MCQOPTIONS
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MCQOPTIONS
This section includes 116 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Overfire burning in a furnace is a phenomenon characterised by____________________? |
| A. | Supply of excess fuel |
| B. | Supply of excess air |
| C. | Burning carbon monoxide and other incombustible in upper zone of furnace by supplying more air |
| D. | None of these |
| Answer» D. None of these | |
| 52. |
Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about ____________ percent? |
| A. | 10-15 |
| B. | 25-30 |
| C. | 45-50 |
| D. | 65-70 |
| Answer» C. 45-50 | |
| 53. |
Out of the following fuels used in a furnace exhausting flue gas at a temperature of 600°C, the percentage stack loss will be maximum in case of complete combustion of_________________? |
| A. | Furnace oil with air |
| B. | Furnace oil with oxygen |
| C. | Blast furnace gas with air |
| D. | Blast furnace gas with oxygen |
| Answer» D. Blast furnace gas with oxygen | |
| 54. |
Ostwald charts are meant for__________________? |
| A. | Computing the excess/deficiency of combustion air |
| B. | Calculation of flue gas temperature |
| C. | Computation of flue gas analysis |
| D. | None of these |
| Answer» B. Calculation of flue gas temperature | |
| 55. |
Neutral atmosphere is maintained in a/an ____________ furnace? |
| A. | Cold rolled steel coil annealing |
| B. | Open hearth |
| C. | Soaking pit |
| D. | Walking beam reheating |
| Answer» B. Open hearth | |
| 56. |
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 |
| Answer» C. 1050 | |
| 57. |
Means for giving direction to the circulation of gases in furnaces are_____________________? |
| A. | Fans |
| B. | Arrangement of heating stock in the furnaces |
| C. | Location of outlet ports and heating & combustion devices |
| D. | All A., B. and C. |
| Answer» E. | |
| 58. |
Maximum thermal efficiency of boiler may be about _____________ percent? |
| A. | 10 |
| B. | 25 |
| C. | 65 |
| D. | 90 |
| Answer» E. | |
| 59. |
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 |
| Answer» D. Either A., B. or C.; depends on the type of furnace | |
| 60. |
Main gas valve in a gaseous fuel burner is a ______________ valve? |
| A. | Gate |
| B. | Butterfly |
| C. | Globe |
| D. | None of these |
| Answer» B. Butterfly | |
| 61. |
Large tonnage of refractory bricks are dried in a_____________________? |
| A. | Shaft furnace |
| B. | Rotary hearth furnace |
| C. | Tunnel kiln |
| D. | Muffle furnace |
| Answer» D. Muffle furnace | |
| 62. |
______________ is an indirectly heated furnace? |
| A. | Open hearth furnace |
| B. | Muffle furnace |
| C. | Soaking pit |
| D. | Reheating furnace |
| Answer» C. Soaking pit | |
| 63. |
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. |
| Answer» E. | |
| 64. |
In salt bath furnace, heat is transferred to the charge mainly by __________________? |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | None of these |
| Answer» B. Convection | |
| 65. |
In reverberatory furnace, charge is heated mainly by__________________? |
| A. | Conduction |
| B. | Natural convection |
| C. | Radiation of heat from the roof of the combustion chamber |
| D. | None of these |
| Answer» D. None of these | |
| 66. |
In producer gas making furnace, steam is added along with air to mainly control the____________________? |
| A. | Fusion of coal ash & clinker formation |
| B. | C. V. of producer gas |
| C. | Temperature of producer gas |
| D. | Tar content in producer gas |
| Answer» B. C. V. of producer gas | |
| 67. |
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 |
| Answer» D. Use of excessive positive draft in the furnace | |
| 68. |
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 |
| Answer» B. Less of excess air | |
| 69. |
In low or standard frequency induction furnace, heat is produced by the_______________________? |
| A. | Combination of induced current and skin effect |
| B. | Induction and resistance |
| C. | Current flow through a heating element |
| D. | None of these |
| Answer» C. Current flow through a heating element | |
| 70. |
In furnaces operating at very high temperature (say) 1250°C, e.g. soaking pit), the maximum heat transfer takes place by__________________? |
| A. | Conduction |
| B. | Convection |
| C. | Radiation |
| D. | Cannot be predicted |
| Answer» D. Cannot be predicted | |
| 71. |
In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of_________________? |
| A. | Transportation of coal |
| B. | Drying of coal |
| C. | Combustion of coal by supplying it around the burner |
| D. | Preheating the primary air |
| Answer» D. Preheating the primary air | |
| 72. |
In a muffle furnace, the muffle_________________? |
| A. | Retards the heat transfer |
| B. | Assists in temperature equalisation in the charge |
| C. | Permits the use of controlled atmosphere for the protection of stock |
| D. | All A., B. and C. |
| Answer» E. | |
| 73. |
