MCQOPTIONS
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MCQOPTIONS
This section includes 336 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
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. | |
| 252. |
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. | |
| 253. |
Unit of furnace loading is |
| A. | ton stock/hr/m2 hearth area |
| B. | ton stock/hr |
| C. | ton stock/m2 hearth area |
| D. | both (b) and (c) |
| Answer» B. ton stock/hr | |
| 254. |
Thermal efficiency of blast furnace stoves used for heating blast (air) may be about __________ percent. |
| A. | 20 |
| B. | 40 |
| C. | 60 |
| D. | 80 |
| Answer» E. | |
| 255. |
The heating capacity of muffle furnace depends on the |
| A. | surface area & emissivity of the stock. |
| B. | properties of the muffle wall (temperature, area, emissivity). |
| C. | both (a) & (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 256. |
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 | |
| 257. |
While the fuel fired furnace can be used upto a maximum temperature of about 1700°C, the electric furnace can be used upto a temperature of about __________ °C.$ |
| A. | 2000 |
| B. | 3000 |
| C. | 4500 |
| D. | 6000 |
| Answer» D. 6000 | |
| 258. |
Regenerators are normally provided in the |
| A. | glass melting furnace. |
| B. | open hearth furnace. |
| C. | by product coke ovens. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 259. |
Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by |
| A. | preheating the combustion air. |
| B. | oxygen enrichment of combustion air. |
| C. | preheating the fuel gas. |
| D. | all (a), (b) & (c). |
| Answer» E. | |
| 260. |
Presence of SO2 in furnace gases attacks the ferrous metal by way of |
| A. | accelerating the rate of scaling. |
| B. | causing metal embrittlement. |
| C. | attacking the grain boundaries; particularly severe on low carbon and nickel bearing steels at high temperature. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 261. |
Use of pulverised coal in boilers provides |
| A. | higher calorific value |
| B. | better combustion |
| C. | smokeless burning |
| D. | less erosion on furnace wall. |
| Answer» C. smokeless burning | |
| 262. |
The thermal efficiency of an air/fuel gas preheating recuperator may be as high as __________ percent. |
| A. | 50 |
| B. | 65 |
| C. | 85 |
| D. | 99 |
| Answer» D. 99 | |
| 263. |
An example of shaft furnace is the |
| A. | L.D. converter |
| B. | glass melting tank |
| C. | blast furnace |
| D. | soaking pit |
| Answer» D. soaking pit | |
| 264. |
Which furnace employs preheating, heating and soaking zones ? |
| A. | Soaking pit |
| B. | Reheating furnace |
| C. | Open hearth furnace |
| D. | Cupola |
| Answer» C. Open hearth furnace | |
| 265. |
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. | |
| 266. |
Soaking pits are meant for heating steel |
| A. | ingots |
| B. | coils |
| C. | sheets |
| D. | slabs |
| Answer» B. coils | |
| 267. |
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). |
| Answer» E. | |
| 268. |
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. |
| Answer» C. reducing atmosphere. | |
| 269. |
Which of the following is not a directly fired furnace ? |
| A. | By-product coke oven |
| B. | Calcination kiln |
| C. | Sintering furnace |
| D. | Open hearth furnace |
| Answer» B. Calcination kiln | |
| 270. |
Acid dew point temperature (ADT) of a flue gas produced by the combustion of a fuel containing 1% sulphur may be about __________ °C.$ |
| A. | 80 |
| B. | 130 |
| C. | 180 |
| D. | 250 |
| Answer» C. 180 | |
| 271. |
In which of the following furnaces, the gases are sucked through the stock bed from below? |
| A. | Soaking pit |
| B. | Sintering machine |
| C. | Beehive oven |
| D. | None of these |
| Answer» C. Beehive oven | |
| 272. |
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. | |
| 273. |
Calcination of limestone to produce lime is done in a __________ kiln. |
| A. | tunnel |
| B. | rotary |
| C. | vertical shaft |
| D. | both (b) and (c) |
| Answer» E. | |
| 274. |
Which is a continuous furnace ? |
| A. | Coke ovens |
| B. | Annealing furnace |
| C. | Glass tank furnace |
| D. | None of these |
| Answer» D. None of these | |
| 275. |
The purpose of controlling the furnace atmosphere is to prevent surface attack by |
| A. | oxidation/scaling |
| B. | decarburising |
| C. | sulphur penetration |
| D. | either of the above |
| Answer» E. | |
| 276. |
Which is not accomplished in an underfired furnace ? |
| A. | Increase in heating capacity/m2 of floor space. |
