Ingress of cold air in the furnaces through cracks, charging doors, openings etc(A) Reduces the flue gas temperature and makes the furnace atmosphereoxidising(B) Increases the load on the induced draft fan(C) Reduces the furnace draught(D) All (A), (B) and (C)

Ingress of cold air in the furnaces through cracks, charging doors,
openings etc
(A) Reduces the flue gas temperature and makes the furnace atmosphere
oxidising
(B) Increases the load on the induced draft fan
(C) Reduces the furnace draught
(D) All (A), (B) and (C)
by

1 Answer

Answer :

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

Related questions

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

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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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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)

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In a furnace employing forced draught as compared to induced draught, (A) Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced (B) The fan operates hot and hence blades are liable to corrosion and erosion (C) Positive pressure exists in the furnace (D) None of these

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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

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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

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Why is induced draught considered better than the forced draught? a) Because power requirement is high for forced draught b) Maintenance of induced draught fan is costlier c) Forced draught is less efficient d) Forced draught produces less amount of speed of air

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Which of the following is used to produce draught in the locomotive boilers? (A) Chimney (B) Induced draught fan (C) Forced draught fan (D) Steam jet arrangement

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Which one is not an induced draught furnace? (A) Blast furnace stove (B) Sintering furnace (C) High pressure boiler (D) None of these

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The lintels are preferred to arches because (A) Arches require more headroom to span the openings like doors, windows etc. (B) Arches require strong abutments to withstand arch thrust (C) Arches are difficult in construction (D) All of the abo

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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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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)

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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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Which of the following is the most important deterrents to an extended use of pulverised coal in boiler firing? (A) Ash disposal problem (B) Excessive fly ash discharge from the stack (C) Higher power consumption in its transportation (D) Erosion of induced draft fan blades

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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)

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Natural draft created by the chimney depends upon (A) Temperature of the flue gas (B) Its height (C) Both (A) & (B) (D) Neither (A) nor (B)

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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

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Presence of free moisture in coal during its high temperature carbonisation (A) Reduces the coking time (B) Protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls (C) Increases the loss of fine coal dust from the ovens when charging (D) None of these

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Circulation of gases in furnace is caused by the (A) Change in volume during a change of temperature (B) Difference in density between hot and cold gases (C) Furnace pressure in conjunction with draft in flues(D) All (A), (B) and (C

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Differentiate induced draft and forced draft cooling towers based on (i) Location of fan (ii) Corrosion of blades (iii) Efficiency (iv) Fan size

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Maximum heat transfer in high temperature furnaces is by (A) Conduction (B) Convection (C) Radiation (D) Either (A), (B) or (C); depends on the type of furnace

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In order to maintain an oxidising atmosphere in a furnace, it should have (A) More of excess air (B) Less of excess air (C) More of CO in flue gas (D) More of CO2 in flue gas

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Where the water table meets the ground surface groundwater bubbles or flows out of cracks in the rock in openings called?

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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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Furnace aerodynamics is related to the __________ in the furnace. (A) Movement of gases (B) Measurement of flue gas volume (C) Temperature control

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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)

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