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)

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)
by

1 Answer

Answer :

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

Related questions

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

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)

Supply of excess air for complete combustion of fuel is necessitated to facilitate (A) Its thorough mixing with air (B) Attainment of chemical equilibrium (C) Attainment of high temperature (D) None of these

Description : Supply of excess air for complete combustion of fuel is necessitated to facilitate (A) Its thorough mixing with air (B) Attainment of chemical equilibrium (C) Attainment of high temperature (D) None of these

Last Answer : (A) Its thorough mixing with air

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

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

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

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

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

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)

The amount of combustible escaping unconsumed from the furnace, depends upon the (A) Air supplied and furnace temperature (B) Burner design (thoroughness of mixing versus stratification) (C) Air preheat and the flow of gases in the furnace (mixing by induction, by acceleration or by change of direction) (D) All (A), (B) and (C)

Description : The amount of combustible escaping unconsumed from the furnace, depends upon the (A) Air supplied and furnace temperature (B) Burner design (thoroughness of mixing versus stratification) (C) Air preheat and the flow of ... , by acceleration or by change of direction) (D) All (A), (B) and (C)

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

Sooty and sulphurous smog formed due to combustion of fossil fuels particularly in winter, continues throughout the day and night. When the moist atmospheric air's water vapor condenses on the solid particles of smoke thereby forming smog (smoke + fog), it causes (A) Poor visibility due to sky darkening (B) Irritation in eyes (C) Respiratory trouble (D) All (A), (B) and (C)

Description : Sooty and sulphurous smog formed due to combustion of fossil fuels particularly in winter, continues throughout the day and night. When the moist atmospheric air's water vapor condenses on the solid particles of smoke thereby ... B) Irritation in eyes (C) Respiratory trouble (D) All (A), (B) and (C)

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

Combustion is the ideal air/fuel ratio where a. the mixing proportion is correct, b. the fuel is completely burned c. the oxygen is entirely consumed d. All of the above

Description : Combustion is the ideal air/fuel ratio where a. the mixing proportion is correct, b. the fuel is completely burned c. the oxygen is entirely consumed d. All of the above

Last Answer : d. All of the above

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)

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)

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

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

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

The main drawback of supplying more excess air in the combustion of fuel is the (A) Excessive power requirement of air blower (B) Enhanced sensible heat loss in the flue gas (C) Intermittent and uncontrolled combustion of the fuel (D) High exit flue gas temperature from the furnace

Description : The main drawback of supplying more excess air in the combustion of fuel is the (A) Excessive power requirement of air blower (B) Enhanced sensible heat loss in the flue gas (C) Intermittent and uncontrolled combustion of the fuel (D) High exit flue gas temperature from the furnace

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

Which of the following 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

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

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

Description : 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

Last Answer : (B) Very high excess air

Based on the exhaust gas analysis, a controller maintains stoichiometric combustion __ a. by commanding a servo motor to adjust the combustion air damper b. By commanding servo motor to adjust the fuel supply valve. c. Both a. & b. d. None of the above.

Description : Based on the exhaust gas analysis, a controller maintains stoichiometric combustion __ a. by commanding a servo motor to adjust the combustion air damper b. By commanding servo motor to adjust the fuel supply valve. c. Both a. & b. d. None of the above.

Last Answer : c. Both a. & b.

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

Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse (B) Packed towers are preferred over plate towers for handling corrosive and foamy liquids (C) Diameter of randomly packed tower is normally more than 1.2 metres (D) Due to uneven supply and improper distribution of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers

Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres

The engine produces dark black smoke due to a) Burning of oil b) Due of incomplete combustion c) Due to moisture in fuel d) None of these Ans. b

Description : The engine produces dark black smoke due to a) Burning of oil b) Due of incomplete combustion c) Due to moisture in fuel d) None of these Ans. b

Last Answer : ans b

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

Description : 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

Last Answer : (C) Friability & oxygen content

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

What would happen in a collision between two particles if there was insufficient kinetic energy and improper geometric orientation?

Description : What would happen in a collision between two particles if there was insufficient kinetic energy and improper geometric orientation?

Last Answer : The particles would rebound and there would be no reaction. The particles would keep bouncing off each other until they eventually react, therefore the rate would be slow.

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

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

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

Last Answer : (A) CO content

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

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

Last Answer : (C) Natural gas

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

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

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

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

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

A 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

The lowest temperature, at which a solid fuel produces enough vapors to support continuous combustion, is called (A) Fire point (B) Smoke point (C) Burning temperature (D) Kindling temperature

Description : The lowest temperature, at which a solid fuel produces enough vapors to support continuous combustion, is called (A) Fire point (B) Smoke point (C) Burning temperature (D) Kindling temperature

Last Answer : (C) Burning temperature

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

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

Last Answer : (D) Carbon monoxide

What is defined as the ratio of the net electrical power output to the rate of fuel energy input?  A. Combustion efficiency  B. Thermal efficiency  C. Overall efficiency  D. Furnace efficiency

Description : What is defined as the ratio of the net electrical power output to the rate of fuel energy input?  A. Combustion efficiency  B. Thermal efficiency  C. Overall efficiency  D. Furnace efficiency

Last Answer : Overall efficiency

Which of the following gases is produced due to incomplete combustion of fuel? (1) Carbon Dioxide (2) Carbon Monoxide (3) Methane (4) Ethane

Description : Which of the following gases is produced due to incomplete combustion of fuel? (1) Carbon Dioxide (2) Carbon Monoxide (3) Methane (4) Ethane

Last Answer : (2) Carbon Monoxide Explanation: Carbon monoxide (CO) is an odorless, colorless gas formed by the incomplete com bustion of fuels. It is produced from the partial oxidation of carbon-containing com pounds; it forms when there is not enough oxygen to produce carbon dioxide.

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)

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

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

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)

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)

The main function of a muffle in the muffle furnace is to (A) Protect the charge from the effects of the products of combustion (B) Smooth out temperature inequalities on the combustion side of the muffle wall (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : The main function of a muffle in the muffle furnace is to (A) Protect the charge from the effects of the products of combustion (B) Smooth out temperature inequalities on the combustion side of the muffle wall (C) Both (A) & (B) (D) Neither (A) nor (B)

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