Ceramic coating material for furnace refractory, which increases itsemissivity and thus the radiation heat transfer rate in the furnace, comprises of (A) Graphite powder (B) Thoria (C) Zircon powder (D) Beryllium

Ceramic coating material for furnace refractory, which increases itsemissivity and thus the radiation heat transfer rate in the furnace,
comprises of
(A) Graphite powder
(B) Thoria
(C) Zircon powder
(D) Beryllium
by

1 Answer

Answer :

(C) Zircon powder
by

Related questions

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

Description : 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

Last Answer : (A) Type of fuels viz. solid, liquid or gaseous

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

Tar is a better fuel than furnace oil, because of its (A) Higher calorific value (B) Lower sulphur content (C) Higher emissivity (0.8-0.9) resulting in higher radiation heat transfer rate (D) Both (A) and (B)

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

Coke oven gas is a better fuel than blast furnace gas, because of its higher (A) Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) (B) Adiabatic flame temperature (C) Heat release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)

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Description : In a heat treatment shop, steel components are heat-treated in batches of 80 Tons. The  heat treatment cycle is as follows;  Increase temperature from 30 OC to 850 OC in 3 hours.  ... efficiency of 80%, for same requirement. The investment towards installation of  the new furnace is Rs. 50

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A refractory wall separating the stock and the source of heat is provided in a (A) Updraft kiln (B) Muffle furnace (C) Continuous furnace (D) None of these

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A furnace is made of a refractory brick wall of thickness 0.5 metre and thermal conductivity 0.7 W/m.°K For the same temperature drop and heat loss, this refractory wall can be replaced by a layer of diatomaceous earth of thermal conductivity 0.14 W/m.K and thickness __________ metre. (A) 0.01 (B) 0.1 (C) 0.25 (D) 0.5

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Last Answer : (B) 0.1

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 a furnace with heating element temperature at 1700°C, the dominant mechanism of heat transfer will be (A) Conduction (B) Radiation (C) Natural convection (D) Forced convection

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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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__________ moderator is used in a fast breeder reactor. (A) Graphite (B) Heavy water (C) Beryllium (D) No

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The most commonly used moderator in nuclear power plants is (A) Graphite (B) Light water (C) Heavy water (D) Beryllium

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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

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Pick out the correct statement about the condensation. (A) Filmwise condensation gives a lower heat transfer rate than the dropwise condensation (B) Suitable coating or vapour additive is used to promote film wise condensation (C) If a condensing liquid does not wet the surface dropwise, even then condensation will take place on it (D) Reynolds number of condensing liquid is based on its mass flow rate

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Which of the following does not have a sharp melting point? (A) Thoria (B) Glass (C) Ice (D) Pig iron

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Gun powder, which is an explosive comprises of charcoal, sulphur and (A) Glycerine (B) Salt petre (C) Nitro glycerine (D) Dynamite

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Heat transfer takes place through a liquid medium surrounding the submerged material under heating, in case of a/an (A) Blast furnace (B) Steam boiler (C) Salt bath furnace (D) Annealing furnace

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Tank furnace used for melting of glass is made of (A) Mild steel (B) Cast iron (C) Refractory blocks (D) Stainless steel

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Large tonnage of refractory bricks are dried in a (A) Shaft furnace (B) Rotary hearth furnace (C) Tunnel kiln (D) Muffle furnace

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Pot furnace which is either regenerative or recuperative, is used in the manufacture of (A) Glass (B) Stainless steel (C) Potteries (D) Refractory bricks

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Test specimen for determination of refractoriness under load (RUL) of a refractory is heated in a (A) Furnace employing neutral atmosphere (B) Carbon resistance furnace (C) Reducing atmosphere (D) Furnace employing negative pressure

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Refractory bricks having high thermal conductivity is desirable, when it is to be used in the (A) L.D. converter (B) Blast furnace (C) Rotary kiln (D) Recuperator

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Most of the phosphorous present in the blast furnace burden enters into (A) Hot metal (B) Flue gases (C) Slag (D) Refractory lining

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The refractory lining of the bottom in a basic electric arc furnace is made of (A) Silica (B) Alumina (C) Magnesia (D) Fireclay

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With increase in the distance between the heat source and the object receiving the heat, the radiation heat transfer (A) Decreases (B) Increases (C) Increases exponentially (D) Remain unaffected

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What is the best Ceramic Coating for Cars?

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. The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C-1 respectively. The ambient air is at 30°C and the heat transfer co-efficient between the outer surface of wall and air is 20 W.m-2 .°C-1 . The rate of heat loss from the outer surface in W.m-2 is (A) 165.4 (B) 167.5 (C) 172.5 (D) 175

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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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(3) made cathode and a pure nickel red, the anode Explanation: Electroplating is the deposition by electrolysis of a coating of metal upon a conducting surface. The simplest system makes the object to be plated the negative electrode (cathode) or plate in a galvanic couple. Thus a spoon or other object may be connected by a wire to a plate of nickel. The process that occurs on the spoon is called reduction and, therefore, the spoon is also referred to as a cathode.

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Leukotriene antagonists are used in bronchial asthma: A. For terminating acute attacks B. As monotherapy in place of β2 agonists C. As adjuvants to β2 agonists for avoiding corticosteroids D. As nebulized powder in refractory cases

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If heat transfer rate varies with the time, it is termed as (A) Forced convection (B) Steady state conduction (C) Monochromatic radiation (D) None of these

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A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C. (A) 50 (B) 100 (C) 150 (D) 200

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The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2 . The flux, when the element temperature is increased to 1000°C for the same furnace temperature is (A) 11.2 kW/m2(B) 12.0 kW/m2(C) 14.6 kW/m2(D) 16.5 kW/m

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