1. Capture low-volatile components and improve distillation efficiency
(1) Principle
During the molecular distillation process, components with different volatilities are vaporized on the heating surface. Due to their different vapor pressures, they are separated according to their volatility characteristics under a high vacuum environment. Among them, some low-volatile components may migrate with the airflow of high-volatile components. The external cold trap can effectively cool and capture these low-volatile components by providing an extremely low temperature environment.
For example, in the molecular distillation process of fish oil, low-volatile components such as saturated fatty acids in fish oil may reach the subsequent collection device together with unsaturated fatty acids (relatively high-volatile components) during the separation process if there is no external cold trap, affecting the purity of the product. The external cold trap can capture these low-volatile components such as saturated fatty acids in time, so that unsaturated fatty acids can be collected more purely, greatly improving the separation efficiency of molecular distillation.
(2) Improving vacuum
The presence of the external cold trap reduces the residence time and migration distance of low-volatile components in the distillation system. If there is no external cold trap, low-volatile components circulate in the system, which may cause pressure fluctuations during the distillation process, affecting the stability and separation effect of the distillation. The external cold trap captures these components in time, condenses the water vapor, oil gas and other vapors in the vacuum chamber into liquid or solid, reduces the impact of these vapors on the vacuum degree, and thus improves the vacuum degree of the vacuum system of the molecular distillation equipment. This is crucial for molecular distillation to work in a high vacuum environment, because molecular distillation relies on the difference in the mean free path of molecular motion of different substances to achieve separation, and requires certain high vacuum conditions to ensure the separation effect.
2. Protect subsequent equipment and product purity
(1) Prevent pollution and blockage
For the subsequent collection devices, pipelines and other components of the molecular distillation equipment, if there is no external cold trap for pre-separation, low-volatile components may condense or deposit inside them. In some applications with extremely high purity requirements, such as molecular distillation and purification of pharmaceutical intermediates, the contamination of these low-volatile components may be catastrophic. The external cold trap is like a loyal guard, intercepting the low-volatile components before they reach these key parts, preventing equipment contamination and blockage.
For example, during the molecular distillation of cosmetic raw materials, if some impurities (low volatility) in the raw materials are not captured by the external cold trap, they may form precipitation in the subsequent collection container, affecting the color, texture and other quality characteristics of the cosmetic raw materials, and may even breed bacteria and other microorganisms, destroying the quality and safety of the product.
(2) Ensure high purity of the product
The precise capture function of the external cold trap can control the purity of the product from the source. It ensures that the target product collected in the end is a high-purity component that truly reaches the required volatility range during the molecular distillation process. For those industries with strict purity requirements, such as electronic chemicals and high-purity materials, the external cold trap is one of the key equipment to ensure product quality.
(3) Protect the vacuum pump
The cold trap can capture and condense corrosive gases or oil vapors in the vacuum system to prevent these harmful substances from entering the vacuum pump, thereby protecting the vacuum pump from contamination and corrosion and extending the service life of the vacuum pump. During the molecular distillation process, some corrosive gases or oil vapors may be generated. The cold trap can block and collect these substances to ensure the stable operation of the vacuum pump.
3. Meeting special process requirements and improving equipment flexibility
(1) Customized separation
In some complex material systems, the separation requirements for different components may be very precise. The external cold trap can achieve more precise control of components with different volatilities by adjusting its cold trap temperature and other parameters. For example, in the molecular distillation extraction of some natural products, there may be multiple components with similar structures but slightly different volatilities. By reasonably setting the temperature of the external cold trap, components in a specific volatility range can be captured and separated in a targeted manner to meet customized process requirements.
(2) Possibility of equipment combination
The independence of the external cold trap allows it to be flexibly combined with different types of molecular distillation equipment. Whether in intermittent or continuous molecular distillation processes, the configuration of the external cold trap can be easily added or adjusted. This provides greater flexibility for the company's production. According to different product requirements and production scales, the most suitable external cold trap solution can be selected to optimize the overall process of the molecular distillation process.
The external cold trap is like a shining pearl in the molecular distillation equipment. Its outstanding performance in capturing low-volatile components, protecting subsequent equipment, ensuring product purity and meeting special process requirements provides a solid guarantee for the efficient and precise operation of molecular distillation technology.