Free Chemical Process Principles MCQs with Answers

• A. Light paraffinic fuel oils is equal to that of equivalent olefins
• B. n-paraffin is lower than that of iso-paraffins of the same compounds
• C. Light paraffinic fuel oils is lower than that of equivalent olefins
• D. Light paraffinic fuel oils is higher than that of equivalent olefins

Explanation: Paraffinic hydrocarbons contain more hydrogen per carbon than the corresponding olefins, so their combustion releases more heat.

• A. Fixed carbon
• B. Total carbon
• C. Hydrogen
• D. Nitrogen

Explanation: Ultimate analysis determines elemental carbon, hydrogen, nitrogen, sulfur and oxygen, whereas fixed carbon is obtained from proximate…

• A. Less reactive
• B. All A., B. & C.
• C. Smaller in size
• D. Stronger

Explanation: Narrower coke-oven chambers generally produce smaller coke pieces with greater strength and lower reactivity because of the more severe…

• A. 5
• B. 10
• C. 20
• D. 35

Explanation: Preheating combustion air supplies part of the required heat before combustion, reducing the furnace fuel demand for the same duty.

• A. Yield of coke oven gas is 290 Nm3 /ton dry coal
• B. Volatile matter in coke is zero
• C. Yield of tar is about 3% of dry coal
• D. Temperature maintained is 700°C

Explanation: Low-temperature carbonisation is carried out roughly in the 500–700°C range, with about 700°C commonly used as its upper operating…

• A. Winkler process
• B. Lurgi Process
• C. Kopper-Totzek process
• D. None of these

Explanation: The Lurgi process is a single-stage, fixed-bed gasifier operating at high pressure.

• A. N2 & CH4
• B. N2 & H2
• C. N2 & CO
• D. CH4 & CO2

Explanation: Blast-furnace gas contains a large amount of nitrogen from the air blast and carbon monoxide formed during coke combustion and reduction…

• A. 20
• B. 12.5
• C. 0
• D. 10

Explanation: On a 100-mole flue-gas basis, 70 mol CO₂ and 20 mol CO represent 90 mol of carbon, requiring 90 mol O₂ for complete combustion.

• A. All A., B. and C.
• B. Yield of gas and tar
• C. Fuel consumption in coking
• D. Time of carbonisation

Explanation: Preheating removes moisture and raises the initial temperature of the charge, so carbonisation takes less time and requires less firing…

• A. Producer gas
• B. Liquefied petroleum gas
• C. Natural gas
• D. Carburetted water gas

Explanation: LPG consists mainly of propane and butane, which release far more heat per normal cubic metre than the dilute combustible gases in…

• A. Increase the output of the coke
• B. Facilitate uniform heating of the oven
• C. Facilitate easy discharging of coke as it swells during carbonisation
• D. None of these

Explanation: Coke swells as carbonisation proceeds, so the coke-side opening is made slightly wider to reduce resistance during discharge.

• A. Both A. and B.
• B. Height of the chimney
• C. Density of the chimney gases
• D. Neither A. nor B.

Explanation: Chimney draft is produced by the density difference between hot chimney gases and outside air, and it increases with chimney height.

• A. Critical air blast (CAB) value
• B. Coke reactivity index (CRI)
• C. Porosity
• D. Both B. and C.

Explanation: A highly reactive coke reacts readily with carbon dioxide, so its CRI is high, not low.

• A. Low octane number
• B. High cost & availability
• C. Low flash point
• D. Low calorific value

Explanation: Alcohol fuels have useful antiknock properties, but their direct use is limited mainly by relatively high cost and inadequate availability…

• A. 0.21
• B. 3.76
• C. 4.76
• D. 0.79

Explanation: Dry air contains approximately 79% nitrogen and 21% oxygen by volume, giving an N₂/O₂ ratio of 79/21, or about 3.76.

• A. Ignites less easily than anthracite
• B. Is generally coking
• C. Burns with smoky yellow flame
• D. Both B. and C.

Explanation: Bituminous coal commonly has caking properties and burns with a smoky yellow flame because of its relatively high volatile matter.

• A. Process of conversion of lignite into anthracite
• B. Underground gasification of coal
• C. Complete combustion of coal
• D. Direct hydrogenation of coal

Explanation: Coalification is the progressive conversion of low-rank coal such as lignite into higher-rank coal, ultimately approaching anthracite…

• A. 1
• B. > 1
• C. < 1
• D. Unpredictable

Explanation: Ultimate analysis measures all carbon, including carbon present in the volatile matter, whereas proximate fixed carbon excludes that…

• A. It contains large amount of volatile matter
• B. It is stored in tall heaps
• C. Smaller fines are stored in large quantity
• D. All A., B. and C.

Explanation: Volatile coal oxidizes readily, while tall heaps retain heat and fine particles provide a large surface area for oxidation.

• A. Low
• B. High
• C. Very high, if the fuel is of low calorific value
• D. None of these

Explanation: A higher heat capacity allows the combustion products to absorb more heat for the same energy release, so their temperature rises less.