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

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
by

1 Answer

Answer :

(B) 750
by

Related questions

Ceramic recuperators compared to metallic recuperators for the same duty (A) Are lighter (B) Occupy more space (C) Are less costly (D) Have higher pressure differential between flue gas & air side

Description : Ceramic recuperators compared to metallic recuperators for the same duty (A) Are lighter (B) Occupy more space (C) Are less costly (D) Have higher pressure differential between flue gas & air side

Last Answer : (B) Occupy more space

Fusion zone in the electric furnace used for reduction of phosphate rock to elemental phosphorous is maintained at __________ °C. (A) 250-300 (B) 500-750 (C) 950-1050 (D) 1400-1450

Description : Fusion zone in the electric furnace used for reduction of phosphate rock to elemental phosphorous is maintained at __________ °C. (A) 250-300 (B) 500-750 (C) 950-1050 (D) 1400-1450

Last Answer : (D) 1400-1450

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)

Description : 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)

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

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

Description : 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 ... (temperature difference): 120 oC h (recovery factor): 50% a. 21600 b. 43200 c. 25600 d. 34000

Last Answer : 21600

Regenerators as compared to recuperators for the same duty(A) Store smaller quantity of waste heat (B) Are lighter & compact (C) Involve higher initial cost (D) All (A), (B) & (C)

Description : Regenerators as compared to recuperators for the same duty(A) Store smaller quantity of waste heat (B) Are lighter & compact (C) Involve higher initial cost (D) All (A), (B) & (C)

Last Answer : (C) Involve higher initial cost

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

Description : 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

Last Answer : (B) Regenerator

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

Description : 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

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

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)

Hot extrusion of aluminium is done in the temperature range of __________ °C. (A) 550-600 (B) 450-500 (C) 350-400 (D) 250-300

Description : Hot extrusion of aluminium is done in the temperature range of __________ °C. (A) 550-600 (B) 450-500 (C) 350-400 (D) 250-300

Last Answer : (C) 350-400

Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above __________ °C. (A) 250 (B) 650 (C) 850 (D) 1000

Description : Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above __________ °C. (A) 250 (B) 650 (C) 850 (D) 1000

Last Answer : (B) 650

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

A high temperature waste heat recovery unit consists of recovering waste heat at temperaturesgreater than _______. a) 200 °C b) 500 °C c) 300 °C d) 400 °C

Description : A high temperature waste heat recovery unit consists of recovering waste heat at temperaturesgreater than _______. a) 200 °C b) 500 °C c) 300 °C d) 400 °C

Last Answer : 400 °C

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

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

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

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

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Last Answer : (C) 150

The temperature at which this compound is formed is in the range? a) 350-550°C b) 550-800°C c) 800-1050°C d) 1050-1500°C

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High speed steel tools retain their hardness upto a temperature of __________ °C.(A) 500 (B) 750 (C) 900 (D) 1100

Description : High speed steel tools retain their hardness upto a temperature of __________ °C. (A) 500 (B) 750 (C) 900 (D) 1100

Last Answer : (C) 900

Coal is heated in presence of air to a temperature of about __________ °C, while determining its ash content for proximate analysis. (A) 500 (B) 750 (C) 950 (D) 1100

Description : Coal is heated in presence of air to a temperature of about __________ °C, while determining its ash content for proximate analysis. (A) 500 (B) 750 (C) 950 (D) 1100

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Coal is heated in absence of air for 7 minutes at a temperature of about __________ °C, during its volatile matter determination for proximateanalysis.(A) 550(B) 750(C) 950(D) 1150

Description : Coal is heated in absence of air for 7 minutes at a temperature of about __________ °C, during its volatile matter determination for proximateanalysis. (A) 550 (B) 750 (C) 950 (D) 1150

Last Answer : (C) 950

High speed steel tools retain their hardness upto a temperature of __________ °C. (A) 500 (B) 750 (C) 900 (D) 1100

Description : High speed steel tools retain their hardness upto a temperature of __________ °C. (A) 500 (B) 750 (C) 900 (D) 1100

Last Answer : Option C

Fusion point of coal ash generally varies from 1000 to 1700° C. Ash having fusion point less than __________ °C is liable to form clinker. (A) 1100 (B) 1250 (C) 1350 (D) 1400

