The best career choice presently where qualified professionals are in high demand is chemical engineering. The main role of a chemical engineer is to gather materials, design process so that few properties are altered in order to offer them another purpose.

There are ample industries that entrust chemical engineers in order to produce new materials. Hence, their role in any industry leads to many opportunities.

Large scale processes are designed by chemical engineers where they convert raw materials, living cells, microorganisms, chemicals and energy into beneficial products.

In order to get recruited in the best organization, prior preparation for an interview is mandatory.

In that aspect let’s glimpse through a few common interview questions for chemical engineers.

interview questions chemical engineers

27 Common Interview Questions for Chemical Engineers:

1. What is flow control?

Flow control is also mentioned as optimized production technology where the effectual flow of material is concentrated by means of the production process. Bottlenecks are the main aspect which the flow control philosophy focuses on.

A simple example can be that owner who makes use of flow control process would never intend to purchase machines which have the capacity of 1000 units per hour and supply just 500 units.

The systems are to be analysed and the lowest flow must be identified. The identified point must be addressed and assured that its works to its full capability. When maximum productivity is required, flow control plays its role.

2. Mention the difference between unit operation and unit process?

When a unit operation is considered changes take place in mass and concentration where energy is provided from an external source without any chemical change. Few examples would be evaporation, distillation, and mixing.

In the same manner, when a unit process is considered, the reactant is processed in the feed which means that reactants present in the feed are transformed to products by means of chemical reaction and with the assistance of energy being supplied to the system.

3. What is a solvent?

A solvent can be defined as a liquid which has the capability to suspend, dissolve or to take out other chemicals where they do not perform any chemical change to the material or solvent. The main process of solvents is to clean, apply, process or to separate materials.

4. What is material requirement planning?

When the quantity of finished goods is provided it requires an appropriate quantity of raw materials and related components to make them.

Computerized tools that are used to handle at times materials are to be ordered in order to provide supply at a later date is called, material requirement planning system.

When output quantities are known, then MRP is effective. There are a number of small business owners these days that have their own MRP system.

By this way, they store the information required and supply production. Few MRP activities are forecasting demand and computer tracking inventory.

5. What are PCB’s?

The abbreviation for PCB is “Poly Chlorinated Biphenyls” and is mainly utilized for disposal issues usually in the chemical industry.

6. What are the design considerations for a piping system in order to transfer slurries?

The points to be considered in order to design a pipe to transfer slurries are mentioned. The pipe should have the capability to self-drain, in the case where self-drain isn’t possible manual draining facility should be installed.

The other points to be mentioned is that when plugging opportunities are high, blow-out or rod-out connections must be provided in order to clear the lines.

Clean-out connections must be installed on both the sides of the values for proper flushing. Access flanges must make use of T-connections. Flanged connections must be provided to all manifolds for easy usage.

7. Explain the third law of thermodynamics?

The third law of thermodynamics states that “when a system reaches absolute zero, a minimum value is reached by the entropy of the system”.

8. What is just in time?

The production management philosophy which is developed across continuous reduction of waste is called lean manufacturing or just in time. They are mainly used in businesses where production efficiency plays the main role. Any aspect that hinders productivity is considered as waste and enemy in JIT systems. Wasted many hours, reduction of inbound inventory by a formulation of supplier delivery schedules and minimization of outbound stock and more are few techniques that assist JIT. By this way, cash flow is enhanced and sales margin is maximized.

9. What is quicklime and what are its uses?

Quicklime is calcium oxide which is in dehydrated stage and an effective scavenger. When a comparison is made with other scavenger’s as silica, oxazolidines, it is cheap. These are usually found in water sensitive paint formulations.

10. What is angle of repose importance in the chemical industry?

The property of particulate solids is mentioned as an angle of repose. When a bulk solid is poured into a flat surface, a conical pile is developed. The angle that is developed between the pile edge and a flat surface is called angle of repose. The angle of repose depends on certain factors which include surface area, density of the material, coefficient of friction

11. What are the three classes of organic solvent?

Organic solvents are usually classified as hydrocarbon, oxygenated, and halogenated solvents. They also take into account ketones, alcohol, esters, glucometers, and glycol ether esters. When hydrocarbon solvents are considered they include aromatics and aliphatics. Ones which are chlorinated usually fall under halogenated solvents.

