Second hand dual effect evaporator treatmentThe difference between a falling film evaporator and a rising film evaporator is that the feed liquid is added from the top of the evaporator, forms a film along the tube wall under the action of gravity, and evaporates and thickens during this process, obtaining a concentrated liquid at its bottom. Due to the different film-forming mechanism from the rising film evaporator, the falling film evaporator can evaporate materials with higher concentration, viscosity (such as in the range of 0.05-0.45Ns/m2), and thermal sensitivity. However, due to the uneven distribution of liquid film inside the tube and the smaller heat transfer coefficient compared to the rising film evaporator, it is still not suitable for materials that are prone to crystallization or scaling.

Due to the film like flow of the solution in the one-way evaporator, the convective heat transfer coefficient is greatly improved, allowing the solution to reach the required concentration in one pass through the heating chamber without further circulation. Therefore, it has greater advantages than the circulation evaporator. The benefits of not circulating the solution include: (1) the residence time of the solution in the evaporator is very short, making it particularly suitable for the evaporation of thermosensitive materials; (2) The concentration of the entire solution is not always close to the concentration of the finished liquid like in the circulation type, so the effective temperature difference of this evaporator is relatively large. Its main disadvantage is that it is quite sensitive to fluctuations in feed load, and when the design or operation is not suitable, it is not easy to form a film. At this time, the convective heat transfer coefficient will significantly decrease.

3. The scraper evaporator has a heating steam jacket inside the evaporator shell, which is equipped with rotatable blades or scrapers. The scraper is fixed

Component assembly

1. Preheaters and heaters

In most cases, the product to be evaporated must be preheated to boiling point before entering the heating chamber. Usually, straight tube preheaters or plate heat exchangers are used to complete this task.

2. Evaporator

Choosing the appropriate type of evaporator depends on each specific application and the nature of the product.

3. Separators

Each evaporator is equipped with a separator for separating steam and liquid. Select different types of separators according to their application scope, such as centrifugal separators, gravity separators, or separators with internal components. When designing, important factors such as separation efficiency, pressure drop, and cleaning frequency need to be considered.

4. Condenser

In possible situations, the steam heat generated during the evaporation process is used to heat downstream evaporators and preheaters, or to compress the steam as a heating medium. However, the residual steam after the evaporation device cannot be utilized in this way and must be condensed. Evaporation devices can be equipped with surface condensers, contact condensers, or air-cooled condensers.

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Structural features: The falling film chamber adopts a stainless steel integral frame structure with a low overall height, which is very suitable for installation and use in liquid milk workshops. The hot press pump extracts secondary steam to save energy.

The equipment is equipped with cleaning nozzles and CIP internal system, fully enclosed balance cylinder and acid-base cylinder, which can reduce pollution and acid-base volatilization. The automatic control box equipped with a process simulation diagram clearly displays the operating status of the equipment and is easy to operate.

Device design and selection

When designing an evaporation device, various factors must be considered, which are often contradictory to each other. They determine the type, layout, process, and cost data of the design. The important factors are as follows:

(1) Production capacity and operating parameters, processing capacity, concentration, temperature, annual operating hours, product replacement, control, automation, etc.

(2) Characteristics Heat sensitivity, viscosity, fluidity, degree of foam formation, scaling and precipitation properties, boiling point, etc.

(3) Utility steam, cooling water, electricity, cleaning agents, vulnerable parts, etc.

(4) Material selection and surface polishing.

(5) Interest on investment costs and capital recovery.

(6) Personnel costs for operation and maintenance.

(7) The available space on site, climate conditions for outdoor installation, connection between energy and products, work platform, etc.

(8) Mandatory regulations on health and safety, accident prevention, noise, environmental protection, etc. are determined based on specific projects. /Second hand dual effect evaporator treatment