Analysis of Granulation Function and Advantages and Disadvantages of Horizontal Spray Dryer

Horizontal Spray Dryer is one of the most popular Drying Equipment in the industry at present, with a wide range of applications. It can be said to be a Dryer for processing solutions, suspensions or slurry-like materials. The drying effect of the horizontal spray dryer is also very good and the efficiency is high. The product is a powder with uniform particles, and there is no need to increase the pulverization process. At present, the market share of horizontal spray dryers in the chemical, light industry and food industries is very high. Spray Drying Equipment can change operating conditions in a wide range to control product quality indicators, such as particle size distribution, moisture content, biological activity, solubility, color, fragrance, taste, etc., with fast heat transfer, rapid moisture evaporation, and drying time It has short characteristics, good product quality, crisp texture, and good solubility. It can improve the dissolution rate of some preparations and is suitable for heat sensitivity. In addition, spray drying can also be used to prepare microcapsules. The spray drying equipment uses compressed air or water vapor to atomize the material liquid. Through mechanical action, the material to be dried is dispersed into very fine mist-like particles (to increase the evaporation area of water and accelerate the drying process) and hot air In contact, most of the water is removed in an instant, and the solid matter in the material is dried into a powder. The horizontal spray dryer has fast drying speed, and the surface area of the material liquid is greatly increased after atomization. In the hot air flow, 95%-98% of the water can be evaporated instantly, and the drying time is only a few seconds, especially suitable for heat-sensitive materials The dryness. Horizontal spray dryer has good uniformity, fluidity and solubility, high product purity and good quality. The production process is simplified, the operation control is convenient, there is no need to crush and screen after drying, which reduces the production process and improves the purity of the product.

In order to meet market needs, improve product solubility, blending and packaging performance. Some spray drying equipment increases the granulation equipment, but it will increase the thermal denaturation of the product and the loss of aromatic substances. The spray drying equipment effectively solves the integration problem of the drying tower, the separation chamber and the cooling chamber. In the reduced-rate drying stage of spray drying, the temperature of the powder rises as the moisture decreases. Taking dairy products as an example, when the temperature of the drying air in the lower part of the drying tower is 90-100°C, the temperature of the powder is about 60°C. In order to prevent thermal denaturation, it is desirable to cool down quickly at the end of drying. For this, MD horizontal spray dryer is equipped with a flow cooling chamber in the lower part of the drying tower. This system has cyclone-separated fine powder, which is transported by air to the flow cooling chamber at the lower part of the separation chamber, and separated by gravity in the separation chamber. The powder is cooled to about 30°C and then discharged. As a result, the thermal denaturation is well controlled.

Spray drying equipment has fast drying speed and good product performance

After the material liquid is sprayed, it is atomized into dispersed particles, the surface area is greatly increased, and the drying process can be completed in a very short time after contact with hot air. Under normal circumstances, 95%~98% of water can be evaporated within 1~3s at 100~150℃. Since the drying process is completed in an instant, the particles of the finished product can basically maintain a spherical shape similar to the droplets, so that it has good dispersibility, excellent brewability and high solubility.

1. Advantages of horizontal spray dryer:

1. Due to the large surface area/volume ratio of the droplet group in the horizontal spray dryer, the time required for drying the material is very short (usually 15-30 seconds, sometimes only a few seconds). The horizontal spray dryer does not require strict filtering equipment, and the material liquid, such as non-fibrous liquid, basically does not block the material liquid channel. It can be adapted to higher viscosity materials (compared with pressure spray drying). Because the rotation speed of the atomizer is easy to adjust, it is easier to empty the product particle size, and the particle size distribution is also narrow.

2. The horizontal spray dryer has large production capacity and high product quality. The spray volume per hour can reach several hundred tons, which is one of the larger dryers. Although the inlet temperature of the drying medium can reach hundreds of degrees Celsius, the temperature of the material does not exceed the wet bulb temperature of the air during most of the drying process. Therefore, spray drying is particularly suitable for heat-sensitive materials (such as food, medicine, biological products, and dyes). Etc.) dry.

3. The horizontal spray dryer is easy to adjust, and the operating conditions can be changed in a large range to control the quality indicators of the product, such as particle size distribution, moisture content, biological activity, solubility, color, fragrance, taste, etc. When adjusting the processing capacity, there is no need to change the working state of the atomizer, and the same product can be obtained for the feed rate.

4. The horizontal spray dryer simplifies the process flow. The evaporation, crystallization, filtration, pulverization and other operations can be completed in one step by spray drying. Because the mist groups produced by the centrifugal atomizer are basically on the same horizontal plane, the mist droplets move in the combined radial and tangential directions, and there is almost no axial initial velocity, so the diameter of the dryer is relatively large. The diameter and length are relatively small, and the space of the drying chamber can be used to the maximum.

2. Disadvantages of horizontal spray dryer:

1. When the inlet temperature of the drying medium is lower than 150 degrees Celsius, the volumetric heat transfer coefficient of the horizontal spray dryer dryer is relatively low, and the volume of the equipment used is relatively large. In addition, the heat utilization rate of low temperature operation is low, and the drying medium consumption is large, therefore, the power consumption is also large. The processing accuracy of the dispersing disc is required to be high, and it must have good dynamic balance performance. If the balance is not good, the spindle and the bearing are easily damaged;

2. For the production of fine powder products, separation equipment is required to avoid product loss and environmental pollution. The bulk density of the product is lower in the horizontal spray dryer.

3. The contact mode of mist and gas basically belongs to the parallel flow mode, and the dispersion disc cannot be placed vertically;