In a heating process, a heat flow diagram in which the quantities of heat in the various items of a heat balance are represented by the width of a band is called the__________________? |
| A. | Ostwald chart |
| B. | Cox chart |
| C. | Sankey diagram |
| D. | None of these |
| Answer» D. None of these | |
| 74. |
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. |
| Answer» E. | |
| 75. |
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 |
| Answer» D. None of these | |
| 76. |
If the flame is produced under the hearth and then sweeps up into the heating chamber, this is called a/an ______________ furnace? |
| A. | Sidefired |
| B. | Underfired |
| C. | Covered |
| D. | Recirculating |
| Answer» C. Covered | |
| 77. |
If fuel and air are mixed ahead of the burner, it is called a/an ______________ burner? |
| A. | Premix |
| B. | Outside mixing type |
| C. | Rotary |
| D. | Diffusion |
| Answer» B. Outside mixing type | |
| 78. |
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 |
| Answer» B. Preheating the fuel gas | |
| 79. |
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 |
| Answer» D. Annealing furnace | |
| 80. |
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 |
| Answer» D. Thickness of the stock | |
| 81. |
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 |
| Answer» B. Flue gas temperature | |
| 82. |
Heat balance of furnace provides means of determining the_________________? |
| A. | Thermal efficiency of the process |
| B. | Sources of heat losses |
| C. | Scope of reduction of heat losses |
| D. | All A., B. and C. |
| Answer» E. | |
| 83. |
Hearth furnaces are not used for____________________? |
| A. | Roasting |
| B. | Melting |
| C. | Reheating |
| D. | None of these |
| Answer» E. | |
| 84. |
Furnace pressure is normally controlled by regulating the__________________? |
| A. | Air pressure |
| B. | Fuel gas pressure |
| C. | Speed of I.D. fan |
| D. | Damper |
| Answer» E. | |
| 85. |
_____________ furnace is not an electric furnace? |
| A. | Arc |
| B. | Induction |
| C. | Pot |
| D. | Resistance |
| Answer» D. Resistance | |
| 86. |
Furnace aerodynamics is related to the _____________ in the furnace? |
| A. | Movement of gases |
| B. | Measurement of flue gas volume |
| C. | Temperature control |
| D. | Pressure adjustment |
| Answer» B. Measurement of flue gas volume | |
| 87. |
Fuel used in B.F. stove is______________________? |
| A. | Pulverised coal |
| B. | Furnace oil |
| C. | Blast furnace gas/mixed gas |
| D. | Coke oven gas |
| Answer» D. Coke oven gas | |
| 88. |
Fuel economy in an industrial furnace operation cannot be achieved by the use of__________________? |
| A. | Stoichiometric combustion air |
| B. | Non-preheated combustion air |
| C. | Combustion air not enriched with oxygen |
| D. | Recuperators |
| Answer» B. Non-preheated combustion air | |
| 89. |
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. |
| Answer» E. | |
| 90. |
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. |
| Answer» E. | |
| 91. |
Flue gas outlet temperature from the chimney of any furnace should be ideally about ______________ °C? |
| A. | 50 |
| B. | 100 |
| C. | 150 |
| D. | 250 |
| Answer» D. 250 | |
| 92. |
Example of an indirectly heated furnace is__________________? |
| A. | Hood annealing furnace |
| B. | Muffle furnace |
| C. | Both A. and B. |
| D. | Neither A. nor B. |
| Answer» D. Neither A. nor B. | |
| 93. |
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. |
| Answer» C. Corrosive nature of the waste gas | |
| 94. |
Decarburisation of steel__________________? |
| A. | Is the removal of carbon from iron carbide (Fe3C) |
| B. | Affects its crystalline structure |
| C. | Is favoured by CO2 |
| D. | All A., B. and C. |
| Answer» E. | |
| 95. |
Dampers are located__________________? |
| A. | Before the I.D fan |
| B. | After the I.D. fan |
| C. | Near the top of the chimney |
| D. | Anywhere after the I.D. fan |
| Answer» B. After the I.D. fan | |
| 96. |
Combustion of furnace oil in a furnace (soaking pit) with preheated combustion air at 400°C results in saving of about __________ percent furnace oil as compared to its combustion with atmospheric air, if the flue gas outlet temperature from the soaking pit is 1200°C ? |
| A. | 5 |
| B. | 60 |
| C. | 20 |
| D. | 40 |
| Answer» D. 40 | |
| 97. |
Combustion of fuel in a furnace with oxygen enriched air results in higher__________________? |
| A. | Flue gas volume |
| B. | Flame temperature |
| C. | Fuel consumption |
| D. | Stack loss |
| Answer» C. Fuel consumption | |
| 98. |
Coke ovens in steel plant are heated by____________________? |
| A. | Electricity |
| B. | Blast furnace gas/mixed gas |
| C. | Coke oven gas |
| D. | Both B. and C. |
| Answer» E. | |
| 99. |
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. |
| Answer» E. | |
| 100. |
Ceramic recuperators (made of SiC) is economical, only when used for preheating combustion air above _____________ °C? |
| A. | 250 |
| B. | 650 |
| C. | 850 |
| D. | 1000 |
| Answer» C. 850 | |