chemical engineering fuels and combustion Mcqs
351. ____________ process is meant for direct hydrogenation of coal to produce liquid fuel?
comments icon0

A. Fischer-Tropsch

B. None of these

C. Lurgi

D. Bergius
352. Preheating of combustion air is done to ___________________?
comments icon0

A. Complete the combustion of fuel

B. Increase the calorific value of the fuel

C. Increase the adiabatic flame temperature

D. Reduce its requirement for effecting the complete combustion

353. Which of the following is not a binder for coal briquetting ?
comments icon0

A. Coal tar

B. None of these

C. Bitumen

D. Molasses

354. High temperature carbonisation of coal produces__________________?
comments icon0

A. Large quantity of tar compared to low temperature carbonisation

B. None of these

C. Less of gases compared to liquid products

D. Inferior coke compared to low temperature carbonisation

355. Bomb calorimeter is used to determine the (where, GCV Gross Calorific Value. NCV Net Calorific Value.) ?
comments icon0

A. NCV at constant volume

B. GCV at constant pressure

C. NCV at constant pressure

D. GCV at constant volume
356. Calorific value of wood gas is about ______________ kcal/Nm3?
comments icon0

A. 1500

B. 3300

C. 5400

D. 8500

357. Coal tar fuel 200 (CTF 200) is a mixture of __________________?
comments icon0

A. Solar oil and pitch

B. Pitch and creosote oil

C. Anthracene and crecosote oil

D. Light oil and pitch

358. Blast furnace coke is made from coal by_____________________?
comments icon0
A. High temperature carbonisation

B. Heating the coal in an oven in presence of air

C. Medium temperature carbonisation

D. Low temperature carbonisation

359. Light oil whose major component is Benzol, is obtained by the distillation of crude tar in the temperature range of _____________ C?
comments icon0

A. 200-300

B. 280-300

C. 250-270

D. 80-170
360. Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature ?
comments icon0
A. Calorific value of the fuel

B. Flame temperature achieved

C. Speed of combustion of fuel

D. Heat transfer rate to the stock in the furnace

361. Which of the following is a single stage, fixed bed high pressure coal gasification process ?
comments icon0

A. None of these

B. Kopper-Totzek process

C. Lurgi Process

D. Winkler process

362. With increase in calorific value of fuels, their adiabatic flame temperatures__________________?
comments icon0

A. Increase

B. Remain unchanged

C. May increase or decrease; depends on the quantity of products of combustion

D. Decrease

363. About _____________ Nm3 of air will be required for the complete combustion of 2Nm3 of CO?
comments icon0

A. 3

B. 4

C. 2

D. 5
364. Function of secondary air in pulverised coal firing is to_________________?
comments icon0
A. Ensure efficient burning of coal around the burner

B. Transport the coal to the burner

C. Reduce primary air requirement

D. Dry the coal

365. Anthracite can be used for___________________?
comments icon0

A. Blending with highly coking coal to check its swelling which helps in saving coke even walls

B. Recarbonising steel

C. All A., B. and C.

D. m damage and to produce high strength coke

E. Making carbon electrodes

366. A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the_________________?
comments icon0
A. Lack of thorough mixing of fuel with air

B. High sulphur content in the fuel

C. Low calorific value of the fuel

D. Presence of large quantity of hydrogen in the fuel

367. A coal with high _____________ content, would ignite most easily?
comments icon0

A. Fixed carbon

B. Volatile matter

C. Oxygen

D. Ash

368. In flue gas analysis by Orsats apparatus, carbon dioxide is absorbed by______________________?
comments icon0

A. Cuprous chloride

B. Dilute potassium carbonate

C. Alkaline pyrogallol solution

D. Potassium hydroxide
369. High temperature carbonisation of coal takes place at _______________ C?
comments icon0

A. 2000

B. 600

C. 1100

D. 1600

370. Which of the following is not a by-product recovered in a high temperature coal carbonisation plant ?
comments icon0

A. Pitch-creosote mixture (PCM)

B. Benzol

C. Naphthalene

D. Ethylene
371. Critical Air Blast (CAB) value of coke is a direct measure of its__________________?
comments icon0

A. Strength

B. Hardness

C. Reactivity

D. None of these

372. Emission of dense white smoke out of the chimney of a thermal power plant is an indication of the use of__________________?
comments icon0

A. Correct amount of air for combustion

B. Less air for combustion

C. Too much air for combustion

D. Pulverised coal in boilers

373. Which of the following fuels is generally not used in thermal power plant boiler firing ?
comments icon0

A. Coal middling from washeries

B. B.F. gas, coke oven gas and L.D. converter gas

C. Furnace oil, light diesel oil and tar/PCM

D. Pulverised coking coal
374. Efficient burning of anthracite coal requires______________________?
comments icon0
A. Fine grinding

