In high-energy-consuming industries such as chemical, pharmaceutical, and food industries, forced circulation evaporators have become the core equipment for processing complex feed liquids due to their high-efficiency evaporation performance and stable operability. Through its unique working principle and optimized design, it solves the problems of low efficiency and easy scaling of traditional evaporators when dealing with high-viscosity and easily crystallizable feed liquids.

 

I. Core Structure and Working Principle of Forced Circulation Evaporators

The core system of a forced circulation evaporator consists of a heating chamber, an evaporation separation chamber, and a circulation pump. Its working principle is different from that of natural circulation evaporators. An external circulation pump provides power to force the feed liquid to flow at a high speed of 1.5 - 5 meters per second in the heating tubes. In the heating chamber, the feed liquid is heated to a superheated state and then enters the evaporation separation chamber. At this time, the sudden pressure drop triggers a flash evaporation phenomenon. The secondary steam is discharged from the top of the separation chamber. After being filtered by a demister to remove liquid droplets, the purity of the steam and the product quality are ensured. The concentrated feed liquid then enters the heating tubes again through the circulation pump, forming a continuous concentration cycle until it reaches the target concentration and is discharged from the system.

 

II. Equipment Advantages and Applicable Scenarios

1. High-Efficiency Heat Transfer and Anti-Scaling Performance

The high-speed flow characteristic of the feed liquid in a forced circulation evaporator significantly improves the heat transfer efficiency. At the same time, the scouring effect on the tube wall reduces the risk of crystallization and scaling. It is especially suitable for processing solutions containing high-concentration solid particles, such as chemical waste liquids and pharmaceutical intermediates.

2. Flexible Adjustability

By adjusting the power of the circulation pump, the flow rate of the feed liquid can be precisely controlled. Combined with the design of vertical or horizontal heating tubes, it can meet the requirements of different processes for heat load and space layout. For example, the horizontal tube structure can reduce the total height of the equipment, but regular maintenance is required to ensure cleanliness.

3. Multi-Effect Design and Energy-Saving Potential

The equipment supports single-effect, double-effect, or multi-effect system configurations. In double-effect or triple-effect evaporators, by using the secondary steam generated in the previous effect as the heat source for the subsequent effect, the energy consumption can be reduced by 30% - 50%. It is suitable for large-scale industrial production scenarios.

 

III. Industry Applications and Key Points for Selection

In the chemical field, forced circulation evaporators are widely used for concentrating crystalline solutions such as ammonium sulfate and sodium chloride; in the pharmaceutical industry, the concentration of traditional Chinese medicine extraction liquids and antibiotic mother liquors depends on its stable protection ability for heat-sensitive substances; in food processing, it is used for the high-efficiency concentration of syrups and fruit juices. For scenarios with corrosive media, 316L stainless steel or titanium materials can improve the corrosion resistance of the equipment and extend its service life.

 

Selection Suggestions:

- Matching with Feed Liquid Characteristics: For feed liquids with high viscosity, easy crystallization, or high solid content, a design with a higher flow rate (3 - 5 meters per second) should be selected;

- Consideration of Energy Efficiency: The initial investment of a multi-effect system is relatively high, but it can significantly reduce steam consumption in long-term operation;

- Maintenance Convenience: Priority should be given to the selection of a detachable and cleanable separation chamber and a modular pipeline design to reduce downtime.

 

IV. Technological Development Trends

In recent years, technological upgrades have focused on integration and intelligence. The combination of MVR (Mechanical Vapor Recompression) technology and forced circulation evaporators further reduces energy consumption by using electric energy to replace steam drive; while the automatic control system realizes real-time monitoring and adjustment of concentration, temperature, and pressure to ensure process stability.