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This section includes 408 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
101. |
The advantage of firing pulverised coal in the furnace lies in the fact, that it____________________? |
A. | Permits the use of high ash content coal |
B. | Permits the use of low fusion point ash coal |
C. | Accelerates the burning rate and economises on fuel combustion |
D. | All A., B. and C. |
Answer» D. All A., B. and C. | |
102. |
Safe condition for storage of high V.M. bituminous coal is that ___________________? |
A. | Height of the coal heap should be < 3 metres |
B. | Maximum 200 tons should be stored in a heap |
C. | Both A. and B. |
D. | Neither A. nor B. |
Answer» D. Neither A. nor B. | |
103. |
Removal of hydrogen from coke oven gas ___________________? |
A. | Increases its calorific value |
B. | Decreases its calorific value |
C. | Does not alter its calorific value |
D. | Is not possible on commercial scale |
Answer» B. Decreases its calorific value | |
104. |
Ratio of primary air to secondary air increases with increase in the rank of coal, because the__________________? |
A. | High rank coals have higher amount of volatile matter |
B. | Ratio of fixed carbon to volatile matter increases |
C. | Oxygen content progressively decreases |
D. | Calorific value of the coal increases |
Answer» C. Oxygen content progressively decreases | |
105. |
Rate of low temperature oxidation of coal due to bad storage conditions_______________? |
A. | Decreases with increase in surface area |
B. | Does not vary with increase in surface area |
C. | Is more for low volatile coal compared to high volatile coal |
D. | Is accelerated by storage in large heaps with small surface to volume ratio |
Answer» E. | |
106. |
Quantity of coke oven gas produced by high temperature carbonisation of one ton of dry coal may be around ______________ Nm3? |
A. | 30 |
B. | 300 |
C. | 3,000 |
D. | 30,000 |
Answer» C. 3,000 | |
107. |
Quantity of coke produced from metallurgical coal may be around _____________ percent? |
A. | 30 |
B. | 50 |
C. | 75 |
D. | 95 |
Answer» D. 95 | |
108. |
Purity of coke means that, it is high in carbon and low in __________________? |
A. | Volatiles |
B. | Ash |
C. | Iron |
D. | Moisture |
Answer» B. Ash | |
109. |
Pure carbon is completely burnt in oxygen. The flue gas analysis is 70%CO2, 20%CO and 10%O2. The percent excess oxygen used is __________________? |
A. | 20 |
B. | 12.5 |
C. | 0 |
D. | 10 |
Answer» D. 10 | |
110. |
Pulverised coal used in boiler firing need not have____________________? |
A. | Less moisture content |
B. | High fusion point of its ash |
C. | High bulk density |
D. | Lower ash content |
Answer» C. High bulk density | |
111. |
Proximate analysis of coal determines its ______________ content? |
A. | Moisture, ash, sulphur & volatile matter |
B. | Moisture, volatile matter, ash & fixed carbon |
C. | Moisture, sulphur, nitrogen & fixed carbon |
D. | None of these |
Answer» C. Moisture, sulphur, nitrogen & fixed carbon | |
112. |
_____________ prohibits the use of alcohols directly in petrol engines ? |
A. | Low octane number |
B. | High cost & availability |
C. | Low flash point |
D. | Low calorific value |
Answer» C. Low flash point | |
113. |
Producer gas comprises mainly of _______________________? |
A. | CO & N2 |
B. | CO & H2 |
C. | CO2 & N2 |
D. | CO2 & H2 |
Answer» B. CO & H2 | |
114. |
Producer gas containing least amount of tar is produced by the_________________? |
A. | Partial combustion of coal |
B. | Partial combustion of large size (< 50 mm) coke |
C. | High pressure gasification of coal (e.g. in Lurgi gasifier) |
D. | Atmospheric pressure gasification of coal (e.g., in Kopper-Totzek gasifier) |
