Junior Engineer - Chemical Interview Questions and Answers

Different types of fire extinguishers are used for different types of fires.

• Class A fires (ordinary combustibles) can be extinguished with water, foam, or dry chemical extinguishers.

• Class B fires (flammable liquids and gases) require foam, dry chemical, or carbon dioxide extinguishers.

• Class C fires (electrical fires) require carbon dioxide or dry chemical extinguishers.

• Class D fires (flammable metals) require special dry powder extinguishers.

• Class K fires (cooking oils and fa...read more

Heat exchangers transfer heat between two fluids while condensers convert vapor to liquid by releasing heat.

• Heat exchangers come in various types such as shell and tube, plate and frame, and spiral

• Uses of heat exchangers include heating and cooling processes in chemical plants, power generation, and HVAC systems

• Design considerations for heat exchangers include fluid flow rates, pressure drop, and material selection

• Condensers are a type of heat exchanger that convert vapor to ...read more

Distillation columns are used to separate components of a mixture based on their boiling points.

• There are two main types of distillation columns: batch and continuous

• Batch distillation columns are used for small-scale operations and have a single feed and product stream

• Continuous distillation columns are used for large-scale operations and have multiple feed and product streams

• The working principle of a distillation column is based on the fact that different components of a m...read more

The question is asking about the process of double sizing a distillation centrifugal pump from its original diameter.

• Double sizing a pump involves increasing the diameter of the impeller and casing to handle higher flow rates and pressures.

• This process may require redesigning the pump internals and adjusting the motor power to accommodate the larger size.

• Examples of factors to consider include pump efficiency, NPSH requirements, and system compatibility.

Calibration of Blaine apparatus is essential for accurate measurement of fineness of cement.

• Calibration ensures that the apparatus is providing accurate and consistent results.

• Calibration involves checking the accuracy of the pressure gauge, air flow rate, and other components.

• Regular calibration helps in maintaining the quality of cement production.

• Example: Using a reference standard powder with known specific surface area for calibration.