| B. | Elimination of cold spot at the bottom of the charge. |
| C. | Reduction in the temperature of furnace gases. |
| D. | Portection of the periphery of the charge from excessive radiation. |
| Answer» B. Elimination of cold spot at the bottom of the charge. | |
| 277. |
Power required in case of forced draught as compared to induced draught (for the same draught produced) is |
| A. | same |
| B. | less |
| C. | more |
| D. | either more or less; depends on the flue gas density |
| Answer» C. more | |
| 278. |
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. | |
| 279. |
Thickness of stock does not affect the fuel economy of furnaces, if the material to be heated is of |
| A. | low emissivity |
| B. | high thermal conductivity |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 280. |
Low stack loss indicates the |
| A. | use of sub-stoichiometric air for combustion. |
| B. | efficient use of fuel. |
| C. | inefficient use of fuel. |
| D. | oxygen enrichment of combustion air. |
| Answer» C. inefficient use of fuel. | |
| 281. |
Pot furnace which is either regenerative or recupterative, is used in the manufacture of |
| A. | glass |
| B. | stainless steel |
| C. | potteries |
| D. | refractory bricks. |
| Answer» B. stainless steel | |
| 282. |
Tunnel kilns are usually used for |
| A. | roasting of pyrites. |
| B. | drying/tempering of refractories. |
| C. | reheating of slabs. |
| D. | melting of glass. |
| Answer» C. reheating of slabs. | |
| 283. |
Reducing atmosphere is maintained in a |
| A. | calcination kiln |
| B. | blast furnace |
| C. | soaking pit |
| D. | L.D. converter |
| Answer» C. soaking pit | |
| 284. |
In which of the waste heat recovery equipment, the flow of flue gas and air is alternately reversed after a fixed interval of time ? |
| A. | Recuperator |
| B. | Regenerator |
| C. | Waste heat boiler |
| D. | None of these |
| Answer» C. Waste heat boiler | |
| 285. |
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 | |
| 286. |
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. | |
| 287. |
Pulverised fuel fired furnaces employ __________ fuel firing. |
| A. | horizontal |
| B. | vertical |
| C. | tangential |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 288. |
Recuperator is |
| A. | not used for fuel gas preheating. |
| B. | an intermittant waste heat recovery equipment. |
| C. | a continuous waste heat recovery equipment. |
| D. | heavier than regenerator meant for the same duty. |
| Answer» D. heavier than regenerator meant for the same duty. | |
| 289. |
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 | |
| 290. |
Which of the following is not an additive for flue gases from furnace to reduce its dew-point? |
| A. | Ammonia |
| B. | Fine dolomite |
| C. | Alkaline powders |
| D. | None of these |
| Answer» E. | |
| 291. |
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. | |
| 292. |
Artificial draught produced by a fan in the furnace can be controlled by the |
| A. | speed of the fan. |
| B. | damper. |
| C. | variation in the pitch of fan blades. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 293. |
Waste heat from the outgoing flue gases in a thermal power plant is recovered by a/an |
| A. | economiser |
| B. | steam superheater |
| C. | air preheater |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 294. |
Which is not a hearth furnace ? |
| A. | Glass tank furnace |
| B. | Open hearth furnace |
| C. | Cupola |
| D. | Reheating furnace |
| Answer» D. Reheating furnace | |
| 295. |
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). |
| Answer» E. | |
| 296. |
An improved and fuel efficient version of the pusher type reheating furnace is the __________ furnace. |
| A. | walking beam |
| B. | shaft |
| C. | tunnel |
| D. | rotary hearth |
| Answer» B. shaft | |
| 297. |
The amount of combustible escaping uncon-sumed from the furnace, depends upon the |
| A. | air supplied and furnace temperature. |
| B. | burner design (thoroughness of mixing versus stratification). |
| C. | air preheat and the flow of gases in the furnace (mixing by induction, by acceleration or by change of direction). |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 298. |
Which of the following is not a recuperative furnace ? |
| A. | Soaking pit |
| B. | Reheating furnace |
| C. | Steamboiler |
| D. | Coke oven. |
| Answer» E. | |
| 299. |
Higher furnace temperature can not 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. | |
| 300. |
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 intermittant. |
| D. | all (a), (b) and (c) |
| Answer» E. | |