White smoke coming out of the chimney of a furnace indicates the useof(A) Low excess air(B) Very high excess air(C) Gaseous fuel in the furnace(D) Liquid fuel in the furnace

White smoke coming out of the chimney of a furnace indicates the useof
(A) Low excess air
(B) Very high excess air
(C) Gaseous fuel in the furnace
(D) Liquid fuel in the furnace
by

1 Answer

Answer :

(B) Very high excess air
by

Related questions

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

White flue gas (resembling steam) coming out of the chimney of a thermal power plant indicates that the fuel used in the boiler furnace is (A) Tar (B) Coke oven gas (C) Pitch (D) Pulverised coke

Description : White flue gas (resembling steam) coming out of the chimney of a thermal power plant indicates that the fuel used in the boiler furnace is (A) Tar (B) Coke oven gas (C) Pitch (D) Pulverised coke

Last Answer : (B) Coke oven gas

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

Short/intense flame is produced during combustion of gaseous fuel by using (A) High amount/current of combustion air(B) Low amount/current of combustion air(C) Preheated secondary air(D) Very little excess air

Description : Short/intense flame is produced during combustion of gaseous fuel by using (A) High amount/current of combustion air (B) Low amount/current of combustion air (C) Preheated secondary air (D) Very little excess air

Last Answer : (A) High amount/current of combustion air

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

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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

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

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

Last Answer : (A) Type (solid, liquid or gaseous)

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

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

Flue gases coming out from furnace is first going through a) Turbine b) Economizer c) Air pre-heater d) Chimney

Description : Flue gases coming out from furnace is first going through a) Turbine b) Economizer c) Air pre-heater d) Chimney

Last Answer : Ans: Economizer

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

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

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)

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

Pick out the wrong statement. (A) Strongly caking coal should not be used in the Lurgi gasifier (B) Acetylene gas cannot be used for illumination purpose (C) Water gas is called blue gas because of the color of the flame, when it is burnt (D) Gaseous fuels require less percentage of excess air for combustion as compared to liquid fuels

Description : Pick out the wrong statement. (A) Strongly caking coal should not be used in the Lurgi gasifier (B) Acetylene gas cannot be used for illumination purpose (C) Water gas is called blue gas ... is burnt (D) Gaseous fuels require less percentage of excess air for combustion as compared to liquid fuels

Last Answer : (B) Acetylene gas cannot be used for illumination purpose

Overfire burning in a furnace is a phenomenon characterised by (A) Supply of excess fuel (B) Supply of excess air (C) Burning carbon monoxide and other incombustible in upper zone of furnace by supplying more air (D) None of these

Description : Overfire burning in a furnace is a phenomenon characterised by (A) Supply of excess fuel (B) Supply of excess air (C) Burning carbon monoxide and other incombustible in upper zone of furnace by supplying more air (D) None of these

Last Answer : (C) Burning carbon monoxide and other incombustible in upper zone of furnace by supplying more air

Overfire burning" in a furnace is a phenomenon characterised by the (A) Supply of excess fuel (B) Supply of excess air (C) Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air (D) None of these

Description : Overfire burning" in a furnace is a phenomenon characterised by the (A) Supply of excess fuel (B) Supply of excess air (C) Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air (D) None of these

Last Answer : (C) Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air

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

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

Last Answer : (A) Low(A) Low

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)

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

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

Last Answer : (A) Requires larger combustion chamber than rich gaseous fuel

Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock

Description : Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock

Last Answer : (A) Type of fuels viz. solid, liquid or gaseous

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

Pig iron obtained from the furnace which is properly provided with fuel at a very high temperature, is called (A) Bessemer pig (B) Grey or foundry pig (C) White or forge pig (D) Mottled pig

Description : Pig iron obtained from the furnace which is properly provided with fuel at a very high temperature, is called (A) Bessemer pig (B) Grey or foundry pig (C) White or forge pig (D) Mottled pig

Last Answer : Answer: Option B

Which of the following accentuates clinkering troubles on furnace grate burning coal? (A) Low reactivity of carbonised residue containing high proportion of iron & sulphur (B) Low forced draft & fuel bed temperature (C) Thick firebed and preheated primary air (D) All (A), (B) and (C)

Description : Which of the following accentuates clinkering troubles on furnace grate burning coal? (A) Low reactivity of carbonised residue containing high proportion of iron & sulphur (B) Low forced draft & fuel bed temperature (C) Thick firebed and preheated primary air (D) All (A), (B) and (C)

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

Which of the following accentuates clinkering trouble on furnace grate burning coal? (A) Low reactivity of carbonised residue containing high proportions of iron & sulphur (B) Low forced draught and fuel bed temperature (C) Thick fire bed and preheated primary air (D) All (A), (B) and (C)

