Chemical Engineering – Page 294

2931. The calorific value of a gas of composition CO₂ = 20%, H₂ = 50%, CH₄ = 30%, is y. If the composition of gas is changed to H₂ = 50%, CH₄ = 30%, CO₂ = 10%, N₂ = 10%, then the calorifice value will be

0.95 y

1.05 y

1.8 y

✅ The correct answer is option A.

2932. Which of the following is used for making the explosive ‘TNT’?

Benzol

Toluene

Pyridine

Cerosote

✅ The correct answer is option B.

2933. Gas yield in the Kopper-Totzek coal gasifier is about __________ Nm³/ton coal (ash = 35%).

150

1500

3500

5000

✅ The correct answer is option B.

2934. The most matured coal out of the following is

Lignite

Semi-anthracite

Sub-bituminous

Bituminous

✅ The correct answer is option B.

2935. A carbonaceous fuel (containing no H₂ or hydrocarbons) is burnt and the resulting flue gas contains 21% CO₂. It means that

21% excess air has been used for combustion

21% excess oxygen has been used for combustion

Complete combustion of fuel has taken place

No excess air has been used for combustion

✅ The correct answer is option C.

2936. The lowest temperature, at which a solid fuel produces enough vapors to support continuous combustion, is called

Fire point

Smoke point

Burning temperature

Kindling temperature

✅ The correct answer is option C.

2937. Function of secondary air in pulverised coal firing is to

Transport the coal to the burner

Dry the coal

Ensure efficient burning of coal around the burner

Reduce primary air requirement

✅ The correct answer is option C.

2938. High ash coals

Are soft & friable (poor strength and size stability)

Require longer time of carbonisation as ash offers resistance to heat transfer

Produce larger quantity of coke oven gas

None of these

✅ The correct answer is option B.

2939. KOH solution used in orsat apparatus absorbs

CO₂

SO₂

Both A & B

Neither A nor B

✅ The correct answer is option C.

2940. Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher

Calorific value

Higher C/H ratio

Sulphur content

Difference in gross & net calorific value

✅ The correct answer is option B.