In which of the waste heat recovery equipment, the flow of flue gas and air is alternately reversed after a fixed interval of time? (A) Recuperator (B) Regenerator (C) Waste heat boiler (D) None of these

In which of the waste heat recovery equipment, the flow of flue gas and
air is alternately reversed after a fixed interval of time?
(A) Recuperator
(B) Regenerator
(C) Waste heat boiler
(D) None of these
by

1 Answer

Answer :

(B) Regenerator
by

Related questions

Which of the following is not a continuous waste heat recovery equipment from the flue gases going out of furnace? (A) Economiser (B) Regenerator (C) Ceramic recuperator (D) Waste heat boiler

Description : Which of the following is not a continuous waste heat recovery equipment from the flue gases going out of furnace? (A) Economiser (B) Regenerator (C) Ceramic recuperator (D) Waste heat boiler

Last Answer : (B) Regenerator

Sensible heat of hot industrial flue gases cannot be recovered by a/an (A) Economiser (B) Regenerator (C) Ceramic recuperator (D) None of these

Description : Sensible heat of hot industrial flue gases cannot be recovered by a/an (A) Economiser (B) Regenerator (C) Ceramic recuperator (D) None of these

Last Answer : (D) None of these

In a low to medium temperature waste heat recovery system which of the device is most suitable a) Economiser b) Heat wheels c) air preheater d) Recuperator

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Which of the following is the most suitable for preheating combustion air above 650°C? (A) Regenerator (B) Metallic recuperator (C) Ceramic recuperator (D) None of these

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An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a (A) Boiler (B) Heat exchanger (C) Recuperator (D) Regenerato

Description : An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a (A) Boiler (B) Heat exchanger (C) Recuperator (D) Regenerato

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Calculate the recoverable waste heat (Q, in kCal/hour) from flue gases using the followingparameters: V (flow rate of the substance) 2000 m3/hr r (density of the flue gas): 0.9 kg/m3 Cp (specific heat of the substance): 0.20 kCal/kg oC DT (temperature difference): 120 oC h (recovery factor): 50% a. 21600 b. 43200 c. 25600 d. 34000

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Last Answer : 21600

To reduce the stack loss, heat recovery from flue gas can be done by (A) Preheating of cold stock (B) Preheating of combustion air (C) Steam generation in waste heat boilers (D) All (A), (B) and (C)

Description : To reduce the stack loss, heat recovery from flue gas can be done by (A) Preheating of cold stock (B) Preheating of combustion air (C) Steam generation in waste heat boilers (D) All (A), (B) and (C)

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

Metallic recuperators are not used for waste heat recovery, if the hot flue gas temperature is above __________ °C, because corrosion prevails at higher temperatures. (A) 350 (B) 750 (C) 1050 (D) 1250

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Thermal efficiency of furnaces can be improved by (A) Waste heat recovery from flue gas (B) Minimising heat losses from furnace walls(C) Maintaining proper draught(D) All (A), (B) and (C

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

Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its (A) Emissivity factor is higher (B) Sulphur content is lower (C) Flue gas has lower dew point thereby facilitating more waste heat recovery (D) All (A), (B) and (C)

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

Pick up the odd one out: b) Regenerator c) Recuperator d) Metallic recuperator e) Economiser

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Last Answer : (B) Dust concentration & nature of dust in waste gas

Heat recovery equipment will be most effective when the temperature of flue gas is: a) 250oC b) 200 oC c)400 oC d) 280 oC

Description : Heat recovery equipment will be most effective when the temperature of flue gas is: a) 250oC b) 200 oC c)400 oC d) 280 oC

Last Answer : 400 oC

Recovery of heat from dryer exhaust air is a typical application of: a) Waste heat recovery boiler b) Heat pump c) Heat wheel d) Economizer

Description : Recovery of heat from dryer exhaust air is a typical application of: a) Waste heat recovery boiler b) Heat pump c) Heat wheel d) Economizer

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Air preheater is not used as a waste heat recovery system in a____. a) Boiler b) billet Reheating Furnace c) Heat treatment furnace d) compressor

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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

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Last Answer : preheating the boiler feed water

Recovery of waste heat from hot fluid to fluid is called: a) thermo compressor b) waste heat recovery boiler c) heat Pump d) economizer

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Last Answer : heat Pump

Recuperated is used mainly as a waste heat recovery system in a ____. a) Boiler b) Billet Reheating Furnace c) Compressor d) None of the above

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The economiser is used in boilers to........ A]Increase thermal efficiency of boiler B]Economise on fuel C]Extract heat from the exhaust the gases D]Increase flue gas temperature

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Last Answer : A]Increase thermal efficiency of boiler

Waste heat from the outgoing flue gases in a thermal power plant is recovered by a/an (A) Economiser (B) Steam superheater (C) Air preheater (D) All (A), (B) and (C)

