Solid Liquid Extraction Unit

ALPHA CHEM-1320  Solid Liquid Extraction Unit

The heart of the solid/liquid extraction system is a continuously rotating extraction cell divided into compartments. The raw material is fed into these compartments from the input hopper using a screw feeder mechanism. The material is then passed under three solvent sprinkler bars, one for each stage of the process, and the dissolved product is captured in three drainage compartments. Pumps are provided to pump the product from the drainage compartment of one stage to the sprinkler of the next stage. At the end of the process the spent carrier material is dropped into a collection vessel, assisted by water sprayed from above.

The system is configured as a three stage, counter current flow process, but may also be configured as a one or two stage process for teaching purposes. Full temperature control is provided at each stage of the process using the three integrated PID controllers and related heating elements. Direct control is also provided over the product feed rate, the cell rotation speed and the inter-stage pump speeds.

In addition to the rotary cell, an independent vessel is provided, which enables batch extractions to be performed. The unit is fully instrumented with each stage of the process equipped with sensors, giving a temperature and a millivolt (mV) conductivity probe output. When using the standard water/potassium bicarbonate system, the sensor readings can be related to the percentage weight of potassium bicarbonate in the solution using experimental data.

All temperatures and voltage outputs from the conductivity sensors, together with the feed, extractor cell and individual pump rates can also be displayed directly on a computer using the optional data logging package. Using this package it is also possible to display and log the product concentration (when using the recommended material).

The equipment is designed to teach all relevant aspects of solid/liquid extraction in a simple and safe manner. It does not require the use of toxic, volatile or flammable solvents, as it is designed to use water or water based solvents. This ensures the process is fully visible to students, enabling them to observe and understand the details of the operation at every stage. There is no need for expensive solvent recovery equipment, such as a distillation column.

The solid carrier is a light porous material, a quantity of which is supplied with the equipment. It can be impregnated with a salt such as potassium bicarbonate or sodium bicarbonate, which is then extracted by the process. The use of a salt enables real time monitoring of the process using the sensors and instrumentation. The carrier material is reusable.

Specifications :

Solvent Temperatures: Ambient to 50°C, individually controllable

Pump Rate: 0-13.5L/hr

Feed Rate: 0-3L/hr

Rotation Speed: 1 rev/15min (4revs/hr)

Cell Compartment Capacity: 0.16L