Description : Fusion point of coal ash generally varies from 1000 to 1700° C. Ash having fusion point less than __________ °C is liable to form clinker. (A) 1100 (B) 1250 (C) 1350 (D) 1400

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Temperature of coke oven gas just before entering into saturator (for recovery of NH3 ) is about __________ °C. (A) 30 (B) 65 (C) 120

Description : Temperature of coke oven gas just before entering into saturator (for recovery of NH3 ) is about __________ °C. (A) 30 (B) 65 (C) 120

Last Answer : (B) 65

Most of the plastics are safe to be used upto a maximum temperature of __________ °C. (A) 100 (B) 150 (C) 350 (D) 450

Description : Most of the plastics are safe to be used upto a maximum temperature of __________ °C. (A) 100 (B) 150 (C) 350 (D) 450

Last Answer : (B) 150

The temperature at which plastic layer formation takes place during carbonisation of coal varies from __________ °C. (A) 100 to 150 (B) 350 to 450 (C) 550 to 650 (D) 700 to 850

Description : The temperature at which plastic layer formation takes place during carbonisation of coal varies from __________ °C. (A) 100 to 150 (B) 350 to 450 (C) 550 to 650 (D) 700 to 850

Last Answer : (B) 350 to 450

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

In industrial operations fluids with temperature less than __________ are set as the limit for waste heat recovery because of the risk of condensation of corrosive liquids a. 80C b. 100C c. 120C d. 200C

Description : In industrial operations fluids with temperature less than __________ are set as the limit for waste heat recovery because of the risk of condensation of corrosive liquids a. 80C b. 100C c. 120C d. 200C

Last Answer : 100C

A, B and C enter into a partnership and their shares are in ratio 1/2 : 1/3 : 1/4, after 2 months, A withdraws half of his capital and after 12 months, a profit of Rs 1050 is divided among them. What is B’s share ? A.Rs.420 B.Rs. 300 C.Rs.400 D.Rs.350

Description : A, B and C enter into a partnership and their shares are in ratio 1/2 : 1/3 : 1/4, after 2 months, A withdraws half of his capital and after 12 months, a profit of Rs 1050 is divided among them. What is B’s share ? A.Rs.420 B.Rs. 300 C.Rs.400 D.Rs.350

Last Answer : Answer- C(Rs.400) Explanation : Ratio of investments =1/2 : 1/3 : 1/4 , LCM of 2, 3, 4 = 12 ,multiply ratios with 12 we get 6 : 4 : 3 , so,initial investment be 6x, 2x and 3x so, we can write: A : B :C =(6x X 2 + 3x X 10 ) : (4x X 12) :(3x X 12) = 7:8:6 B’s share= (8/21) x 1050 = 400

Traditionally, waste heat of low temperature range ________ has not been used for electricitygeneration despite efforts by ORC companies, mainly because the Carnot efficiency is rather low. a) 0-250 °C b) 0-150 °C c) 0-200 °C d) 0-120 °C

Description : Traditionally, waste heat of low temperature range ________ has not been used for electricitygeneration despite efforts by ORC companies, mainly because the Carnot efficiency is rather low. a) 0-250 °C b) 0-150 °C c) 0-200 °C d) 0-120 °C

Last Answer : 0-120 °C

In a counter flow heat exchanger, hot fluid enters at 170°C & leaves at 150°C, while the cold fluid enters at 50°C & leaves at 70°C. The arithmetic mean temperature difference in this case is __________ °C. (A) 20 (B) 60 (C) 120 (D) ∞

Description : In a counter flow heat exchanger, hot fluid enters at 170°C & leaves at 150°C, while the cold fluid enters at 50°C & leaves at 70°C. The arithmetic mean temperature difference in this case is __________ °C. (A) 20 (B) 60 (C) 120 (D) ∞

Last Answer : (D) ∞

A mixture of 10% C6H6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C. (A) 21.7 (B) 20 (C) 27.3 (D) 18.7