Answer» C. High pressure gasification of coal (e.g. in Lurgi gasifier) | |
115. |
____________ process is meant for direct hydrogenation of coal to produce liquid fuel? |
A. | Fischer-Tropsch |
B. | Bergius |
C. | Lurgi |
D. | None of these |
Answer» C. Lurgi | |
116. |
Prime coking coal is always blended with medium or non- coking coal before carbonisation__________________? |
A. | To check against its excessive swelling during heating, which may exert high pressure and damage coke oven walls |
B. | Because, it alone produces unreactive coke |
C. | Both A. and B. |
D. | Neither A. nor B. |
Answer» D. Neither A. nor B. | |
117. |
_____________ present in coal is not determined in its ultimate analysis ? |
A. | Fixed carbon |
B. | Total carbon |
C. | Hydrogen |
D. | Nitrogen |
Answer» B. Total carbon | |
118. |
Presence of phosphorous in metallurgical coal__________________? |
A. | Is not undesirable |
B. | Reduces its calorific value |
C. | Badly affects the quality of steel |
D. | Increases its caking power |
Answer» D. Increases its caking power | |
119. |
Presence of nitrogen in combustion air does not reduce the ____________________? |
A. | Amount of heat liberated |
B. | Flame temperature |
C. | Flue gas temperature |
D. | Any of the above |
Answer» B. Flame temperature | |
120. |
Presence of ______________ in a dry gaseous fuel does not contribute to its calorific value? |
A. | Sulphur |
B. | Oxygen |
C. | Hydrogen |
D. | Carbon |
Answer» C. Hydrogen | |
121. |
Presence of free moisture in coal is most disadvantageous during_________________? |
A. | Its pulverisation (as it requires more power) |
B. | Combustion of fire slacks on the grates |
C. | Handling (e.g. when emptying wagons) |
D. | None of these |
Answer» B. Combustion of fire slacks on the grates | |
122. |
Presence of force moisture in coal is most disadvantageous during its __________________? |
A. | Transportation and handling |
B. | Washing |
C. | Pulverisation |
D. | Storage |
Answer» D. Storage | |
123. |
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 |
Answer» C. Increases the loss of fine coal dust from the ovens when charging | |
124. |
Preheating of ______________ the flame temperature? |
A. | The gaseous fuel before combustion decreases |
B. | Combustion air decreases |
C. | Either the fuel or the air or both, increases |
D. | Either the fuel or the air does not affect |
Answer» D. Either the fuel or the air does not affect | |
125. |
Preheating of combustion air is done to ___________________? |
A. | Increase the adiabatic flame temperature |
B. | Increase the calorific value of the fuel |
C. | Complete the combustion of fuel |
D. | Reduce its requirement for effecting the complete combustion |
Answer» B. Increase the calorific value of the fuel | |
126. |
Preheating of a gaseous fuel results in increased____________________? |
A. | Flame length |
B. | Flame temperature |
C. | Quantity of flue gas |
D. | Ignition temperature |
Answer» C. Quantity of flue gas | |
127. |
Preheating of coal charge for the coke ovens reduces the __________________? |
A. | Time of carbonisation |
B. | Yield of gas and tar |
C. | Fuel consumption in coking |
D. | All A., B. and C. |
Answer» E. | |
128. |
Power alcohol as compared to straight run gasoline has lower ________________? |
A. | Calorific value |
B. | Octane number |
C. | Specific gravity |
D. | Viscosity |
Answer» B. Octane number | |
129. |
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. |
Answer» E. | |
130. |
Pick the odd man out? |
A. | Briquettes |
B. | Wood |
C. | Oil gas |
D. | Pitch creosote mixture |
Answer» C. Oil gas | |
131. |
Percentage of nitrogen in blast furnace gas may be around__________________? |
A. | 5 |
B. | 25 |
C. | 55 |
