Tube falling film evaporators are used in many standard applications and smaller evaporation capacities than plate falling film evaporators. In particular, the separation of droplets and the cleaning of the apparatus play an essential role, where GIG Karasek has been realizing customized solutions for years.
Model & functional principle:
Falling film evaporators use gravity to move the medium evenly over the heating surface from top to bottom and are therefore very energy efficient in operation. In the case of the tubular falling film evaporator, the medium is internally guided through the externally heated tubes which act as a heating surface to concentrate and evaporate it. Due to the distribution cup, a uniform supply of all tubes is ensured. The circulation pump and the recirculation conveyed conveyed the medium in a circle and is thus further evaporated. Evaporation of the more volatile liquid at the heating surface produces vapor vapor, which is conveyed downwards through the tube bundle in cocurrent with the concentrate. Subsequently, the vapor phase is separated from the liquid phase while the vapor of the broth still has to be separated by means of a droplet separator from entrained droplets of the medium.
One possibility is to realize this by means of cyclone separators, whereby different solutions are conceivable here. The Brüdendampf can then be used to heat the tube bundle by the steam inlet of the next evaporation stage in a multi-stage evaporation or by mechanical vapor recompression (MBV) or thermal vapor recompression (TBV) in the same evaporator stage for heating the tube bundles. The condensed Brüdendampf (condensate) on the shell side of the tubes is finally discharged through a condensate outlet at the bottom of the tube bundle. The concentrate on the other hand is withdrawn at the bottom of the evaporator body and passed to the next stage of the evaporator or the next process step.
For optimization, several evaporator stages are possible in one apparatus, whereby the evaporation rate can be significantly increased.
In particular, the droplet separation is a challenge with tubular film evaporators which is optimized and adapted by GIG Karasek by customer-specific circumstances. Years of experience and different areas of application make different solutions possible here.
Cleaning and soiling of the heating surfaces:
To ensure efficient operation and even evaporation, it is important to use regular washing cycles, depending on the medium. In regular downtime, a manual cleaning can be performed. In the case of particularly polluting media, there is the danger of the tubes becoming completely blocked, which can no longer be cleaned and finally only dimmed. As an alternative, GIG Karasek can offer disk-type film evaporators as a much cheaper solution. Otherwise, the use of rinsing chemicals is conceivable and possible if necessary.
Other types of tube evaporator:
Also other types of evaporators in tube design are conceivable and are realized by GIG Karasek:
- Rising film evaporator
- Forced circulation evaporator
- Natural circulation evaporator
Due to the significantly higher operating costs and lower evaporation rates, these technologies are rarely realized today and are no longer state of the art. Most fall film evaporators are used because of significant technical advantages for a variety of applications.
Capacitors, heat exchangers, preheaters, etc. can also be designed in tube construction and supplied by GIG Karasek.
- Can be used from smallest evaporation capacities
- Often used in various industries and good experience
- Several evaporator stages are possible in one apparatus
- Low circulating pump power necessary
- Little space needed
- Recovery of solvents & alcohols
- Separation of water, solvents, alcohols and more
- Recovery of recyclables
- Volume reduction of liquid-liquid mixtures
- Separation of multi-substance mixtures
- Concentration of starch products and derivatives in the starch industry
- Concentration of waste liquor in the pulp industry