Description : Which of the following accentuates clinkering trouble on furnace grate burning coal? (A) Low reactivity of carbonised residue containing high proportions of iron & sulphur (B) Low forced draught and fuel bed temperature (C) Thick fire bed and preheated primary air (D) All (A), (B) and (C)

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

Safe limit' called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is the (A) Industrial chimney exhaust (B) Automobiles exhaust (C) Photochemical reaction in polluted atmosphere (D) Burning of domestic fuel

Description : Safe limit' called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is the (A) Industrial chimney exhaust (B) Automobiles exhaust (C) Photochemical reaction in polluted atmosphere (D) Burning of domestic fuel

Last Answer : (B) Automobiles exhaust

A stable interface between solid _________ liquid ____________ and gaseous ___________ promotes high rate of electrode processes. a) Fuel, electrolyte, electrode b) Electrode, fuel, electrolyte c) Electrode, electrolyte, fuel d) Fuel, electrode, electrolyte

Description : A stable interface between solid _________ liquid ____________ and gaseous ___________ promotes high rate of electrode processes. a) Fuel, electrolyte, electrode b) Electrode, fuel, electrolyte c) Electrode, electrolyte, fuel d) Fuel, electrode, electrolyte

Last Answer : c) Electrode, electrolyte, fuel

Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are normally carried out at about __________ °C. (A) 400-500 (B) 900-1000 (C) 1400-1500 (D) 1700-1800

Description : Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are ... __________ °C. (A) 400-500 (B) 900-1000 (C) 1400-1500 (D) 1700-1800

Last Answer : (B) 900-1000

Flue gas outlet temperature from the chimney of any furnace should be ideally about __________ °C. (A) 50 (B) 100 (C) 150

Description : Flue gas outlet temperature from the chimney of any furnace should be ideally about __________ °C. (A) 50 (B) 100 (C) 150

Last Answer : (C) 150

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)

If the furnace is provided with insufficient fuel at low temperatures, the type of pig iron produced, is called (A) Bessemer pig (B) Grey or foundry pig (C) White or forge pig (D) Mottled pig

Description : If the furnace is provided with insufficient fuel at low temperatures, the type of pig iron produced, is called (A) Bessemer pig (B) Grey or foundry pig (C) White or forge pig (D) Mottled pig

Last Answer : Answer: Option C

In tractor engine which of the following is a device in which liquid fuel is converted into gaseous fuel? 1. Piston 2. Carburetor 3. Both 1 and 2 4. none of these ans 1

Description : In tractor engine which of the following is a device in which liquid fuel is converted into gaseous fuel? 1. Piston 2. Carburetor 3. Both 1 and 2 4. none of these ans 1

Last Answer : ans 1

Fuels that may classified conveniently in solid, liquid and gaseous.  a. Unleaded fuel  b. Diesel fuel  c. Fossil fuel  d. All of the above

Description : Fuels that may classified conveniently in solid, liquid and gaseous.  a. Unleaded fuel  b. Diesel fuel  c. Fossil fuel  d. All of the above

Last Answer : Fossil fuel

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)

The advantages 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 consumption (D) All (A), (B) and (C)

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

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)

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Which of the following is not a gaseous air pollutant? (1) Oxides of nitrogen (2) Hydrocarbon (3) Smoke (4) Oxides of sulphur

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Which of the following is not a gaseous air pollutant? (1) Oxides of nitrogen (2) Hydrocarbon (3) Smoke (4) Oxides of sulphur

Description : Which of the following is not a gaseous air pollutant? (1) Oxides of nitrogen (2) Hydrocarbon (3) Smoke (4) Oxides of sulphur

Last Answer : Hydrocarbon

In order to maintain an oxidising atmosphere in a furnace, it should have (A) More of excess air (B) Less of excess air (C) More of CO in flue gas (D) More of CO2 in flue gas

Description : In order to maintain an oxidising atmosphere in a furnace, it should have (A) More of excess air (B) Less of excess air (C) More of CO in flue gas (D) More of CO2 in flue gas

Last Answer : (A) More of excess air

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)

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

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

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

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

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Last Answer : (A) Pressure has no effect

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

Vapour lock is a. complete or partial stoppage of fuel supply due to vaporization of the fuel b. locking of carburetor due to high vapor pressure c. excess fuel supply to the engine d. supply of liquid fuel to the engine

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Description : Ringelmann chart is used for the measurement of the (A) Combustibles present in automobile exhaust (B) Smoke density from a chimney (C) Exhaust gas density (D) Flue gas temperature

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Presence of predominantly large quantity of aromatics (polynuclear) is not desirable in aviation fuel, because it has (A) High pour point and low smoke point (B) Low viscosity index (C) High self-ignition temperature (D) All (A), (B) and (C)

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Last Answer : (B) Low viscosity index

Which of the following gaseous fuels has the lowest calorific value? (A) Gobar gas (B) Refinery gas (C) Converter gas (D) Blast furnace gas

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