chemical engineering furnace technology MCQs – Page 3

Practise multiple-choice questions from chemical engineering furnace technology for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering furnace technology Mcqs
101. Which of the following accentuates clinkering troubles on furnace grate burning coal ?
comments icon0
A. All A., B. and C.

B. Thick firebed and preheated primary air

C. Low reactivity of carbonised residue containing high proportion of iron & sulphur

D. Low forced draft & fuel bed temperature

102. Thermal efficiency of a limestone calcination rotary kiln may be around ______________ percent?
comments icon0

A. 80

B. 65

C. 40

D. 20

103. Hearth furnaces are not used for____________________?
comments icon0
A. None of these

B. Melting

C. Reheating

D. Roasting

104. In reverberatory furnace, charge is heated mainly by__________________?
comments icon0

A. None of these

B. Natural convection

C. Conduction

D. Radiation of heat from the roof of the combustion chamber
105. _____________ furnace is not an electric furnace?
comments icon0

A. Resistance

B. Arc

C. Induction

D. Pot
106. Forced recirculation of furnace gases is practised_______________?
comments icon0

A. To increase heat transfer by convection

B. All A., B. and C.

C. To ensure uniform temperature

D. In furnaces, operating below 750C

107. The function of an economiser in a boiler is to preheat the _____________________?
comments icon0
A. Feedwater

B. Furnace oil

C. Combustion air

D. Pulverised coal

108. Use of pulverised coal in boilers provides____________________?
comments icon0

A. Less erosion on furnace wall

B. Better combustion

C. Smokeless burning

D. Higher calorific value

109. Combustion of furnace oil in a furnace (soaking pit) with preheated combustion air at 400C 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 1200C ?
comments icon0

A. 60

B. 5

C. 40

D. 20
110. Waste heat from the outgoing flue gases in a thermal power plant is recovered by a/an_________________?
comments icon0

A. Steam superheater

B. Air preheater

C. All A., B. and C.

D. Economiser

111. Maximum heat transfer in high temperature furnaces is by____________________?
comments icon0

A. Either A., B. or C.; depends on the type of furnace

B. Radiation

C. Conduction

D. Convection

112. 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__________________?
comments icon0
A. Sankey diagram

B. Ostwald chart

C. Cox chart

D. None of these

113. Which of the following is not an additive for flue gases from furnace to reduce its dewpoint ?
comments icon0

A. Ammonia

B. Fine dolomite

C. None of these

D. Alkaline powders

114. An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called ____________ furnace?
comments icon0

A. Low frequency induction

B. None of these

C. Resistance

D. Arc
115. ______________ is an indirectly heated furnace?
comments icon0

A. Open hearth furnace

B. Soaking pit

C. Muffle furnace

D. Reheating furnace

116. The advantages of firing pulverised coal in the furnace lies in the fact that, it_____________________?
comments icon0

A. Permits the use of high ash content coal

B. Accelerates the burning rate and economises on fuel consumption

C. All A., B. and C.

D. Permits the use of low fusion point ash coal

117. Scaling of furnace stock is reduced by _______________ in flue gas?
comments icon0

A. CO

B. H2

C. All A., B. & C.

D. High CO/CO2

118. Thermal efficiency of furnaces can be improved by____________________?
comments icon0

A. Minimising heat losses from furnace walls

B. Maintaining proper draught

C. All A., B. and C.

D. Waste heat recovery from flue gas

119. Which is a regenerative furnace ?
comments icon0

A. Coke oven heating chamber

B. Open hearth furnace

C. Both A. and B.

D. Neither A. nor B.

120. Turn down ratio of a burner____________________?
comments icon0

A. Should be 1:1 for a batch type furnace

B. Is the ratio of maximum to minimum permissible heat input rates

C. Is normally much more for a continuous furnace as compared to a batch furnace

D. Should be as low as possible i.e., 1 : 2

121. If the flame is produced under the hearth and then sweeps up into the heating chamber, this is called a/an ______________ furnace?
comments icon0
A. Underfired

