)

Description : Fussain (A) Is friable, charcoal like substance (B) Has highest fixed carbon and lowest volatile matter content of all the four banded components of coal (C) Is non-coking, but when blended with highly coking ... its swelling and produces high strength coke on carbonisation (D) All (A), (B) and (C)

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

Anthracite coal (A) Contains more volatile matter than bituminous coal (B) Ignites more easily than bituminous coal (C) Is essentially a coking coal (D) Burns with short, bluish, yellow-tipped flame producing very little smoke

Description : Anthracite coal (A) Contains more volatile matter than bituminous coal (B) Ignites more easily than bituminous coal (C) Is essentially a coking coal (D) Burns with short, bluish, yellow-tipped flame producing very little smoke

Last Answer : (D) Burns with short, bluish, yellow-tipped flame producing very little smoke

Coal containing large quantity of __________ are difficult to wash. (A) Ash (B) Inherent mineral matter (C) Free impurities (D) Volatile matter

Description : Coal containing large quantity of __________ are difficult to wash. (A) Ash (B) Inherent mineral matter (C) Free impurities (D) Volatile matter

Last Answer : (B) Inherent mineral matter

Ultimate analysis of coal determines its __________ content. (A) Carbon, hydrogen, nitrogen & sulphur (B) Carbon, ash, sulphur & nitrogen (C) Carbon, sulphur, volatile matter & ash (D) Carbon, volatile matter, ash & moisture

Description : Ultimate analysis of coal determines its __________ content. (A) Carbon, hydrogen, nitrogen & sulphur (B) Carbon, ash, sulphur & nitrogen (C) Carbon, sulphur, volatile matter & ash (D) Carbon, volatile matter, ash & moisture

Last Answer : (A) Carbon, hydrogen, nitrogen & sulphur

Cannel coal (A) Is non-coking (B) Has a high volatile matter content and burns with a luminous smoky flame (C) Is a non-banded coal which can be ignited easily with a match stick or candle flame, hence is so named (D) All (A), (B) and (C

Description : Cannel coal (A) Is non-coking (B) Has a high volatile matter content and burns with a luminous smoky flame (C) Is a non-banded coal which can be ignited easily with a match stick or candle flame, hence is so named (D) All (A), (B) and (C

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

A coal containing high amount of volatile matter will have (A) Low ignition temperature (B) Very little ash content (C) High fusion point of its ash (D) Low adiabatic flame temperature

Description : A coal containing high amount of volatile matter will have (A) Low ignition temperature (B) Very little ash content (C) High fusion point of its ash (D) Low adiabatic flame temperature

Last Answer : (A) Low ignition temperature

For long flame and easy ignition, the coal used should have (A) High volatile matter (B) Low ash (C) High calorific value (D) High ash

Description : For long flame and easy ignition, the coal used should have (A) High volatile matter (B) Low ash (C) High calorific value (D) High ash

Last Answer : (A) High volatile matter

Proximate analysis of coal determines its __________ content. (A) Moisture, ash, sulphur & volatile matter (B) Moisture, volatile matter, ash & fixed carbon (C) Moisture, sulphur, nitrogen & fixed carbon (D) None of these

Description : Proximate analysis of coal determines its __________ content. (A) Moisture, ash, sulphur & volatile matter (B) Moisture, volatile matter, ash & fixed carbon (C) Moisture, sulphur, nitrogen & fixed carbon (D) None of these

Last Answer : (B) Moisture, volatile matter, ash & fixed carbon

Fat' coal means a coal having (A) Low calorific value (B) High volatile matter (C) Low ash content

Description : Fat' coal means a coal having (A) Low calorific value (B) High volatile matter (C) Low ash content

Last Answer : (B) High volatile matter

A coal having higher volatile matter content will necessarily have lower (A) Ash fusion temperature (B) Calorific value (C) Ignition temperature (D) Caking index

Description : A coal having higher volatile matter content will necessarily have lower (A) Ash fusion temperature (B) Calorific value (C) Ignition temperature (D) Caking index

Last Answer : (C) Ignition temperature

Degree of carbonisation of coal during coke making can be roughly judged by the __________ of the coke produced. (A) Colour (B) Moisture content (C) Ash content (D) Volatile matter

Description : Degree of carbonisation of coal during coke making can be roughly judged by the __________ of the coke produced. (A) Colour (B) Moisture content (C) Ash content (D) Volatile matter

Last Answer : (D) Volatile matter

Volatile matter content in coking coal may be about __________ percent. (A) 1 (B) 7 (C) 22 (D) 46

Description : Volatile matter content in coking coal may be about __________ percent. (A) 1 (B) 7 (C) 22 (D) 46

Last Answer : (C) 22

A coal with high __________ content, would ignite most easily. (A) Fixed carbon (B) Volatile matter (C) Ash (D) Oxygen

Description : A coal with high __________ content, would ignite most easily. (A) Fixed carbon (B) Volatile matter (C) Ash (D) Oxygen

Last Answer : (B) Volatile matter

A coal having higher volatile matter content, has lower (A) Smoking tendency on burning (B) Coke oven gas yield on carbonisation (C) Chance of catching fire during storage in open space (D) Ignition temperature

Description : A coal having higher volatile matter content, has lower (A) Smoking tendency on burning (B) Coke oven gas yield on carbonisation (C) Chance of catching fire during storage in open space (D) Ignition temperature

Last Answer : (D) Ignition temperature

Which will have the least volatile matter and hence will be the most difficult to ignite? (A) Bituminous coal (B) Coke (C) Semi-bituminous coal (D) Anthracite

Description : Which will have the least volatile matter and hence will be the most difficult to ignite? (A) Bituminous coal (B) Coke (C) Semi-bituminous coal (D) Anthracite

Last Answer : (B) Coke

The fuel ratio of a coal is (A) The ratio of its percentage of fixed carbon to that of volatile matter (B) Helpful in estimation of its rank (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : The fuel ratio of a coal is (A) The ratio of its percentage of fixed carbon to that of volatile matter (B) Helpful in estimation of its rank (C) Both (A) and (B) (D) Neither (A) nor (B)

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