Classification of fluidized bed dryers With the continuous development of application technology, the types and applications of fluidized bed dryers are increasing, and the classification methods of equipment are also different. According to the materials to be dried, they can be divided into three categories: the first type is granular material; the second type is paste material; the third type is liquid material such as suspension and solution. According to the operating conditions, there are basically two types: continuous and intermittent. According to the state of the structure, there are general fluidized type, stirred fluidized type, vibration, fluidized type, pulsed fluidized type, and collision fluidized type (inert particles are used as carriers). With the continuous improvement and expansion of fluidized bed drying equipment, it has become one of the main models of drying equipment.
Fluidized bed dryers have been used in many applications in the industry for many years. Below are the drying materials of various dryers.
(1) The single-layer cylindrical fluidized bed has been used for drying of materials such as ammonium sulfate, ammonium chloride, anhydrous sodium sulfite, salt, polytetrafluoroethylene, calcium gluconate, basic Qinglian dye, and catalyst particles.
(2) Multi-layer cylindrical fluidized bed dryer has been used for drying polyester slicing, sodium salicylate, aminopyrine, oxytetracycline, chlortetracycline, tetracycline, tablet starch granules, sugar powder and the like.
(3) Horizontal multi-chamber fluidized bed dryer has been used for polyvinyl chloride resin, polypropylene resin, nylon 1010, o-chlorobenzoic acid, tetracycline, oxytetracycline, chloramphenicol, oxytetracycline, liver powder, sugar Drying of powder, SMP, APC and other materials.
(4) Fluidized bed with agitator has been used for drying of materials such as ammonium sulfate, copper sulfate, sodium fluoride, amino acids, anhydride casein, polypropylene resin, phenolic resin and the like.
(5) Inert particle fluidized bed has been used for drying of titanium ***, pesticide, zinc, pigment, dye, diatomaceous earth, sodium humate, humic acid and the like.
(6) Vibrating fluidized bed dryer has been used for drying sugar, asbestos mine, milk powder and other materials.
(7) Spray fluidization granulation drying has been used for urea, glucose, sodium bromide, potassium bromide, ammonium bromide, titanium ***, sodium malonate, fluorescent whitening agent, potassium acetate, calcium chloride, Drying of materials such as ammonium nitrate.
The following mainly introduces single-layer and multi-layer fluidized bed dryers:
1. Single-cylinder fluidized dryer Single-layer fluidized bed can be divided into continuous and intermittent operation methods. The continuous operation residence time is widely distributed, and the average residence time required is actually long, so it is often applied to products that are relatively easy to dry, or products whose drying degree is not very strict. In 1969, a large-scale fluidized bed drying device with a diameter of 3000mm was designed and built to dry ammonium chloride. The single-layer fluidized bed can also be used for the drying of materials with high water content. The water content is 35%. The drying of calcium gluconate is an example. The operation is intermittent. When the material is discharged, the distribution plate is turned over by 90°, and the material is discharged at the lower part of the bed. The batch-operated single-layer fluidized bed dryer was also successfully used for the drying of a catalyst having a water content of 20%, and the discharge was carried out by blowing the material into a cyclone with a high-speed gas stream. For some materials with uneven graininess and certain viscosity, a low bed operation with a stirrer in the bed is often used. The drying of the anhydride casein and the drying of the coconut are carried out by this method. Single-layer cylindrical fluidized dryers are generally used for products that are easier to dry or less dry. Since the particles in the fluidized bed are close to the fully mixed state, in order to reduce the discharge of the undried particles, it is necessary to lengthen the average residence time, so that the height of the fluidized bed must be increased, and the pressure loss is also increased. Due to this characteristic, it is necessary to use hot air having the highest temperature as possible to increase the thermal efficiency and appropriately reduce the bed height. Therefore, the single-layer cylindrical fluidized bed dryer is only suitable for drying materials containing surface water and not strict to dryness.
Second, multi-layer vibrating fluidized bed dryer adopts multi-layer fluidized bed dryer, which can increase the drying time of materials and improve the uniformity of water content of dry products, thus easy to control the dry quality of products. However, as the number of layers increases in the multi-layer fluidized bed dryer, the distribution plate increases correspondingly, and the bed resistance increases. At the same time, between the layers, the material should be quantitatively transferred from the upper layer to the lower layer, and to ensure a stable fluidization state, an overflow device must be used, which increases the complexity of the equipment structure. For the removal of moisture-bound materials, it is appropriate to use a multi-layer fluidized bed. For example, a double-layer fluidized bed is used to dry aminopyrine with a water content of 15% to 30%; a five-layer fluidized bed is used to dry the polyester resin to make the moisture content of the product reach 0.03%, which are successful examples.
(1) The working principle of the multi-layer vibrating fluidized bed dryer is synchronously reversed by two vibrating motors installed in the lower part of the main machine, so that the main body composed of the multi-layer annular orifice plate installed thereon generates vertical vibration and torsional vibration. Therefore, the material entering from the inlet port continuously jumps from the upper layer to the lower layer along the horizontal annular orifice plate. The hot air passes through the layer of material from the lower layer to the upper layer through the layers of the orifice to achieve uniform drying of the material.
(2) Performance characteristics (1) Energy conservation. Since the material is opposite to the hot air and is fully reversely contacted, the dryer of the same type saves 30% of heat energy and saves 10% of electric energy. (2) The drying quality is high and the effect is good. The material jumps along the horizontal annular orifice plate, so there is no local overheating and uneven drying. The material has a low crushing rate and less wear, and the finished product moisture content is less than 0.1%. (3) Investment province. Thanks to the multi-layer form, the material moves vertically in a ring shape, so it is compact and covers only one-fifth of the same type of dryer. It is rugged, reliable, easy to maintain and lightweight. (4) Wide use. The material movement state and flow rate can be adjusted steplessly, so that the powdery material with a water content of not less than 40% and a temperature not exceeding 400 °C can be applied. (5) Low noise and good vibration isolation performance. It can be floated on the floor and is easy to install and dispose, and the working environment is good. (6) High production efficiency. When the material moves, it is in full contact with hot air many times, and the thermal efficiency is high, so the hourly output is 2.2~3 times that of the same type of dryer.
(III) Application range of multi-layer vibrating fluidized bed dryer This machine is suitable for drying of powdery materials in food, chemical, medicine, feed, bait, plastic, salt, grain, seed, tobacco, sugar, metallurgy and other industries. cool down. Changzhou Binda Dry Granulation Equipment Co., Ltd. welcomes customers to inquire.