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Products  |  Process Engineering  |  Thermal Process Engineering  |  CE 520
CE 520 Cooling Crystallisation Show data sheet (pdf file) Print page
Technical Description

  Crystallisation enables dissolved substances from solutions to be transformed into a solid and separated.
  This trainer has been developed in cooperation with the
 Chair of the Thermal Process Technology at the Martin-Luther University, Halle-Wittenberg (Prof. Dr. Ulrich).
  A pump delivers a saturated potassium sulphate solution in a circuit with a tank. To prevent premature crystallisation, the solution is heated above saturation temperature using a heating circuit. Both circuits are connected by two heat exchangers. A small amount of this undersaturated solution is fed through the crystallisation cell as a bypass. To crystallise this part of the solution, it is cooled by cooling water using two heat exchangers. Reducing the temperature converts the solution into an oversaturated, metastable state.
  The crystallisation cell is a tube fitted with porous filter media at both the inlet and outlet. The removable cell can be opened to allow the addition of seed crystals. The porous filter media are selected in a way that the crystals can't escape from the cell. The flow conditions cause a fluidised bed in the cell. The dissolved potassium sulphate crystallises out of the metastable solution at the seed crystals. The crystals grow. The growth rate can be determined by weighing the crystals before and after the experiment and by measurement of time.
  A stirred tank with heat exchanger is available to prepare a saturated potassium sulphate solution. The temperatures in the two tanks and the temperature required in the bypass for crystallisation are recorded and controlled using sensors.

  A drying chamber, a balance, a screening machine and a microscope are recommended for evaluating the experiments. Potassium sulphate is not included.
  The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.


Learning Objectives / Experiments

- fundamental principle of cooling crystallisation
- investigation of the factors influencing crystal

  * oversaturation
  * saturation time

* Crystallisation from solutions1
* Investigation of crystal growth in a fluidised bed1
* Transparent materials for observation of processes
[1] crystallisation from solutions in fluidised bed
[2] stirred tank for preparation of a saturated solution
[3] circuit for undersaturated solution with tank, 2 heat exchangers for heating and pump
[4] bypass for oversaturated solution with crystallisation cell and 2 heat exchangers for cooling
[5] removable and fillable crystallisation cell, PMMA
[6] heating circuit with pump, tank, heater and thermostat
[7] adjustment of flow rate in bypass using valves
[8] measurement and control of temperatures in stirred tank, tank for undersaturated solution and in crystallisation cell
Technical Data

- stirred tank: approx. 25L
- for undersaturated solution: approx. 25L
- heating circuit: approx. 32L
Pump (solution)
- max. flow rate: approx. 21L/min
- max. head: approx. 38m
Pump (heating circuit)
- max. flow rate: approx. 6L/min
- max. head: approx. 9m
Crystallisation cell
- diameter: approx. 40mm
- height: approx. 80mm
Heater power output: approx. 2kW

Measuring ranges
- temperature: 3x 0...100C, 1x 0...80C
- flow rate: 1x 0...12L/min


Dimensions and Weight
LxWxH: 2.000x800x1.850mm
Weight: approx. 255kg
Required for Operation

230V, 50Hz, 1 phase or 230V, 60Hz/CSA, 3 phase

Cold water connection required: min. 3bars; max. 15C

Scope of Delivery

1 trainer

1 hose

1 set of tools
1 set of instructional material

Order Details
083.52000  CE 520  Cooling Crystallisation
© 2005 G.U.N.T. Gerätebau GmbH