Engineering Questions with Answers - Multiple Choice Questions
Chemical Process Technology MCQ’s – Natural Products – Petroleum – 2
1 - Question
Which of the following unit operation is based on difference in freezing point?
Explanation: All are physical changes or unit operations used in petroleum refinery process. Unit operation crystallization is based on difference in freezing point difference. Wax preparation process uses crystallization method.
2 - Question
Which of the following relation between driving force and unit operation is correct?
a) Crystallization – relative solubility in different solvents
b) Extraction – relative volatilities
c) Absorption – freezing point difference
d) Adsorption – relative adherence
Explanation: The general driving force for any unit operation is concentration gradient or more precisely chemical potential. The correct option is that adsorption is based on relative adherence.
3 - Question
Which one of the following is a wrong statement?
a) Pressure and temperature requirements are higher for catalytic cracking
b) Rate of polymerization is increased by increasing pressure
c) Thermal pyrolysis of methane and ethane require quenching
d) Higher the molecular weight, higher is the coking tendency
Explanation: The statement is wrong as pressure and temperature requirements are lower for catalytic cracking. Gas oil undergoes catalytic cracking to produce high yield of petrol fraction.
4 - Question
Which catalyst doesn’t have high tolerance towards S when it is reactivated with steam in catalytic cracking process?
Explanation: Chromium doesn’t have high tolerance towards S when it is reactivated with steam in catalytic cracking process. Catalyst must be selected in such a way that it is not poisoned by metals.
5 - Question
Increase in pressure during catalytic cracking process ____________ octane number.
c) Doesn’t effect
d) Remains same
Explanation: Increase in pressure during catalytic cracking process; decreases unsaturation and hence octane number decreases, which results in increase in coke production though reactor throughput also increases.
6 - Question
Which of the following is not a distinctive feature of catalytic cracking process?
a) Less polymerization
b) High quality petrol
c) Less coke production
d) Less Isomerization
Explanation: Distinctive features of catalytic cracking process are high quality products, selective cracking, less light ends, more Isomerization, less polymerization, and little coke.
7 - Question
Thermodynamically dehydrogenation reactions are favorable at ___________
a) High temperature, low pressure
b) Low temperature, high pressure
c) High temperature, high pressure
d) Low temperature, low pressure
Explanation: Thermodynamically dehydrogenation reactions are favorable at High temperature and low pressure. Hydro cracking and carbon deposition can occur at high temperature, hence high hydrogen pressures are used to reduce them.
8 - Question
Which of the following statement is wrong regarding Catalytic reformates?
a) They contain no olefins
b) They are resistant to oxidation
c) They have low sulfur and gum content
d) They are low in octane number
Explanation: Catalytic reformates contains no olefins, forms blending stocks, high in octane number, low in S and gum content, stable, resistant to oxidation, can make cold weather petrol due to its broad boiling point range.