D. | 80 |
Answer» D. 80 | |
132. |
Percentage of hydrogen in coke oven gas may be around ___________________? |
A. | 10 |
B. | 25 |
C. | 45 |
D. | 60 |
Answer» E. | |
133. |
Percentage of methane in coke oven gas may be around _____________________? |
A. | 5 |
B. | 15 |
C. | 25 |
D. | 50 |
Answer» D. 50 | |
134. |
Percentage of carbon monoxide in blast furnace gas may be around ____________________ ? |
A. | 8 |
B. | 14 |
C. | 22 |
D. | 52 |
Answer» D. 52 | |
135. |
Pensky-Marten apparatus is used for those oils, whose flash points are _____________ °F? |
A. | < 120 |
B. | > 120 |
C. | < 90 |
D. | 90-110 |
Answer» C. < 90 | |
136. |
Oxygen percentage (by weight) in atmospheric air is_________________? |
A. | 19 |
B. | 21 |
C. | 23 |
D. | 29 |
Answer» D. 29 | |
137. |
Oxygen required for theoretically complete combustion of 1 Nm3 methane is ______________ Nm3? |
A. | 2 |
B. | 4 |
C. | 6 |
D. | 1 |
Answer» B. 4 | |
138. |
Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around ______________ percent? |
A. | 4 |
B. | 96 |
C. | 20 |
D. | 40 |
Answer» D. 40 | |
139. |
“Overfire burning” in a furnace is a phenomenon characterised by the __________________? |
A. | Supply of excess fuel |
B. | Supply of excess air |
C. | Burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air |
D. | None of these |
Answer» D. None of these | |
140. |
Out of the following fuels, the difference between the net and gross calorific value is maximum in case of_________________? |
A. | Pitch |
B. | Fuel oil |
C. | Blast furnace gas |
D. | Bituminous coal |
Answer» C. Blast furnace gas | |
141. |
Out of the following fuels, the difference between gross and net calorific value will be minimum in case of___________________? |
A. | Coke oven gas |
B. | Water gas |
C. | Natural gas |
D. | Blast furnace gas |
Answer» E. | |
142. |
Orsat apparatus__________________? |
A. | Gives flue gas analysis on dry basis |
B. | Determines N2 in flue gas indirectly |
C. | Can’t determine CO in flue gas, if it is < 0.2% |
D. | All A., B. & C. |
Answer» E. | |
143. |
Orsat apparatus is meant for ___________________? |
A. | Gravimetric analysis of flue gas |
B. | Finding out combustion efficiency |
C. | Direct determination of nitrogen in flue gas by absorbing it in ammoniacal cuprous chloride |
D. | None of these |
Answer» E. | |
144. |
Optimum preheating temperature for pitch creosote mixture (PCM) which is also termed as C.T.F-200, before atomisation through burners is_________________? |
A. | 200 °F |
B. | 200 °C |
C. | 200 °K |
D. | 200 °R |
Answer» B. 200 °C | |
145. |
One kg of carbon for theoretically complete combustion requires ______________ kg of air? |
A. | 11.5 |
B. | 0.5 |
C. | 23 |
D. | 12 |
Answer» B. 0.5 | |
146. |
ombustion of pulverised coal compared to the lumpy coal __________________? |
A. | Provides better control of furnace temperature |
B. | Facilitates combustion with lower excess air |
C. | Provides higher thermal efficiency & flame temperature |
D. | All A., B. & C. |
Answer» E. | |
147. |
Of the total tar present in raw coke oven gas, the tar recovered in primary cooler is about _______________ percent? |
A. | 5 |
B. | 25 |
C. | 55 |
D. | 75 |
Answer» C. 55 | |
148. |
_____________ of the coal is the basis for Seylor’s coal classification? |
A. | Proximate analysis |
B. | Ultimate analysis |
C. | Caking index |
D. | Calorific value |
Answer» C. Caking index | |
149. |
Octane number of 2, 2, 4 – trimethyl pentane is __________________? |
A. | 0 |
B. | 100 |
C. | In between 0 and 100 |
D. | More than 100 |
Answer» C. In between 0 and 100 | |
150. |
Number of macrocomponents present in coal according to Stopes are ___________________? |
A. | Four |
B. | Five |
C. | Six |
D. | Two |
Answer» B. Five | |