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

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
by

1 Answer

Answer :

(B) Ratio of fixed carbon to volatile matter increases
by

Related questions

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

Ignition temperature decreases progressively from anthracite to lignite, because (A) Volatile matter content increases (B) Carbon content decreases (C) Moisture content increases (D) Ash content increases

Description : Ignition temperature decreases progressively from anthracite to lignite, because (A) Volatile matter content increases (B) Carbon content decreases (C) Moisture content increases (D) Ash content increases

Last Answer : (A) Volatile matter content increases

Pick out the wrong statement. (A) Angle of repose of coal increases with its increasing size (B) Specific gravity of coal increases with its increasing maturity (C) Refractive index and reflectance of coal increases with the increasing rank of coal (D) Specific heat of coal decreases with increases in the volatile matter and decrease in the C/H ratio of coal

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Last Answer : (D) Specific heat of coal decreases with increases in the volatile matter and decrease in the C/H ratio of coal

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)

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

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

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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

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Pick out the correct statement. (A) Oxygen content decreases from lignite to bituminous coal as the coalification increases (B) The less the oxygen content, better is the coal, as it reduces the calorific value (C) With increase in oxygen content, moisture holding capacity of coal increases and the caking power decreases (D) All (A), (B) and (C)

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

With increase in the temperature of carbonisation of coal (A) Hydrogen content of coke oven gas increases due to cracking ofhydrocarbons(B) Methane content in the coke oven gas decreases and carbon monoxidecontent increases(C) Calorific value of the coke oven gas decreases due to cracking ofhydrocarbons which is not compensated by increase in CO & H2 content(D) All (A), (B) and (C)

Description : With increase in the temperature of carbonisation of coal (A) Hydrogen content of coke oven gas increases due to cracking ofhydrocarbons (B) Methane content in the coke oven gas decreases and carbon monoxide content increases ( ... compensated by increase in CO & H2 content (D) All (A), (B) and (C)

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

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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

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)

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With increase in moisture content of coal, its (A) Calorific value increases sometimes (B) Bulk density always decreases (C) Clinkering tendency during combustion increases (D) None of these

Description : With increase in moisture content of coal, its (A) Calorific value increases sometimes (B) Bulk density always decreases (C) Clinkering tendency during combustion increases (D) None of these

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With increase in the oxygen content of the coal, its __________ decreases. (A) Calorific value (B) Caking power (C) Both (A) & (B) (D) Neither (A) nor (B)

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Assam (India) coals suffers mainly from the disadvantage of high __________ content. (A) Ash (B) Volatile matter (C) Sulphur (4-6%)

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Coals used for the generation of producer gas should have (A) High caking index (B) Low fusion point of ash (C) High volatile matter content (D) Very low ash content (8-10%)

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Fat coals' are those coals which have very high (A) Caking capacity (B) Volatile matter content (C) Fusion point of its ash (D) Inherent moisture conten

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Pick out the wrong statement: (A) Carburetted water gas is also called blue gas (B) Coals are divided in four species according to their carbon content in Seylor's classification (C) Carbonisation time in a by-product coke oven is about 16 hours (D) Gross and net calorific value of a fuel is the same, if it does not contain hydrogen or hydrocarbons

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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

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

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Low temperature oxidation of stored coal results in the (A) Decrease in its caking power & calorific value (B) Decrease in its carbon & hydrogen content (C) Increase in its oxygen content (D) All (A), (B) and (A)

Description : Low temperature oxidation of stored coal results in the (A) Decrease in its caking power & calorific value (B) Decrease in its carbon & hydrogen content (C) Increase in its oxygen content (D) All (A), (B) and (A)

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

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

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A coal with high ash content (A) Has higher calorific value (B) Is harder and stronger(C) Is not subjected to washing(D) Has low quantity of mineral matter

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As the equilibrium moisture content of the coal increases, its (A) Calorific value increases (B) Swelling number decreases (C) Swelling number increases (D) Bulk density decreases

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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

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Improper storage condition results in the weathering of coal and spontaneous combustion, which increases its (A) Caking index (B) Yield of carbonised products (C) Friability & oxygen content (D) Calorific value

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A coal gasifier operating at 20 atm. (e.g. Lurgi gasifier) as compared to one operating at atmospheric pressure (e.g. Kopper-Totzek or Winkler gasifier) will produce a gas having (A) Higher methane content and thus higher calorific value (B) Higher carbon monoxide content(C) Lower carbon dioxide content(D) None of these

Description : A coal gasifier operating at 20 atm. (e.g. Lurgi gasifier) as compared to one operating at atmospheric pressure (e.g. Kopper-Totzek or Winkler gasifier) will produce a gas having (A) Higher ... calorific value (B) Higher carbon monoxide content (C) Lower carbon dioxide content (D) None of these

Last Answer : (A) Higher methane content and thus higher calorific value

Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher (A) Calorific value (B) Higher C/H ratio (C) Sulphur content (D) Difference in gross & net calorific value

Description : Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher (A) Calorific value (B) Higher C/H ratio (C) Sulphur content (D) Difference in gross & net calorific value

Last Answer : (B) Higher C/H ratio

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

With increase in moisture content of coal, its (A) Calorific value increases (B) Caking properties diminish (C) Swelling during carbonisation becomes excessive (D) None of these

Description : With increase in moisture content of coal, its (A) Calorific value increases (B) Caking properties diminish (C) Swelling during carbonisation becomes excessive (D) None of these

Last Answer : (B) Caking properties diminish

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

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

Explain higher and lower calorific value of a coal having following composition by mass Carbon 81%,Hydrogen 7%, Oxygen 8%,Nitrogen 2.5%, sulphur 1.5% and remaining is ash

