Falling film soft concentration device

Falling film soft concentration deviceIt is a new type of distillation equipment independently developed by our company. The evaporation principle is shown in Figure (1). A multi-component liquid mixture is added from the top of the evaporator and sprayed onto the evaporator tube wall through a distributor. Due to the surface tension and gravity, the material naturally forms a liquid film on the evaporator tube wall and is pushed down layer by layer in the form of liquid droplets. The heating medium flowing inside the evaporator tube continuously transfers heat to the liquid film, and the light components in the mixed liquid will become vapor phase molecules and detach from the evaporator tube wall. During the upward movement of vapor phase molecules and the downward movement of liquid droplets, they collide with each other for vapor-liquid exchange and secondary distribution. Finally, the concentrated liquid flows out and is collected from the bottom of the evaporator, and the light phase substance (solvent) is discharged in the form of gas phase from the top of the evaporator for condensation and recovery.

The complete process flow is shown in Figure (2). First, evacuate the equipment system to a negative pressure state, close the vacuum valve V03, open the feed valve V01, and the mixed liquid in storage tank B01 is sucked into the evaporator under pressure difference. The vaporized light phase substance (solvent) is condensed by condensers HE01 and HE02 and collected in storage tanks B03 and B04. The heavy phase concentrate flows out from the bottom of the evaporator and collected in storage tank B02. As the distillation proceeds, the material in tank B01 enters the negative pressure system, causing the pressure inside the system to rise. When a certain limit is reached, the feeding is stopped, and the system is vacuumed again before feeding. This cycle controls the distillation to be carried out in a closed manner within a certain pressure range. After one cycle of operation, the concentrated solution is sampled and analyzed from V02. If the residual solvent does not meet the requirements, it can be transported to storage tank B01 for secondary concentration through the feeding pump VP01.

Process advantage

1. The contact time between the material and the heating surface is short, and evaporation occurs in the form of a thin film under reduced pressure. Therefore, the evaporation temperature is low and the amount of contact with oxygen is small, making it an ideal method for concentrating thermosensitive materials.

2. The entire distillation process is carried out in a closed system, with no distillation loss and high solvent recovery rate.

3. Without a transmission device, it avoids the leakage caused by rotating seals and the introduction of mechanical impurities caused by operating friction, meeting the requirements of high-precision and high-purity material production.

4. By using liquid film heating method, there is no pressure drop caused by static liquid level difference, and it is easy to achieve extremely low solvent residue requirements by concentrating in a reduced pressure system.

5. The densely staggered distribution of evaporator heat transfer tubes not only plays a role in heat transfer, but also plays a role in reflux and turbulence. In addition, the complete set of equipment is equipped with a reflux column, which reduces the heavy phase components carried by light components (solvents) and achieves high yield of concentrated products.

6. Safe and environmentally friendly. When recycling solvents in small-scale chemical production, there will be a large amount of solvent (chemical) loss. These unrecoverable chemicals are distributed in the production site and become a great safety factor. If they encounter static electricity, they can cause safety accidents such as fire and explosion, and are also a major source of environmental pollution,Falling film soft concentration deviceA higher recycling rate is a guarantee of safety and environmental protection.