Evaporators

Thin film or wiped film evaporators are used to separate a mixture of liquids having different boiling points. It is also used to increase the concentration of liquids.

Principle of Operation
The liquid feed is distributed on the heated wall of the evaporator to form a uniform thin film with the help of suitable configuration of blades. The volatile component or the component with lower boiling point gets evaporated and is vacuumed out of the evaporator, while the component with higher boiling point flows down the wall and is collected at the bottom. The vapours are passed through a condenser and collected separately.

Operating Features
The heat transfer in thin film evaporator is very quick and efficient, thus demanding lower surface area and heat input as compared to other types of evaporator. Due to high vacuum distillation and very short residence time the thin film evaporator are suitable for handling wide range of heat sensitive, high boiling and viscous feeds. Due to low rotor speeds in the range of 100 to 150rpm, the horse power requirements are very low. To reduce the pressure drop between the evaporator and condenser, the internal condensers can be provided to achieve short path distillation. The thin film evaporators are designed to handle various products with operating pressures up to O.1torr. Liquids with viscosities above 2,00,000cps can be handeled in these evaporators.

Construction of ATFE

The Agitated Thin Film Evaporator consists of a jacketed shell having a machined surface on the inner side. The rotor assembly consisting of different configuration of blades depending upon the nature of product is mounted in the shell. Feed inlet is provided at the top side. Specially designed feed distributor is integral with the rotor at the top side. The rotor is also fitted with an entrainment separator. Generally the vapour outlet is provided on the top side of the shell. The different types of blade configurations available are:

• Fixed blade rotor
• Spring loaded rotor
• Cylindrical wiper rotor
• Centrifugal blade rotor

The construction of the evaporator is such that different types of rotors can be mounted in the same equipment for different products. The evaporators having surface area up to 50sq.m. can be supplied.

Excel Plants Agitated Thin Film Evaporator Models

Model Surface area (m2) Diameter (mm.) (D) Total height (mm) (H) Motor hp. EP-5 0.5 250 2250 2 EP-10 1 350 2650 3 EP-30 3 450 3500 5 EP-50 5 600 4750 7.5 EP-75 7.5 700 5750 10 EP-100 10 800 6500 15 EP-150 15 950 7500 20 EP-200 20 1100 8000 25 EP-250 25 1350 8500 30 EP-350 35 1600 9500 40 EP-500 50 2000 11000 60

They are long tube evaporators most suitable for low temperature applications and for high thermal efficiency.They can be used non-fouling and relatively non viscous products.

• Low fixed and operating costs
• Optimum heat transfer area
• Good heat transfer coefficients at all temperature gradients
• Easy accessibility and compact layout
• Self cleaning action from salting
• Scaling and fouling
• Large evaporation capacities
• Low temperature operation
• Best suited for clear, foaming and corrosive solution
• High viscosity
• Solvent Recovery
  

  Industry Applications:____________________________________________

  Chemical Industry Dyes Dye Intermediates Tanning Agents Sodium Sulphate Glycerol Solution Calcium Chloride	Pharmaceutical Industry Herbal Extract Protein Hydrolysate Gelatine
  Starch Industry Maltodextrine Dextrose Sorbitol Corn Steep Liquor Glucose	Food Industry Juices Milk Coffee

They are short tube evaporators with very high velocity in tubes. They are the conventional type preferred mostly for fouling and viscous products.

Scrapped surface Evaporator is used for evaporating the heat sensitive material under high vacuum using thin/scraped film technology. Thin film yields high heat transfer coefficients, making the process highly effective.

• Low fixed and operating costs
• Optimum heat transfer area
• Good heat transfer coefficients at all temperature gradients
• Easy accessibility and compact layout
• Self cleaning action from salting
• Scaling and fouling
• Large evaporation capacities
• Low temperature operation
• Best suited for clear, foaming and corrosive solution
• High viscosity
• Solvent Recovery

Chemical Industry Dyes Dye Intermediates Tanning Agents Sodium Sulphate Glycerol Solution Calcium Chloride	Pharmaceutical Industry Herbal Extract Protein Hydrolysate Gelatine
Starch Industry Maltodextrine Dextrose Sorbitol Corn Steep Liquor Glucose	Food Industry Juices Milk Coffee

They are thermally efficient and are for low temperature and foaming application. They are flexible enough to convert to forced circulation types.

Chemical Industry Dyes Dye Intermediates Tanning Agents Sodium Sulphate Glycerol Solution Calcium Chloride	Pharmaceutical Industry Herbal Extract Protein Hydrolysate Gelatine
Starch Industry Maltodextrine Dextrose Sorbitol Corn Steep Liquor Glucose	Food Industry Juices Milk Coffee