Description : Explain higher and lower calorific value of a coal having following composition by mass Carbon 81%,Hydrogen 7%, Oxygen 8%,Nitrogen 2.5%, sulphur 1.5% and remaining is ash

Last Answer : Carbon C = 81% = 0.81 Hydrogen = H2 = 7% = 0.07 Oxygen = O2 = 8% = 0.08 Nitrogen = N = 2.5% = 0.025 Sulphur = S =1.5% = 0.015 Ash = 2.5% = 0.025 Dulong's formula: H.C.V. of coal = 33800 C + 144500 ... = H.C.V.- 9H2 x 2442 KJ / Kg = 36187.5- 9 x 0.07 x 2442 L.C.V. of coal = 34649.04 KJ / Kg 

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

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

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 : (C) Carbon, sulphur, volatile matter & ash

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 : Option D

Rate of low temperature oxidation of coal due to bad storage conditions (A) Decreases with increase in surface area (B) Does not vary with increase in surface area (C) Is more for low volatile coal compared to high volatile coal (D) Is accelerated by storage in large heaps with small surface to volume ratio

Description : Rate of low temperature oxidation of coal due to bad storage conditions (A) Decreases with increase in surface area (B) Does not vary with increase in surface area (C) Is more for low volatile ... to high volatile coal (D) Is accelerated by storage in large heaps with small surface to volume ratio

Last Answer : (D) Is accelerated by storage in large heaps with small surface to volume ratio

Coke oven gas produced by high temperature carbonisation of coal (as compared to that produced by low temperature carbonisation), has (A) Higher calorific value (B) Lower hydrogen content (C) Both (A) and (B) (D) Neither (A) nor (B)

Description : Coke oven gas produced by high temperature carbonisation of coal (as compared to that produced by low temperature carbonisation), has (A) Higher calorific value (B) Lower hydrogen content (C) Both (A) and (B) (D) Neither (A) nor (B)

Last Answer : (D) Neither (A) nor (B)

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

Description : 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

Last Answer : (B) Completely burn the volatile matter

In Lurgi coal gasifier, (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Larger quantity of coal can be processed

Description : In Lurgi coal gasifier, (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Larger quantity of coal can be processed

Last Answer : (D) Larger quantity of coal can be processed

In the Lurgi coal gasifier (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Large quantity of coal can be processed

Description : In the Lurgi coal gasifier (A) Coking coals cannot be used (B) Low carbon conversion efficiency is achieved (C) Entrainment of solids is higher (D) Large quantity of coal can be processed

Last Answer : (D) Large quantity of coal can be processed

A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the (A) Presence of large quantity of hydrogen in the fuel (B) Low calorific value of the fuel (C) High sulphur content in the fuel (D) Lack of thorough mixing of fuel with air

Description : A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the (A) Presence of large ... fuel (C) High sulphur content in the fuel (D) Lack of thorough mixing of fuel with air

Last Answer : (D) Lack of thorough mixing of fuel with air

In low temperature carbonisation of coal as compared to high temperature carbonisation __________ produced is less. (A) Difference in gross & net calorific value of the coke oven gas (B) Free carbon content in tar (C) Yield percentage of coke (D) Yield of ammonia present in coke oven gas

Description : In low temperature carbonisation of coal as compared to high temperature carbonisation __________ produced is less. (A) Difference in gross & net calorific value of the coke oven gas (B) Free carbon content in tar (C) Yield percentage of coke (D) Yield of ammonia present in coke oven gas

Last Answer : (A) Difference in gross & net calorific value of the coke oven gas

The disintegration rate of a radioactive element (A) Progressively increases (B) Progressively decreases (C) Remains constant throughout (D) May increase or decrease depending on the material

Description : The disintegration rate of a radioactive element (A) Progressively increases (B) Progressively decreases (C) Remains constant throughout (D) May increase or decrease depending on the material

Last Answer : (B) Progressively decreases

64-132) rank coal (ASTM) means a coal with 64% (A) Fixed carbon and having a heating value around 13, 200 BTU/1b (B) Ash and heating value around 13, 200 BTU/1b (C) Fixed carbon and heating value around 132 BTU/1b (D) None of these

Description : 64-132) rank coal (ASTM) means a coal with 64% (A) Fixed carbon and having a heating value around 13, 200 BTU/1b (B) Ash and heating value around 13, 200 BTU/1b (C) Fixed carbon and heating value around 132 BTU/1b (D) None of these

Last Answer : (A) Fixed carbon and having a heating value around 13, 200 BTU/1b

64-132) rank coal (ASTM) means a coal with 64% (A) Fixed carbon and having a heat value of 13, 200 BTU/1b (B) Ash and a heating value of 13, 200 BTU/1b (C) Fixed carbon and a heating value of 132 BTU/1b (D) None of these

Description : 64-132) rank coal (ASTM) means a coal with 64% (A) Fixed carbon and having a heat value of 13, 200 BTU/1b (B) Ash and a heating value of 13, 200 BTU/1b (C) Fixed carbon and a heating value of 132 BTU/1b (D) None of these

Last Answer : (A) Fixed carbon and having a heat value of 13, 200 BTU/1b

Washing of coal (A) Reduces its sulphur and ash content (B) Controls its ash fusibility and increases its calorific value(C) Improves its coking properties(D) All (A), (B) and (C)

Description : Washing of coal (A) Reduces its sulphur and ash content (B) Controls its ash fusibility and increases its calorific value (C) Improves its coking properties (D) All (A), (B) and (C)

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

Low temperature oxidation of coal during storage does not decrease its (A) Oxygen content (B) Caking power (C) Calorific value (D) None of these

Description : Low temperature oxidation of coal during storage does not decrease its (A) Oxygen content (B) Caking power (C) Calorific value (D) None of these

Last Answer : (D) None of these