Unit Operations in Chemical Engineering

Mass Transfer Operations

• Absorption: The separation of components of a gas mixture using a liquid that dissolves specific components.
• Distillation: Separating the components of a liquid mixture by vaporization and partial condensation of steam. This can be simple distillation or rectification (with reflux).
• Extraction: Separation of the components of a mixture through a solvent that is immiscible with it. This may be solid-solid or liquid-liquid extraction.
• Ion-Exchange: Chemical reactions between ions in a solution and a solid phase that is insoluble in the solution and placed in contact with it.
• Adsorption: The separation of components of a liquid or gaseous mixture through a solid surface.
• Electrodialysis: Separation using ion-exchange membranes and applying an electrical potential to concentrate or dilute solutions.
• Reverse Osmosis: Separation or concentration of electrolytes by increasing pressure on the side of higher concentration.

Heat Transfer Operations

• Evaporation: The process of concentrating a solute by removing a volatile solvent through evaporation.
• Gas Conditioning: Modifying the humidity and temperature conditions of an airflow through interaction with a stream of water.
• Crystallization: The formation of crystalline solid particles within a homogeneous phase.
• Humidification: The contact between a pure liquid and a gas that is almost insoluble in that liquid.
• Dehumidification: The process of placing a wet gas in contact with a cooler liquid.
• Lyophilization: Removing water from a solid by the process of sublimation.
• Drying: Reducing the water content of a solid, typically through sublimation or evaporation.

Momentum Transfer Operations

• Fluid Flow: The separation of solid particles in fluid suspension (gas or liquid). This includes internal circulation (fluid inside pipes) and external circulation (solids within the fluid).
• Flow through Porous Beds: The movement of fluid through a bed of solid particles.
• Filtration: Separating solid particles suspended in a fluid through a filter medium that only allows the passage of the fluid.
• Fluidization: The suspension of solid particles from a bed by a fluid passing through it in an upward direction.
• Sedimentation: Separating suspended solids by gravity, allowing them to settle.
• Hydraulic Classification: Separating solid particles by size through the entrainment of a liquid.
• Pneumatic Transport: The dragging and transport of solid particles by a fluid stream.

Mechanical Unit Operations

• Storage: The containment and preservation of materials.
• Solid-Polymer Blending: The mixing of solid materials and polymers.
• Grinding and Crushing: Reducing the size of solids through friction (grinding) or compressive force (crushing).
• Screening: The separation of particles in a solid mixture based on their size.
• Centrifugation: The separation of two phases of similar density using centrifugal force.