Drying machines are familiar to everyone, as they are an important equipment frequently used in industrial production processes. A vacuum dryer is an important type of drying equipment. Today, I will talk to you about the topic of vacuum dryers. What are the general reasons that affect the regeneration of adsorbents in vacuum dryers? What is the reason for the dew point at the outlet of the vacuum dryer? Below, we will provide a detailed explanation of the influencing factors and common problems in the generation of adsorbents in vacuum dryers.

【 Explanation of the reasons that affect the regeneration of adsorbents in the vacuum dryer 】

The regeneration and degree of adsorbent in a vacuum dryer are influenced by factors such as the degree of adsorbent adsorption, heating desorption temperature and heating desorption time, drying agent cooling temperature and cooling time, heating regeneration gas volume, and cooling regeneration gas volume.

The adsorption degree of the vacuum dryer is related to the composition of the adsorbent, the quality and flow rate of the intake air, and the duration of adsorption. In general, the dew point of the air at the outlet of the dryer decreases with the increase of the contact time between the wet airflow and the adsorbent; After determining the drying model, the contact time between the air intake and the desiccant can be adjusted by adjusting the air intake flow rate; The thickness of the water layer adsorbed on the surface of the adsorbent particles is related to the adsorption duration. If the actual adsorption amount exceeds the dynamic adsorption amount too much during operation, the adsorbent enters the "conversion point" early, which not only increases the dew point of the outlet gas, but also affects the stability of the dew point during the cycle.

The regeneration process is divided into two stages: heating desorption and blowing cooling regeneration. A low desorption temperature can lead to excessive residual water in the desiccant, while a high temperature can cause premature deterioration of the desiccant. Part of the energy consumption during desorption comes from the electric heater, and part comes from heating and regeneration gas. If the flow rate of regenerated gas is too small, not only will it overheat locally, but it will also cause uneven heat transfer, which will affect the heating and desorption effect.

After the heating and desorption are completed, the desiccant needs to be cooled and dehumidified, and the cooled gas will be used as the outlet gas of the dryer. Research has shown that desiccants at different temperatures have different adsorption rates, and the two are inversely proportional. In an ideal state, the final cooling temperature of the desiccant is the temperature of the regenerated gas after blowing.

What are the reasons that affect the dew point at the outlet of the vacuum dryer

The dew point at the outlet is an important application indicator for suction dryers (i.e. adsorption dryers). Generally speaking, the requirement for dew point should have two meanings: one should be "low" and the other should be "stable", both of which are indispensable. During the operation of the vacuum dryer, it is inevitable that the dew point at the outlet will gradually rise due to the continuous increase in adsorption water volume (i.e., the increase in dynamic adsorption capacity) during the adsorption process. Therefore, timely regeneration is necessary.

During the adsorption drying process, the adsorbent is the basic material guarantee. Different adsorbents have different application ranges, such as activated alumina. Under rated usage conditions, the dew point of the finished product can generally reach below -40 ℃. However, if the dew point of the finished product is lower (such as below -60 ℃), alumina is reluctant to use it. This inherent physical characteristic cannot be easily changed by any regeneration method. Therefore, when preparing extremely dry compressed air, molecular sieves are still needed to solve the problem.

There are many factors that affect the dew point of the finished product of the vacuum dryer. Under the same intake state and other conditions, the duration of adsorption has an impact on the finished product.