Free Chemical Process Principles MCQs with Answers
2,710 Chemical Process Principles MCQs from Chemical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. Propane and LPG
- B. Propane and acetylene
- C. Sewage gas and gobar gas
- D. B.F. gas and coke oven gas
Explanation: Propane and acetylene have nearly equal calorific values per unit mass, but propane has a higher mass per normal cubic metre, giving it an…
Correct answer: Propane and acetylene- A. Fusion point of its ash
- B. Porosity
- C. Sulphur & phosphorous content
- D. Hardness & strength
Explanation: Metallurgical coke should contain very little sulphur and phosphorus because these impurities contaminate the metal and impair its…
Correct answer: Sulphur & phosphorous content- A. Reduces its sulphur and ash content
- B. Controls its ash fusibility and increases its calorific value
- C. Improves its coking properties
- D. All A., B. and C.
Explanation: Coal washing removes mineral matter, thereby lowering ash and some sulphur, raising calorific value, and improving coking behaviour.
Correct answer: All A., B. and C.- A. Origin of coal
- B. Origin of petroleum oil
- C. Coalification
- D. Variation of coal quality with depth
Explanation: In-situ theory proposes that coal formed where the original plant material grew, whereas drift theory proposes transport and deposition…
Correct answer: Origin of coal- A. Colour
- B. Volatile matter
- C. Ash content
- D. Moisture content
Explanation: Carbonisation drives off volatile constituents, so the volatile-matter content of coke is a practical indication of how far carbonisation…
Correct answer: Volatile matter- A. Incomplete combustion
- B. Dry gas/stack gas loss
- C. Moisture loss
- D. All A., B. and C.
Explanation: Combustion loses energy through unburned fuel, heat carried away in dry stack gas, and the heating or vaporisation of moisture.
Correct answer: All A., B. and C.- A. Volatile matter
- B. Fixed carbon
- C. Ash
- D. Oxygen
Explanation: Volatile matter contains easily vaporised combustible compounds, so coal rich in it ignites readily at a lower temperature.
Correct answer: Volatile matter748. Which of the following fuel gases will require maximum amount of air for combustion of 1 Nm3 gas ?
- A. Blast furnace gas
- B. Natural gas
- C. Producer gas
- D. Water gas
Explanation: Natural gas is mainly methane, whose combustion requires about 9.5 Nm³ of air per Nm³ of gas.
Correct answer: Natural gas- A. Has poor strength and abrasion resistance
- B. Produces more slag when used in the blast furnace
- C. Is desirable in producer gas manufacture
- D. None of these
Explanation: Ash is carried into the blast furnace with coke and combines with flux to form slag, so high-ash coke increases slag production.
Correct answer: Produces more slag when used in the blast furnace- A. Caking power
- B. Calorific value
- C. Oxygen content
- D. Hydrogen content
Explanation: Low-temperature oxidation consumes combustible constituents and lowers caking power, hydrogen content and calorific value.
Correct answer: Oxygen content- A. Contains more than 90% durain
- B. Contains more than 90% fussain
- C. Is non-coking
- D. Contains mainly vitrain & clarain and is generally coking
Explanation: Bright coal is composed mainly of the bright bands vitrain and clarain, and it is generally suitable for coking.
Correct answer: Contains mainly vitrain & clarain and is generally coking- A. 1 to 2
- B. 5 to 15
- C. 3 to 4
- D. 20 to 40
Explanation: When coal is stored on an unpaved or soft floor, the lower layer becomes pressed into the ground and is lost as carpet loss.
Correct answer: 5 to 15- A. Have high adiabatic flame temperature
- B. Have high calorific value
- C. Require smaller combustion chamber
- D. None of these
Explanation: A high heat-release rate allows the required heat duty to be obtained in a smaller furnace volume, so the combustion chamber can be…
Correct answer: Require smaller combustion chamber- A. Yield of ammonia present in coke oven gas
- B. Free carbon content in tar
- C. Yield percentage of coke
- D. Difference in gross & net calorific value of the coke oven gas
Explanation: Low-temperature carbonisation produces coke-oven gas with a lower hydrogen proportion than high-temperature carbonisation, so less water…
Correct answer: Difference in gross & net calorific value of the coke oven gas- A. 5
- B. 25
- C. 55
- D. 80
Explanation: Blast-furnace gas contains a large amount of nitrogen brought in with the air blast, commonly around 50 to 60% by volume.
Correct answer: 55- A. Decreases
- B. Increases
- C. Remain constant
- D. None of these
Explanation: Coking drives off volatile matter while the mineral ash remains with the coke.
Correct answer: Increases- A. 6
- B. 12
- C. 18
- D. 24
Explanation: Ash is conserved during coking, but volatile matter is removed, so its percentage rises.
Correct answer: 24- A. Coke oven gas
- B. Water gas
- C. Producer gas
- D. Blast furnace gas
Explanation: Coke-oven gas contains a relatively high proportion of hydrogen and methane, giving it the greatest calorific value among these gases.
Correct answer: Coke oven gas- A. Is less liable to spontaneous combustion on storage
- B. None of these
- C. Requires smaller combustion space and less secondary air
- D. Is more difficult to ignite and produces a shorter flame
Explanation: A high volatile-matter-to-fixed-carbon ratio makes coal easier to ignite and gives a longer flame, while also increasing its tendency to…
Correct answer: None of these- A. Fixed
- B. Moving
- C. Entrained
- D. Fluidised
Explanation: The Koppers-Totzek gasifier pulverises coal and carries it with oxygen and steam through the reaction zone.
Correct answer: Entrained