NACL Industries DCS Engineer Interview Questions, Process, and Tips

Critical speed of ball mill is the speed at which the centrifugal forces equal gravitational forces at the mill shell's inside surface.

• Critical speed is calculated by the formula: Nc = 1/(2*pi*sqrt(D/g)) where Nc is the critical speed, D is the diameter of the mill in meters, and g is the acceleration due to gravity (9.81 m/s^2).

• At critical speed, the grinding media in the mill starts rotating with the mill shell and n...read more

Distillation column design principles involve understanding the separation process, heat transfer, and fluid dynamics.

• Understanding the separation process is crucial for designing an efficient distillation column.

• Consider the heat transfer requirements to ensure proper temperature control within the column.

• Fluid dynamics play a key role in determining the flow patterns and efficiency of the distillation process.

Bumping clearance in a reciprocating compressor is the minimum distance between the piston and the cylinder head at the top dead center.

• Bumping clearance is crucial to prevent contact between the piston and the cylinder head during operation.

• It is necessary to allow for thermal expansion of the components and to avoid damage.

• Proper bumping clearance ensures efficient operation and prolongs the lifespan of the compresso...read more

A mechanical seal is a device that helps prevent leakage between two moving or stationary parts in a machine.

• Used in pumps, compressors, and other rotating equipment

• Consists of two main parts: stationary seal face and rotating seal face

• Common types include cartridge seals, component seals, and split seals

Pressure vessels are made in cylindrical or spherical shapes for structural integrity, ease of fabrication, and efficient use of material.

• Cylindrical shape provides uniform stress distribution and is easier to fabricate compared to other shapes.

• Spherical shape can withstand higher internal pressure due to uniform stress distribution in all directions.

• Cylindrical shape is commonly used for horizontal pressure vessels li...read more

ASME codes are primarily used for pressure vessels and piping systems, while API codes are focused on the oil and gas industry.

• ASME codes are more general and cover a wide range of industries, while API codes are specific to the oil and gas industry.

• ASME codes are developed by the American Society of Mechanical Engineers, while API codes are developed by the American Petroleum Institute.

• ASME codes focus on design, cons...read more

Micro alloy elements added to alloy steel improve strength, toughness, and hardenability.

• Common micro alloy elements include vanadium, niobium, titanium, and boron.

• These elements help refine the grain structure of the steel, resulting in improved mechanical properties.

• Micro alloying also allows for the use of lower carbon content, reducing the risk of cracking during heat treatment.

Euler's equation is a mathematical formula that relates the values of trigonometric functions to complex exponential functions.

• Euler's equation is e^(ix) = cos(x) + i*sin(x)

• It is used in various fields including physics, engineering, and signal processing

• It is named after the Swiss mathematician Leonhard Euler

Law of motion is a fundamental concept in physics that describes the behavior of objects in motion.

• There are three laws of motion formulated by Sir Isaac Newton.

• The first law states that an object at rest will remain at rest, and an object in motion will remain in motion with a constant velocity, unless acted upon by a net external force.

• The second law states that the acceleration of an object is directly proportional ...read more

PID stands for Proportional-Integral-Derivative, a control loop feedback mechanism used in industrial processes to maintain desired setpoints.

• PID is a control algorithm that calculates an error value as the difference between a desired setpoint and a measured process variable.

• The PID controller then adjusts the process control inputs to minimize the error and keep the process variable close to the setpoint.

• The Proporti...read more

A thermowell in a tank is a protective device used to shield temperature sensors from the harsh environment inside the tank.

• Thermowells are typically made of metal and are inserted into the tank to provide a sealed chamber for the temperature sensor.

• They help protect the sensor from corrosion, pressure, and other damaging factors inside the tank.

• Thermowells also allow for easy removal and replacement of the temperature...read more