B. All A., B. and C

C. Low preheat of air

D. High excess air

375. Which of the following would require maximum amount of % excess air for complete combustion ?
comments icon0

A. Coke oven gas

B. Furnace oil

C. Lump coal (fixed on chain grate)

D. Pulverised coal

376. Which of the following is not a manufactured fuel ?
comments icon0

A. Furnace oil

B. Kerosene

C. Semi-coke

D. Bagasse
377. Out of the following fuels, the difference between gross and net calorific value will be minimum in case of___________________?
comments icon0

A. Coke oven gas

B. Natural gas

C. Blast furnace gas

D. Water gas

378. Hard pitch is used for making_____________________?
comments icon0
A. Pulverised fuel

B. Perfumes

C. Plastics

D. Insecticides

379. Which of the following constituents of a fuel does not contribute to its calorific value on combustion ?
comments icon0

A. Sulphur

B. None of these

C. Hydrogen

D. Carbon

380. For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm3), while the C.V. is same on weight basis (i.e., kcal/kg) ?
comments icon0

A. Sewage gas and gobar gas

B. B.F. gas and coke oven gas

C. Propane and LPG

D. Propane and acetylene
381. Coal tar (produced by high temperature carbonisation) is the main source of_________________?
comments icon0

A. Paraffins

B. Olefins

C. Aliphatic compounds

D. Aromatic compounds
382. Deficiency of combustion air during combustion of a gaseous fuel_____________________?
comments icon0

A. Lengthens the flame

B. Causes heat loss of fuel by its partial combustion

C. Both A. & B.

D. Shortens the flame

383. Ammonia content in raw coke oven gas is about _____________ gm/Nm3?
comments icon0
A. 5

B. 1

C. 100

D. 50

384. Calorific value of furnace oil is about _______________ Kcal/kg?
comments icon0

A. 15,000

B. 5,000

C. 10,000

D. 20,000

385. Pulverised coal used in boiler firing need not have____________________?
comments icon0
A. High fusion point of its ash

B. Less moisture content

C. High bulk density

D. Lower ash content

386. In flue gas analysis by Orsats apparatus, oxygen is absorbed by____________________?
comments icon0

A. None of these

B. Potassium hydroxide

C. Alkaline pyrogallol solution

D. Cuprous chloride

387. The main advantage of forced draft over natural draft is that____________________?
comments icon0

A. Smaller height chimney can be used

B. Furnace control is easier

C. All A., B. & C.

D. Combustion of fuel is complete

388. In high temperature carbonisation of coal compared to low temperature carbonisation ?
comments icon0

A. Calorific value of the coke oven gas is lower

B. H2 content in the coke oven gas is more

C. Aromatic content of tar is low

D. Yield of ammonia is less

389. When the coal is heated in absence of air, it is called its ________________?
comments icon0
A. Carbonisation

B. Gasification

C. Deoxidation

D. Coalification

390. During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the____________________?
comments icon0

A. Incomplete combustion

B. High oxygen in flue gas

C. None of these

D. Complete combustion
391. Preheating of coal charge for the coke ovens reduces the __________________?
comments icon0

A. Time of carbonisation

B. All A., B. and C.

C. Yield of gas and tar

D. Fuel consumption in coking

392. Gas yield in the Kopper-Totzek coal gasifier is about ______________ Nm3/ton coal (ash = 35%)?
comments icon0

A. 3500

B. 5000

C. 150

D. 1500
393. Stack (chimney) height in a big thermal power plant is dictated by the___________________?
comments icon0
A. Draught to be created

B. None of these

C. Pollution control aspect

D. Limitation of constructional facilities

394. Which of the following has the highest flame speed ?
comments icon0

A. C2H6

B. H2

C. CH4

D. CO

395. Ratio of primary air to secondary air increases with increase in the rank of coal, because the__________________?
comments icon0
A. Ratio of fixed carbon to volatile matter increases

B. Calorific value of the coal increases

C. High rank coals have higher amount of volatile matter

D. Oxygen content progressively decreases

396. Gobar gas is produced by the ______________ of cow dung?
comments icon0
A. Fermentation

B. Oxidation

C. None of these

D. Hydrogenation

397. One kg of carbon for theoretically complete combustion requires ______________ kg of air?
comments icon0
A. 11.5

B. 0.5

C. 12

D. 23

398. Coke oven gas after passing through return electrostatic tar precipitator (RETP) is used for the_______________?
comments icon0

A. Mixing with blast furnace gas

B. Hot scarfing of steel slabs

C. Coke oven battery heating

D. Steel ladle drying

399. Spontaneous combustion of coal on storage results due to___________________?
comments icon0

A. Inadequate ventilation

B. Storage in large heaps with small surface to volume ratio

C. All A., B. and C.

D. Low temperature oxidation

400. Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around ______________ percent?
comments icon0

A. 40

B. 20

C. 96

D. 4