Method for improving evaporation efficiency of vacuum evaporation process

Abstract

According to the method for improving the evaporation efficiency of the vacuum evaporation process, in a vacuum area of a vacuum evaporator, a solution is dispersed into liquid drops through physical methods such as spraying and atomization, the existence state of a large number of small liquid drops is continuously kept, the surface area of the solution is large, and the evaporation speed is effectively improved; air or other safe gas is introduced into a vacuum area of the vacuum evaporator at a certain speed, the vapor pressure of water is reduced, evaporation of water in a solution is accelerated, flowing of the air drives vapor to rapidly break away from the surface of the solution, the evaporation speed of the liquid is increased, gas circulation is formed, and the evaporation efficiency of the vacuum evaporation process is improved.

Description

Technical Field

[0001] The invention discloses a method for improving the evaporation efficiency of a vacuum evaporation process, and relates to a method for improving the evaporation efficiency of a vacuum evaporation process. Background Art

[0002] In industrial production, some evaporation and concentration processes, vacuum evaporation process is widely used due to its advantages such as low energy consumption and fast evaporation speed. It is a universal evaporation and concentration method. The key process parameters of vacuum evaporation process are solution temperature, vacuum degree, evaporator volume, and solution surface area. In production practice, the parameters actually controlled are some easy-to-achieve parameters such as temperature and vacuum degree. The size of the evaporator determines the surface area of ​​the solution. However, due to factors such as equipment cost, it is impossible to increase the size of the equipment at will. Therefore, although the current vacuum evaporation process maintains good evaporation efficiency and cost advantages, it has not been substantially improved in terms of further improving evaporation efficiency for a long time. At the same time, for some solutions with high viscosity, high acidity, and solid phase precipitation in the liquid during evaporation, the existing vacuum evaporation process is also difficult to effectively adapt and efficiently complete the treatment. Summary of the invention

[0003] The present invention aims at the problems existing in the above vacuum evaporation process in terms of improving production efficiency and selectivity of treatment solution, and provides a method for improving evaporation efficiency of vacuum evaporation process, which is characterized by:

[0004] In the vacuum area of ​​the vacuum evaporator, the solution is dispersed into droplets and a large number of small droplets are continuously maintained through continuous spraying, atomization and other physical methods. The more droplets there are and the smaller the volume, the larger the surface area of ​​the solution. Under the same temperature and vacuum conditions, the increased surface area of ​​the solution effectively increases the evaporation rate.

[0005] Introducing gas circulation: Introducing air or other safe gases into the vacuum zone of the vacuum evaporator at a certain speed can, on the one hand, reduce the vapor pressure of water and accelerate the evaporation of water in the solution; on the other hand, the flow of air drives the evaporated water vapor to quickly leave the surface of the solution, accelerating the evaporation rate of the liquid. The gas takes out water vapor from the vacuum zone of the vacuum evaporator, and the gas that separates the water at normal pressure is then introduced into the vacuum zone, forming a gas circulation to improve the evaporation efficiency of the vacuum evaporation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Instructions attached Figure 1 This is a schematic diagram of the vacuum zone structure of the vacuum evaporator. The numbers in the figure represent:

[0007] 1. Vacuum zone structure of vacuum evaporator; 2. Pipeline for transporting liquid for spraying and dispersion treatment;

[0008] 3. The solution outlet on the evaporator for transporting the solution for spraying or heating treatment; 4. The gas inlet;

[0009] 5. Liquid in the evaporator; 6. Liquid surface in the evaporator; 7. Liquid droplets sprayed out;

[0010] 8. Mist droplets sprayed out; 9. Arrows showing the direction of the evaporated steam;

[0011] 10. The solid crystallized from the solution settles to the bottom of the evaporator; 11. The solid matter outlet. DETAILED DESCRIPTION

[0012] Embodiment 1

[0013] Using tap water to produce distilled water

[0014] Vacuum evaporator vacuum area: Φ100*350mm

[0015] The liquid level in the vacuum zone is 80 mm high, and tap water is continuously added during the evaporation process to keep the liquid level constant.

[0016] Evaporation process conditions: vacuum degree -40kPa to -65kPa, evaporation temperature 75℃ to 85℃.

[0017] During the evaporation process, water is pumped out from the vacuum zone and sent to the dispersion pipe at a delivery rate of 0.5L per minute, and is dispersed into the vacuum zone through 20 holes with a diameter of 2mm on the dispersion pipe.

[0018] The amount of distilled water evaporated per minute reaches 3.0 mL, which is 50% higher than 2.0 mL per minute without dispersion treatment.

[0019] Embodiment 2

[0020] Using tap water to produce distilled water

[0021] Vacuum evaporator vacuum area: Φ100*350mm

[0022] The liquid level in the vacuum zone is 80 mm high, and tap water is continuously added during the evaporation process to keep the liquid level constant.

[0023] Evaporation process conditions: vacuum degree -40kPa to -65kPa, evaporation temperature 75℃ to 85℃.

[0024] During the evaporation process, the solution is drawn out from the vacuum zone and sent to the dispersion pipe at a delivery rate of 0.5L per minute, and is dispersed into the vacuum zone through 20 holes with a diameter of 2mm on the dispersion pipe.

[0025] During the evaporation process, circulating air is introduced into the vacuum zone: the air enters the vacuum zone at a speed of 1L / min, and the mixture of air and water vapor circulates out of the vacuum zone. Under normal pressure, the water vapor condenses into water droplets. After the water droplets are separated by centrifugation, the air enters the vacuum zone of the vacuum evaporator again, forming an air cycle.

[0026] The amount of distilled water evaporated per minute reaches 3.5mL to 3.8L, which is 75% to 90% higher than 2.0mL per minute without dispersion treatment and gas circulation.

Claims

1. In the vacuum area of ​​the vacuum evaporator, the solution is dispersed into droplets and a large number of small droplets are continuously maintained through continuous spraying, atomization and other physical methods. The more droplets there are and the smaller the volume, the larger the surface area of ​​the solution. Under the same temperature and vacuum conditions, the increased surface area of ​​the solution effectively increases the evaporation rate.

2. Introduce gas circulation: Introduce air or other safe gases into the vacuum area of ​​the vacuum evaporator at a certain speed. On the one hand, it reduces the vapor pressure of water and accelerates the evaporation of water in the solution. On the other hand, the flow of air drives the evaporated water vapor to quickly leave the surface of the solution, accelerating the evaporation rate of the liquid. The gas takes out water vapor from the vacuum area of ​​the vacuum evaporator, and the gas that separates the water at normal pressure is then introduced into the vacuum area, forming a gas circulation to improve the evaporation efficiency of the vacuum evaporation process.

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