Description : If oxygen content in the flue gas rises too high, fuel is being wasted by (A) Incomplete combustion (B) Dry gas/stack gas loss (C) Moisture loss (D) None of these
Last Answer : (B) Dry gas/stack gas loss
Description : During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the (A) Incomplete combustion (B) Complete combustion (C) High oxygen in flue gas (D) None of these
Last Answer : (B) Complete combustion
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
Description : Which of the following accounts for maximum energy loss in a boiler? (A) Flue gases (B) Ash content in the fuel (C) Incomplete combustion (D) Unburnt carbon in flue gases
Last Answer : (A) Flue gases
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
Description : Too much of excess air in combustion results in high (A) Fuel consumption for the same heat load (B) Stack gas temperature (C) Percentage of oxygen in flue gases (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
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.
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
Description : __________ the exhaust gas is an indication of the incomplete combustion of fuel. (A) Low temperature of (B) High temperature of (C) High % of CO in (D) High % of CO2in
Last Answer : (C) High % of CO in
Description : When incomplete combustion loss is high, the flue gas analysis shows large amount of (A) CO2 (B) CO (C) O2 (D) C
Last Answer : (B) CO
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
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
Description : measures oxygen and temperature of the flue gas. a) Fuel efficiency monitor. b) Combustion analyzer. c) Contact thermometer. d) Infrared thermometer.
Last Answer : Combustion analyzer
Description : Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about __________ °C. (A) 80 (B) 130 (C) 180 (D) 250
Last Answer : (B) 130
Description : Efficiency of the combustion of a fuel is judged by the __________ the flue gas. (A) % of CO2 in (B) % of O2 in (C) Temperature of (D) Colour of
Last Answer : (B) % of O2 in
Description : Acid rains are produced by (a) excess NO2 and SO2 from burning fossil fuels (b) excess production of NH3 by industry and coal gas (c) excess release of carbon monoxide by incomplete combustion (d) excess formation of CO2 by combustion and animal respiration.
Last Answer : (a) excess NO2 and SO2 from burning fossil fuels
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
Description : A carbonaceous fuel (containing no H2 or hydrocarbons) is burnt and the resulting flue gas contains 21% CO2 . It means that (A) 21% excess air has been used for combustion (B) 21% excess oxygen has ... (C) Complete combustion of fuel has taken place (D) No excess air has been used for combustion
Last Answer : (C) Complete combustion of fuel has taken place
Description : High sulphur content in a fuel __________ of the flue gases. (A) Decreases the dew point (B) Increases the dew point (C) Reduces the combustion efficiency by limiting the permissible temperature reduction (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
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
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
Description : Oxygen trim control strategy __ a. continuously measures the oxygen content in the flue gas b. adjusts the combustion air flow c. Continually tuning the air-fuel mixture. d. All of above
Last Answer : d. All of above
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
Description : The major carbon compound formed from the incomplete combustion of a hydrocarbon in air is (a) carbon dioxide (b) carbon monoxide (c) water (d) alkyl chains
Last Answer : carbon monoxide
Description : Wutomobile catalytic converters cause the carbon monoxide and hydrocarbons which result from incomplete combustion to be converted into what two substances?
Last Answer : ANSWER: CARBON DIOXIDE (CO2) AND WATER (H2O)
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
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
Description : Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around __________ percent. (A) 4 (B) 96 (C) 20 (D) 40
Last Answer : (C) 20
Description : Oxygen enrichment of combustion air does not result in increase of the (A) Flame temperature (B) Oxygen in the flue gas (C) Stack loss (D) Heat transfer rate in the furnace
Last Answer : (B) Oxygen in the flue gas
Description : Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case ofcomplete combustion of (A) Furnace oil with air (B) Furnace oil with oxygen (C) Blast furnace gas with air (D) Blast furnace gas with oxygen
Last Answer : (C) Blast furnace gas with air
Description : _______ is highly poisonous gas produced as a result of incomplete combustion. a) oxygen b)carbon dioxide c)carbon mono oxide d)soot
Last Answer : c)carbon mono oxide
Description : Flue gas obtained on complete combustion of pure acetylene (a hydrocarbon fuel) will contain (A) CO (B) CO2 (C) H2O (D) Both (B) & (C)
Last Answer : (D) Both (B) & (C)
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
Description : Fuel combustion is never cent per cent efficient due to (A) Incomplete combustion (B) Dry gas/stack gas loss (C) Moisture loss (D) All (A), (B) and (C)
Description : In flue gas analysis by Orsat's apparatus, carbon monoxide is absorbed by (A) Cuprous chloride (B) Potassium hydroxide (C) Alkaline pyrogallol solution (D) None of these
Last Answer : (A) Cuprous chloride
Description : High excess air in combustion of fuels results in (A) Increased fuel consumption (B) Incomplete combustion (C) Smoky flame (D) None of these
Last Answer : (A) Increased fuel consumption
Description : Economizer is provided to utilize the flue gas heat for ___ a) preheating the boiler feed water b) preheating the stock c) preheating the combustion air d) preheating fuel
Last Answer : preheating the boiler feed water
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
Description : Advantages of fluidised bed combustion are (A) Reduced NOx formation in flue gas (B) Lower furnace operating temperature (C) High heat transfer rate (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : 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 ... dust collection equipment for removal of submicronic dust particles present in flue gas (D) None of these
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
Description : The main source of carbon monoxide is (1) Industrial process (2) Fuel combustion (3) Transportation (4) Solid waste disposal
Last Answer : (3) Transportation Explanation: The main source of carbon monoxide is burning of fossil fuel
Last Answer : Transportation
Description : Combustion of an alkene with sufficient oxygen will produce (a) carbon dioxide and water (b) carbon monoxide and water (c) only carbon dioxide (d) only carbon monoxide
Last Answer : carbon dioxide and water
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
Description : Ostwald charts are meant for (A) Computing the excess/deficiency of combustion air (B) Calculation of flue gas temperature (C) Computation of flue gas analysis (D) None of these
Last Answer : (A) Computing the excess/deficiency of combustion air
Description : Presence of nitrogen in combustion air does not reduce the (A) Amount of heat liberated (B) Flame temperature (C) Flue gas temperature (D) Any of the above
Last Answer : (A) Amount of heat liberated
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
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)
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)