Description : A mixture of 10% C6H6 vapour in air at 25°C and 750 mm Hg has a dew point of 20°C. Its dew point at 30°C and 700 mm Hg will be around __________ °C. (A) 21.7 (B) 20 (C) 27.3 (D) 18.7

Last Answer : (D) 18.7

Hydrogen content in petroleum products varies from 12 to 15% (by weight). As a result the difference between gross and net heating value of petroleum fuels varies in the range of __________ kcal/kg. (A) 600-750 (B) 250-350 (C) 1000-1500 (D) 2000-2500

Description : Hydrogen content in petroleum products varies from 12 to 15% (by weight). As a result the difference between gross and net heating value of petroleum fuels varies in the range of __________ kcal/kg. (A) 600-750 (B) 250-350 (C) 1000-1500 (D) 2000-2500

Last Answer : (A) 600-750

Design of waste heat boiler for recovery of waste heat from furnace gases depends upon the(A) Quantity & temperature of waste gas(B) Dust concentration & nature of dust in waste gas(C) Corrosive nature of the waste gas(D) All (A), (B) and (C)

Description : Design of waste heat boiler for recovery of waste heat from furnace gases depends upon the (A) Quantity & temperature of waste gas (B) Dust concentration & nature of dust in waste gas (C) Corrosive nature of the waste gas (D) All (A), (B) and (C)

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

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

What is the range of tempering temperature (°C) for most of the materials? (A) 75-100 (B) 200-300 (C) 350-450 (D) 500-600

Description : What is the range of tempering temperature (°C) for most of the materials? (A) 75-100 (B) 200-300 (C) 350-450 (D) 500-600

Last Answer : (B) 200-300

A metallic alloy in general as compared to their pure metal components is (A) More corrosion resistant (B) Having higher melting point (C) Having lower hardness, reactivity and fusibility (D) Having lower electrical conductivity

Description : A metallic alloy in general as compared to their pure metal components is (A) More corrosion resistant (B) Having higher melting point (C) Having lower hardness, reactivity and fusibility (D) Having lower electrical conductivity

Last Answer : (A) More corrosion resistant

The cutter bar of a tractor operated on owner makes strokes/min (a) 400 – 500 (b) 500 – 750 (c) 800 – 1200 (d) 1250 – 1500

Description : The cutter bar of a tractor operated on owner makes strokes/min (a) 400 – 500 (b) 500 – 750 (c) 800 – 1200 (d) 1250 – 1500

Last Answer : (c) 800 – 1200

Normal values of overflow rate for plain sedimentation tank using coagulants, is (A) 750 to 1000 litres/hr/m2(B) 1000 to 1250 litres/hr/m2(C) 1250 to 1500 litres/hr/m2(D) 1500 litres/hr/m

Description : Normal values of overflow rate for plain sedimentation tank using coagulants, is (A) 750 to 1000 litres/hr/m2 (B) 1000 to 1250 litres/hr/m2 (C) 1250 to 1500 litres/hr/m2 (D) 1500 litres/hr/m

Last Answer : (B) 1000 to 1250 litres/hr/m2

Normal values of overflow rate for sedimentation tanks using coagulants in litres/hr/m2 , generally range between (A) 250 to 500 (B) 500 to 750 (C) 750 to 1000 (D) 1000 to 1250

Description : Normal values of overflow rate for sedimentation tanks using coagulants in litres/hr/m2 , generally range between (A) 250 to 500 (B) 500 to 750 (C) 750 to 1000 (D) 1000 to 1250

Last Answer : (D) 1000 to 1250

Normal values of overflow rate for plain sedimentation tank, is (A) 250 to 500 litres/hr/m2 (B) 500 to 750 litres/hr/m2 (C) 750 to 1000 litres/hr/m2 (D) 1000 to 1250 litres/hr/m

Description : Normal values of overflow rate for plain sedimentation tank, is  (A) 250 to 500 litres/hr/m2 (B) 500 to 750 litres/hr/m2 (C) 750 to 1000 litres/hr/m2 (D) 1000 to 1250 litres/hr/m

Last Answer : (B) 500 to 750 litres/hr/m

A three hinged arch is loaded with an isolated load 1000 kg at a horizontal distance of 2.5 m from the crown, 1 m above the level of hinges at the supports 10 metres apart. The horizontal thrust is (A) 1250 kg (B) 125 kg (C) 750 kg (D) 2500 kg

