The forced circulation short tube evaporator is suitable for processing liquors which are susceptible to scaling or crystallizing i.e. in later effects of evaporator station. Liquid is circulated at a high rate through the calandria, boiling being prevented within the unit by virtue of a hydrostatic head maintained above the top tube plate. As the liquid reaches at the top tube sheet where the absolute pressure is slightly less than in the tube bundle, the liquid flashes to form vapour. These have the advantage that these can be used both for scaling & non-scaling solutions.

The main applications for a forced circulation evaporator are in the concentration of inversely soluble materials, crystallizing duties, and in the concentration of thermally degradable materials which result in the deposition of solids.

Conventional forced circulation evaporators were normally more expensive than falling film evaporators because of the need for large bore circulating pipe work and large recirculation pumps.

SED provides an optimized solution for a forced circulation evaporator with following distinct features:

• Honeycomb Calandria for:
1. Improved circulation with least friction losses at entry & exit.
2. Higher heat transfer area.
3. Least deposition.


• Specially designed bottom mounted mechanical circulator with reduced shaft length and high quality mechanical sealing system ensures:
1. Increased circulation rate to a great extent.
2. Effective in arresting any air / fluid leakages.
3. Suitable for high temperature and pressure conditions.
4. Extended life & low maintenance requirements.


• Central down take.
• Optimally designed W-saucer bottom aiding circulation. No dead corners.
• Essential wetted parts lined with stainless steel / stainless steel construction.
• Process automation features for optimized results.
• Operational advantages:
1. Optimal design for increased heat transfer coefficient, homogeneity, least chances of scaling and ability to handle higher viscosities (upto around 80 CP) as compared to conventional evaporators.

Forced Circulation Evaporator as a multi effect concentrator tower

Forced circulation chambers can be superimposed on each other to form a multi effect tower which can be utilized for increasing concentration in following process applications:

1. Spent Wash Concentration
2. Melt (Refined Sugar) Concentration
3. Syrup Concentration

The multi effect forced circulation tower has various valuable features over other concentrators.

1. Self supporting tower with least floor space.
2. Reduced piping.
3. Multi effect configuration hence more steam economy.
4. Online cleaning of individual chamber.