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.
| 201. |
Scaling of furnace stock is reduced by __________ in flue gas. |
| A. | CO |
| B. | H2 |
| C. | high CO/CO2 |
| D. | all (a), (b) & (c) |
| Answer» E. | |
| 202. |
An example of recuperative furnace is the |
| A. | soaking pit |
| B. | open hearth furnace |
| C. | coke ovens |
| D. | none of these |
| Answer» B. open hearth furnace | |
| 203. |
Rate of heat release in a furnace, which is the measure of heat intensity is defined as |
| A. | kcal/hr/m3 combustion space. |
| B. | kcal/m3 combustion space. |
| C. | kcal/hr. |
| D. | none of these. |
| Answer» B. kcal/m3 combustion space. | |
| 204. |
Which of the following furnaces will have maximum thermal efficiency ? |
| A. | Soaking pits |
| B. | Walking beam reheating furnace |
| C. | Boiler furnace |
| D. | Rotary kilns |
| Answer» D. Rotary kilns | |
| 205. |
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. | |
| 206. |
Air filtration in a furnace |
| A. | reduces its thermal efficiency. |
| B. | is indicated by flame sting out. |
| C. | increases the flue gas temperature. |
| D. | none of these. |
| Answer» B. is indicated by flame sting out. | |
| 207. |
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 | |
| 208. |
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. | |
| 209. |
Advantages of use of preheated combustion air are |
| A. | saving in fuel consumption. |
| B. | reduction in scale losses. |
| C. | increase in flame temperature. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 210. |
Thermal efficiency of an open hearth furnace may be about __________ percent. |
| A. | 5 |
| B. | 20 |
| C. | 50 |
| D. | 80 |
| Answer» C. 50 | |
| 211. |
In a furnace operation, which is not preheated ? |
| A. | Solid fuels. |
| B. | Hydrocarbon containing fuel gases (e.g. coke oven gas, refinery gas etc.). |
| C. | Both (a) and (b). |
| D. | Neither (a) nor (b). |
| Answer» D. Neither (a) nor (b). | |
| 212. |
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. | |
| 213. |
Specific heating capacity of a furnace is expressed as |
| A. | weight heated/hr |
| B. | weight heated/furnace volume |
| C. | weight heated/hr/furnace volume |
| D. | none of these |
| Answer» D. none of these | |
| 214. |
The advantages 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 consumption. |
| D. | all (a), (b) and (c). |
| Answer» D. all (a), (b) and (c). | |
| 215. |
Shaft furnaces are used for |
| A. | smelting |
| B. | calcining |
| C. | roasting |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 216. |
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 | |
| 217. |
Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about __________ percent. |
| A. | 42278 |
| B. | 25-30 |
| C. | 45-50 |
| D. | 65-70 |
| Answer» C. 45-50 | |
| 218. |
Which of the following is a rotary furnace? |
| A. | Lime kiln |
| B. | Soaking pit |
| C. | Stoves |
| D. | Annealing furnace. |
| Answer» B. Soaking pit | |
| 219. |
The rate of scaling of furnace stock depends upon the |
| A. | temperature |
| B. | time |
| C. | nature of atmosphere |
| D. | all (a), (b) and (c) |
| Answer» E. | |
| 220. |
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. | |
| 221. |
Protective gas used in the annealing furnace for steel coil comprises of |
| A. | 95% N2 + 5% H2 |
| B. | 5% H2 + 9% N2 |
| C. | 100% CO |
| D. | 100 %H2 |
| Answer» B. 5% H2 + 9% N2 | |
| 222. |
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. | |
| 223. |
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. | |
| 224. |
An electric furnace producing heat by means of an electric arc struck between each of three electrodes and the charge is called __________ furnace. |
| A. | resistance |
| B. | arc |
| C. | low frequency induction |
| D. | none of these |
| Answer» C. low frequency induction | |
| 225. |
Rotary kilns are used in the |
| A. | calcination of limestone & dolomite. |
| B. | cement manufacture. |
| C. | both (a) and (b). |
| D. | neither (a) nor (6). |
