A centrifugal extractor, often called a centrifuge or separator, is a device that separates components of a liquid or gas mixture using centrifugal force. It employs the movement of the rotor within a centrifuge to mix two immiscible liquids outside the rotor and separate the liquids inside the rotor using gravity. A centrifugal extractor produces a continuous extraction from one liquid phase to another.
The basic principle of a centrifugal extractor is to rotate a mixture at high speed, causing the denser components to migrate outward and the lighter components to move inward. A recent compilation contains a description of contactor design ideas and applications.
Here’s a brief overview of how a centrifugal extractor works:
- Rotation: The mixture is introduced into a rotating container, which is typically a cylindrical or conical vessel. The container rotates at high speeds, creating a centrifugal force that acts radially outward from the center of rotation.
- Separation: Due to the centrifugal force, the components of the mixture are forced towards the outer edges of the rotating container. The heavier components, having higher inertia, move towards the outer wall, while the lighter components move towards the center.
- Collection: The separated components are collected or removed from their respective locations. This could involve draining off liquids or collecting solids from the outer wall.
Centrifugal extractors are utilized in various industries for different purposes:
- Chemical Industry: Separation of immiscible liquids, purification of chemicals, and extraction of specific components from mixtures.
- Food and Beverage Industry: Clarification of fruit juices, separation of cream from milk, and extraction of edible oils.
- Biotechnology: Separation of cells and cell components, protein purification, and DNA extraction.
- Environmental Applications: Treatment of wastewater, separation of pollutants, and sludge dewatering.
- Oil and Gas Industry: Separation of oil and water in petroleum processing.
Centrifugal extractors are classified into three types: disk-stack centrifuges, tubular centrifuges, and decanter centrifuges. Each kind is built for a distinct application. The type of centrifuge used is determined by the nature of the mixture, the desired separation efficiency, and the required throughput.