Description : A three hinged arch is loaded with an isolated load 1000 kg at a horizontal distance of 2.5 m from the crown, 1 m above the level of hinges at the supports 10 metres apart. The horizontal thrust is (A) 1250 kg (B) 125 kg (C) 750 kg (D) 2500 kg

Last Answer : (A) 1250 kg

Concrete pavement is provided if daily traffic per lane exceeds (A) 500 tonnes (B) 750 tonnes (C) 1000 tonnes (D) 1250 tonnes

Description : Concrete pavement is provided if daily traffic per lane exceeds (A) 500 tonnes (B) 750 tonnes (C) 1000 tonnes (D) 1250 tonnes

Last Answer : Answer: Option C

How many mL of a 1:500 w/v stock solution should be used to make 5 liters of 1:2000 w/v solution? (A) 750 mL (B) 1000 mL (c) 1250 mL (D) 1500 mL

Description : How many mL of a 1:500 w/v stock solution should be used to make 5 liters of 1:2000 w/v solution? (A) 750 mL (B) 1000 mL (c) 1250 mL (D) 1500 mL

Last Answer : (c) 1250 mL

A sells an article to B at 15% profit. B sells it to C at 10% loss. If C pays Rs 517.50 for it then A purchased it at: 1. Rs 500 2. Rs 750 3. Rs 1000 4. Rs 1250

Description : A sells an article to B at 15% profit. B sells it to C at 10% loss. If C pays Rs 517.50 for it then A purchased it at: 1. Rs 500 2. Rs 750 3. Rs 1000 4. Rs 1250

Last Answer : 1. Rs 500

Solvay process as compared to dual process (i.e. modified Solvay process). (A) Can use low grade brine (B) Has less corrosion problems (C) Involves higher investment in NH3 recovery units than that for crystallisation units for NH4Cl(D) Both (B) and (C)

Description : Solvay process as compared to dual process (i.e. modified Solvay process). (A) Can use low grade brine (B) Has less corrosion problems (C) Involves higher investment in NH3 recovery units than that for crystallisation units for NH4Cl (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

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

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

Last Answer : heat Pump

Yield of urea can be increased with excess ammonia and higher pressure & temperature, but because of __________ this is normally not done. (A) Increased biuret formation (B) High corrosion rate (C) Increased cost of equipment (D) All (A), (B) & (C)

Description : Yield of urea can be increased with excess ammonia and higher pressure & temperature, but because of __________ this is normally not done. (A) Increased biuret formation (B) High corrosion rate (C) Increased cost of equipment (D) All (A), (B) & (C)

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

Secondary hardening in steels arises out of the (A) Precipitation of fine alloy carbides at high temperatures (B) Refinement of ferrite grain size by working (C) Decomposition of retained austenite upon heat treatment (D) Precipitation of complex inter-metallic upon heat treatment

Description : Secondary hardening in steels arises out of the (A) Precipitation of fine alloy carbides at high temperatures (B) Refinement of ferrite grain size by working (C) Decomposition of retained austenite upon heat treatment (D) Precipitation of complex inter-metallic upon heat treatment

Last Answer : Option C

Viscosity of water is about __________ times that of air at room temperature. (A) 15 (B) 55 (C) 155 (D) 1050

Description : Viscosity of water is about __________ times that of air at room temperature. (A) 15 (B) 55 (C) 155 (D) 1050

Last Answer : (B) 55

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Description : Hot water (0.01 m3 /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m3 /min) of density 800 kg/m3 and specific heat of ... mean temperature difference in °C is approximately (A) 32 (B) 37 (C) 45 (D) 50

Last Answer : (A) 32

Which of the following statements regarding evacuated tube collectors (ETC) are true? i) ETC is used for high temperatures upto 150oC ii) because of use of vacuum between two concentric glass tube, higher amount of heat is retained in ETC iii) heat loss due to conduction back to atmosphere from ETC is high iv) performance of evacuated tube is highly dependent upon the ambient temperature i & iii b) ii & iii c) i & iv d) i & ii

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Last Answer : d) i & ii