Evaporator

Manufacture of evaporators

The “Teplo-Polis” enterprise supplies PVA series evaporators – plate evaporators with a rising film, used for obtaining highly concentrated solutions with high viscosity.

Evaporation is the process of concentrating solutions of non-volatile substances by partially evaporating the solvent during the boiling of the liquid, i.e., under conditions where the vapor pressure above the solution is equal to the pressure in the working volume of the apparatus. Evaporation is used to concentrate solutions in the production of sugar, mineral fertilizers, alcohol, feed yeast, as well as in the concentration of aqueous solutions of alkaline salts (NaCl, NH4NO3, Na2SO4), for the regeneration of various solutions with the aim of returning them to the technological cycle, thermal neutralization of industrial effluents, etc.

The solvent removed in vapor form is most often water vapor, referred to as secondary steam. The overall material balance of the apparatus is expressed by the equation:

G_н=G_к+W,

where Gн is the amount of incoming raw solution with concentration bн; Gк is the amount of removed concentrated solution with concentration bк; W is the amount of solvent.

The Working Principle of a PVA Evaporator

The solution is fed through two nozzles F3 and F4, after which it enters the channels formed by the corrugations of the plates, where it boils under the action of heat from the heating steam. The resulting secondary steam, rising upwards, carries the solution in the form of a thin layer across the entire perimeter of the plate. The solution, captured from below, due to surface friction, moves at high speed along the entire length of the plate, evaporates, and is discharged into the separator. The concentrated solution is removed from the apparatus through nozzle F6. The heating steam enters the inter-plate space of the apparatus through nozzle A1. Condensate is removed through two nozzles F3 and F4. Secondary steam is discharged through nozzle F6.

In the PVA unit, special plates are used. The tightness of the construction is ensured by rubber seals, the material of which can be EPDM, NBR, or Viton.

Advantages of a PVA evaporator system of European standard

Evaporators are modern equipment used for evaporating liquids, particularly effective when dealing with highly concentrated and viscous products. Unlike traditional shell-and-tube evaporators, vacuum evaporators offer a number of distinct advantages that make them more economical and efficient, namely:

1. High heat transfer efficiency
   High turbulence achieved by a special surface pattern on the plate leads to a significantly higher heat transfer coefficient compared to shell-and-tube evaporators. The effectiveness of using PVA is particularly high when evaporating highly concentrated and viscous products.
2. Economic benefit
   The production of PVA systems requires significantly less material compared to shell-and-tube heat exchangers. This makes evaporation equipment exceptionally cost-effective, especially in cases where the technological process requires the use of expensive materials such as titanium, nickel, Hastelloy, SMO, etc. Additionally, the compactness and flexibility of PVA system design substantially reduce costs associated with transportation, installation, and assembly.
3. Ease of maintenance and operation
   The high turbulence along the entire plate surface prevents fouling and the formation of “dead” zones. Structurally, the PVA system is very convenient for both mechanical and chemical cleaning. For mechanical cleaning or inspection of plate surfaces, it is only necessary to loosen the bolts and move the pressure plate aside. When performing chemical cleaning, the requirement for chemicals is significantly lower compared to shell-and-tube installations.
4. Increased productivity
   An exceptional feature of PVA systems is the ability to adjust the productivity of the system by adding or removing plates using an existing frame. This capability to regulate productivity is a significant advantage of plate evaporator systems compared to shell-and-tube evaporators, where productivity is fixed and determined during installation.
5. Space optimization in the European style
   
   The figure illustrates a comparison of the dimensions between a 3-stage shell-and-tube evaporator system and a 3-stage plate evaporator system.

A list of products for which a PVA evaporator system is used

This list shows the products that can be obtained with evaporation equipment, emphasising its versatility and efficiency in various processes:

• Aluminate solution
• Ammonium lactate
• Ammonium nitrate
• Beet sugar
• Calcium chloride
• Cane sugar
• Copper electrolytes
• Process water in corn starch production
• Dextrose
• Wastewater
• Electrolytes
• Reboilers in ethanol production
• Ethylene glycol
• Iron chloride
• Fish and meat extracts
• Fish and meat glue water
• Fish silage
• Fructose
• Fruit juices
• Gelatin
• Glucose
• Glycerin
• Hydrolysates
• Kaolin
• Lactic acid
• Lysine
• Maltodextrin
• Maltose
• MEA (Monoethanolamine)
• Polyols
• Soap
• Sodium chloride
• Sodium hydroxide
• Sodium sulfate
• Sorbitol
• Stillage
• Stocks
• Vinasse

Vacuum evaporator provides high flexibility, efficiency and cost-effectiveness, which makes it indispensable.

Applications of a PVA evaporator unit

1. A 3-stage PVA evaporator system for concentrating a NaOH solution from 30% to 50% concentration.
   
2. A 2-stage evaporation station using a PVA evaporator system for concentrating fructose.
3. A 2-stage evaporative system with thermal re-compression at a sugar refinery.
4. A 4-stage evaporative station using PVA evaporators allows for the concentration of apple juice from 10% to 72%.
5. The PVA evaporator unit is utilized in an evaporative system with mechanical re-compression for evaporating stillage at an ethanol production plant.
   
6. An evaporator unit for evaporating brackish wastewater.

How to buy an evaporator unit

If you want to buy an evaporation plant, the process is simple and convenient. We are ready to provide you with equipment that will fully meet your production requirements.

1. Definition of initial data: In order to calculate the cost of an evaporation plant and offer you the best solution, we need to know a number of input data such as:
   • The type and physico-chemical properties of the product to be treated (e.g. viscosity, density, temperature);
   • Required plant capacity (quantity of liquid treated per unit of time);
   • Operating conditions: temperature, pressure, operating mode (continuous or intermittent cycle);
   • Materials required for plant construction (e.g. steel, titanium, Hastelloy for handling aggressive liquids);
   • Requirements for energy consumption and heat transfer efficiency.
2. Contact us for more details:
   • You can call us on the phone number listed on the website. Our specialists will give you a consultation and clarify all the necessary data for an accurate calculation.
   • If it is more convenient for you, you can send the parameters to our e-mail address. Simply fill in the application form on the website or send us a description of your requirements.
3. Calculation process: Once we have received your raw data, our engineers will carry out an evaporator plant calculation taking into account all your technical requirements. This will help to select the optimum equipment with the right capacity and parameters to give you maximum efficiency at minimum cost.
4. Commercial offer: After the calculation we will provide you with a commercial offer, which will specify the exact cost of the evaporator plant and the delivery time. We are ready to answer all your questions and clarify details as required.
5. Delivery and installation: Once your order has been confirmed, we will organise the delivery of the evaporator plant to your region. We can also offer installation and commissioning services so that you can start using the plant in your production process immediately.

Buying an evaporator plant from us is a simple and transparent solution for your business. We take all your needs into account to offer the most suitable equipment at the best price and with all technical specifications.