Evaporation & Rectification
Evaporation & Rectification – concept and selection
corosys builds evaporator systems for a wide range of applications in the beverage, food and chemical-pharmaceutical industries. For this purpose, we have built up and continuously developed special know-how, notably for film evaporation applications. Central differences between film evaporators and conventional evaporators are the very short retention time and the negligible hydrostatic pressure on the boiling liquid, which allows operation at very low pressures and thus significantly reduced boiling temperatures. Accordingly, these evaporator systems are particularly suitable for the evaporation of high-boiling and temperature-sensitive mixtures of substances.
| Evaporator type |
Lab & Pilot |
Production |
Visc. |
Foam |
Fouling |
Solids |
CIP |
T-sens. |
VWZ |
Retention Time |
| Falling Film EFF |
0,06 – 1,5 m² |
up to >1.000 m² |
- |
+ |
o |
o |
+ |
+/o |
+ |
+ |
| Thin Film ETF |
0,02 – 0,6 m² |
up to >10 m² |
+ |
+ |
+ |
+ |
o |
+ |
+ |
o |
| Short Film ESF |
0,02 – 0,3 m² |
up to >10 m² |
+ |
- |
+ |
+ |
o |
++ |
+ |
- |
1) Laboratory & pilot plants are offered as standardized systems, production plants are designed on request
2) Selection criteria are listed as examples, further process-dependent criteria will be considered in cooperation with our customers
Combinations are advantageous for many applications:
- Combinations of evaporators with each other – e.g. for the evaporation of larger quantities of solvent in a falling film evaporator stage and downstream a concentration of the remaining higher boiling components in e.g. a thin film or short path evaporator stage.
- Combinations of evaporators with a separation column – e.g. for the separation of higher boiling mixtures with closely spaced boiling points of the components to be separated.
Some of the standard combinations are shown in the following table. In addition, further process-specific variants are considered and implemented in cooperation with the customer.
| Evaporator types |
Typical application |
| Evaporator combination EFF-ETF |
Starting mixture with high boilers and large quantity of low-viscosity low boilers |
| Evaporator combination EFF-ESF |
Starting mixture with very high-boiling high boilers and a large quantity of low-viscosity low boilers |
| Falling film evaporator with rectification EFR |
Startingmixture with closely spaced boiling points of the components |
| Thin film evaporator with rectification ETR |
Starting mixture with closely spaced boiling points of the components and a high boiling partial fraction |
In addition to known processes, this method can only be used to pre-select the appropriate unit or combination of units and to make a rough estimate of the sizes and costs. For validation, tests are then required for most applications. For these validation tests different corosys evaporator types are available, which can be carried out by corosys or at the customer’s site with corosys support, depending on the customer and application. To characterize the separation task, please use the attached evaporator form or contact our experts directly.
Known and newly developed processes alike will gladly be evaluated beyond that. If desired, together with our customers, we check for possibilities of energy saving as well as resource-saving plant cleaning within the scope of our engineering. Especially for processes with a relevant and largely homogeneous low-boiling component, numerous applications have been developed in recent years. Examples are given in the section “Applications”.