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

What are the benefits or the advantages of waste heat recovery units (WHRU)? a) Reduced Pollution b) Reduced equipment sizes c) Reduced auxiliary energy consumption. d) All of the above

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Last Answer : All of the above

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Which of the following will be unsuitable for dust cleaning from flue gas at 400°C from a pulverised coal fired boiler? (A) Multicyclones (B) Bag filter (C) Wet scrubber (D) Hydrocyclones

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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

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The thermal efficiency of an air/fuel gas preheating recuperator may be as high as __________ percent. (A) 50 (B) 65 (C) 85 (D) 99

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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

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Last Answer : • To generate steam at constant pressure

Nellore to medium temperature waste heat recovery system the most suitable device is ------ a) Economizer b) Heat wheels c) Air preheater d) Recuperate d) Carbonate

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Which furnace employs an I.D. fan for the removal of flue gases from the furnace? (A) Coke oven(B) Blast furnace stoves(C) Beehive coke oven(D) High pressure boiler

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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

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

Water-tube boiler is the one, in which (A) Water passes through tubes and flue gases around it (B) Tube carrying hot flue gases are immersed in a pool of water (C) Tubes are placed in vertical position (D) None of these

Description : Water-tube boiler is the one, in which (A) Water passes through tubes and flue gases around it (B) Tube carrying hot flue gases are immersed in a pool of water (C) Tubes are placed in vertical position (D) None of these

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Water-tube boiler is the one, in which (A) Water passes through tubes and flue gases around it (B) Tube carrying hot flue gases are immersed in a pool of water (C) Tubes are placed in vertical position (D) None of these

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Last Answer : Option A

Most efficient and suitable dust removal equipment for removal of fly￾ash from flue gas in a thermal power plant is the (A) Gravity settling chamber (B) Cyclone separator (C) Electrostatic precipitator (D) Bag filter

Description : Most efficient and suitable dust removal equipment for removal of fly￾ash from flue gas in a thermal power plant is the (A) Gravity settling chamber (B) Cyclone separator (C) Electrostatic precipitator (D) Bag filter

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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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In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred (A) Through a metallic wall (B) By direct contact of hot flue gas with air (C) By heating an intermediate material (like chequor bricks) and then heating the air from this hot material (D) None of these

Description : In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred (A) Through a metallic wall (B) By direct contact of hot flue gas with air (C) By ... material (like chequor bricks) and then heating the air from this hot material (D) None of these

Last Answer : (C) By heating an intermediate material (like chequor bricks) and then heating the air from this hot material

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

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

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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

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

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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)

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)

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

Regenerators are used for waste heat recovery in (A) By-product coke ovens (B) Beehive coke oven (C) Blast furnace stoves (D) Soaking pits

Description : Regenerators are used for waste heat recovery in (A) By-product coke ovens (B) Beehive coke oven (C) Blast furnace stoves (D) Soaking pits

Last Answer : (A) By-product coke ovens

Heat transfer rate to the stock/charge in the furnace does not depend upon the(A) Emissivity of the refractory walls(B) Size of the furnace(C) Use of waste heat recovery equipments(D) Thickness of the stock

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Last Answer : (C) Use of waste heat recovery equipments

Capillary wick is a part of a) heat pump b) heat wheel c) heat pipe d) regenerator

Description : Capillary wick is a part of a) heat pump b) heat wheel c) heat pipe d) regenerator

Last Answer : heat pipe

Regenerator is widely used in: a) Reheating Furnaces b) heat treatment furnaces c) Baking Ovens d) glass melting furnaces

Description : Regenerator is widely used in: a) Reheating Furnaces b) heat treatment furnaces c) Baking Ovens d) glass melting furnaces

Last Answer : glass melting furnaces

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

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Last Answer : d. All of above

The diameter of internal flue tubes of a Lancashire boiler is about _______ that of it’s shell a. One fourth b. One third c. Two fifth d. One half

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Last Answer : c. Two fifth

The biggest loss in the boiler is a) Moisture in fuel b) Dry flue gases c) Steam formation d) Unburnt carbon

Description : The biggest loss in the boiler is a) Moisture in fuel b) Dry flue gases c) Steam formation d) Unburnt carbon

Last Answer : b) Dry flue gases

The use of regenerator in a gas turbine cycle

Description : The use of regenerator in a gas turbine cycle  (1) increases efficiency but has no effect on output (2) increases output but has no effect on efficiency (3) increases both efficiency and output (4) increases efficiency but decreases output

Last Answer : The use of regenerator in a gas turbine cycle increases efficiency but has no effect on output

Define the term waste heat recovery?

Description : Define the term waste heat recovery?

Last Answer : Waste heat is the heat which is not at all used and exhausted out as a waste product. Waste heat is normally available from the industry in the form of process steam and water at high ... industries. This heat can be recovered for useful purpose. This process is known-as waste heat recovery.