A complete solution of the advantages and disadvantages of drying equipment and the factors restricting its performance

  Drying equipment is used to make the moisture in the material (generally refers to moisture or other volatile liquid components) vapor to escape by heating to obtain a solid material with a specified moisture content. The purpose of drying is for material use or further processing. In fact, drying is a relatively simple process, but, in some cases, the particles cannot be completely dried. The reason for this is that some external factors affect the drying effect, specifically the following aspects:

  1. Drying temperature: refers to the temperature of the air entering the drying barrel. Due to its physical properties, such as molecular structure, specific gravity, specific heat, moisture content and other factors, the drying temperature has certain restrictions. When the temperature is too high, it will cause The local additives in the raw materials volatilize and deteriorate or agglomerate, and if they are too low, some crystalline raw materials cannot reach the required drying conditions. In addition, insulation and heat preservation are required in the selection of dry barrels to avoid loss of drying temperature, resulting in lack of drying temperature or waste of energy.

  2. Dew point: In the dryer, first remove the humid air to make it contain very low residual moisture (dew point). Then, the relative humidity is reduced by heating the air. At this time, the vapor pressure of the dry air is low. By heating, the water molecules inside the particles get rid of the bondage of the bonding force and diffuse to the air around the particles.

  3. Time: In the air around the particles, it takes a certain time for the absorption of heat and the diffusion of water molecules to the surface of the particles. Therefore, the resin supplier should specify the time required for the material to effectively dry at the appropriate temperature and dew point.

  4. Air flow: The dry hot air transfers heat to the particles in the drying silo, removes moisture on the surface of the particles, and then sends the moisture back to the dryer. Therefore, there must be enough airflow to heat the resin to the drying temperature and maintain that temperature for a certain period of time.

  5. Air volume: The air volume takes away the moisture in the raw material only as the Y medium. The air volume will affect the dehumidification effect. Excessive air flow will cause the return air temperature to be too high, causing overheating and affecting its stability. If the air flow is too small, the moisture in the raw materials cannot be completely taken away. The air flow also represents the dehumidification capacity of the desiccant dryer.

  Advantages:

  1. Due to the large surface area of the droplet group, the drying time of the material is very short (in seconds).

  2. In the high-temperature air flow, the temperature of the surface wetting material does not exceed the wet bulb temperature of the drying medium. Due to the rapid drying, the final product temperature is not high. Therefore, spray drying is suitable for heat-sensitive materials.

  3. High production efficiency and few operators. Large production capacity and high product quality. The spray volume per hour can reach hundreds of tons, and it is one of the people with the largest handling capacity of the dryer.

4. According to the flexibility of spray drying operation, it can meet the quality indicators of various products, such as particle size distribution, product shape, product properties (no dust, fluidity, wettability, instant dissolution), product color, fragrance, Taste, biological activity and moisture content of the final product.

  5. Simplify the technological process. The solution can be directly made into powder products in the drying tower. In addition, spray drying is easy to realize mechanization and automation, reduce dust flying, and improve the working environment.