12. What do you understand by wet bulb globe temperature?

Measuring the sultriness of the environment is achieved with the help of wet bulb globe temperature. The calculation of sultriness is made on the basis of air speed, humidity affects, the heating factor of sun’s radiant, temperature and air speed. It is a known fact that it could be fatal with sultriness and hence must concentrate about it.

It was in 1950’s that the wet bulb globe temperature was developed and now agreed as an international standard. Their temperature readings are taken into considerations which include ordinary dry bulb temperature, wet bulb temperature, and black bulb globe temperature.

13. What is Gibbs free energy?

It is mentioned as the maximum amount of mechanical work or available energy which is done by the system under stable temperature and pressure.

14. What happens when the paint dries?

In the manufacturing process of paints, solvents are being added to them so that paint thinner is made. This solvent is used in order to apply to different surfaces. After the application of the paint, the solvents are evaporated and the pigments and resins make the paint form a solid and thin coating on the surface.

15. Can you mention something about additives?

Additives are mentioned as something that is mixed with any process. This is also mentioned as the primary staple. They are identified in very small quantities and are not associated by any means to the terminal output. They are mainly used as an enhancer in order to avoid some unwanted reaction. Simple examples can be an addition of reactors, evaporators and more.

To avoid foaming, styrene systems are added with inhibitors to avoid polymerization. A famed additive is the detergent mixed with gasoline and motor oils so that the engine is kept clean.

16. How is particle size distribution determined for given bulk solid?

Making use of sieve stack is the simplest method that can be utilized in order to find out the particle size distribution. By making use of varied mesh sizes, stacks are developed at every stack level. The structure is formulated in a manner that the largest mesh size resides on the top and smallest at the bottom. With the pattern, the weight, before beginning and other values are made note of.

With all these setups, the topmost cylinder is where solid is placed. Now without disturbing the setup is exposed to vertical and horizontal movements. The process here is that the solid is made to pass through varied mesh sizes where particles are separated according to their sizes. In order to determine the size of the particle and distribution, advanced methodologies such as laser diffraction, video imaging can be utilized.

17. What is an isochoric process?

An isochoric process is defined as a thermodynamic process at a constant value. This is also mentioned as an isovolumetric process.

18. Explain the functioning of three-way catalytic converter?

The main functions of three-way catalytic converter are nitrogen oxide reduction, carbon monoxide oxidation, and uncombusted hydrocarbon oxidation.

19. What are the disadvantages and advantages of PFR?

The advantages of PFR are high conversion rate, continuous operation, and operating at less cost. The disadvantages of PFR are high maintenance costs and temperature gradients.

20. What are the characteristics that affect the flow of bulk solids and how?

Few characteristics that affect the flow of bulk solids are moisture content where enhanced moisture content in solids makes bulk solids sticky. Absorption of the moisture sometimes by the atmosphere by some solids happens. The other characteristic is a temperature where it affects bulk solids at times when they are exposed to a specific temperature. Time at rest is a way which affects the solids when they are kept still or rest. The more rest they take, the more slowly the flow of bulk solids takes place. Particle size is one characteristic where it is easy to handle round particles than the odd and asymmetric ones.

21. What is a CSTR and what are its basic assumptions?

The abbreviation for CSTR is continuous stirred tank reactor. Here assumptions are steady state, constant temperature, constant density and one irreversible first order reaction.

22. What is meant by global warming in engineer’s perspective and common man?

When a common man perspective is considered, he thinks that global warming is the rise in world temperature. The average temperature enhancement at the surface of the earth is mentioned as global warming by an engineer’s view. This is because of the enhanced effect of the greenhouse gasses. The greenhouse gasses are ones that capture heat which is emitted by the globe into the atmosphere which leads to temperature rise.

23. List the greenhouse gasses found in the earth’s atmosphere?

Few greenhouse gases in the atmosphere of the earth are water vapor, methane, carbon dioxide, nitrous oxide, and CFC.

24. What is carbon sequestration?

Carbon sequestration is a methodology for seizing carbon dioxide for the long term so that its effect on global warming is reduced.

25. Define octane number?

An octane number is defined as a resistance to an explosion of fuel specifically in spark engine ignition when made a comparison with the isooctane-n-heptane mixture.

26. What is the critical radius of insulation?

When the convection resistance is not affected due to the depth of insulation, then it is mentioned as critical radius of insulation.

27. What is a black body?

A black body is considered as an ideal object that absorbs all the electromagnetic radiation.
These are a few interview questions and answers specifically for chemical engineers.

Graduates who are about to attend for a chemical engineering interview can run through these questions and answers and get benefitted.