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)

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)
by

1 Answer

Answer :

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

The heat recoverable from flue gases of furnaces depends on the (A) Thermal efficiency of furnace (B) Quantity of flue gases (C) Flue gas temperature drop through the furnace (D) All (A), (B) and (C)

Description : The heat recoverable from flue gases of furnaces depends on the (A) Thermal efficiency of furnace (B) Quantity of flue gases (C) Flue gas temperature drop through the furnace (D) All (A), (B) and (C)

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

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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Last Answer : compressor

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

Description : 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

Last Answer : Billet Reheating Furnace

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)

In a gas-liquid shell and tube heat exchanger, the(A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure gases are corrosive in nature (C) Gases to be heated/cooled is normally routed through the shell side, because the corrosion caused by the cooling water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Description : In a gas-liquid shell and tube heat exchanger, the (A) Presence of a non-condensable gas decreases the condensing film co￾efficient (B) Gases under high pressure are routed through the tube side, because high pressure ... water or steam condensate remain localised to the tubes (D) All 'a', 'b' & 'c'

Last Answer : (D) All 'a', 'b' & 'c'

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

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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

In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the (A) Rate of firing and emissivity of flame (B) Thermal conductivity of the charge & structural materials of furnace (C) Nature of process; whether batch, continuous or intermittent (D) All (A), (B) and (C)

Description : In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the (A) Rate of firing and emissivity of flame (B) Thermal conductivity of the charge & ... (C) Nature of process; whether batch, continuous or intermittent (D) All (A), (B) and (C)

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

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

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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

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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)

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

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Last Answer : 21600

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)

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

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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The rate of scaling of furnace stock depends upon the (A) Temperature (B) Time(C) Nature of atmosphere(D) All (A), (B) and (C)

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

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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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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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Amount of coal lost in ash particle, which is carried through the boiler system, depends upon the (A) Physical nature, ash content and fineness of the coal (B) Amount of excess air supplied and load on the boiler (C) Type of burner and combustion chamber (D) All (A), (B) and (C)

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

Velocity of a reaction depends upon the (A) Nature of the reactants (B) Concentration of the reactants (C) Temperature at which the reaction is carried (D) All (A), (B) and (C)

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

Dust collection efficiency of a cyclone separator depends upon its (A) Diameter (B) Inlet gas velocity (C) Overall height (D) All (A), (B) & (C)

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

Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2 .°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the (A) Higher condensing film co-efficient is desired (B) Condensate is corrosive in nature (C) Lower pressure drop through the exchanger is desired (D) Temperature of the incoming vapor is very high Answer: Option B

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Last Answer : (B) Supersaturated

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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Typical waste gases temperature from glass melting furnace a) 1000-1550 oC b) 800-950 oC c) 650–750 oC d) 760-815 oC

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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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Heat transfer to the water wall in a high pressure water wall type boiler furnace is mainly by (A) Conduction (B) Convection (C) Radiation (D) Both 'a' & 'b'

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The concentration of water vapour in troposphere, which depends upon the altitude & temperature, varies in the range of zero to __________ percent. (A) 1 (B) 4 (C) 8 (D) 12

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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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A waste heat recovery unit is an energy recovery heat exchanger that transfers heat from process outputs at ........ a) High temperature b) Medium temperature c) Low temperature d) Both a & b

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Diffusion co-efficient generally depends upon the temperature, pressure & the nature of the components of the system. Its dimension is not the same as that of the (A) Mass transfer co-efficient (B) Thermal diffusivity (C) Kinematic viscosity (D) Volumetric diffusivity

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Leidenfrost point is a term concerned with the (A) Condensation of the saturated vapor on a cold surface (B) Concentration of a corrosive solution by evaporation (C) Heat transfer between two highly viscous liquids (D) Boiling of a liquid on a hot surface

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The heating capacity of continuous reheating furnace depends upon the (A) Hearth area and furnace temperature (B) Emissivity of the stock (C) Ratio of wall surface to stock surface (D) All (A), (B) and (C)

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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

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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)

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

H2SO4 (< 50% concentration) is corrosive to (A) Aluminium, mild steel, stainless steel, concrete & tin (B) Copper, cast iron & high silicon iron (14% Si) (C) Rubber (butyl and hard), silicone rubber & Teflon (D) Glass, graphite, porcelain & stoneware

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Which of the following is an undesirable property of a manometricliquid? (A) Non-sticky & non-corrosive nature (B) High vapour pressure (C) Low viscosity & surface tension (D) Low co-efficient of thermal expansion

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Battery charging rooms should be well ventilated because the charging process produces_____________. A. highly poisonous gas B. highly combustible oxygen C. explosive gases D. corrosive gases

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Which of the following statement is not correct with respect to alcohols as alternate fuel in IC engines a) anti-knock characteristics of alcohol is poor b) alcohol contains about half the heat energy of gasoline/litre c) alcohol does not vaporize as easily as gasoline d) alcohols are corrosive in nature

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The work done in an adiabatic change in a particular gas depends upon changes in the __________ only. (A) Temperature (B) Specific heat (C) Volume (D) Pressure

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Last Answer : (D) None of these

Forced recirculation of furnace gases is practised (A) To increase heat transfer by convection (B) To ensure uniform temperature (C) In furnaces, operating below 750°C (D) All (A), (B) and (C)

Description : Forced recirculation of furnace gases is practised (A) To increase heat transfer by convection (B) To ensure uniform temperature (C) In furnaces, operating below 750°C (D) All (A), (B) and (C)

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

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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Economics of 'Solvay Process' depends upon the efficiency of (A) Carbonating tower (B) Ammonia recovery (C) Ammonia recovery and size of the plant (D) Ammoniation of salt solution

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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

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A waste heat recovery unit (WHRU) is an_________ that transfers heat from process outputs at high temperature to another part of the process for some purpose, usually increased efficiency. a) Energy recovery heat exchanger b) Energy recovery heat diffuser c) Both ‘a’ and ‘b’ d) None of the above

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