Co-Current and Counter Current Setups
While many factors have crucial influence on the efficiency of the drying process, there is one particular aspect of the rotary dryer that often needs close attention from a designer. Air-flow setup has great significance for rotary dryers and often affects design decisions more than other important factors like heat level, bulk density, moisture content, abrasion, etc. Air-flow configuration determines how exactly hot gases inside the drum move across the vessel and interact with the material.
There are two air-flow setups. Both co-current and counter current variations are efficient and provide sufficient drying capabilities. However, air-flow configuration may tailor the dryer for your specific needs. Optimal setup will significantly increase the drying speed. The most optimal setup is chosen based on a variety of factors including characteristics of the materials and production conditions. Usually the choice is predetermined since both air-flow setups have been studied and time-tested. However, it is incredibly important to be informed about both options in order to make the right decision.
Also known as parallel flow, Co-current setup is perfect to quickly remove moisture content from the material. This configuration ensures immediate intimate contact between hot air flowing inside the vessel and the most moisturized parts of the materials. At the same time, prompt direct contact between moisture and hot gases cool down the air extremely quickly. This prevents the shell from heating up and allows for better temperature management. One of the best examples of the material that requires co-current air-flow configuration is glass since it needs to lost moisture as quickly as possible, but without overheating. Co-current air-flow is a perfect solution in many industrial applications and serves a slightly different role compared to Counter current setups.
Counter Current Air-flow
As the name suggests, hot gases inside the vessel in the direction opposite to that of the flow of the material when counter current system is implemented. This setup makes certain that the most moisturized material is contacting with the coolest part of the airflow. When the liquid contents are partially removed, the material meets the hottest part of the airflow. This configuration is the best choice for those processes that require the material to be heated up to high temperatures. Counter current configuration ensures gradual heating that is usually needed for processing specific minerals and various ores. Some of these materials need to be heated up to high temperature. All materials that have complicated moisture contents and tend to be drying for a long time will be processed efficiently with the counter current configuration.
Sometimes, choosing the best configuration is a hard task as rotary dryers often need to be versatile and process various types of materials. Additionally, many materials need specific conditions to be processed as efficiently as possible. Strommashina specialists will gladly assist you in choosing the most suitable option for your production process. In order to choose the best construction of your dryer, we will run multiple tests and check various air-flow configurations. If you need additional consultations on this matter, please contact our specialists right away and receive extensive support!