In today's food industry, where innovation and efficiency are constantly increasing, the use of dehumidifiers in spray towers plays a vital role in processing and preserving food products. In spray towers used for drying liquid or semi-liquid food products into powder form, dehumidifiers placed in front of the suction fans are classified as auxiliary equipment. Spray towers are crucial for the production of products such as milk powder, coffee, tea extracts, various fruit and vegetable powders, and food flavors. This method, through high heating and rapid drying, preserves the nutritional values of food, providing a long shelf life and easy storage. The use of spray towers stands out as part of the ongoing development and increasing quality standards in the food industry.
In spray tower and fluid bed drying systems, both drying time and product quality are highly affected by changing climatic conditions. The air included in the system from the variable atmosphere is heated to a specific temperature and delivered to the drying line by blowers. To maximize drying capacity, increase existing spray tower production capacity, and minimize the negative impact of temperature/humidity changes in outdoor air on production output, dehumidifiers should be properly integrated into the system. In summer, the increased absolute humidity leads to higher energy costs for reaching heating temperatures and delays in achieving the desired product dryness level. Dehumidifiers stabilize the inlet air humidity of spray towers, providing a constant absolute humidity level independent of seasonal effects.
With high airflow and low water vapor content, less water vapor is introduced into the system, minimizing microbial growth risk. Air dried using dehumidifiers has a higher capacity to absorb more water vapor. This accelerates the drying process and increases the efficiency of energy usage. Low humidity air contributes to more uniform drying and, therefore, a more consistent particle size distribution in the product. For powdered products, particle size and distribution affect solubility, flowability, and overall processability. Additionally, integrating a dehumidifier into a spray tower helps preserve the product's color and aroma. High humidity air can cause unwanted reactions in the product (e.g., Maillard reaction), leading to color and taste changes. To prevent the oxidation and other degradation reactions of sensitive nutrients (vitamins, essential fatty acids, etc.), maintaining a stable absolute humidity independent of external humidity conditions with a dehumidifier is crucial. Controlling air humidity year-round in spray drying processes is preferred to ensure the highest level of product quality stability.
Products processed by drying in spray towers are then transferred to fixed bed and fluid bed dryers for additional drying and processing. After spray drying, products typically have a specific moisture content. In the fixed bed dryer, the product is further dried on a fixed bed while hot air is passed over or under the bed. Dehumidifiers added to the suction of fixed bed fans prevent the reintroduction of humid air into the process. At this stage, the moisture level of the products is further reduced, enhancing product quality and extending shelf life. Finally, the products are transferred to a fluid bed dryer. In this stage, the products are fluidized and homogeneously dried with dry air from the dehumidifier. Fluid bed drying optimizes the moisture content of the product and improves its physical properties (e.g., particle size, density). This multi-stage process maximizes the quality and stability of the products.
For more information and expert support, please contact us through the form below.