Praxair Interview Questions and Answers

The diameter of a distillation column is designed based on factors such as feed flow rate, composition, pressure, and efficiency.

• Calculate the required vapor and liquid flow rates based on the feed composition and desired separation efficiency.

• Consider the pressure drop along the column and the desired residence time for the vapor and liquid phases.

• Use design equations and correlations to determine the optimal diameter...read more

Number of trays and reflux ratio can be calculated using various methods such as McCabe-Thiele method or Fenske equation.

• Use McCabe-Thiele method for distillation columns to determine number of trays required.

• Calculate reflux ratio by dividing the liquid returning to the column by the liquid leaving the top tray.

• Consider factors such as desired separation efficiency and operating conditions when determining number of t

Tray is used for organizing items while packing is the process of placing items in a container for transportation or storage.

• Tray is typically used for organizing small items or serving food, while packing involves placing items in a container for transportation or storage.

• Trays can come in various sizes and materials, such as plastic, metal, or wood, while packing materials can include boxes, bags, or containers.

• Examp...read more

To calculate pressure drop in a pipe, use the Darcy-Weisbach equation or the Hazen-Williams equation.

• Use the Darcy-Weisbach equation: ΔP = f * (L/D) * (ρ * V^2) / 2

• Use the Hazen-Williams equation: ΔP = 10.67 * Q^1.85 / (C^1.85 * D^4.87)

• Where ΔP is the pressure drop, f is the Darcy friction factor, L is the pipe length, D is the pipe diameter, ρ is the fluid density, V is the fluid velocity, Q is the flow rate, and C is...read more

Le Chatelier's principle states that a system at equilibrium will respond to a stress by shifting to counteract the stress and restore equilibrium.

• If a stress is applied to a system at equilibrium, the system will adjust to minimize the effect of the stress.

• Changes in concentration, pressure, or temperature can cause a shift in equilibrium.

• For example, if more reactants are added to a system at equilibrium, the system ...read more