B. Sidefired

C. Recirculating

D. Covered

122. Heat balance of furnace provides means of determining the_________________?
comments icon0
A. All A., B. and C.

B. Scope of reduction of heat losses

C. Sources of heat losses

D. Thermal efficiency of the process

123. Which of the following is not a directly fired furnace ?
comments icon0

A. Calcination kiln

B. By-product coke oven

C. Sintering furnace

D. Open hearth furnace

124. In a muffle furnace, the muffle_________________?
comments icon0

A. Permits the use of controlled atmosphere for the protection of stock

B. Retards the heat transfer

C. All A., B. and C.

D. Assists in temperature equalisation in the charge

125. Heat transfer rate to the charge/stock in a furnace does not depend upon the________________?
comments icon0

A. Flue gas temperature

B. Emissivity of refractory walls

C. Initial temperature of the charged stock

D. Type of fuels viz. solid, liquid or gaseous
126. Pick out the wrong statement ?
comments icon0

A. Addition of methane to the furnace atmosphere reduces decarburising by hydrogen

B. None of these

C. Active nitrogen (formed by cracking ammonia at the metal surface) cause nitride formation

D. h increase in surface hardness

E. burise the surface of steel at annealing temperatures

F. Nitrogen in presence of steam decor-burises high carbon steel, whereas hydrocarbon gases

127. In a furnace employing forced draught as compared to induced draught______________________?
comments icon0
A. Positive pressure exists in the furnace

B. The fan operates hot and hence blades are liable to corrosion and erosion

C. None of these

D. Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced

128. Which is a continuous furnace ?
comments icon0

A. Coke ovens

B. Glass tank furnace

C. Annealing furnace

D. None of these

129. Which one shows the diagrammatic heat balance in a furnace ?
comments icon0

A. Ostwald chart

B. Sankey diagram

C. None of these

D. Cox chart

130. In producer gas making furnace, steam is added along with air to mainly control the____________________?
comments icon0

A. Tar content in producer gas

B. Temperature of producer gas

C. Fusion of coal ash & clinker formation

D. C. V. of producer gas

131. The reason for excessive clinker formation in gas producers is the_____________________?
comments icon0

A. Use of coal/coke containing a high % of fines and ash

B. All A., B. and C.

C. Development of hot spots in the fuel bed and an abnormally high rate of gasification

D. Use of fuel having too low an ash fusion temperature

132. Air filtration in a furnace___________________?
comments icon0

A. Is indicated by flame sting out

B. None of these

C. Reduces its thermal efficiency

D. Increases the flue gas temperature

133. Artificial draught produced by a fan in the furnace can be controlled by the___________________?
comments icon0

A. Variation in the pitch of fan blades

B. All A., B. and C.

C. Damper

D. Speed of the fan

134. Unit of furnace loading is____________________?
comments icon0
A. Ton stock/hr/m2 hearth area

B. Ton stock/hr

C. Ton stock/m2 hearth area

D. Both B. and C.

135. Which of the following is a directly fired intermittent furnace ?
comments icon0

A. Tunnel kiln

B. Walking beam reheating furnace

C. Reverberatory furnace

D. Tower furnace

136. Turndown ratio of a burner gives an idea of the ______________ in the furnace?
comments icon0

A. Minimum heat input rate only

B. Range of fuel firing rates

C. Maximum heat input rate only

D. Volume of the combustion chamber

137. The purpose of controlling the furnace atmosphere is to prevent surface attack by__________________?
comments icon0

A. Oxidation/scaling

B. Either of the above

C. Decarburising

D. Sulphur penetration

138. Dampers are located__________________?
comments icon0

A. After the I.D. fan

B. Before the I.D fan

C. Near the top of the chimney

D. Anywhere after the I.D. fan

139. Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about _____________ percent?
comments icon0

A. < 8

B. < 2

C. < 10

D. < 5

140. Thermal efficiency of an open hearth furnace may be about _____________ percent?
comments icon0
A. 20

B. 80

C. 5

D. 50