| Answer» D. neither (a) nor (6). | |
| 226. |
The function of an economiser in a boiler is to preheat the |
| A. | feedwater |
| B. | combustion air |
| C. | pulverised coal |
| D. | furnace oil |
| Answer» B. combustion air | |
| 227. |
Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about __________ percent. |
| A. | < 2 |
| B. | < 5 |
| C. | < 8 |
| D. | < 10 |
| Answer» B. < 5 | |
| 228. |
Size of the combustion chamber of a furnace depends upon the |
| A. | heat release rate of the fuel. |
| B. | preheat temperature of fuel & air. |
| C. | method of mixing the fuel & air. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 229. |
Main gas valve in a gaseous fuel burner is a __________ valve. |
| A. | gate |
| B. | butterfly |
| C. | globe |
| D. | none of these |
| Answer» B. butterfly | |
| 230. |
Maximum thermal efficiency of boiler may be about __________ percent. |
| A. | 10 |
| B. | 25 |
| C. | 65 |
| D. | 90 |
| Answer» E. | |
| 231. |
Which one shows the diagramatic heat balance in a furnace ? |
| A. | Sankey diagram |
| B. | Cox chart |
| C. | Ostwald chart |
| D. | None of these |
| Answer» B. Cox chart | |
| 232. |
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 | |
| 233. |
Which of the following is a directly fired intermittant furnace ? |
| A. | Walking beam reheating furnace |
| B. | Reverberatory furnace |
| C. | Tower furnace |
| D. | Tunnel kiln |
| Answer» C. Tower furnace | |
| 234. |
Which of the following variables does not affect the furnace capacity ? |
| A. | Size of the furnace. |
| B. | Gas velocity in furnace. |
| C. | Ratio of wall surface to surface of stock. |
| D. | None of these. |
| Answer» E. | |
| 235. |
__________ furnace is not an electric furnace. |
| A. | Arc |
| B. | Induction |
| C. | Pot |
| D. | Resistance. |
| Answer» D. Resistance. | |
| 236. |
Which of the following is a periodic furnace? |
| A. | Tunnel kiln |
| B. | Rotary kiln |
| C. | Soaking pit |
| D. | Reheating furnace. |
| Answer» D. Reheating furnace. | |
| 237. |
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 | |
| 238. |
Regenerators compared to the recuperators for the same duty |
| A. | occupy more space |
| B. | are less costly |
| C. | are of smaller size |
| D. | all (a), (b) and (c) |
| Answer» B. are less costly | |
| 239. |
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 | |
| 240. |
Regenerators are used for waste heat recovery in |
| A. | by-product coke ovens |
| B. | beehive coke oven |
| C. | blast furnace stoves |
| D. | soaking pits |
| Answer» B. beehive coke oven | |
| 241. |
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 | |
| 242. |
Reheating furnace (pusher type) is used for heating |
| A. | ingots |
| B. | slabs |
| C. | steel coils |
| D. | steel sheets |
| Answer» C. steel coils | |
| 243. |
Which of the following advantages is not associated with the use of preheated air for combustion of a fuel in the furnace ? |
| A. | Increase in calorific value of the fuel. |
| B. | Increase in flame temperature. |
| C. | Reduction in scale losses. |
| D. | Saving in fuel consumption. |
| Answer» B. Increase in flame temperature. | |
| 244. |
Which one is not an induced draught furnace? |
| A. | Blast furnace stove |
| B. | Sintering furnace |
| C. | High pressure boiler |
| D. | None of these |
| Answer» B. Sintering furnace | |
| 245. |
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. | |
| 246. |
Hearth furnaces are not used for |
| A. | roasting |
| B. | melting |
| C. | reheating |
| D. | none of these |
| Answer» E. | |
| 247. |
Operation of blast furnace stove is based on the principles of a __________ furnace. |
| A. | regenerative |
| B. | recuperative |
| C. | both (a) and (b) |
| D. | neither (a) nor (b). |
| Answer» B. recuperative | |
| 248. |
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 | |
| 249. |
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. | can not be predicted. |
| Answer» D. can not be predicted. | |
| 250. |
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. | |