Chemical Plant Utilities Quiz – Page 2 – Insight into Chemical Engineering

CPU Quiz – 2

Q 1: The multi-stage compression as compared to single-stage compression.

A) Improves volumetric efficiency for the given pressure ratio

B) Reduces work done per kg of air

C) Reduces cost of compressor

D) All of the above

Answer is D)

Explanation: The air is compressed in stages by a multistage compressor. So, it has various advantages over a single-stage compressor.

Q 2: A compressor increases the _______________ of gas by ____________ its _____________

A) pressure, reducing, volume

B) pressure, increasing, volume

C) pressure, reducing, temperature

D) pressure, increasing, temperature

Answer is A)

Explanation: The primary function of a compressor is to increase the pressure of a gas. It can be done by reducing the volume of gas.

Q 3: Water boils at a lower temperature at high altitudes, because

A) the air pressure is less

B) outside temperature is less

C) latent heat is less

D) None of the above

Answer is A)

Explanation: At altitude, the available amount of oxygen gas is less compared to sea level. As a result, air pressure (atmospheric pressure) is lower at higher altitudes. The temperature at which the vapor pressure equals atmospheric pressure is known as the boiling point. At high altitude, the vapor pressure becomes equal to atmospheric pressure at lower temperature.

Q 4: The type of cooling towers with maximum heat transfer from air to water is

A) Natural draft

B) Mechanical draft

C) Both A and B

D) None of these

Answer is B)

Explanation: In natural Draft, air circulates naturally without any external force. In a mechanical draft, fans are used for the circulation of air. So, the mechanical draft provides maximum heat transfer from air to water.

Q 5: L / G ratio in a cooling tower is the ratio of

A) Length and girth

B) Water flow rate and air mass flow rate

C) Air mass flow rate and water flow rate

D) Length and temperature gradient

Answer is B)

Explanation: L stands for liquid and G stands for gas. So, L/G is the ratio of water flow rate and air flow rate.

Q 6: Compressor is used to __________ the pressure of a fluid.

A) increase

B) decrease

Answer is A)

Explanation: The primary function of a compressor is to increase the pressure of a gas.

Q 7: Which volume will you define as swept volume?

A) Volume of air delivered by a compressor

B) Volume of air sucked by a compressor during suction

C) Clearance volume

D) None of these

Answer is B)

Explanation: Swept volume is the volume of air sucked by a compressor during suction.

Q 8: Which compressor can supply more volume of air?

A) Single acting reciprocating compressor

B) Double acting reciprocating compressor

C) None of these

Answer is B)

Explanation: Double-acting compressor uses both sides of the piston to suck and compress the air. As a result, it can supply a more volume of air.

Q 9: Work done on the air in a single-acting reciprocating compressor is minimum when

A) Compression is isentropic

B) Compression is isothermal

C) Compression is polytropic

Answer is B)

Explanation: In the PV diagram, an area under the curve gives the work done.

Q 10: Which of the following are not positive displacement compressors?

A) Roots blower compressor

B) Vane blower compressor

C) Centrifugal blower compressor

Answer is C)

Explanation: In a positive displacement compressor, the air is trapped between two moving parts and forced to occupy a lower volume. In a centrifugal compressor, the rotating impeller imparts kinetic energy to the air.

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CPU Quiz – 2

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