Application Parameters of Thin Film Evaporator in Removing Low Molecular Weight Components?

Thin film evaporator in the removal of low molecular weight components of the application parameters

In the process of chemical production, thin film evaporator is widely used in the process of removing low molecular weight components as an efficient separation equipment. The core advantage of the thin film evaporator is its efficient heat and mass transfer performance, which can quickly remove the low molecular weight components in the solution, so as to realize the purification or concentration of the product. This paper will start with several key parameters to analyze the application of thin film evaporator in the removal of low molecular weight components.

1. Thin film evaporator working temperature

The working temperature of thin film evaporator is one of the important parameters affecting its performance. The low molecular weight component generally has a higher vapor pressure and therefore evaporates at a lower temperature. In the design and use of thin film evaporators, it is necessary to determine the appropriate operating temperature based on the thermal sensitivity, boiling point and process requirements of the components to be separated.

For heat-sensitive substances, the high heat transfer efficiency of the thin-film evaporator can significantly reduce the heating temperature, thereby avoiding the decomposition or denaturation of the substance. The control of the temperature also takes into account the degree of vacuum in the evaporation system, because under vacuum conditions, the boiling point of the low molecular weight components will be reduced, thereby reducing the required evaporation temperature. For example, in a molecular distillation process, a thin film evaporator can efficiently separate high value-added heat-sensitive products at a relatively low temperature (e. g., 50-100°C).

2. Thin film evaporator vacuum

Thin-film evaporators typically operate under vacuum conditions, which makes them particularly suitable for processing high-boiling or heat-sensitive materials. The level of vacuum directly affects the evaporation efficiency: a higher vacuum can reduce the boiling point of the material, reduce the heating power, and accelerate the evaporation rate.

When removing low molecular weight components, the adjustment of vacuum degree needs to comprehensively consider the vapor pressure and separation requirements of the target components. For example, for low molecular weight components with a higher vapor pressure, such as water or alcohols, a lower vacuum may be sufficient, while for components with a lower vapor pressure, such as certain organic compounds, a higher vacuum may be required to ensure efficient evaporation.

The leakage rate and sealing performance of the vacuum system are also parameters that need to be focused on. Leakage will cause the vacuum degree to drop and affect the evaporation efficiency. Therefore, when designing and using the thin film evaporator, the air tightness of the vacuum system must be ensured.

3. Thin film evaporator evaporation area

The evaporation area is one of the key geometric parameters of the thin film evaporator, which directly determines its processing capacity. The larger evaporation area can improve heat transfer efficiency while allowing higher feed liquid flow, thereby increasing production efficiency. For the removal of low molecular weight components, the rational design of the evaporation area is particularly important.

In practical applications, the choice of evaporation area should be based on the properties of the material (such as viscosity, surface tension) and the requirements of the evaporation rate. For example, for high viscosity materials, a larger evaporation area may be required to avoid fouling or insufficient heat transfer. The utilization ratio of the evaporation area is also affected by the film forming conditions, such as the structure and rotation speed of the film scraper.

4. Thin film evaporator operating pressure and liquid flow rate

Operating pressure and feed flow rate are two important parameters that affect the performance of thin film evaporators. Under vacuum conditions, the operating pressure is usually lower, which helps to lower the boiling point of the feed. An excessively low operating pressure may result in insufficient vapor pressure, thereby affecting the evaporation efficiency.

The flow rate directly affects the thickness and distribution of the film. Too high flow rate may cause the film to be too thick and reduce the heat transfer efficiency; while too low flow rate may cause the material to stay in the evaporator for too long and increase the risk of fouling. Therefore, in the design of thin film evaporator, it is necessary to consider the operating pressure and liquid flow rate to optimize the heat transfer and separation effect.

5. Thin film evaporator scraped membrane structure

The scraped membrane structure of thin film evaporator is one of the key components to achieve efficient evaporation. The function of the film scraper is to evenly coat the feed liquid on the heating surface of the evaporator, and at the same time scrape off the evaporated residual liquid to prevent fouling. For the removal of low molecular weight components, the design of the scraped membrane structure directly affects the evaporation efficiency and the service life of the equipment.

Common scraped film structures include spin-scraped and swing, which structure depends on the nature of the material and process requirements. For example, the rotary scraper is suitable for high-viscosity materials, while the oscillating scraper is more suitable for low-viscosity materials. The material and surface roughness of the film scraper also need to be selected according to the chemical nature of the material to avoid corrosion or adhesion.

Conclusion

The application parameters of thin film evaporator in the removal of low molecular weight components involve many aspects, including working temperature, vacuum degree, evaporation area, operating pressure, feed liquid flow rate and scraped membrane structure. The reasonable selection and optimization of these parameters is the key to ensure the efficient operation of the thin film evaporator. Through in-depth understanding of the influence mechanism of these parameters, and combined with the specific process requirements, the advantages of thin film evaporator can be better used to achieve efficient removal of low molecular weight components. For engineers and researchers, the rational design and use of thin-film evaporators can not only improve production efficiency, but also reduce energy consumption, providing strong support for industrial applications.